Merge branch 'simpler-item-previews'

When I run `bin/deploy:precompile` on the previous version, I get an
error from libsass that `vw` and `vh` are incompatible units. I don't
get this error in development, only when compiling for production.

My inference is:
1. For the production build, Sass is trying to preprocess even non-SASS
   files, maybe to help minify them?
2. In Sass, their `min()` existed before CSS's `min()`, so it's
   treating it Like That, and returning a reasonable-in-some-cases-but-
   not-here error that `min(100vw, 100vh)` can't be *precomputed*.

Anyway, wrapping it in `calc()` isn't a *problem*, and helps the Sass
compiler not try to precompute it, so. Okay!
https://github.com/sass/node-sass/issues/2815#issuecomment-575926329

app/assets/javascripts/items/show.js

@@ -0,0 +1,76 @@
+// When the species face picker changes, update and submit the main picker form.
+document.addEventListener("change", (e) => {
+    if (!e.target.matches("species-face-picker")) return;
+
+    try {
+        const mainPickerForm = document.querySelector(
+            "#item-preview species-color-picker form");
+        const mainSpeciesField =
+            mainPickerForm.querySelector("[name='preview[species_id]']");
+        mainSpeciesField.value = e.target.value;
+        mainPickerForm.requestSubmit(); // `submit` doesn't get captured by Turbo!
+    } catch (error) {
+        console.error("Couldn't update species picker: ", error);
+    }
+});
+
+class SpeciesColorPicker extends HTMLElement {
+    #internals;
+
+    constructor() {
+        super();
+        this.#internals = this.attachInternals();
+    }
+
+    connectedCallback() {
+        // Listen for changes to auto-submit the form, then tell CSS about it!
+        this.addEventListener("change", this.#handleChange);
+        this.#internals.states.add("auto-loading");
+    }
+
+    #handleChange(e) {
+        this.querySelector("form").requestSubmit();
+    }
+}
+
+class SpeciesFacePicker extends HTMLElement {
+    connectedCallback() {
+        this.addEventListener("click", this.#handleClick);
+    }
+
+    get value() {
+        return this.querySelector("input[type=radio]:checked")?.value;
+    }
+
+    #handleClick(e) {
+        if (e.target.matches("input[type=radio]")) {
+            this.dispatchEvent(new Event("change", {bubbles: true}));
+        }
+    }
+}
+
+class SpeciesFacePickerOptions extends HTMLElement {
+    static observedAttributes = ["inert", "aria-hidden"];
+
+    connectedCallback() {
+        // Once this component is loaded, we stop being inert and aria-hidden. We're ready!
+        this.#activate();
+    }
+
+    attributeChangedCallback() {
+        // If a Turbo Frame tries to morph us into being inert again, activate again!
+        // (It's important that the server's HTML always return `inert`, for progressive
+        // enhancement; and it's important to morph this element, so radio focus state
+        // is preserved. To thread that needle, we have to monitor and remove!)
+        this.#activate();
+    }
+
+    #activate() {
+        this.removeAttribute("inert");
+        this.removeAttribute("aria-hidden");
+    }
+}
+
+customElements.define("species-color-picker", SpeciesColorPicker);
+customElements.define("species-face-picker", SpeciesFacePicker);
+customElements.define("species-face-picker-options", SpeciesFacePickerOptions);

app/assets/javascripts/lib/idiomorph.js

@@ -0,0 +1,850 @@
+// https://raw.githubusercontent.com/bigskysoftware/idiomorph/v0.3.0/dist/idiomorph.js
+
+// base IIFE to define idiomorph
+var Idiomorph = (function () {
+        'use strict';
+
+        //=============================================================================
+        // AND NOW IT BEGINS...
+        //=============================================================================
+        let EMPTY_SET = new Set();
+
+        // default configuration values, updatable by users now
+        let defaults = {
+            morphStyle: "outerHTML",
+            callbacks : {
+                beforeNodeAdded: noOp,
+                afterNodeAdded: noOp,
+                beforeNodeMorphed: noOp,
+                afterNodeMorphed: noOp,
+                beforeNodeRemoved: noOp,
+                afterNodeRemoved: noOp,
+                beforeAttributeUpdated: noOp,
+
+            },
+            head: {
+                style: 'merge',
+                shouldPreserve: function (elt) {
+                    return elt.getAttribute("im-preserve") === "true";
+                },
+                shouldReAppend: function (elt) {
+                    return elt.getAttribute("im-re-append") === "true";
+                },
+                shouldRemove: noOp,
+                afterHeadMorphed: noOp,
+            }
+        };
+
+        //=============================================================================
+        // Core Morphing Algorithm - morph, morphNormalizedContent, morphOldNodeTo, morphChildren
+        //=============================================================================
+        function morph(oldNode, newContent, config = {}) {
+
+            if (oldNode instanceof Document) {
+                oldNode = oldNode.documentElement;
+            }
+
+            if (typeof newContent === 'string') {
+                newContent = parseContent(newContent);
+            }
+
+            let normalizedContent = normalizeContent(newContent);
+
+            let ctx = createMorphContext(oldNode, normalizedContent, config);
+
+            return morphNormalizedContent(oldNode, normalizedContent, ctx);
+        }
+
+        function morphNormalizedContent(oldNode, normalizedNewContent, ctx) {
+            if (ctx.head.block) {
+                let oldHead = oldNode.querySelector('head');
+                let newHead = normalizedNewContent.querySelector('head');
+                if (oldHead && newHead) {
+                    let promises = handleHeadElement(newHead, oldHead, ctx);
+                    // when head promises resolve, call morph again, ignoring the head tag
+                    Promise.all(promises).then(function () {
+                        morphNormalizedContent(oldNode, normalizedNewContent, Object.assign(ctx, {
+                            head: {
+                                block: false,
+                                ignore: true
+                            }
+                        }));
+                    });
+                    return;
+                }
+            }
+
+            if (ctx.morphStyle === "innerHTML") {
+
+                // innerHTML, so we are only updating the children
+                morphChildren(normalizedNewContent, oldNode, ctx);
+                return oldNode.children;
+
+            } else if (ctx.morphStyle === "outerHTML" || ctx.morphStyle == null) {
+                // otherwise find the best element match in the new content, morph that, and merge its siblings
+                // into either side of the best match
+                let bestMatch = findBestNodeMatch(normalizedNewContent, oldNode, ctx);
+
+                // stash the siblings that will need to be inserted on either side of the best match
+                let previousSibling = bestMatch?.previousSibling;
+                let nextSibling = bestMatch?.nextSibling;
+
+                // morph it
+                let morphedNode = morphOldNodeTo(oldNode, bestMatch, ctx);
+
+                if (bestMatch) {
+                    // if there was a best match, merge the siblings in too and return the
+                    // whole bunch
+                    return insertSiblings(previousSibling, morphedNode, nextSibling);
+                } else {
+                    // otherwise nothing was added to the DOM
+                    return []
+                }
+            } else {
+                throw "Do not understand how to morph style " + ctx.morphStyle;
+            }
+        }
+
+
+        /**
+         * @param possibleActiveElement
+         * @param ctx
+         * @returns {boolean}
+         */
+        function ignoreValueOfActiveElement(possibleActiveElement, ctx) {
+            return ctx.ignoreActiveValue && possibleActiveElement === document.activeElement;
+        }
+
+        /**
+         * @param oldNode root node to merge content into
+         * @param newContent new content to merge
+         * @param ctx the merge context
+         * @returns {Element} the element that ended up in the DOM
+         */
+        function morphOldNodeTo(oldNode, newContent, ctx) {
+            if (ctx.ignoreActive && oldNode === document.activeElement) {
+                // don't morph focused element
+            } else if (newContent == null) {
+                if (ctx.callbacks.beforeNodeRemoved(oldNode) === false) return oldNode;
+
+                oldNode.remove();
+                ctx.callbacks.afterNodeRemoved(oldNode);
+                return null;
+            } else if (!isSoftMatch(oldNode, newContent)) {
+                if (ctx.callbacks.beforeNodeRemoved(oldNode) === false) return oldNode;
+                if (ctx.callbacks.beforeNodeAdded(newContent) === false) return oldNode;
+
+                oldNode.parentElement.replaceChild(newContent, oldNode);
+                ctx.callbacks.afterNodeAdded(newContent);
+                ctx.callbacks.afterNodeRemoved(oldNode);
+                return newContent;
+            } else {
+                if (ctx.callbacks.beforeNodeMorphed(oldNode, newContent) === false) return oldNode;
+
+                if (oldNode instanceof HTMLHeadElement && ctx.head.ignore) {
+                    // ignore the head element
+                } else if (oldNode instanceof HTMLHeadElement && ctx.head.style !== "morph") {
+                    handleHeadElement(newContent, oldNode, ctx);
+                } else {
+                    syncNodeFrom(newContent, oldNode, ctx);
+                    if (!ignoreValueOfActiveElement(oldNode, ctx)) {
+                        morphChildren(newContent, oldNode, ctx);
+                    }
+                }
+                ctx.callbacks.afterNodeMorphed(oldNode, newContent);
+                return oldNode;
+            }
+        }
+
+        /**
+         * This is the core algorithm for matching up children.  The idea is to use id sets to try to match up
+         * nodes as faithfully as possible.  We greedily match, which allows us to keep the algorithm fast, but
+         * by using id sets, we are able to better match up with content deeper in the DOM.
+         *
+         * Basic algorithm is, for each node in the new content:
+         *
+         * - if we have reached the end of the old parent, append the new content
+         * - if the new content has an id set match with the current insertion point, morph
+         * - search for an id set match
+         * - if id set match found, morph
+         * - otherwise search for a "soft" match
+         * - if a soft match is found, morph
+         * - otherwise, prepend the new node before the current insertion point
+         *
+         * The two search algorithms terminate if competing node matches appear to outweigh what can be achieved
+         * with the current node.  See findIdSetMatch() and findSoftMatch() for details.
+         *
+         * @param {Element} newParent the parent element of the new content
+         * @param {Element } oldParent the old content that we are merging the new content into
+         * @param ctx the merge context
+         */
+        function morphChildren(newParent, oldParent, ctx) {
+
+            let nextNewChild = newParent.firstChild;
+            let insertionPoint = oldParent.firstChild;
+            let newChild;
+
+            // run through all the new content
+            while (nextNewChild) {
+
+                newChild = nextNewChild;
+                nextNewChild = newChild.nextSibling;
+
+                // if we are at the end of the exiting parent's children, just append
+                if (insertionPoint == null) {
+                    if (ctx.callbacks.beforeNodeAdded(newChild) === false) return;
+
+                    oldParent.appendChild(newChild);
+                    ctx.callbacks.afterNodeAdded(newChild);
+                    removeIdsFromConsideration(ctx, newChild);
+                    continue;
+                }
+
+                // if the current node has an id set match then morph
+                if (isIdSetMatch(newChild, insertionPoint, ctx)) {
+                    morphOldNodeTo(insertionPoint, newChild, ctx);
+                    insertionPoint = insertionPoint.nextSibling;
+                    removeIdsFromConsideration(ctx, newChild);
+                    continue;
+                }
+
+                // otherwise search forward in the existing old children for an id set match
+                let idSetMatch = findIdSetMatch(newParent, oldParent, newChild, insertionPoint, ctx);
+
+                // if we found a potential match, remove the nodes until that point and morph
+                if (idSetMatch) {
+                    insertionPoint = removeNodesBetween(insertionPoint, idSetMatch, ctx);
+                    morphOldNodeTo(idSetMatch, newChild, ctx);
+                    removeIdsFromConsideration(ctx, newChild);
+                    continue;
+                }
+
+                // no id set match found, so scan forward for a soft match for the current node
+                let softMatch = findSoftMatch(newParent, oldParent, newChild, insertionPoint, ctx);
+
+                // if we found a soft match for the current node, morph
+                if (softMatch) {
+                    insertionPoint = removeNodesBetween(insertionPoint, softMatch, ctx);
+                    morphOldNodeTo(softMatch, newChild, ctx);
+                    removeIdsFromConsideration(ctx, newChild);
+                    continue;
+                }
+
+                // abandon all hope of morphing, just insert the new child before the insertion point
+                // and move on
+                if (ctx.callbacks.beforeNodeAdded(newChild) === false) return;
+
+                oldParent.insertBefore(newChild, insertionPoint);
+                ctx.callbacks.afterNodeAdded(newChild);
+                removeIdsFromConsideration(ctx, newChild);
+            }
+
+            // remove any remaining old nodes that didn't match up with new content
+            while (insertionPoint !== null) {
+
+                let tempNode = insertionPoint;
+                insertionPoint = insertionPoint.nextSibling;
+                removeNode(tempNode, ctx);
+            }
+        }
+
+        //=============================================================================
+        // Attribute Syncing Code
+        //=============================================================================
+
+        /**
+         * @param attr {String} the attribute to be mutated
+         * @param to {Element} the element that is going to be updated
+         * @param updateType {("update"|"remove")}
+         * @param ctx the merge context
+         * @returns {boolean} true if the attribute should be ignored, false otherwise
+         */
+        function ignoreAttribute(attr, to, updateType, ctx) {
+            if(attr === 'value' && ctx.ignoreActiveValue && to === document.activeElement){
+                return true;
+            }
+            return ctx.callbacks.beforeAttributeUpdated(attr, to, updateType) === false;
+        }
+
+        /**
+         * syncs a given node with another node, copying over all attributes and
+         * inner element state from the 'from' node to the 'to' node
+         *
+         * @param {Element} from the element to copy attributes & state from
+         * @param {Element} to the element to copy attributes & state to
+         * @param ctx the merge context
+         */
+        function syncNodeFrom(from, to, ctx) {
+            let type = from.nodeType
+
+            // if is an element type, sync the attributes from the
+            // new node into the new node
+            if (type === 1 /* element type */) {
+                const fromAttributes = from.attributes;
+                const toAttributes = to.attributes;
+                for (const fromAttribute of fromAttributes) {
+                    if (ignoreAttribute(fromAttribute.name, to, 'update', ctx)) {
+                        continue;
+                    }
+                    if (to.getAttribute(fromAttribute.name) !== fromAttribute.value) {
+                        to.setAttribute(fromAttribute.name, fromAttribute.value);
+                    }
+                }
+                // iterate backwards to avoid skipping over items when a delete occurs
+                for (let i = toAttributes.length - 1; 0 <= i; i--) {
+                    const toAttribute = toAttributes[i];
+                    if (ignoreAttribute(toAttribute.name, to, 'remove', ctx)) {
+                        continue;
+                    }
+                    if (!from.hasAttribute(toAttribute.name)) {
+                        to.removeAttribute(toAttribute.name);
+                    }
+                }
+            }
+
+            // sync text nodes
+            if (type === 8 /* comment */ || type === 3 /* text */) {
+                if (to.nodeValue !== from.nodeValue) {
+                    to.nodeValue = from.nodeValue;
+                }
+            }
+
+            if (!ignoreValueOfActiveElement(to, ctx)) {
+                // sync input values
+                syncInputValue(from, to, ctx);
+            }
+        }
+
+        /**
+         * @param from {Element} element to sync the value from
+         * @param to {Element} element to sync the value to
+         * @param attributeName {String} the attribute name
+         * @param ctx the merge context
+         */
+        function syncBooleanAttribute(from, to, attributeName, ctx) {
+            if (from[attributeName] !== to[attributeName]) {
+                let ignoreUpdate = ignoreAttribute(attributeName, to, 'update', ctx);
+                if (!ignoreUpdate) {
+                    to[attributeName] = from[attributeName];
+                }
+                if (from[attributeName]) {
+                    if (!ignoreUpdate) {
+                        to.setAttribute(attributeName, from[attributeName]);
+                    }
+                } else {
+                    if (!ignoreAttribute(attributeName, to, 'remove', ctx)) {
+                        to.removeAttribute(attributeName);
+                    }
+                }
+            }
+        }
+
+        /**
+         * NB: many bothans died to bring us information:
+         *
+         *  https://github.com/patrick-steele-idem/morphdom/blob/master/src/specialElHandlers.js
+         *  https://github.com/choojs/nanomorph/blob/master/lib/morph.jsL113
+         *
+         * @param from {Element} the element to sync the input value from
+         * @param to {Element} the element to sync the input value to
+         * @param ctx the merge context
+         */
+        function syncInputValue(from, to, ctx) {
+            if (from instanceof HTMLInputElement &&
+                to instanceof HTMLInputElement &&
+                from.type !== 'file') {
+
+                let fromValue = from.value;
+                let toValue = to.value;
+
+                // sync boolean attributes
+                syncBooleanAttribute(from, to, 'checked', ctx);
+                syncBooleanAttribute(from, to, 'disabled', ctx);
+
+                if (!from.hasAttribute('value')) {
+                    if (!ignoreAttribute('value', to, 'remove', ctx)) {
+                        to.value = '';
+                        to.removeAttribute('value');
+                    }
+                } else if (fromValue !== toValue) {
+                    if (!ignoreAttribute('value', to, 'update', ctx)) {
+                        to.setAttribute('value', fromValue);
+                        to.value = fromValue;
+                    }
+                }
+            } else if (from instanceof HTMLOptionElement) {
+                syncBooleanAttribute(from, to, 'selected', ctx)
+            } else if (from instanceof HTMLTextAreaElement && to instanceof HTMLTextAreaElement) {
+                let fromValue = from.value;
+                let toValue = to.value;
+                if (ignoreAttribute('value', to, 'update', ctx)) {
+                    return;
+                }
+                if (fromValue !== toValue) {
+                    to.value = fromValue;
+                }
+                if (to.firstChild && to.firstChild.nodeValue !== fromValue) {
+                    to.firstChild.nodeValue = fromValue
+                }
+            }
+        }
+
+        //=============================================================================
+        // the HEAD tag can be handled specially, either w/ a 'merge' or 'append' style
+        //=============================================================================
+        function handleHeadElement(newHeadTag, currentHead, ctx) {
+
+            let added = []
+            let removed = []
+            let preserved = []
+            let nodesToAppend = []
+
+            let headMergeStyle = ctx.head.style;
+
+            // put all new head elements into a Map, by their outerHTML
+            let srcToNewHeadNodes = new Map();
+            for (const newHeadChild of newHeadTag.children) {
+                srcToNewHeadNodes.set(newHeadChild.outerHTML, newHeadChild);
+            }
+
+            // for each elt in the current head
+            for (const currentHeadElt of currentHead.children) {
+
+                // If the current head element is in the map
+                let inNewContent = srcToNewHeadNodes.has(currentHeadElt.outerHTML);
+                let isReAppended = ctx.head.shouldReAppend(currentHeadElt);
+                let isPreserved = ctx.head.shouldPreserve(currentHeadElt);
+                if (inNewContent || isPreserved) {
+                    if (isReAppended) {
+                        // remove the current version and let the new version replace it and re-execute
+                        removed.push(currentHeadElt);
+                    } else {
+                        // this element already exists and should not be re-appended, so remove it from
+                        // the new content map, preserving it in the DOM
+                        srcToNewHeadNodes.delete(currentHeadElt.outerHTML);
+                        preserved.push(currentHeadElt);
+                    }
+                } else {
+                    if (headMergeStyle === "append") {
+                        // we are appending and this existing element is not new content
+                        // so if and only if it is marked for re-append do we do anything
+                        if (isReAppended) {
+                            removed.push(currentHeadElt);
+                            nodesToAppend.push(currentHeadElt);
+                        }
+                    } else {
+                        // if this is a merge, we remove this content since it is not in the new head
+                        if (ctx.head.shouldRemove(currentHeadElt) !== false) {
+                            removed.push(currentHeadElt);
+                        }
+                    }
+                }
+            }
+
+            // Push the remaining new head elements in the Map into the
+            // nodes to append to the head tag
+            nodesToAppend.push(...srcToNewHeadNodes.values());
+            log("to append: ", nodesToAppend);
+
+            let promises = [];
+            for (const newNode of nodesToAppend) {
+                log("adding: ", newNode);
+                let newElt = document.createRange().createContextualFragment(newNode.outerHTML).firstChild;
+                log(newElt);
+                if (ctx.callbacks.beforeNodeAdded(newElt) !== false) {
+                    if (newElt.href || newElt.src) {
+                        let resolve = null;
+                        let promise = new Promise(function (_resolve) {
+                            resolve = _resolve;
+                        });
+                        newElt.addEventListener('load', function () {
+                            resolve();
+                        });
+                        promises.push(promise);
+                    }
+                    currentHead.appendChild(newElt);
+                    ctx.callbacks.afterNodeAdded(newElt);
+                    added.push(newElt);
+                }
+            }
+
+            // remove all removed elements, after we have appended the new elements to avoid
+            // additional network requests for things like style sheets
+            for (const removedElement of removed) {
+                if (ctx.callbacks.beforeNodeRemoved(removedElement) !== false) {
+                    currentHead.removeChild(removedElement);
+                    ctx.callbacks.afterNodeRemoved(removedElement);
+                }
+            }
+
+            ctx.head.afterHeadMorphed(currentHead, {added: added, kept: preserved, removed: removed});
+            return promises;
+        }
+
+        //=============================================================================
+        // Misc
+        //=============================================================================
+
+        function log() {
+            //console.log(arguments);
+        }
+
+        function noOp() {
+        }
+
+        /*
+          Deep merges the config object and the Idiomoroph.defaults object to
+          produce a final configuration object
+         */
+        function mergeDefaults(config) {
+            let finalConfig = {};
+            // copy top level stuff into final config
+            Object.assign(finalConfig, defaults);
+            Object.assign(finalConfig, config);
+
+            // copy callbacks into final config (do this to deep merge the callbacks)
+            finalConfig.callbacks = {};
+            Object.assign(finalConfig.callbacks, defaults.callbacks);
+            Object.assign(finalConfig.callbacks, config.callbacks);
+
+            // copy head config into final config  (do this to deep merge the head)
+            finalConfig.head = {};
+            Object.assign(finalConfig.head, defaults.head);
+            Object.assign(finalConfig.head, config.head);
+            return finalConfig;
+        }
+
+        function createMorphContext(oldNode, newContent, config) {
+            config = mergeDefaults(config);
+            return {
+                target: oldNode,
+                newContent: newContent,
+                config: config,
+                morphStyle: config.morphStyle,
+                ignoreActive: config.ignoreActive,
+                ignoreActiveValue: config.ignoreActiveValue,
+                idMap: createIdMap(oldNode, newContent),
+                deadIds: new Set(),
+                callbacks: config.callbacks,
+                head: config.head
+            }
+        }
+
+        function isIdSetMatch(node1, node2, ctx) {
+            if (node1 == null || node2 == null) {
+                return false;
+            }
+            if (node1.nodeType === node2.nodeType && node1.tagName === node2.tagName) {
+                if (node1.id !== "" && node1.id === node2.id) {
+                    return true;
+                } else {
+                    return getIdIntersectionCount(ctx, node1, node2) > 0;
+                }
+            }
+            return false;
+        }
+
+        function isSoftMatch(node1, node2) {
+            if (node1 == null || node2 == null) {
+                return false;
+            }
+            return node1.nodeType === node2.nodeType && node1.tagName === node2.tagName
+        }
+
+        function removeNodesBetween(startInclusive, endExclusive, ctx) {
+            while (startInclusive !== endExclusive) {
+                let tempNode = startInclusive;
+                startInclusive = startInclusive.nextSibling;
+                removeNode(tempNode, ctx);
+            }
+            removeIdsFromConsideration(ctx, endExclusive);
+            return endExclusive.nextSibling;
+        }
+
+        //=============================================================================
+        // Scans forward from the insertionPoint in the old parent looking for a potential id match
+        // for the newChild.  We stop if we find a potential id match for the new child OR
+        // if the number of potential id matches we are discarding is greater than the
+        // potential id matches for the new child
+        //=============================================================================
+        function findIdSetMatch(newContent, oldParent, newChild, insertionPoint, ctx) {
+
+            // max id matches we are willing to discard in our search
+            let newChildPotentialIdCount = getIdIntersectionCount(ctx, newChild, oldParent);
+
+            let potentialMatch = null;
+
+            // only search forward if there is a possibility of an id match
+            if (newChildPotentialIdCount > 0) {
+                let potentialMatch = insertionPoint;
+                // if there is a possibility of an id match, scan forward
+                // keep track of the potential id match count we are discarding (the
+                // newChildPotentialIdCount must be greater than this to make it likely
+                // worth it)
+                let otherMatchCount = 0;
+                while (potentialMatch != null) {
+
+                    // If we have an id match, return the current potential match
+                    if (isIdSetMatch(newChild, potentialMatch, ctx)) {
+                        return potentialMatch;
+                    }
+
+                    // computer the other potential matches of this new content
+                    otherMatchCount += getIdIntersectionCount(ctx, potentialMatch, newContent);
+                    if (otherMatchCount > newChildPotentialIdCount) {
+                        // if we have more potential id matches in _other_ content, we
+                        // do not have a good candidate for an id match, so return null
+                        return null;
+                    }
+
+                    // advanced to the next old content child
+                    potentialMatch = potentialMatch.nextSibling;
+                }
+            }
+            return potentialMatch;
+        }
+
+        //=============================================================================
+        // Scans forward from the insertionPoint in the old parent looking for a potential soft match
+        // for the newChild.  We stop if we find a potential soft match for the new child OR
+        // if we find a potential id match in the old parents children OR if we find two
+        // potential soft matches for the next two pieces of new content
+        //=============================================================================
+        function findSoftMatch(newContent, oldParent, newChild, insertionPoint, ctx) {
+
+            let potentialSoftMatch = insertionPoint;
+            let nextSibling = newChild.nextSibling;
+            let siblingSoftMatchCount = 0;
+
+            while (potentialSoftMatch != null) {
+
+                if (getIdIntersectionCount(ctx, potentialSoftMatch, newContent) > 0) {
+                    // the current potential soft match has a potential id set match with the remaining new
+                    // content so bail out of looking
+                    return null;
+                }
+
+                // if we have a soft match with the current node, return it
+                if (isSoftMatch(newChild, potentialSoftMatch)) {
+                    return potentialSoftMatch;
+                }
+
+                if (isSoftMatch(nextSibling, potentialSoftMatch)) {
+                    // the next new node has a soft match with this node, so
+                    // increment the count of future soft matches
+                    siblingSoftMatchCount++;
+                    nextSibling = nextSibling.nextSibling;
+
+                    // If there are two future soft matches, bail to allow the siblings to soft match
+                    // so that we don't consume future soft matches for the sake of the current node
+                    if (siblingSoftMatchCount >= 2) {
+                        return null;
+                    }
+                }
+
+                // advanced to the next old content child
+                potentialSoftMatch = potentialSoftMatch.nextSibling;
+            }
+
+            return potentialSoftMatch;
+        }
+
+        function parseContent(newContent) {
+            let parser = new DOMParser();
+
+            // remove svgs to avoid false-positive matches on head, etc.
+            let contentWithSvgsRemoved = newContent.replace(/<svg(\s[^>]*>|>)([\s\S]*?)<\/svg>/gim, '');
+
+            // if the newContent contains a html, head or body tag, we can simply parse it w/o wrapping
+            if (contentWithSvgsRemoved.match(/<\/html>/) || contentWithSvgsRemoved.match(/<\/head>/) || contentWithSvgsRemoved.match(/<\/body>/)) {
+                let content = parser.parseFromString(newContent, "text/html");
+                // if it is a full HTML document, return the document itself as the parent container
+                if (contentWithSvgsRemoved.match(/<\/html>/)) {
+                    content.generatedByIdiomorph = true;
+                    return content;
+                } else {
+                    // otherwise return the html element as the parent container
+                    let htmlElement = content.firstChild;
+                    if (htmlElement) {
+                        htmlElement.generatedByIdiomorph = true;
+                        return htmlElement;
+                    } else {
+                        return null;
+                    }
+                }
+            } else {
+                // if it is partial HTML, wrap it in a template tag to provide a parent element and also to help
+                // deal with touchy tags like tr, tbody, etc.
+                let responseDoc = parser.parseFromString("<body><template>" + newContent + "</template></body>", "text/html");
+                let content = responseDoc.body.querySelector('template').content;
+                content.generatedByIdiomorph = true;
+                return content
+            }
+        }
+
+        function normalizeContent(newContent) {
+            if (newContent == null) {
+                // noinspection UnnecessaryLocalVariableJS
+                const dummyParent = document.createElement('div');
+                return dummyParent;
+            } else if (newContent.generatedByIdiomorph) {
+                // the template tag created by idiomorph parsing can serve as a dummy parent
+                return newContent;
+            } else if (newContent instanceof Node) {
+                // a single node is added as a child to a dummy parent
+                const dummyParent = document.createElement('div');
+                dummyParent.append(newContent);
+                return dummyParent;
+            } else {
+                // all nodes in the array or HTMLElement collection are consolidated under
+                // a single dummy parent element
+                const dummyParent = document.createElement('div');
+                for (const elt of [...newContent]) {
+                    dummyParent.append(elt);
+                }
+                return dummyParent;
+            }
+        }
+
+        function insertSiblings(previousSibling, morphedNode, nextSibling) {
+            let stack = []
+            let added = []
+            while (previousSibling != null) {
+                stack.push(previousSibling);
+                previousSibling = previousSibling.previousSibling;
+            }
+            while (stack.length > 0) {
+                let node = stack.pop();
+                added.push(node); // push added preceding siblings on in order and insert
+                morphedNode.parentElement.insertBefore(node, morphedNode);
+            }
+            added.push(morphedNode);
+            while (nextSibling != null) {
+                stack.push(nextSibling);
+                added.push(nextSibling); // here we are going in order, so push on as we scan, rather than add
+                nextSibling = nextSibling.nextSibling;
+            }
+            while (stack.length > 0) {
+                morphedNode.parentElement.insertBefore(stack.pop(), morphedNode.nextSibling);
+            }
+            return added;
+        }
+
+        function findBestNodeMatch(newContent, oldNode, ctx) {
+            let currentElement;
+            currentElement = newContent.firstChild;
+            let bestElement = currentElement;
+            let score = 0;
+            while (currentElement) {
+                let newScore = scoreElement(currentElement, oldNode, ctx);
+                if (newScore > score) {
+                    bestElement = currentElement;
+                    score = newScore;
+                }
+                currentElement = currentElement.nextSibling;
+            }
+            return bestElement;
+        }
+
+        function scoreElement(node1, node2, ctx) {
+            if (isSoftMatch(node1, node2)) {
+                return .5 + getIdIntersectionCount(ctx, node1, node2);
+            }
+            return 0;
+        }
+
+        function removeNode(tempNode, ctx) {
+            removeIdsFromConsideration(ctx, tempNode)
+            if (ctx.callbacks.beforeNodeRemoved(tempNode) === false) return;
+
+            tempNode.remove();
+            ctx.callbacks.afterNodeRemoved(tempNode);
+        }
+
+        //=============================================================================
+        // ID Set Functions
+        //=============================================================================
+
+        function isIdInConsideration(ctx, id) {
+            return !ctx.deadIds.has(id);
+        }
+
+        function idIsWithinNode(ctx, id, targetNode) {
+            let idSet = ctx.idMap.get(targetNode) || EMPTY_SET;
+            return idSet.has(id);
+        }
+
+        function removeIdsFromConsideration(ctx, node) {
+            let idSet = ctx.idMap.get(node) || EMPTY_SET;
+            for (const id of idSet) {
+                ctx.deadIds.add(id);
+            }
+        }
+
+        function getIdIntersectionCount(ctx, node1, node2) {
+            let sourceSet = ctx.idMap.get(node1) || EMPTY_SET;
+            let matchCount = 0;
+            for (const id of sourceSet) {
+                // a potential match is an id in the source and potentialIdsSet, but
+                // that has not already been merged into the DOM
+                if (isIdInConsideration(ctx, id) && idIsWithinNode(ctx, id, node2)) {
+                    ++matchCount;
+                }
+            }
+            return matchCount;
+        }
+
+        /**
+         * A bottom up algorithm that finds all elements with ids inside of the node
+         * argument and populates id sets for those nodes and all their parents, generating
+         * a set of ids contained within all nodes for the entire hierarchy in the DOM
+         *
+         * @param node {Element}
+         * @param {Map<Node, Set<String>>} idMap
+         */
+        function populateIdMapForNode(node, idMap) {
+            let nodeParent = node.parentElement;
+            // find all elements with an id property
+            let idElements = node.querySelectorAll('[id]');
+            for (const elt of idElements) {
+                let current = elt;
+                // walk up the parent hierarchy of that element, adding the id
+                // of element to the parent's id set
+                while (current !== nodeParent && current != null) {
+                    let idSet = idMap.get(current);
+                    // if the id set doesn't exist, create it and insert it in the  map
+                    if (idSet == null) {
+                        idSet = new Set();
+                        idMap.set(current, idSet);
+                    }
+                    idSet.add(elt.id);
+                    current = current.parentElement;
+                }
+            }
+        }
+
+        /**
+         * This function computes a map of nodes to all ids contained within that node (inclusive of the
+         * node).  This map can be used to ask if two nodes have intersecting sets of ids, which allows
+         * for a looser definition of "matching" than tradition id matching, and allows child nodes
+         * to contribute to a parent nodes matching.
+         *
+         * @param {Element} oldContent  the old content that will be morphed
+         * @param {Element} newContent  the new content to morph to
+         * @returns {Map<Node, Set<String>>} a map of nodes to id sets for the
+         */
+        function createIdMap(oldContent, newContent) {
+            let idMap = new Map();
+            populateIdMapForNode(oldContent, idMap);
+            populateIdMapForNode(newContent, idMap);
+            return idMap;
+        }
+
+        //=============================================================================
+        // This is what ends up becoming the Idiomorph global object
+        //=============================================================================
+        return {
+            morph,
+            defaults
+        }
+    })();

app/assets/javascripts/outfit-viewer.js

@@ -0,0 +1,219 @@
+class OutfitViewer extends HTMLElement {
+	#internals;
+
+	constructor() {
+		super();
+		this.#internals = this.attachInternals(); // for CSS `:state()`
+	}
+
+	connectedCallback() {
+		// The `<outfit-layer>` is connected to the DOM right before its
+		// children are. So, to engage with the children, wait a tick!
+		setTimeout(() => this.#connectToChildren(), 0);
+	}
+
+	#connectToChildren() {
+		const playPauseToggle = document.querySelector(".play-pause-toggle");
+
+		// Read our initial playing state from the toggle, and subscribe to changes.
+		this.#setIsPlaying(playPauseToggle.checked);
+		playPauseToggle.addEventListener("change", () => {
+			this.#setIsPlaying(playPauseToggle.checked);
+			this.#setIsPlayingCookie(playPauseToggle.checked);
+		});
+	}
+
+	#setIsPlaying(isPlaying) {
+		// TODO: Listen for changes to the child list, and add `playing` when new
+		// nodes arrive, if playing.
+		const thirtyDays = 60 * 60 * 24 * 30;
+		if (isPlaying) {
+			this.#internals.states.add("playing");
+			for (const layer of this.querySelectorAll("outfit-layer")) {
+				layer.play();
+			}
+		} else {
+			this.#internals.states.delete("playing");
+			for (const layer of this.querySelectorAll("outfit-layer")) {
+				layer.pause();
+			}
+		}
+	}
+
+	#setIsPlayingCookie(isPlaying) {
+		const thirtyDays = 60 * 60 * 24 * 30;
+		const value = isPlaying ? "true" : "false";
+		document.cookie = `DTIOutfitViewerIsPlaying=${value};max-age=${thirtyDays}`;
+	}
+}
+
+class OutfitLayer extends HTMLElement {
+	#internals;
+
+	constructor() {
+		super();
+		this.#internals = this.attachInternals();
+
+		// An <outfit-layer> starts in the loading state, and then might very
+		// quickly decide it's not after `#connectToChildren`. This is to prevent a
+		// flash of *non*-loading state, when a new layer loads in. (e.g. In the
+		// time between our parent <turbo-frame> loading, which shows the loading
+		// spinner; and us being marked `:state(loading)`, which shows the loading
+		// spinner; we don't want the loading spinner to do its usual *immediate*
+		// total fade-out; then have to fade back in again, on the usual delay.)
+		this.#setStatus("loading");
+	}
+
+	connectedCallback() {
+		setTimeout(() => this.#connectToChildren(), 0);
+	}
+
+	disconnectedCallback() {
+		// When this `<outfit-layer>` leaves the DOM, stop listening for iframe
+		// messages, if we were.
+		window.removeEventListener("message", this.#onMessage);
+	}
+
+	play() {
+		this.#sendMessageToIframe({ type: "play" });
+	}
+
+	pause() {
+		this.#sendMessageToIframe({ type: "pause" });
+	}
+
+	#connectToChildren() {
+		const image = this.querySelector("img");
+		const iframe = this.querySelector("iframe");
+
+		if (image) {
+			// If this is an image layer, track its loading state by listening
+			// to the load/error events, and initialize based on whether it's
+			// already `complete` (which it can be if it loaded from cache).
+			this.#setStatus(image.complete ? "loaded" : "loading");
+			image.addEventListener("load", () => this.#setStatus("loaded"));
+			image.addEventListener("error", () => this.#setStatus("error"));
+		} else if (iframe) {
+			this.iframe = iframe;
+
+			// Initialize status to `loading`, and asynchronously request a
+			// status message from the iframe if it managed to load before this
+			// triggers (impressive, but I think I've seen it happen!). Then,
+			// wait for messages or error events from the iframe to update
+			// status further if needed.
+			this.#setStatus("loading");
+			this.#sendMessageToIframe({ type: "requestStatus" });
+			window.addEventListener("message", (m) => this.#onMessage(m));
+			this.iframe.addEventListener("error", () =>
+				this.#setStatus("error"),
+			);
+		} else {
+			throw new Error(
+				`<outfit-layer> must contain an <img> or <iframe> tag`,
+			);
+		}
+	}
+
+	#onMessage({ source, data }) {
+		// Ignore messages that aren't from *our* frame.
+		if (source !== this.iframe.contentWindow) {
+			return;
+		}
+
+		// Validate the incoming status message, then set our status to match.
+		if (data.type === "status") {
+			if (data.status === "loaded") {
+				this.#setStatus("loaded");
+				this.#setHasAnimations(data.hasAnimations);
+			} else if (data.status === "error") {
+				this.#setStatus("error");
+			} else {
+				throw new Error(
+					`<outfit-layer> got unexpected status: ` +
+						JSON.stringify(data.status),
+				);
+			}
+		} else {
+			throw new Error(
+				`<outfit-layer> got unexpected message: ` +
+					JSON.stringify(data),
+			);
+		}
+	}
+
+	/**
+	 * Set the status value that the CSS `:state()` selector will match.
+	 * For example, when loading, `:state(loading)` matches this element.
+	 */
+	#setStatus(newStatus) {
+		this.#internals.states.delete("loading");
+		this.#internals.states.delete("loaded");
+		this.#internals.states.delete("error");
+		this.#internals.states.add(newStatus);
+	}
+
+	/**
+	 * Set whether CSS selector `:state(has-animations)` matches this element.
+	 */
+	#setHasAnimations(hasAnimations) {
+		if (hasAnimations) {
+			this.#internals.states.add("has-animations");
+		} else {
+			this.#internals.states.delete("has-animations");
+		}
+	}
+
+	#sendMessageToIframe(message) {
+		// If we have no frame or it hasn't loaded, ignore this message.
+		if (this.iframe == null) {
+			return;
+		}
+		if (this.iframe.contentWindow == null) {
+			console.debug(
+				`Ignoring message, frame not loaded yet: `,
+				this.iframe,
+				message,
+			);
+			return;
+		}
+
+		// The frame is sandboxed (origin == null), so send to Any origin.
+		this.iframe.contentWindow.postMessage(message, "*");
+	}
+}
+
+customElements.define("outfit-viewer", OutfitViewer);
+customElements.define("outfit-layer", OutfitLayer);
+
+// Morph turbo-frames on this page, to reuse asset nodes when we want to—very
+// important for movies!—but ensure that it *doesn't* do its usual behavior of
+// aggressively reusing existing <outfit-layer> nodes for entirely different
+// assets. (It's a lot clearer for managing the loading state, and not showing
+// old incorrect layers!) (We also tried using `id` to enforce this… no luck.)
+function morphWithOutfitLayers(currentElement, newElement) {
+	Idiomorph.morph(currentElement, newElement.innerHTML, {
+		morphStyle: "innerHTML",
+		callbacks: {
+			beforeNodeMorphed: (currentNode, newNode) => {
+				// If Idiomorph wants to transform an <outfit-layer> to
+				// have a different data-asset-id attribute, we replace
+				// the node ourselves and abort the morph.
+				if (
+					newNode.tagName === "OUTFIT-LAYER" &&
+					newNode.getAttribute("data-asset-id") !==
+						currentNode.getAttribute("data-asset-id")
+				) {
+					currentNode.replaceWith(newNode);
+					return false;
+				}
+			},
+		},
+	});
+}
+addEventListener("turbo:before-frame-render", (event) => {
+	// Rather than enforce Idiomorph must be loaded, let's just be resilient
+	// and only bother if we have it. (Replacing content is not *that* bad!)
+	if (typeof Idiomorph !== "undefined") {
+		event.detail.render = (a, b) => morphWithOutfitLayers(a, b);
+	}
+});

app/assets/javascripts/swf_assets/show.js

@@ -0,0 +1,356 @@
+const canvas = document.getElementById("asset-canvas");
+const libraryScript = document.getElementById("canvas-movie-library");
+const libraryUrl = libraryScript.getAttribute("src");
+
+// Read the asset ID from the URL, as an extra hint of what asset we're
+// logging for. (This is helpful when there's a lot of assets animating!)
+const assetId = document.location.pathname.split("/").at(-1);
+const logPrefix = `[${assetId}] `.padEnd(9);
+
+// State for controlling the movie.
+let loadingStatus = "loading";
+let playingStatus = getInitialPlayingStatus();
+
+// State for loading the movie.
+let library = null;
+let movieClip = null;
+let stage = null;
+
+// State for animating the movie.
+let frameRequestId = null;
+let lastFrameTime = null;
+let lastLogTime = null;
+let numFramesSinceLastLog = 0;
+
+// State for error reporting.
+let hasLoggedRenderError = false;
+
+function loadImage(src) {
+	const image = new Image();
+	image.crossOrigin = "anonymous";
+
+	const promise = new Promise((resolve, reject) => {
+		image.onload = () => {
+			resolve(image);
+		};
+		image.onerror = () => {
+			reject(new Error(`Failed to load image: ${JSON.stringify(src)}`));
+		};
+		image.src = src;
+	});
+
+	return promise;
+}
+
+async function getLibrary() {
+	if (Object.keys(window.AdobeAn?.compositions || {}).length === 0) {
+		throw new Error(
+			`Movie library ${libraryUrl} did not add a composition to window.AdobeAn.compositions.`,
+		);
+	}
+	const [compositionId, composition] = Object.entries(
+		window.AdobeAn.compositions,
+	)[0];
+	if (Object.keys(window.AdobeAn.compositions).length > 1) {
+		console.warn(
+			`Grabbing composition ${compositionId}, but there are >1 here: `,
+			Object.keys(window.AdobeAn.compositions).length,
+		);
+	}
+	delete window.AdobeAn.compositions[compositionId];
+
+	const library = composition.getLibrary();
+
+	// One more loading step as part of loading this library is loading the
+	// images it uses for sprites.
+	//
+	// TODO: I guess the manifest has these too, so we could put them in preload
+	// meta tags to get them here faster?
+	const librarySrcDir = libraryUrl.split("/").slice(0, -1).join("/");
+	const manifestImages = new Map(
+		library.properties.manifest.map(({ id, src }) => [
+			id,
+			loadImage(librarySrcDir + "/" + src),
+		]),
+	);
+
+	await Promise.all(manifestImages.values());
+
+	// Finally, once we have the images loaded, the library object expects us to
+	// mutate it (!) to give it the actual image and sprite sheet objects from
+	// the loaded images. That's how the MovieClip's internal JS objects will
+	// access the loaded data!
+	const images = composition.getImages();
+	for (const [id, image] of manifestImages.entries()) {
+		images[id] = await image;
+	}
+	const spriteSheets = composition.getSpriteSheet();
+	for (const { name, frames } of library.ssMetadata) {
+		const image = await manifestImages.get(name);
+		spriteSheets[name] = new window.createjs.SpriteSheet({
+			images: [image],
+			frames,
+		});
+	}
+
+	return library;
+}
+
+function buildMovieClip(library) {
+	let constructorName;
+	try {
+		const fileName = decodeURI(libraryUrl).split("/").pop();
+		const fileNameWithoutExtension = fileName.split(".")[0];
+		constructorName = fileNameWithoutExtension.replace(/[ -]/g, "");
+		if (constructorName.match(/^[0-9]/)) {
+			constructorName = "_" + constructorName;
+		}
+	} catch (e) {
+		throw new Error(
+			`Movie libraryUrl ${JSON.stringify(libraryUrl)} did not match expected ` +
+				`format: ${e.message}`,
+		);
+	}
+
+	const LibraryMovieClipConstructor = library[constructorName];
+	if (!LibraryMovieClipConstructor) {
+		throw new Error(
+			`Expected JS movie library ${libraryUrl} to contain a constructor ` +
+				`named ${constructorName}, but it did not: ${Object.keys(library)}`,
+		);
+	}
+	const movieClip = new LibraryMovieClipConstructor();
+
+	return movieClip;
+}
+
+function updateStage() {
+	try {
+		stage.update();
+	} catch (e) {
+		// If rendering the frame fails, log it and proceed. If it's an
+		// animation, then maybe the next frame will work? Also alert the user,
+		// just as an FYI. (This is pretty uncommon, so I'm not worried about
+		// being noisy!)
+		if (!hasLoggedRenderError) {
+			console.error(`Error rendering movie clip ${libraryUrl}`, e);
+			// TODO: Inform user about the failure
+			hasLoggedRenderError = true;
+		}
+	}
+}
+
+function updateCanvasDimensions() {
+	// Set the canvas's internal dimensions to be higher, if the device has high
+	// DPI. Scale the movie clip to match, too.
+	const internalWidth = canvas.offsetWidth * window.devicePixelRatio;
+	const internalHeight = canvas.offsetHeight * window.devicePixelRatio;
+	canvas.width = internalWidth;
+	canvas.height = internalHeight;
+	movieClip.scaleX = internalWidth / library.properties.width;
+	movieClip.scaleY = internalHeight / library.properties.height;
+}
+
+async function startMovie() {
+	// Load the movie's library (from the JS file already run), and use it to
+	// build a movie clip.
+	library = await getLibrary();
+	movieClip = buildMovieClip(library);
+
+	updateCanvasDimensions();
+
+	if (canvas.getContext("2d") == null) {
+		console.warn(`Out of memory, can't use canvas for ${libraryUrl}.`);
+		// TODO: "Too many animations!"
+		return;
+	}
+
+	stage = new window.createjs.Stage(canvas);
+	stage.addChild(movieClip);
+	updateStage();
+
+	loadingStatus = "loaded";
+	canvas.setAttribute("data-status", "loaded");
+
+	updateAnimationState();
+}
+
+function updateAnimationState() {
+	const shouldRunAnimations =
+		loadingStatus === "loaded" && playingStatus === "playing";
+
+	if (shouldRunAnimations && frameRequestId == null) {
+		lastFrameTime = document.timeline.currentTime;
+		lastLogTime = document.timeline.currentTime;
+		numFramesSinceLastLog = 0;
+		documentHiddenSinceLastFrame = document.hidden;
+		frameRequestId = requestAnimationFrame(onAnimationFrame);
+	} else if (!shouldRunAnimations && frameRequestId != null) {
+		cancelAnimationFrame(frameRequestId);
+		lastFrameTime = null;
+		lastLogTime = null;
+		numFramesSinceLastLog = 0;
+		documentHiddenSinceLastFrame = false;
+		frameRequestId = null;
+	}
+}
+
+function onAnimationFrame() {
+	const targetFps = library.properties.fps;
+	const msPerFrame = 1000 / targetFps;
+	const msSinceLastFrame = document.timeline.currentTime - lastFrameTime;
+	const msSinceLastLog = document.timeline.currentTime - lastLogTime;
+
+	// If it takes too long to render a frame, cancel the movie, on the
+	// assumption that we're riding the CPU too hard. (Some movies do this!)
+	//
+	// But note that, if the page is hidden (e.g. the window is not visible),
+	// it's normal for the browser to pause animations. So, if we detected that
+	// the document became hidden between this frame and the last, no
+	// intervention is necesary.
+	if (msSinceLastFrame >= 2000 && !documentHiddenSinceLastFrame) {
+		pause();
+		console.warn(`Paused movie for taking too long: ${msSinceLastFrame}ms`);
+		// TODO: Display message about low FPS, and sync up to the parent.
+		return;
+	}
+
+	if (msSinceLastFrame >= msPerFrame) {
+		updateStage();
+		lastFrameTime = document.timeline.currentTime;
+
+		// If we're a little bit late to this frame, probably because the frame
+		// rate isn't an even divisor of 60 FPS, backdate it to what the ideal time
+		// for this frame *would* have been. (For example, without this tweak, a
+		// 24 FPS animation like the Floating Negg Faerie actually runs at 20 FPS,
+		// because it wants to run every 41.66ms, but a 60 FPS browser checks in
+		// every 16.66ms, so the best it can do is 50ms. With this tweak, we can
+		// *pretend* we ran at 41.66ms, so that the next frame timing correctly
+		// takes the extra 9.33ms into account.)
+		const msFrameDelay = msSinceLastFrame - msPerFrame;
+		if (msFrameDelay < msPerFrame) {
+			lastFrameTime -= msFrameDelay;
+		}
+
+		numFramesSinceLastLog++;
+	}
+
+	if (msSinceLastLog >= 5000) {
+		const fps = numFramesSinceLastLog / (msSinceLastLog / 1000);
+		console.debug(`${logPrefix} FPS: ${fps.toFixed(2)} (Target: ${targetFps})`);
+		lastLogTime = document.timeline.currentTime;
+		numFramesSinceLastLog = 0;
+	}
+
+	frameRequestId = requestAnimationFrame(onAnimationFrame);
+	documentHiddenSinceLastFrame = document.hidden;
+}
+
+// If `document.hidden` becomes true at any point, log it for the next
+// animation frame. (The next frame will reset the state, as will starting or
+// stopping the animation.)
+document.addEventListener("visibilitychange", () => {
+	if (document.hidden) {
+		documentHiddenSinceLastFrame = true;
+	}
+});
+
+function play() {
+	playingStatus = "playing";
+	updateAnimationState();
+}
+
+function pause() {
+	playingStatus = "paused";
+	updateAnimationState();
+}
+
+function getInitialPlayingStatus() {
+	const params = new URLSearchParams(document.location.search);
+	if (params.has("playing")) {
+		return "playing";
+	} else {
+		return "paused";
+	}
+}
+
+/**
+ * Recursively scans the given MovieClip (or child createjs node), to see if
+ * there are any animated areas.
+ */
+function hasAnimations(createjsNode) {
+	return (
+		// Some nodes have simple animation frames.
+		createjsNode.totalFrames > 1 ||
+		// Tweens are a form of animation that can happen separately from frames.
+		// They expect timer ticks to happen, and they change the scene accordingly.
+		createjsNode?.timeline?.tweens?.length >= 1 ||
+		// And some nodes have _children_ that are animated.
+		(createjsNode.children || []).some(hasAnimations)
+	);
+}
+
+function sendStatus() {
+	if (loadingStatus === "loading") {
+		sendMessage({ type: "status", status: "loading" });
+	} else if (loadingStatus === "loaded") {
+		sendMessage({
+			type: "status",
+			status: "loaded",
+			hasAnimations: hasAnimations(movieClip),
+		});
+	} else if (loadingStatus === "error") {
+		sendMessage({ type: "status", status: "error" });
+	} else {
+		throw new Error(
+			`unexpected loadingStatus ${JSON.stringify(loadingStatus)}`,
+		);
+	}
+}
+
+function sendMessage(message) {
+	parent.postMessage(message, document.location.origin);
+}
+
+window.addEventListener("resize", () => {
+	updateCanvasDimensions();
+
+	// Redraw the stage with the new dimensions - but with `tickOnUpdate` set
+	// to `false`, so that we don't advance by a frame. This keeps us
+	// really-paused if we're paused, and avoids skipping ahead by a frame if
+	// we're playing.
+	stage.tickOnUpdate = false;
+	updateStage();
+	stage.tickOnUpdate = true;
+});
+
+window.addEventListener("message", ({ data }) => {
+	// NOTE: For more sensitive messages, it's important for security to also
+	// check the `origin` property of the incoming event. But in this case, I'm
+	// okay with whatever site is embedding us being able to send play/pause!
+	if (data.type === "play") {
+		play();
+	} else if (data.type === "pause") {
+		pause();
+	} else if (data.type === "requestStatus") {
+		sendStatus();
+	} else {
+		throw new Error(`unexpected message: ${JSON.stringify(data)}`);
+	}
+});
+
+startMovie()
+	.then(() => {
+		sendStatus();
+	})
+	.catch((error) => {
+		console.error(logPrefix, error);
+
+		loadingStatus = "error";
+		sendStatus();
+
+		// If loading the movie fails, show the fallback image instead, by moving
+		// it out of the canvas content and into the body.
+		document.body.appendChild(document.getElementById("fallback"));
+		console.warn("Showing fallback image instead.");
+	});

app/assets/stylesheets/_items.sass

@@ -5,9 +5,15 @@ body.items-index, body.items-show, body.items-needed, body.item_trades
 
   text-align: center
 
+  .item-search-form
+    display: flex
+    gap: .5em
+    justify-content: center
+
     input[type=text]
       font-size: 125%
       width: 15em
+      flex: 0 1 auto
 
   h1
     margin-bottom: 1em

app/assets/stylesheets/_responsive.sass

@@ -0,0 +1,12 @@
+body.use-responsive-design
+    #container
+        max-width: 100%
+        padding-inline: 1rem
+        box-sizing: border-box
+
+    #home-link
+        margin-left: 1rem
+        padding-inline: 0
+
+    #userbar
+        margin-right: 1rem

app/assets/stylesheets/application.css.sass

@@ -4,6 +4,7 @@
 @import partials/clean/mixins
 
 @import layout
+@import responsive
 
 @import partials/jquery.jgrowl
 
@@ -20,5 +21,4 @@
 @import outfits/index
 @import outfits/new
 @import pets/bulk
-@import swf_assets/links
 @import users/top_contributors

app/assets/stylesheets/application/hanger-spinner.css

@@ -0,0 +1,64 @@
+.hanger-spinner {
+	height: 32px;
+	width: 32px;
+
+	@media (prefers-reduced-motion: no-preference) {
+		animation: 1.2s infinite hanger-spinner-swing;
+		transform-origin: top center;
+	}
+
+	@media (prefers-reduced-motion: reduce) {
+		animation: 1.6s infinite hanger-spinner-fade-pulse;
+	}
+}
+
+/*
+	Adapted from animate.css "swing". We spend 75% of the time swinging,
+	then 25% of the time pausing before the next loop.
+
+	We use this animation for folks who are okay with dizzy-ish motion.
+	For reduced motion, we use a pulse-fade instead.
+*/
+@keyframes hanger-spinner-swing {
+	15% {
+		transform: rotate3d(0, 0, 1, 15deg);
+	}
+
+	30% {
+		transform: rotate3d(0, 0, 1, -10deg);
+	}
+
+	45% {
+		transform: rotate3d(0, 0, 1, 5deg);
+	}
+
+	60% {
+		transform: rotate3d(0, 0, 1, -5deg);
+	}
+
+	75% {
+		transform: rotate3d(0, 0, 1, 0deg);
+	}
+
+	100% {
+		transform: rotate3d(0, 0, 1, 0deg);
+	}
+}
+
+/*
+	A homebrew fade-pulse animation. We use this for folks who don't
+	like motion. It's an important accessibility thing!
+*/
+@keyframes hanger-spinner-fade-pulse {
+	0% {
+		opacity: 0.2;
+	}
+
+	50% {
+		opacity: 1;
+	}
+
+	100% {
+		opacity: 0.2;
+	}
+}

app/assets/stylesheets/items/_show.sass

@@ -37,3 +37,314 @@ body.items-show
   .nc-icon
     height: 16px
     width: 16px
+
+  outfit-viewer
+    display: block
+    position: relative
+    width: 300px
+    height: 300px
+    border: 1px solid $module-border-color
+    border-radius: 1em
+    overflow: hidden
+    margin: 0 auto
+
+    // There's no useful text in here, but double-clicking the play/pause
+    // button can cause a weird selection state. Disable text selection.
+    user-select: none
+    -webkit-user-select: none
+
+    outfit-layer
+      display: block
+      position: absolute
+      inset: 0
+
+      // We disable pointer-events most importantly for the iframes, which
+      // will ignore our `cursor: wait` and show a plain cursor for the
+      // inside of its own document. But also, the context menus for these
+      // elements are kinda actively misleading, too!
+      pointer-events: none
+
+      img, iframe
+        width: 100%
+        height: 100%
+
+    .loading-indicator
+      position: absolute
+      z-index: 1000
+      bottom: 0px
+      right: 4px
+      padding: 8px
+      background: radial-gradient(circle closest-side, white 45%, #ffffff00)
+
+      opacity: 0
+      transition: opacity .5s
+
+    .play-pause-button
+      position: absolute
+      z-index: 1001
+      left: 8px
+      bottom: 8px
+      display: none
+      align-items: center
+      justify-content: center
+      color: white
+      background: rgba(0, 0, 0, 0.64)
+      width: 2.5em
+      height: 2.5em
+      border-radius: 100%
+      border: 2px solid transparent
+      transition: all .25s
+
+      .playing-label, .paused-label
+        display: none
+        width: 1em
+        height: 1em
+
+      .play-pause-toggle
+        // Visually hidden
+        clip: rect(0 0 0 0)
+        clip-path: inset(50%)
+        height: 1px
+        overflow: hidden
+        position: absolute
+        white-space: nowrap
+        width: 1px
+
+        &:checked ~ .playing-label
+          display: block
+
+        &:not(:checked) ~ .paused-label
+          display: block
+
+      &:hover, &:has(.play-pause-toggle:focus)
+        border: 2px solid $module-border-color
+        background: $module-bg-color
+        color: $text-color
+
+      &:has(.play-pause-toggle:active)
+        transform: translateY(2px)
+
+    &:has(outfit-layer:state(has-animations))
+      .play-pause-button
+        display: flex
+
+  .error-indicator
+    font-size: 85%
+    color: $error-color
+    margin-top: .25em
+    margin-bottom: .5em
+    display: none
+
+  // When loading, fade in the loading spinner after a brief delay. (We only
+  // apply the delay here, because fading *out* on load should be instant.)
+  // We are loading when the <turbo-frame> is busy, or when at least one layer
+  // is loading.
+  #item-preview[busy] outfit-viewer, outfit-viewer:has(outfit-layer:state(loading))
+    cursor: wait
+    .loading-indicator
+      opacity: 1
+      transition-delay: 2s
+
+  #item-preview:has(outfit-layer:state(error))
+    outfit-viewer
+      border: 2px solid red
+    .error-indicator
+      display: block
+
+  species-color-picker
+    .error-icon
+      cursor: help
+      margin-right: .25em
+
+    form[data-is-valid="false"]
+      select
+        border-color: $error-border-color
+        color: $error-color
+
+    // If JS is enabled, but auto-loading isn't ready yet (script loading or
+    // failed?), hide the submit button for .75sec, to give it time to load.
+    @media (scripting: enabled)
+      input[type=submit]
+        position: absolute
+        margin-left: .5em
+        opacity: 0
+        animation: fade-in .25s forwards
+        animation-delay: .75s
+
+    // Once the auto-loading behavior is ready, remove the submit button.
+    &:state(auto-loading)
+      input[type=submit]
+        display: none
+
+  species-face-picker
+    display: block
+    position: relative
+    max-height: 200px // 4 rows of 50px images, and padding will offer a hint of below
+    padding: 10px // leave enough room for the zoomed-in selected face
+    margin-top: -10px
+    overflow: auto
+
+    species-face-picker-options
+      display: flex
+      justify-content: center
+      flex-wrap: wrap
+
+    img
+      width: 50px
+      height: 50px
+      transition: all 0.2s
+
+      // Calm down the default color, just a smidge! There's a lot of color
+      // on this page already, y'know?
+      opacity: .9
+      filter: saturate(90%)
+
+    label
+      display: flex
+      overflow: hidden
+      transition: all 0.2s
+      position: relative
+      line-height: 1
+
+      // NOTE: The box-shadows here were copy-pasted from Impress 2020, which uses
+      //       Chakra UI's styling system to generate them! (The colors are from their
+      //       color palette, too.)
+      &:has(input:checked)
+        border-radius: 6px
+        z-index: 1
+        background: #9AE6B4
+        box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1),0 10px 10px -5px rgba(0, 0, 0, 0.04), #2F855A 0 0 2px 2px
+        transform: scale(1.1)
+
+      &:has(input:focus)
+        background: #BEE3F8
+        box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1),0 10px 10px -5px rgba(0, 0, 0, 0.04), #4299e1 0 0 0 3px
+        transform: scale(1.2)
+
+    input[type=radio]
+      position: absolute
+      left: -10000px
+      top: auto
+      width: 1px
+      height: 1px
+      overflow: hidden
+
+      &:checked + img
+        opacity: 1
+        filter: saturate(110%)
+
+      &:disabled + img
+        opacity: .6
+        filter: saturate(0%)
+
+    label:has(input[type=radio]:disabled)
+      cursor: not-allowed
+
+    noscript
+      position: absolute
+      inset: 0
+      background: rgba(white, .75)
+      z-index: 1
+      cursor: auto
+
+      display: flex
+      align-items: center
+      justify-content: center
+      text-align: center
+
+    &:has(species-face-picker-options[inert])
+      cursor: wait
+
+  .item-preview-meta-info
+    display: grid
+    grid-template-columns: 1fr auto
+    gap: .5em
+    align-items: center
+
+  .item-zones-info
+    h3
+      display: inline
+      font: inherit
+      font-weight: bold
+      &:after
+        content: ": "
+
+    ul
+      list-style-type: none
+      display: inline
+
+      li
+        display: inline
+        &:not(:last-of-type):after
+          content: ", "
+
+    .no-zones
+      font-style: italic
+      opacity: .85
+
+    .zone-species-info
+      font-style: italic
+      text-decoration: underline dotted
+
+  // Many of these styles copied from Impress 2020 and its Chakra UI styles!
+  .item-html5-info
+    display: flex
+    align-items: center
+    border: 1px solid
+    border-radius: .375em
+    padding: 4px 8px
+    min-height: 30px
+    box-sizing: border-box
+    box-shadow: rgba(0, 0, 0, 0.1) 0px 4px 6px -1px, rgba(0, 0, 0, 0.06) 0px 2px 4px -1px
+
+    &[data-status=converted]
+      background: $module-bg-color
+      color: $text-color
+
+      svg:nth-of-type(2)
+        margin-right: -4px // spacing hacks!
+
+    &[data-status=unconverted]
+      background: $warning-bg-color
+      color: #975A16
+      gap: .25em // spacing hacks!
+
+    svg:first-of-type
+      width: 12px
+      height: 12px
+
+    svg:nth-of-type(2)
+      width: 20px
+      height: 20px
+
+  #item-preview
+    display: flex
+    flex-direction: column
+    gap: .75em
+
+    @media (min-width: 600px)
+      display: grid
+      grid-template-areas: "viewer faces" "picker meta"
+      gap: .5em
+
+      outfit-viewer
+        grid-area: viewer
+        width: 350px
+        height: 350px
+
+      species-color-picker
+        grid-area: picker
+
+      species-face-picker
+        grid-area: faces
+        max-height: 350px
+        margin: -10px
+
+      .item-preview-meta-info
+        grid-area: meta
+
+@keyframes fade-in
+  from
+    opacity: 0
+  to
+    opacity: 1

app/assets/stylesheets/partials/_item_header.sass

@@ -35,6 +35,7 @@
       text-align: left
       display: flex
       align-items: center
+      flex-wrap: wrap
       gap: 1em
 
       abbr
@@ -127,6 +128,7 @@
   .item-subpages-nav
     display: flex
     align-items: flex-end
+    gap: 1em
 
     .preview-link
       margin-right: auto

app/assets/stylesheets/swf_assets/_links.sass

@@ -1,10 +0,0 @@
-@import "../partials/assets-list"
-
-body.swf_assets-links
-  #swf-assets
-    +assets-list
-
-    li
-      span
-        font-size: 75%
-        word-wrap: break-word

app/assets/stylesheets/swf_assets/show.css

@@ -0,0 +1,12 @@
+#asset-canvas,
+#asset-image,
+#fallback {
+	position: absolute;
+	left: 0;
+	top: 0;
+
+	/* HACK: `calc` isn't needed, but works around a bug in our asset pipeline,
+	 * where libsass is trying to preprocess it. (We're not SASS tho?) */
+	width: calc(min(100vw, 100vh));
+	height: calc(min(100vw, 100vh));
+}

app/controllers/items_controller.rb

@@ -82,6 +82,21 @@ class ItemsController < ApplicationController
             group_by_owned
           @current_user_quantities = current_user.item_quantities_for(@item)
         end
+
+        @selected_preview_pet_type = load_selected_preview_pet_type
+        @preview_outfit = Outfit.new(
+          pet_state: load_preview_pet_type.canonical_pet_state,
+          worn_items: [@item],
+        )
+        @preview_error = validate_preview
+
+        @all_appearances = @item.appearances
+        @appearances_by_occupied_zone = @item.appearances_by_occupied_zone.
+          sort_by { |z, a| z.label }
+        @selected_item_appearance = @preview_outfit.item_appearances.first
+
+        @preview_pet_type_options = PetType.where(color: @preview_outfit.color).
+          includes(:species).merge(Species.alphabetical)
       end
 
       format.gif do
@@ -180,7 +195,7 @@ class ItemsController < ApplicationController
         appearance_params[:color_id], appearance_params[:species_id])
     end
 
-    target.appearances_for(@items.map(&:id), swf_asset_includes: [:zone]).
+    target.appearances_for(@items, swf_asset_includes: [:zone]).
       tap do |appearances|
         # Preload the manifests for these SWF assets concurrently, rather than
         # loading them in sequence when we generate the JSON.
@@ -189,6 +204,43 @@ class ItemsController < ApplicationController
       end
   end
 
+  def load_selected_preview_pet_type
+    color_id = params.dig(:preview, :color_id)
+    species_id = params.dig(:preview, :species_id)
+
+    return load_default_preview_pet_type if color_id.nil? || species_id.nil?
+
+    PetType.find_or_initialize_by(color_id:, species_id:).tap do |pet_type|
+      if pet_type.persisted?
+        cookies["preferred-preview-color-id"] = color_id
+        cookies["preferred-preview-species-id"] = species_id
+      end
+    end
+  end
+
+  def load_preview_pet_type
+    if @selected_preview_pet_type.persisted?
+      @selected_preview_pet_type
+    else
+      load_default_preview_pet_type
+    end
+  end
+
+  def load_default_preview_pet_type
+    @item.compatible_pet_types.
+      preferring_species(cookies["preferred-preview-species-id"] || "<ignore>").
+      preferring_color(cookies["preferred-preview-color-id"] || "<ignore>").
+      preferring_simple.first
+  end
+
+  def validate_preview
+    if @selected_preview_pet_type.new_record?
+      :pet_type_does_not_exist
+    elsif @preview_outfit.item_appearances.any?(&:empty?)
+      :no_item_data
+    end
+  end
+  
   def search_error(e)
     @items = []
     @query = params[:q]

app/controllers/swf_assets_controller.rb

@@ -0,0 +1,44 @@
+class SwfAssetsController < ApplicationController
+	# We're very careful with what content is allowed to load. This is because
+	# asset movies run arbitrary JS, and, while we generally trust content from
+	# Neopets.com, let's not be *allowing* movie JS to do whatever it wants! This
+	# is a good default security stance, even if we don't foresee an attack.
+	content_security_policy do |policy|
+		policy.sandbox "allow-scripts"
+		policy.default_src "none"
+
+		policy.img_src -> {
+			src_list(
+				helpers.image_url("favicon.png"),
+				@swf_asset.image_url,
+				*@swf_asset.canvas_movie_sprite_urls,
+			)
+		}
+
+		policy.script_src -> {
+			src_list(
+				helpers.javascript_url("lib/easeljs.min"),
+				helpers.javascript_url("lib/tweenjs.min"),
+				helpers.javascript_url("swf_assets/show"),
+				@swf_asset.canvas_movie_library_url,
+			)
+		}
+
+		policy.style_src -> {
+			src_list(
+				helpers.stylesheet_url("swf_assets/show"),
+			)
+		}
+	end
+
+	def show
+		@swf_asset = SwfAsset.find params[:id]
+		render layout: nil
+	end
+
+	private
+
+	def src_list(*urls)
+		urls.filter(&:present?).map { |url| url.sub(/\?.*\z/, "") }.join(" ")
+	end
+end

app/helpers/application_helper.rb

@@ -231,6 +231,15 @@ module ApplicationHelper
     @hide_title_header = true
   end
 
+  def use_responsive_design
+    @use_responsive_design = true
+    add_body_class "use-responsive-design"
+  end
+
+  def use_responsive_design?
+    @use_responsive_design || false
+  end
+
   def signed_in_meta_tag
     %(<meta name="user-signed-in" content="#{user_signed_in?}">).html_safe
   end

app/helpers/items_helper.rb

@@ -33,7 +33,9 @@ module ItemsHelper
   def standard_species_search_links
     all_species = Species.alphabetical.map(&:id)
     PetType.random_basic_per_species(all_species).map do |pet_type|
-      image = pet_type_image(pet_type, :happy, :zoom)
+      human_name = pet_type.species.human_name
+      image = pet_type_image pet_type, :happy, :zoom,
+                             alt: human_name, title: human_name
       query = "species:#{pet_type.species.name}"
       link_to(image, items_path(:q => query))
     end.join.html_safe
@@ -218,12 +220,37 @@ module ItemsHelper
     end
   end
 
-  private
+  def outfit_viewer_is_playing
+    cookies["DTIOutfitViewerIsPlaying"] == "true"
+  end
 
-  def pet_type_image(pet_type, emotion, size)
+  def item_fits?(item, pet_type)
+    item.appearances.any? { |a| a.fits? pet_type }
+  end
+
+  def species_face_tooltip(pet_type, item)
+    if item_fits?(item, pet_type)
+      "#{pet_type.species.human_name}"
+    else
+      "#{pet_type.species.human_name}: No data yet"
+    end
+  end
+
+  def item_zone_partial_fit?(appearances_in_zone, all_appearances)
+    appearances_in_zone.size < all_appearances.size
+  end
+
+  def item_zone_species_list(appearances_in_zone)
+    appearances_in_zone.map(&:species).uniq.map(&:human_name).sort.join(", ")
+  end
+
+  def pet_type_image(pet_type, emotion, size, **options)
     src = pet_type_image_url(pet_type, emotion:, size:)
-    human_name = pet_type.species.name.humanize
-    image_tag(src, :alt => human_name, :title => human_name)
+    srcset = if size == :face
+      [[pet_type_image_url(pet_type, emotion:, size: :face_2x), "2x"]]
+    end
+
+    image_tag(src, srcset:, **options)
   end
 
   def item_header_user_lists_form_state

app/javascript/item-page.js

@@ -1,15 +0,0 @@
-import React from "react";
-import ReactDOM from "react-dom";
-
-import { AppProvider, ItemPageOutfitPreview } from "./wardrobe-2020";
-
-const rootNode = document.querySelector("#outfit-preview-root");
-const itemId = rootNode.getAttribute("data-item-id");
-// TODO: Use the new React 18 APIs instead!
-// eslint-disable-next-line react/no-deprecated
-ReactDOM.render(
-  <AppProvider>
-    <ItemPageOutfitPreview itemId={itemId} />
-  </AppProvider>,
-  rootNode,
-);

app/models/alt_style.rb

@@ -49,9 +49,9 @@ class AltStyle < ApplicationRecord
     swf_asset.image_url
   end
 
-  # Given a list of item IDs, return how they look on this alt style.
-  def appearances_for(item_ids, ...)
-    Item.appearances_for(item_ids, self, ...)
+  # Given a list of items, return how they look on this alt style.
+  def appearances_for(items, ...)
+    Item.appearances_for(items, self, ...)
   end
 
   def biology=(biology)

app/models/item.rb

@@ -281,23 +281,9 @@ class Item < ApplicationRecord
     occupied_zones.map(&:id)
   end
 
-  def occupied_zones(options={})
-    options[:scope] ||= Zone.all
-    all_body_ids = []
-    zone_body_ids = {}
-    selected_assets = swf_assets.select('body_id, zone_id').each do |swf_asset|
-      zone_body_ids[swf_asset.zone_id] ||= []
-      body_ids = zone_body_ids[swf_asset.zone_id]
-      body_ids << swf_asset.body_id unless body_ids.include?(swf_asset.body_id)
-      all_body_ids << swf_asset.body_id unless all_body_ids.include?(swf_asset.body_id)
-    end
-    zones = options[:scope].find(zone_body_ids.keys)
-    zones_by_id = zones.inject({}) { |h, z| h[z.id] = z; h }
-    total_body_ids = all_body_ids.size
-    zone_body_ids.each do |zone_id, body_ids|
-      zones_by_id[zone_id].sometimes = true if body_ids.size < total_body_ids
-    end
-    zones
+  def occupied_zones
+    zone_ids = swf_assets.map(&:zone_id).uniq
+    Zone.find(zone_ids)
   end
 
   def affected_zones
@@ -438,6 +424,15 @@ class Item < ApplicationRecord
     }.merge(options))
   end
 
+  def compatible_body_ids
+    swf_assets.map(&:body_id).uniq
+  end
+
+  def compatible_pet_types
+    return PetType.all if compatible_body_ids.include?(0)
+    PetType.where(body_id: compatible_body_ids)
+  end
+
   def handle_assets!
     if @parent_swf_asset_relationships_to_update && @current_body_id
       new_swf_asset_ids = @parent_swf_asset_relationships_to_update.map(&:swf_asset_id)
@@ -504,20 +499,48 @@ class Item < ApplicationRecord
   # instead of like a hash, so you can target its children with things like
   # the `include` option. This feels clunky though, I wish I had something a
   # bit more suited to it!
-  Appearance = Struct.new(:body, :swf_assets) do
+  Appearance = Struct.new(:item, :body, :swf_assets) do
     include ActiveModel::Serializers::JSON
+    delegate :present?, :empty?, to: :swf_assets
+    delegate :species, :fits?, :fits_all?, to: :body
+
     def attributes
-      {body: body, swf_assets: swf_assets}
+      {item:, body:, swf_assets:}
+    end
+
+    def html5?
+      swf_assets.all?(&:html5?)
+    end
+
+    def occupied_zone_ids
+      swf_assets.map(&:zone_id).uniq.sort
+    end
+
+    def restricted_zone_ids
+      return [] if empty?
+      ([item] + swf_assets).map(&:restricted_zone_ids).flatten.uniq.sort
     end
   end
   Appearance::Body = Struct.new(:id, :species) do
     include ActiveModel::Serializers::JSON
     def attributes
-      {id: id, species: species}
+      {id:, species:}
+    end
+
+    def fits_all?
+      id == 0
+    end
+
+    def fits?(target)
+      fits_all? || target.body_id == id
     end
   end
 
   def appearances
+    @appearances ||= build_appearances
+  end
+
+  def build_appearances
     all_swf_assets = swf_assets.to_a
 
     # If there are no assets yet, there are no appearances.
@@ -530,28 +553,48 @@ class Item < ApplicationRecord
     # If there are no body-specific assets, return one appearance for them all.
     if swf_assets_by_body_id.empty?
       body = Appearance::Body.new(0, nil)
-      return [Appearance.new(body, swf_assets_for_all_bodies)]
+      return [Appearance.new(self, body, swf_assets_for_all_bodies)]
     end
 
     # Otherwise, create an appearance for each real (nonzero) body ID. We don't
     # generally expect body_id = 0 and body_id != 0 to mix, but if they do,
     # uhh, let's merge the body_id = 0 ones in?
+    species_by_body_id = Species.with_body_ids(swf_assets_by_body_id.keys)
     swf_assets_by_body_id.map do |body_id, body_specific_assets|
       swf_assets_for_body = body_specific_assets + swf_assets_for_all_bodies
-      species = Species.with_body_id(body_id).first!
-      body = Appearance::Body.new(body_id, species)
-      Appearance.new(body, swf_assets_for_body)
+      body = Appearance::Body.new(body_id, species_by_body_id[body_id])
+      Appearance.new(self, body, swf_assets_for_body)
     end
   end
 
-  # Given a list of item IDs, return how they look on the given target (either
-  # a pet type or an alt style).
-  def self.appearances_for(item_ids, target, swf_asset_includes: [])
+  def appearance_for(target, ...)
+    Item.appearances_for([self], target, ...)[id]
+  end
+
+  def appearances_by_occupied_zone_id
+    {}.tap do |h|
+      appearances.each do |appearance|
+        appearance.occupied_zone_ids.each do |zone_id|
+          h[zone_id] ||= []
+          h[zone_id] << appearance
+        end
+      end
+    end
+  end
+
+  def appearances_by_occupied_zone
+    zones_by_id = occupied_zones.to_h { |z| [z.id, z] }
+    appearances_by_occupied_zone_id.transform_keys { |zid| zones_by_id[zid] }
+  end
+
+  # Given a list of items, return how they look on the given target (either a
+  # pet type or an alt style).
+  def self.appearances_for(items, target, swf_asset_includes: [])
     # First, load all the relationships for these items that also fit this
     # body.
     relationships = ParentSwfAssetRelationship.
       includes(swf_asset: swf_asset_includes).
-      where(parent_type: "Item", parent_id: item_ids).
+      where(parent_type: "Item", parent_id: items.map(&:id)).
       where(swf_asset: {body_id: [target.body_id, 0]})
 
     pet_type_body = Appearance::Body.new(target.body_id, target.species)
@@ -562,13 +605,13 @@ class Item < ApplicationRecord
       transform_values { |rels| rels.map(&:swf_asset) }
 
     # Finally, for each item, return an appearance—even if it's empty!
-    item_ids.to_h do |item_id|
-      assets = assets_by_item_id.fetch(item_id, [])
+    items.to_h do |item|
+      assets = assets_by_item_id.fetch(item.id, [])
 
       fits_all_pets = assets.present? && assets.all? { |a| a.body_id == 0 }
       body = fits_all_pets ? all_pets_body : pet_type_body
 
-      [item_id, Appearance.new(body, assets)]
+      [item.id, Appearance.new(item, body, assets)]
     end
   end
 

app/models/outfit.rb

@@ -25,7 +25,12 @@ class Outfit < ApplicationRecord
   before_validation :ensure_unique_name, if: :user_id?
 
   attr_reader :biology
-  delegate :color, to: :pet_state
+  delegate :pose, to: :pet_state
+  delegate :pet_type, to: :pet_state
+  delegate :color, to: :pet_type
+  delegate :color_id, to: :pet_type
+  delegate :species, to: :pet_type
+  delegate :species_id, to: :pet_type
 
   scope :wardrobe_order, -> { order('starred DESC', :name) }
   
@@ -107,18 +112,6 @@ class Outfit < ApplicationRecord
     )
   end
 
-  def color_id
-    pet_state.pet_type.color_id
-  end
-
-  def species_id
-    pet_state.pet_type.species_id
-  end
-
-  def pose
-    pet_state.pose
-  end
-
   def biology=(biology)
     @biology = biology.slice(:species_id, :color_id, :pose, :pet_state_id)
 
@@ -166,6 +159,78 @@ class Outfit < ApplicationRecord
     self.item_outfit_relationships = new_relationships
   end
 
+  def item_appearances(...)
+    Item.appearances_for(worn_items, pet_type, ...).values
+  end
+
+  def visible_layers
+    item_appearances = item_appearances(swf_asset_includes: [:zone])
+
+    pet_layers = pet_state.swf_assets.includes(:zone).to_a
+    item_layers = item_appearances.map(&:swf_assets).flatten
+
+    pet_restricted_zone_ids = pet_layers.map(&:restricted_zone_ids).
+      flatten.to_set
+    item_restricted_zone_ids = item_appearances.
+      map(&:restricted_zone_ids).flatten.to_set
+
+    # When an item restricts a zone, it hides pet layers of the same zone.
+    # We use this to e.g. make a hat hide a hair ruff.
+    #
+    # NOTE: Items' restricted layers also affect what items you can wear at
+    #       the same time. We don't enforce anything about that here, and
+    #       instead assume that the input by this point is valid!
+    pet_layers.reject! { |sa| item_restricted_zone_ids.include?(sa.zone_id) }
+
+    # When a pet appearance restricts a zone, or when the pet is Unconverted,
+    # it makes body-specific items incompatible. We use this to disallow UCs
+    # from wearing certain body-specific Biology Effects, Statics, etc, while
+    # still allowing non-body-specific items in those zones! (I think this
+    # happens for some Invisible pet stuff, too?)
+    #
+    # TODO: We shouldn't be *hiding* these zones, like we do with items; we
+    #       should be doing this way earlier, to prevent the item from even
+    #       showing up even in search results!
+    #
+    # NOTE: This can result in both pet layers and items occupying the same
+    #       zone, like Static, so long as the item isn't body-specific! That's
+    #       correct, and the item layer should be on top! (Here, we implement
+    #       it by placing item layers second in the list, and rely on JS sort
+    #       stability, and *then* rely on the UI to respect that ordering when
+    #       rendering them by depth. Not great! 😅)
+    #
+    # NOTE: We used to also include the pet appearance's *occupied* zones in
+    #       this condition, not just the restricted zones, as a sensible
+    #       defensive default, even though we weren't aware of any relevant
+    #       items. But now we know that actually the "Bruce Brucey B Mouth"
+    #       occupies the real Mouth zone, and still should be visible and
+    #       above pet layers! So, we now only check *restricted* zones.
+    #
+    # NOTE: UCs used to implement their restrictions by listing specific
+    #       zones, but it seems that the logic has changed to just be about
+    #       UC-ness and body-specific-ness, and not necessarily involve the
+    #       set of restricted zones at all. (This matters because e.g. UCs
+    #       shouldn't show _any_ part of the Rainy Day Umbrella, but most UCs
+    #       don't restrict Right-Hand Item (Zone 49).) Still, I'm keeping the
+    #       zone restriction case running too, because I don't think it
+    #       _hurts_ anything, and I'm not confident enough in this conclusion.
+    #
+    # TODO: Do Invisibles follow this new rule like UCs, too? Or do they still
+    #       use zone restrictions?
+    if pet_state.pose === "UNCONVERTED"
+      item_layers.reject! { |sa| sa.body_specific? }
+    else
+      item_layers.reject! { |sa| sa.body_specific? &&
+        pet_restricted_zone_ids.include?(sa.zone_id) }
+    end
+
+    # A pet appearance can also restrict its own zones. The Wraith Uni is an
+    # interesting example: it has a horn, but its zone restrictions hide it!
+    pet_layers.reject! { |sa| pet_restricted_zone_ids.include?(sa.zone_id) }
+
+    (pet_layers + item_layers).sort_by(&:depth)
+  end
+
   def ensure_unique_name
     # If no name was provided, start with "Untitled outfit".
     self.name = "Untitled outfit" if name.blank?

app/models/pet_type.rb

@@ -17,6 +17,17 @@ class PetType < ApplicationRecord
     species = Species.find_by_name!(species_name)
     where(color_id: color.id, species_id: species.id)
   }
+  scope :preferring_species, ->(species_id) {
+    joins(:species).order([Arel.sql("species_id = ? DESC"), species_id])
+  }
+  scope :preferring_color, ->(color_id) {
+    joins(:color).order([Arel.sql("color_id = ? DESC"), color_id])
+  }
+  scope :preferring_simple, -> {
+    joins(:species, :color).
+      merge(Species.order(name: :asc)).
+      merge(Color.order(basic: :desc, standard: :desc, name: :asc))
+  }
 
   def self.random_basic_per_species(species_ids)
     random_pet_types = []
@@ -119,9 +130,9 @@ class PetType < ApplicationRecord
     }.first
   end
 
-  # Given a list of item IDs, return how they look on this pet type.
-  def appearances_for(item_ids, ...)
-    Item.appearances_for(item_ids, self, ...)
+  # Given a list of items, return how they look on this pet type.
+  def appearances_for(item, ...)
+    Item.appearances_for(item, self, ...)
   end
 
   def self.all_by_ids_or_children(ids, pet_states)

app/models/species.rb

@@ -4,11 +4,6 @@ class Species < ApplicationRecord
   
   scope :alphabetical, -> { order(:name) }
   
-  scope :with_body_id, -> body_id {
-    pt = PetType.arel_table
-    joins(:pet_types).where(pt[:body_id].eq(body_id)).limit(1)
-  }
-  
   def as_json(options={})
     super({only: [:id, :name], methods: [:human_name]}.merge(options))
   end
@@ -20,4 +15,15 @@ class Species < ApplicationRecord
       I18n.translate('species.default_human_name')
     end
   end
+
+  # Given a list of body IDs, return a hash from body ID to Species.
+  # (We assume that each body ID belongs to just one species; if not, which
+  # species we return for that body ID is undefined.)
+  def self.with_body_ids(body_ids)
+    species_ids_by_body_id = PetType.where(body_id: body_ids).distinct.
+      pluck(:body_id, :species_id).to_h
+    species_by_id = Species.where(id: species_ids_by_body_id.values).
+      to_h { |s| [s.id, s] }
+    species_ids_by_body_id.transform_values { |id| species_by_id[id] }
+  end
 end

app/models/swf_asset.rb

@@ -15,7 +15,6 @@ class SwfAsset < ApplicationRecord
   belongs_to :zone
   has_many :parent_swf_asset_relationships
   has_one :contribution, :as => :contributed, :inverse_of => :contributed
-  has_many :parent_swf_asset_relationships
 
   before_validation :normalize_manifest_url, if: :manifest_url?
 
@@ -141,7 +140,10 @@ class SwfAsset < ApplicationRecord
         # assets in the same manifest, and earlier ones are broken and later
         # ones are fixed. I don't know the logic exactly, but that's what we've
         # seen!
-        { js: assets_by_ext[:js].last }
+        {
+          js: assets_by_ext[:js].last,
+          sprites: assets_by_ext.fetch(:png, []),
+        }
       else
         # Otherwise, return the first PNG and the first SVG. (Unlike the JS
         # case, it's important to choose the *first* PNG, because sometimes
@@ -186,8 +188,21 @@ class SwfAsset < ApplicationRecord
     nil
   end
 
+  def canvas_movie?
+    canvas_movie_library_url.present?
+  end
+
+  def canvas_movie_library_url
+    manifest_asset_urls[:js]
+  end
+
+  def canvas_movie_sprite_urls
+    return [] unless canvas_movie?
+    manifest_asset_urls[:sprites]
+  end
+
   def canvas_movie_image_url
-    return nil unless manifest_asset_urls[:js]
+    return nil unless canvas_movie?
 
     CANVAS_MOVIE_IMAGE_URL_TEMPLATE.expand(
       libraryUrl: manifest_asset_urls[:js],
@@ -221,6 +236,17 @@ class SwfAsset < ApplicationRecord
     self[:known_glitches] = new_known_glitches
   end
 
+  def html5?
+    # NOTE: This is slightly different than how Impress 2020 reasons about
+    #       this; it checks for an SVG or canvas movie. I *think* we did
+    #       this just to keep the API simpler, and this check is more
+    #       correct? But I do wonder if any assets have a manifest but are
+    #       arguably "not converted" because the manifest is just so bad.
+    # NOTE: Just checking `manifest_url` isn't enough, because there *are*
+    #       assets with a `manifest_url` saved but it 404s.
+    manifest.present?
+  end
+
   def restricted_zone_ids
     [].tap do |ids|
       zones_restrict.chars.each_with_index do |bit, index|

app/models/zone.rb

@@ -1,8 +1,4 @@
 class Zone < ActiveRecord::Base
-  # When selecting zones that an asset occupies, we allow the zone to set
-  # whether or not the zone is "sometimes" occupied. This is false by default.
-  attr_writer :sometimes
-  
   scope :alphabetical, -> { order(:label) }
   scope :matching_label, ->(label) {
     where(plain_label: Zone.plainify_label(label))
@@ -13,10 +9,6 @@ class Zone < ActiveRecord::Base
     super({only: [:id, :depth, :label]}.merge(options))
   end
 
-  def uncertain_label
-    @sometimes ? "#{label} sometimes" : label
-  end
-
   def is_commonly_used_by_items
     # Zone metadata marks item zones with types 2, 3, and 4. But also, in
     # practice, the Biology Effects zone (type 1, ID 4) has been used for a few

app/views/application/_hanger_spinner.html

@@ -0,0 +1,6 @@
+<svg class="hanger-spinner" viewBox="0 0 473 473">
+	<path
+		fill="currentColor"
+		d="M451.426,315.003c-0.517-0.344-1.855-0.641-2.41-0.889l-201.09-88.884v-28.879c38.25-4.6,57.136-29.835,57.136-62.28c0-35.926-25.283-63.026-59.345-63.026c-35.763,0-65.771,29.481-65.771,64.384c0,6.005,4.973,10.882,10.978,10.882c1.788,0,3.452-0.535,4.934-1.291c3.519-1.808,6.024-5.365,6.024-9.591c0-22.702,20.674-42.62,44.217-42.62c22.003,0,37.982,17.356,37.982,41.262c0,23.523-19.011,41.262-44.925,41.262c-6.005,0-10.356,4.877-10.356,10.882v21.267v21.353c0,0.21-0.421,0.383-0.401,0.593L35.61,320.55C7.181,330.792-2.554,354.095,0.554,371.881c3.194,18.293,18.704,30.074,38.795,30.074H422.26c23.782,0,42.438-12.307,48.683-32.942C477.11,348.683,469.078,326.766,451.426,315.003z M450.115,364.031c-3.452,11.427-13.607,18.8-27.846,18.8H39.349c-9.725,0-16.104-5.394-17.5-13.368c-1.587-9.104,4.265-22.032,21.831-28.42l199.531-94.583l196.844,87.65C449.303,340.717,453.434,353.072,450.115,364.031z"
+	/>
+</svg>

app/views/items/_outfit_viewer.html.haml

@@ -0,0 +1,24 @@
+%outfit-viewer
+  .loading-indicator= render partial: "hanger_spinner"
+
+  %label.play-pause-button{title: "Pause/play animations"}
+    %input.play-pause-toggle{
+      type: "checkbox",
+      checked: outfit_viewer_is_playing,
+    }
+    %svg.playing-label{viewBox: "0 0 24 24", "aria-hidden": "true", "aria-label": "Pause"}
+      %path{fill: "currentColor", d: "M6 19h4V5H6v14zm8-14v14h4V5h-4z"}
+    %svg.paused-label{viewBox: "0 0 24 24", "aria-hidden": "true", "aria-label": "Play"}
+      %path{fill: "currentColor", d: "M8 5v14l11-7z"}
+
+  - outfit.visible_layers.each do |swf_asset|
+    %outfit-layer{
+      data: {
+        "asset-id": swf_asset.id,
+        "zone": swf_asset.zone.label,
+      },
+    }
+      - if swf_asset.canvas_movie?
+        %iframe{src: swf_asset_path(swf_asset, playing: outfit_viewer_is_playing ? true : nil)}
+      - else
+        = image_tag swf_asset.image_url, alt: ""

app/views/items/show.html.haml

@@ -1,5 +1,6 @@
 - title @item.name
 - canonical_path @item
+- use_responsive_design
 
 = render partial: "item_header",
   locals: {item: @item, trades: @trades, current_subpage: "preview",
@@ -13,7 +14,96 @@
     how we handle zones. Until then, these items will be <em>very</em> buggy,
     sorry!
 
-#outfit-preview-root{'data-item-id': @item.id}
+= turbo_frame_tag "item-preview" do
+  = render partial: "outfit_viewer", locals: {outfit: @preview_outfit}
+  .error-indicator
+    💥 We couldn't load all of this outfit. Try again?
+
+  %species-color-picker
+    = form_for item_path(@item), method: :get, data: {"is-valid": @preview_error.nil?} do |f|
+      - if @preview_error == :pet_type_does_not_exist
+        %span.error-icon{title: "We haven't seen this kind of pet before."} ⚠️
+      - elsif @preview_error == :no_item_data
+        %span.error-icon{title: "We haven't seen this item on this pet before."} ⚠️
+
+      = select_tag "preview[color_id]",
+        options_from_collection_for_select(Color.funny.alphabetical,
+          "id", "human_name", @selected_preview_pet_type.color_id)
+      = select_tag "preview[species_id]",
+        options_from_collection_for_select(Species.alphabetical,
+          "id", "human_name", @selected_preview_pet_type.species_id)
+      = submit_tag "Go", name: nil
+
+  %species-face-picker
+    %noscript
+      This fancy species picker requires Javascript, but you can still use the
+      dropdowns instead!
+    %species-face-picker-options{
+      inert: true, # waits for JS to remove
+      "aria-hidden": true, # waits for JS to remove
+    }
+      - @preview_pet_type_options.each do |pet_type|
+        %label{
+          title: species_face_tooltip(pet_type, @item),
+        }
+          = radio_button_tag "species_face_id", pet_type.species_id,
+            checked: pet_type == @preview_outfit.pet_type,
+            disabled: !item_fits?(@item, pet_type)
+          = pet_type_image pet_type,
+            item_fits?(@item, pet_type) ? :happy : :sad,
+            :face
+
+  .item-preview-meta-info
+    .item-zones-info
+      %section
+        %h3 Occupies
+        - if @appearances_by_occupied_zone.present?
+          %ul
+            - @appearances_by_occupied_zone.each do |zone, appearances_in_zone|
+              %li
+                = zone.label
+                - if item_zone_partial_fit? appearances_in_zone, @all_appearances
+                  %span.zone-species-info{
+                    title: item_zone_species_list(appearances_in_zone)
+                  }
+                    (#{appearances_in_zone.size} species)
+        - else
+          %span.no-zones (None)
+
+      %section
+        %h3 Restricts
+        - if @item.restricted_zones.present?
+          %ul
+            - @item.restricted_zones.sort_by(&:label).each do |zone|
+              %li= zone.label
+        - else
+          %span.no-zones (None)
+
+    %div
+      - if @selected_item_appearance.html5?
+        .item-html5-info{
+          "data-status": "converted",
+          "aria-label": "HTML5 supported!",
+          title: "This item is converted to HTML5, and ready to use on Neopets.com!",
+        }
+          %svg{viewBox: "0 0 24 24"}
+            %path{fill: "currentColor", d: "M12,0A12,12,0,1,0,24,12,12.014,12.014,0,0,0,12,0Zm6.927,8.2-6.845,9.289a1.011,1.011,0,0,1-1.43.188L5.764,13.769a1,1,0,1,1,1.25-1.562l4.076,3.261,6.227-8.451A1,1,0,1,1,18.927,8.2Z"}
+          %svg{viewBox: "0 0 36 36"}
+            %path{fill: "currentColor", d: "M16.389 14.489c.744-.155 1.551-.31 2.326-.31 3.752 0 6.418 2.977 6.418 6.604 0 5.178-2.851 8.589-8.216 8.589-2.201 0-6.821-1.427-6.821-4.155 0-1.147.961-2.107 2.108-2.107 1.24 0 2.729 1.984 4.806 1.984 2.17 0 3.288-2.109 3.288-4.062 0-1.86-1.055-3.131-2.977-3.131-1.799 0-2.078 1.023-3.659 1.023-1.209 0-1.829-.93-1.829-1.457 0-.403.062-.713.093-1.054l.774-6.544c.341-2.418.93-2.945 2.418-2.945h7.472c1.428 0 2.264.837 2.264 1.953 0 2.14-1.611 2.326-2.17 2.326h-5.829l-.466 3.286z"}
+      - else
+        .item-html5-info{
+          "data-status": "unconverted",
+          "aria-label": "HTML5 not supported",
+          title: "This item isn't converted to HTML5 yet, so it might not appear in " +
+                "Neopets.com customization yet. Once it's ready, it could look a " +
+                "bit different than our temporary preview here. It might even be " +
+                "animated!"
+        }
+          %svg{viewBox: "0 0 24 24"}
+            %path{fill: "currentColor", d: "M23.119,20,13.772,2.15h0a2,2,0,0,0-3.543,0L.881,20a2,2,0,0,0,1.772,2.928H21.347A2,2,0,0,0,23.119,20ZM11,8.423a1,1,0,0,1,2,0v6a1,1,0,1,1-2,0Zm1.05,11.51h-.028a1.528,1.528,0,0,1-1.522-1.47,1.476,1.476,0,0,1,1.448-1.53h.028A1.527,1.527,0,0,1,13.5,18.4,1.475,1.475,0,0,1,12.05,19.933Z"}
+          %svg{viewBox: "0 0 36 36"}
+            %path{fill: "currentColor", d: "M16.389 14.489c.744-.155 1.551-.31 2.326-.31 3.752 0 6.418 2.977 6.418 6.604 0 5.178-2.851 8.589-8.216 8.589-2.201 0-6.821-1.427-6.821-4.155 0-1.147.961-2.107 2.108-2.107 1.24 0 2.729 1.984 4.806 1.984 2.17 0 3.288-2.109 3.288-4.062 0-1.86-1.055-3.131-2.977-3.131-1.799 0-2.078 1.023-3.659 1.023-1.209 0-1.829-.93-1.829-1.457 0-.403.062-.713.093-1.054l.774-6.544c.341-2.418.93-2.945 2.418-2.945h7.472c1.428 0 2.264.837 2.264 1.953 0 2.14-1.611 2.326-2.17 2.326h-5.829l-.466 3.286z"}
+            %path{fill: "#DD2E44", opacity: "0.75", d: "M18 0C8.059 0 0 8.059 0 18s8.059 18 18 18 18-8.059 18-18S27.941 0 18 0zm13 18c0 2.565-.753 4.95-2.035 6.965L11.036 7.036C13.05 5.753 15.435 5 18 5c7.18 0 13 5.821 13 13zM5 18c0-2.565.753-4.95 2.036-6.964l17.929 17.929C22.95 30.247 20.565 31 18 31c-7.179 0-13-5.82-13-13z"}
 
 - unless @contributors_with_counts.empty?
   #item-contributors
@@ -23,6 +113,10 @@
         %li= link_to(contributor.name, user_contributions_path(contributor)) + format_contribution_count(count)
     %footer= t '.contributors.footer'
 
-- content_for :javascripts_body do
-  = javascript_include_tag 'item-page', defer: true
+- content_for :stylesheets do
+  = stylesheet_link_tag "application/hanger-spinner"
 
+- content_for :javascripts do
+  = javascript_include_tag "lib/idiomorph", async: true
+  = javascript_include_tag "outfit-viewer", async: true
+  = javascript_include_tag "items/show", async: true

app/views/layouts/application.html.haml

@@ -13,6 +13,8 @@
     %link{href: image_path('favicon.png'), rel: 'icon'}
     = yield :stylesheets
     = stylesheet_link_tag "application"
+    - if use_responsive_design?
+      %meta{name: "viewport", content: "width=device-width, initial-scale=1"}
     = yield :meta
     = open_graph_tags
     = csrf_meta_tag

app/views/layouts/items.html.haml

@@ -7,7 +7,7 @@
       = image_tag 'https://images.neopets.com/items/mall_floatingneggfaerie.gif'
       %span= t 'infinite_closet'
 - content_for :content do
-  = form_tag items_path, :method => :get do
+  = form_tag items_path, method: :get, class: "item-search-form" do
     = text_field_tag :q, @query.to_s
     = submit_tag t('.search'), :name => nil
   = yield

app/views/swf_assets/show.html.haml

@@ -0,0 +1,36 @@
+!!! 5
+%html
+  %head
+    %meta{charset: "utf-8"}
+    %meta{name: "viewport", content: "width=device-width, initial-scale=1"}
+    %title
+      Embed for Asset ##{@swf_asset.id} | #{t "app_name"}
+    %link{href: image_path("favicon.png"), rel: "icon"}
+
+    -# Load the stylesheet first, because displaying things correctly is the
+    -# actual most essential thing.
+    = stylesheet_link_tag "swf_assets/show", debug: false
+
+    -# NOTE: For all these assets, the Content-Security-Policy doesn't account
+    -# for asset debug mode, so let's just opt out of it with `debug: false`!
+    - if @swf_asset.canvas_movie?
+      -# This is optional, but preloading the sprites can help us from having
+      -# to wait on all the other JS to load and set up before we start!
+      - @swf_asset.canvas_movie_sprite_urls.each do |sprite_url|
+        %link{rel: "preload", href: sprite_url, as: "image", crossorigin: "anonymous"}
+
+      -# Load the scripts: EaselJS libs first, then the asset's "library" file,
+      -# then our page script that starts the movie.
+      = javascript_include_tag "lib/easeljs.min", defer: true, debug: false
+      = javascript_include_tag "lib/tweenjs.min", defer: true, debug: false
+      = javascript_include_tag @swf_asset.canvas_movie_library_url, defer: true,
+        id: "canvas-movie-library"
+      = javascript_include_tag "swf_assets/show", defer: true, debug: false
+  %body
+    - if @swf_asset.canvas_movie?
+      %canvas#asset-canvas
+        -# Show a fallback image, for users with JS disabled. Lazy-load it, so
+        -# the browser won't bother to load it if it's not used.
+        = image_tag @swf_asset.image_url, id: "fallback", alt: "", loading: "lazy"
+    - else
+      = image_tag @swf_asset.image_url, alt: "", id: "asset-image"

config/routes.rb

@@ -37,6 +37,7 @@ OpenneoImpressItems::Application.routes.draw do
     resources :alt_styles, path: 'alt-styles', only: [:index]
   end
   resources :alt_styles, path: 'alt-styles', only: [:index]
+  resources :swf_assets, path: 'swf-assets', only: [:show]
 
   # Loading and modeling pets!
   post '/pets/load' => 'pets#load', :as => :load_pet