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impress/app/models/closet_hanger.rb
Emi Matchu a03ae90697 Move more of the trade-fetching logic into the model
It was a bit tricky to figure out the right API for this, since I'm
looking ahead to the possibility of splitting these across multiple
pages with more detail, like we do in DTI 2020.

What I like about this API is that the caller gets to apply, or not
apply, whatever scopes they want to the underlying hanger set (like
`includes` or `order`), without violating the usual syntax by e.g.
passing it as a parameter to a method.
2024-01-21 00:39:20 -08:00

224 lines
7 KiB
Ruby

class ClosetHanger < ApplicationRecord
belongs_to :item
belongs_to :list, class_name: 'ClosetList', optional: true
belongs_to :user
delegate :name, to: :item, prefix: true
delegate :log_trade_activity, to: :user
validates :item_id, :uniqueness => {:scope => [:user_id, :owned, :list_id]}
validates :quantity, :numericality => {:greater_than => 0}
validates_presence_of :item, :user
validate :list_belongs_to_user
scope :alphabetical_by_item_name, -> {
it = Item::Translation.arel_table
joins(:item => :translations).where(it[:locale].eq(I18n.locale)).
order(it[:name].asc)
}
scope :trading, -> {
ch = arel_table
# sigh… our default-lists continue to be a pain
cl = ClosetList.arel_table
u = User.arel_table
joins(:user).left_outer_joins(:list).where(
ch[:list_id].not_eq(nil).and(cl[:visibility].gteq(
ClosetVisibility[:trading].id))
).or(where(
(
ch[:list_id].eq(nil).and(ch[:owned].eq(true))
).and(
u[:owned_closet_hangers_visibility].gteq(
ClosetVisibility[:trading].id)
)
)).or(where(
(
ch[:list_id].eq(nil).and(ch[:owned].eq(false))
).and(
u[:wanted_closet_hangers_visibility].gteq(
ClosetVisibility[:trading].id)
)
))
}
scope :newest, -> { order(arel_table[:created_at].desc) }
scope :owned_before_wanted, -> { order(arel_table[:owned].desc) }
scope :unlisted, -> { where(:list_id => nil) }
scope :user_is_active, -> {
u = User.arel_table
joins(:user).where(u[:last_trade_activity_at].gteq(6.months.ago))
}
before_validation :merge_quantities, :set_owned_by_list
after_save :log_trade_activity, if: :trading?
after_destroy :log_trade_activity, if: :trading?
def possibly_null_closet_list
list || user.null_closet_list(owned)
end
def trading?
possibly_null_closet_list.trading?
end
def wanted?
!owned?
end
def possibly_null_list_id=(list_id_or_owned)
if list_id_or_owned.to_s == 'true' || list_id_or_owned.to_s == 'false'
self.list_id = nil
self.owned = list_id_or_owned
else
self.list_id = list_id_or_owned
# owned is set in the set_owned_by_list hook
end
end
def verb(subject=:someone)
self.class.verb(subject, owned?)
end
def self.verb(subject, owned, positive=true)
base = (owned) ? 'own' : 'want'
base << 's' if positive && subject != :you && subject != :i
base
end
def self.preload_items(
hangers,
items_scope: Item.all,
item_translations_scope: Item::Translation.all
)
# Preload the records we need. (This is like `includes`, but `includes`
# always selects all fields for all records, and we give the caller the
# opportunity to specify which fields it actually wants via scope!)
items = items_scope.where(id: hangers.map(&:item_id))
translations = item_translations_scope.where(item_id: items.map(&:id))
# Group the records by relevant IDs.
translations_by_item_id = translations.group_by(&:item_id)
items_by_id = items.to_h { |i| [i.id, i] }
# Assign the preloaded records to the records they belong to. (This is like
# doing e.g. i.translations = ..., but that's a database write - we
# actually just want to set the `translations` field itself directly!
# Hacky, ripped from how `ActiveRecord::Associations::Preloader` does it!)
items.each do |item|
item.association(:translations).target = translations_by_item_id[item.id]
end
hangers.each do |hanger|
hanger.association(:item).target = items_by_id[hanger.item_id]
end
end
def self.set_quantity!(quantity, options)
quantity = quantity.to_i
conditions = {:user_id => options[:user_id].to_i,
:item_id => options[:item_id].to_i}
if options[:key] == "true"
conditions[:owned] = true
conditions[:list_id] = nil
elsif options[:key] == "false"
conditions[:owned] = false
conditions[:list_id] = nil
else
conditions[:list_id] = options[:key].to_i
end
hanger = self.where(conditions).first
if quantity > 0
# If quantity is non-zero, create/update the corresponding hanger.
unless hanger
hanger = self.new
hanger.user_id = conditions[:user_id]
hanger.item_id = conditions[:item_id]
# One of the following will be nil, and that's okay. If owned is nil,
# we'll cover for it before validation, as always.
hanger.owned = conditions[:owned]
hanger.list_id = conditions[:list_id]
end
hanger.quantity = quantity
hanger.save!
elsif hanger
# If quantity is zero and there's a hanger, destroy it.
hanger.destroy
end
# If quantity is zero and there's no hanger, good. Do nothing.
end
# Use this with a scoped relation to convert it into a list of trades, e.g.
# `item.hangers.trading.to_trades`.
#
# A trade includes the user who's trading, and the available closet hangers
# (which you can use to get e.g. the list name).
#
# We don't preload anything here - if you want user names or list names, you
# should `includes` them in the hanger scope first, to avoid extra queries!
Trade = Struct.new('Trade', :user_id, :hangers) do
def user
# Take advantage of `includes(:user)` on the hangers, if applied.
hangers.first.user
end
end
def self.to_trades
# Let's ensure that the `trading` filter is applied, to avoid data leaks.
# (I still recommend doing it at the call site too for clarity, though!)
all_trading_hangers = trading.to_a
owned_hangers = all_trading_hangers.filter(&:owned?)
wanted_hangers = all_trading_hangers.filter(&:wanted?)
# Group first into offering vs seeking, then by user.
offering, seeking = [owned_hangers, wanted_hangers].map do |hangers|
hangers.group_by(&:user_id).map do |user_id, user_hangers|
Trade.new(user_id, user_hangers)
end
end
{offering: offering, seeking: seeking}
end
protected
def list_belongs_to_user
if list_id?
if list
errors.add(:list_id, "must belong to you") unless list.user_id == user_id
else
errors.add(:list, "must exist")
end
end
end
def merge_quantities
# Find a hanger that conflicts: for the same item, in the same user's
# closet, same owned status, same list. It also must not be the current
# hanger. Select enough for our logic and to update flex_source.
# TODO: We deleted flex, does this reduce what data we need here?
conflicting_hanger = self.class.select([:id, :quantity, :user_id, :item_id,
:owned]).
where(:user_id => user_id, :item_id => item_id, :owned => owned,
:list_id => list_id).where(['id != ?', self.id]).first
# If there is such a hanger, remove it and merge its quantity into this one.
if conflicting_hanger
self.quantity += conflicting_hanger.quantity
conflicting_hanger.destroy
end
true
end
def set_owned_by_list
self.owned = list.hangers_owned if list
true
end
end