chinwagsocial/app/models/trends/query.rb

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# frozen_string_literal: true
class Trends::Query
include Redisable
include Enumerable
attr_reader :prefix, :klass, :loaded
alias loaded? loaded
def initialize(prefix, klass)
@prefix = prefix
@klass = klass
@records = []
@loaded = false
@allowed = false
@limit = nil
@offset = nil
end
def allowed!
@allowed = true
self
end
def allowed
clone.allowed!
end
def in_locale!(value)
@locale = value
self
end
def in_locale(value)
clone.in_locale!(value)
end
def offset!(value)
@offset = value.to_i
self
end
def offset(value)
clone.offset!(value)
end
def limit!(value)
@limit = value.to_i
self
end
def limit(value)
clone.limit!(value)
end
def records
load
@records
end
delegate :each, :empty?, :first, :last, :size, to: :records
def to_ary
records.dup
end
alias to_a to_ary
def to_arel
if ids_for_key.empty?
klass.none
else
scope = klass.joins(sanitized_join_sql).reorder('x.ordering')
scope = scope.offset(@offset) if @offset.present?
scope = scope.limit(@limit) if @limit.present?
scope
end
end
private
def key
[@prefix, @allowed ? 'allowed' : 'all', @locale].compact.join(':')
end
def load
unless loaded?
@records = perform_queries
@loaded = true
end
self
end
def ids_for_key
@ids_for_key ||= redis.zrevrange(key, 0, -1).map(&:to_i)
end
def sanitized_join_sql
ActiveRecord::Base.sanitize_sql_array(join_sql_array)
end
def join_sql_array
[join_sql_query, ids_for_key]
end
def join_sql_query
<<~SQL.squish
JOIN unnest(array[?]) WITH ordinality AS x (id, ordering) ON #{klass.table_name}.id = x.id
SQL
end
def perform_queries
apply_scopes(to_arel).to_a
end
def apply_scopes(scope)
scope
end
end