# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Collection Proxy
    #
    # Collection proxies in Active Record are middlemen between an
    # <tt>association</tt>, and its <tt>target</tt> result set.
    #
    # For example, given
    #
    #   class Blog < ActiveRecord::Base
    #     has_many :posts
    #   end
    #
    #   blog = Blog.first
    #
    # The collection proxy returned by <tt>blog.posts</tt> is built from a
    # <tt>:has_many</tt> <tt>association</tt>, and delegates to a collection
    # of posts as the <tt>target</tt>.
    #
    # This class delegates unknown methods to the <tt>association</tt>'s
    # relation class via a delegate cache.
    #
    # The <tt>target</tt> result set is not loaded until needed. For example,
    #
    #   blog.posts.count
    #
    # is computed directly through SQL and does not trigger by itself the
    # instantiation of the actual post records.
    class CollectionProxy < Relation
      def initialize(klass, association, **) # :nodoc:
        @association = association
        super klass

        extensions = association.extensions
        extend(*extensions) if extensions.any?
      end

      def target
        @association.target
      end

      def load_target
        @association.load_target
      end

      # Returns +true+ if the association has been loaded, otherwise +false+.
      #
      #   person.pets.loaded? # => false
      #   person.pets.records
      #   person.pets.loaded? # => true
      def loaded?
        @association.loaded?
      end
      alias :loaded :loaded?

      ##
      # :method: select
      #
      # :call-seq:
      #   select(*fields, &block)
      #
      # Works in two ways.
      #
      # *First:* Specify a subset of fields to be selected from the result set.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.select(:name)
      #   # => [
      #   #      #<Pet id: nil, name: "Fancy-Fancy">,
      #   #      #<Pet id: nil, name: "Spook">,
      #   #      #<Pet id: nil, name: "Choo-Choo">
      #   #    ]
      #
      #   person.pets.select(:id, :name)
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy">,
      #   #      #<Pet id: 2, name: "Spook">,
      #   #      #<Pet id: 3, name: "Choo-Choo">
      #   #    ]
      #
      # Be careful because this also means you're initializing a model
      # object with only the fields that you've selected. If you attempt
      # to access a field except +id+ that is not in the initialized record you'll
      # receive:
      #
      #   person.pets.select(:name).first.person_id
      #   # => ActiveModel::MissingAttributeError: missing attribute 'person_id' for Pet
      #
      # *Second:* You can pass a block so it can be used just like <tt>Array#select</tt>.
      # This builds an array of objects from the database for the scope,
      # converting them into an array and iterating through them using
      # <tt>Array#select</tt>.
      #
      #   person.pets.select { |pet| /oo/.match?(pet.name) }
      #   # => [
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]

      # Finds an object in the collection responding to the +id+. Uses the same
      # rules as ActiveRecord::FinderMethods.find. Raises ActiveRecord::RecordNotFound
      # error if the object cannot be found.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.find(1) # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #   person.pets.find(4) # => ActiveRecord::RecordNotFound: Couldn't find Pet with 'id'=4
      #
      #   person.pets.find(2) { |pet| pet.name.downcase! }
      #   # => #<Pet id: 2, name: "fancy-fancy", person_id: 1>
      #
      #   person.pets.find(2, 3)
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def find(*args)
        return super if block_given?
        @association.find(*args)
      end

      ##
      # :method: first
      #
      # :call-seq:
      #   first(limit = nil)
      #
      # Returns the first record, or the first +n+ records, from the collection.
      # If the collection is empty, the first form returns +nil+, and the second
      # form returns an empty array.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.first # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.first(2)
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
      #   #    ]
      #
      #   another_person_without.pets          # => []
      #   another_person_without.pets.first    # => nil
      #   another_person_without.pets.first(3) # => []

      ##
      # :method: second
      #
      # :call-seq:
      #   second()
      #
      # Same as #first except returns only the second record.

      ##
      # :method: third
      #
      # :call-seq:
      #   third()
      #
      # Same as #first except returns only the third record.

      ##
      # :method: fourth
      #
      # :call-seq:
      #   fourth()
      #
      # Same as #first except returns only the fourth record.

      ##
      # :method: fifth
      #
      # :call-seq:
      #   fifth()
      #
      # Same as #first except returns only the fifth record.

      ##
      # :method: forty_two
      #
      # :call-seq:
      #   forty_two()
      #
      # Same as #first except returns only the forty second record.
      # Also known as accessing "the reddit".

      ##
      # :method: third_to_last
      #
      # :call-seq:
      #   third_to_last()
      #
      # Same as #last except returns only the third-to-last record.

      ##
      # :method: second_to_last
      #
      # :call-seq:
      #   second_to_last()
      #
      # Same as #last except returns only the second-to-last record.

      # Returns the last record, or the last +n+ records, from the collection.
      # If the collection is empty, the first form returns +nil+, and the second
      # form returns an empty array.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.last # => #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #
      #   person.pets.last(2)
      #   # => [
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   another_person_without.pets         # => []
      #   another_person_without.pets.last    # => nil
      #   another_person_without.pets.last(3) # => []
      def last(limit = nil)
        load_target if find_from_target?
        super
      end

      # Gives a record (or N records if a parameter is supplied) from the collection
      # using the same rules as ActiveRecord::FinderMethods.take.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.take # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.take(2)
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
      #   #    ]
      #
      #   another_person_without.pets         # => []
      #   another_person_without.pets.take    # => nil
      #   another_person_without.pets.take(2) # => []
      def take(limit = nil)
        load_target if find_from_target?
        super
      end

      # Returns a new object of the collection type that has been instantiated
      # with +attributes+ and linked to this object, but have not yet been saved.
      # You can pass an array of attributes hashes, this will return an array
      # with the new objects.
      #
      #   class Person
      #     has_many :pets
      #   end
      #
      #   person.pets.build
      #   # => #<Pet id: nil, name: nil, person_id: 1>
      #
      #   person.pets.build(name: 'Fancy-Fancy')
      #   # => #<Pet id: nil, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.build([{name: 'Spook'}, {name: 'Choo-Choo'}, {name: 'Brain'}])
      #   # => [
      #   #      #<Pet id: nil, name: "Spook", person_id: 1>,
      #   #      #<Pet id: nil, name: "Choo-Choo", person_id: 1>,
      #   #      #<Pet id: nil, name: "Brain", person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 5 # size of the collection
      #   person.pets.count # => 0 # count from database
      def build(attributes = {}, &block)
        @association.build(attributes, &block)
      end
      alias_method :new, :build

      # Returns a new object of the collection type that has been instantiated with
      # attributes, linked to this object and that has already been saved (if it
      # passes the validations).
      #
      #   class Person
      #     has_many :pets
      #   end
      #
      #   person.pets.create(name: 'Fancy-Fancy')
      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.create([{name: 'Spook'}, {name: 'Choo-Choo'}])
      #   # => [
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 3
      #   person.pets.count # => 3
      #
      #   person.pets.find(1, 2, 3)
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def create(attributes = {}, &block)
        @association.create(attributes, &block)
      end

      # Like #create, except that if the record is invalid, raises an exception.
      #
      #   class Person
      #     has_many :pets
      #   end
      #
      #   class Pet
      #     validates :name, presence: true
      #   end
      #
      #   person.pets.create!(name: nil)
      #   # => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
      def create!(attributes = {}, &block)
        @association.create!(attributes, &block)
      end

      # Replaces this collection with +other_array+. This will perform a diff
      # and delete/add only records that have changed.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [#<Pet id: 1, name: "Gorby", group: "cats", person_id: 1>]
      #
      #   other_pets = [Pet.new(name: 'Puff', group: 'celebrities')]
      #
      #   person.pets.replace(other_pets)
      #
      #   person.pets
      #   # => [#<Pet id: 2, name: "Puff", group: "celebrities", person_id: 1>]
      #
      # If the supplied array has an incorrect association type, it raises
      # an ActiveRecord::AssociationTypeMismatch error:
      #
      #   person.pets.replace(["doo", "ggie", "gaga"])
      #   # => ActiveRecord::AssociationTypeMismatch: Pet expected, got String
      def replace(other_array)
        @association.replace(other_array)
      end

      # Deletes all the records from the collection according to the strategy
      # specified by the +:dependent+ option. If no +:dependent+ option is given,
      # then it will follow the default strategy.
      #
      # For <tt>has_many :through</tt> associations, the default deletion strategy is
      # +:delete_all+.
      #
      # For +has_many+ associations, the default deletion strategy is +:nullify+.
      # This sets the foreign keys to +NULL+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets # dependent: :nullify option by default
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete_all
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size # => 0
      #   person.pets      # => []
      #
      #   Pet.find(1, 2, 3)
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>,
      #   #       #<Pet id: 2, name: "Spook", person_id: nil>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: nil>
      #   #    ]
      #
      # Both +has_many+ and <tt>has_many :through</tt> dependencies default to the
      # +:delete_all+ strategy if the +:dependent+ option is set to +:destroy+.
      # Records are not instantiated and callbacks will not be fired.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :destroy
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete_all
      #
      #   Pet.find(1, 2, 3)
      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
      #
      # If it is set to <tt>:delete_all</tt>, all the objects are deleted
      # *without* calling their +destroy+ method.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :delete_all
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete_all
      #
      #   Pet.find(1, 2, 3)
      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
      def delete_all(dependent = nil)
        @association.delete_all(dependent).tap { reset_scope }
      end

      # Deletes the records of the collection directly from the database
      # ignoring the +:dependent+ option. Records are instantiated and it
      # invokes +before_remove+, +after_remove+, +before_destroy+, and
      # +after_destroy+ callbacks.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy_all
      #
      #   person.pets.size # => 0
      #   person.pets      # => []
      #
      #   Pet.find(1) # => Couldn't find Pet with id=1
      def destroy_all
        @association.destroy_all.tap { reset_scope }
      end

      # Deletes the +records+ supplied from the collection according to the strategy
      # specified by the +:dependent+ option. If no +:dependent+ option is given,
      # then it will follow the default strategy. Returns an array with the
      # deleted records.
      #
      # For <tt>has_many :through</tt> associations, the default deletion strategy is
      # +:delete_all+.
      #
      # For +has_many+ associations, the default deletion strategy is +:nullify+.
      # This sets the foreign keys to +NULL+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets # dependent: :nullify option by default
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete(Pet.find(1))
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   Pet.find(1)
      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>
      #
      # If it is set to <tt>:destroy</tt> all the +records+ are removed by calling
      # their +destroy+ method. See +destroy+ for more information.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :destroy
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete(Pet.find(1), Pet.find(3))
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size # => 1
      #   person.pets
      #   # => [#<Pet id: 2, name: "Spook", person_id: 1>]
      #
      #   Pet.find(1, 3)
      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 3)
      #
      # If it is set to <tt>:delete_all</tt>, all the +records+ are deleted
      # *without* calling their +destroy+ method.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :delete_all
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete(Pet.find(1))
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   Pet.find(1)
      #   # => ActiveRecord::RecordNotFound: Couldn't find Pet with 'id'=1
      #
      # You can pass +Integer+ or +String+ values, it finds the records
      # responding to the +id+ and executes delete on them.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete("1")
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.delete(2, 3)
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def delete(*records)
        @association.delete(*records).tap { reset_scope }
      end

      # Destroys the +records+ supplied and removes them from the collection.
      # This method will _always_ remove record from the database ignoring
      # the +:dependent+ option. Returns an array with the removed records.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy(Pet.find(1))
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy(Pet.find(2), Pet.find(3))
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 0
      #   person.pets       # => []
      #
      #   Pet.find(1, 2, 3) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
      #
      # You can pass +Integer+ or +String+ values, it finds the records
      # responding to the +id+ and then deletes them from the database.
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy("4")
      #   # => #<Pet id: 4, name: "Benny", person_id: 1>
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy(5, 6)
      #   # => [
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 0
      #   person.pets       # => []
      #
      #   Pet.find(4, 5, 6) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (4, 5, 6)
      def destroy(*records)
        @association.destroy(*records).tap { reset_scope }
      end

      ##
      # :method: distinct
      #
      # :call-seq:
      #   distinct(value = true)
      #
      # Specifies whether the records should be unique or not.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.select(:name)
      #   # => [
      #   #      #<Pet name: "Fancy-Fancy">,
      #   #      #<Pet name: "Fancy-Fancy">
      #   #    ]
      #
      #   person.pets.select(:name).distinct
      #   # => [#<Pet name: "Fancy-Fancy">]
      #
      #   person.pets.select(:name).distinct.distinct(false)
      #   # => [
      #   #      #<Pet name: "Fancy-Fancy">,
      #   #      #<Pet name: "Fancy-Fancy">
      #   #    ]

      #--
      def calculate(operation, column_name)
        null_scope? ? scope.calculate(operation, column_name) : super
      end

      def pluck(*column_names)
        null_scope? ? scope.pluck(*column_names) : super
      end

      ##
      # :method: count
      #
      # :call-seq:
      #   count(column_name = nil, &block)
      #
      # Count all records.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   # This will perform the count using SQL.
      #   person.pets.count # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      # Passing a block will select all of a person's pets in SQL and then
      # perform the count using Ruby.
      #
      #   person.pets.count { |pet| pet.name.include?('-') } # => 2

      # Returns the size of the collection. If the collection hasn't been loaded,
      # it executes a <tt>SELECT COUNT(*)</tt> query. Else it calls <tt>collection.size</tt>.
      #
      # If the collection has been already loaded +size+ and +length+ are
      # equivalent. If not and you are going to need the records anyway
      # +length+ will take one less query. Otherwise +size+ is more efficient.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   # executes something like SELECT COUNT(*) FROM "pets" WHERE "pets"."person_id" = 1
      #
      #   person.pets # This will execute a SELECT * FROM query
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size # => 3
      #   # Because the collection is already loaded, this will behave like
      #   # collection.size and no SQL count query is executed.
      def size
        @association.size
      end

      ##
      # :method: length
      #
      # :call-seq:
      #   length()
      #
      # Returns the size of the collection calling +size+ on the target.
      # If the collection has been already loaded, +length+ and +size+ are
      # equivalent. If not and you are going to need the records anyway this
      # method will take one less query. Otherwise +size+ is more efficient.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.length # => 3
      #   # executes something like SELECT "pets".* FROM "pets" WHERE "pets"."person_id" = 1
      #
      #   # Because the collection is loaded, you can
      #   # call the collection with no additional queries:
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]

      # Returns +true+ if the collection is empty. If the collection has been
      # loaded it is equivalent
      # to <tt>collection.size.zero?</tt>. If the collection has not been loaded,
      # it is equivalent to <tt>!collection.exists?</tt>. If the collection has
      # not already been loaded and you are going to fetch the records anyway it
      # is better to check <tt>collection.load.empty?</tt>.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.count  # => 1
      #   person.pets.empty? # => false
      #
      #   person.pets.delete_all
      #
      #   person.pets.count  # => 0
      #   person.pets.empty? # => true
      def empty?
        @association.empty?
      end

      ##
      # :method: any?
      #
      # :call-seq:
      #   any?()
      #
      # Returns +true+ if the collection is not empty.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.count # => 0
      #   person.pets.any?  # => false
      #
      #   person.pets << Pet.new(name: 'Snoop')
      #   person.pets.count # => 1
      #   person.pets.any?  # => true
      #
      # Calling it without a block when the collection is not yet
      # loaded is equivalent to <tt>collection.exists?</tt>.
      # If you're going to load the collection anyway, it is better
      # to call <tt>collection.load.any?</tt> to avoid an extra query.
      #
      # You can also pass a +block+ to define criteria. The behavior
      # is the same, it returns true if the collection based on the
      # criteria is not empty.
      #
      #   person.pets
      #   # => [#<Pet name: "Snoop", group: "dogs">]
      #
      #   person.pets.any? do |pet|
      #     pet.group == 'cats'
      #   end
      #   # => false
      #
      #   person.pets.any? do |pet|
      #     pet.group == 'dogs'
      #   end
      #   # => true

      ##
      # :method: many?
      #
      # :call-seq:
      #   many?()
      #
      # Returns true if the collection has more than one record.
      # Equivalent to <tt>collection.size > 1</tt>.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.count # => 1
      #   person.pets.many? # => false
      #
      #   person.pets << Pet.new(name: 'Snoopy')
      #   person.pets.count # => 2
      #   person.pets.many? # => true
      #
      # You can also pass a +block+ to define criteria. The
      # behavior is the same, it returns true if the collection
      # based on the criteria has more than one record.
      #
      #   person.pets
      #   # => [
      #   #      #<Pet name: "Gorby", group: "cats">,
      #   #      #<Pet name: "Puff", group: "cats">,
      #   #      #<Pet name: "Snoop", group: "dogs">
      #   #    ]
      #
      #   person.pets.many? do |pet|
      #     pet.group == 'dogs'
      #   end
      #   # => false
      #
      #   person.pets.many? do |pet|
      #     pet.group == 'cats'
      #   end
      #   # => true

      # Returns +true+ if the given +record+ is present in the collection.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets # => [#<Pet id: 20, name: "Snoop">]
      #
      #   person.pets.include?(Pet.find(20)) # => true
      #   person.pets.include?(Pet.find(21)) # => false
      def include?(record)
        !!@association.include?(record)
      end

      # Returns the association object for the collection.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.proxy_association
      #   # => #<ActiveRecord::Associations::HasManyAssociation owner="#<Person:0x00>">
      #
      # Returns the same object as <tt>person.association(:pets)</tt>,
      # allowing you to make calls like <tt>person.pets.proxy_association.owner</tt>.
      #
      # See Associations::ClassMethods@Association+extensions for more.
      def proxy_association
        @association
      end

      # Returns a Relation object for the records in this association
      def scope
        @scope ||= @association.scope
      end

      # Equivalent to <tt>Array#==</tt>. Returns +true+ if the two arrays
      # contain the same number of elements and if each element is equal
      # to the corresponding element in the +other+ array, otherwise returns
      # +false+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
      #   #    ]
      #
      #   other = person.pets.to_ary
      #
      #   person.pets == other
      #   # => true
      #
      #
      # Note that unpersisted records can still be seen as equal:
      #
      #   other = [Pet.new(id: 1), Pet.new(id: 2)]
      #
      #   person.pets == other
      #   # => true
      def ==(other)
        load_target == other
      end

      ##
      # :method: to_ary
      #
      # :call-seq:
      #   to_ary()
      #
      # Returns a new array of objects from the collection. If the collection
      # hasn't been loaded, it fetches the records from the database.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   other_pets = person.pets.to_ary
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   other_pets.replace([Pet.new(name: 'BooGoo')])
      #
      #   other_pets
      #   # => [#<Pet id: nil, name: "BooGoo", person_id: 1>]
      #
      #   person.pets
      #   # This is not affected by replace
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]

      def records # :nodoc:
        load_target
      end

      # Adds one or more +records+ to the collection by setting their foreign keys
      # to the association's primary key. Since <tt><<</tt> flattens its argument list and
      # inserts each record, +push+ and +concat+ behave identically. Returns +self+
      # so several appends may be chained together.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 0
      #   person.pets << Pet.new(name: 'Fancy-Fancy')
      #   person.pets << [Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo')]
      #   person.pets.size # => 3
      #
      #   person.id # => 1
      #   person.pets
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def <<(*records)
        proxy_association.concat(records) && self
      end
      alias_method :push, :<<
      alias_method :append, :<<
      alias_method :concat, :<<

      def prepend(*args) # :nodoc:
        raise NoMethodError, "prepend on association is not defined. Please use <<, push or append"
      end

      # Equivalent to +delete_all+. The difference is that returns +self+, instead
      # of an array with the deleted objects, so methods can be chained. See
      # +delete_all+ for more information.
      # Note that because +delete_all+ removes records by directly
      # running an SQL query into the database, the +updated_at+ column of
      # the object is not changed.
      def clear
        delete_all
        self
      end

      # Reloads the collection from the database. Returns +self+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets # uses the pets cache
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets.reload # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      def reload
        proxy_association.reload(true)
        reset_scope
      end

      # Unloads the association. Returns +self+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets # uses the pets cache
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets.reset # clears the pets cache
      #
      #   person.pets  # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      def reset
        proxy_association.reset
        proxy_association.reset_scope
        reset_scope
      end

      def reset_scope # :nodoc:
        @offsets = @take = nil
        @scope = nil
        self
      end

      def inspect # :nodoc:
        load_target if find_from_target?
        super
      end

      def pretty_print(pp) # :nodoc:
        load_target if find_from_target?
        super
      end

      %w(insert insert_all insert! insert_all! upsert upsert_all).each do |method|
        class_eval <<~RUBY, __FILE__, __LINE__ + 1
          def #{method}(...)
            if @association&.target&.any? { |r| r.new_record? }
              association_name = @association.reflection.name
              ActiveRecord.deprecator.warn(<<~MSG)
                Using #{method} on association \#{association_name} with unpersisted records
                is deprecated and will be removed in Rails 8.2.
                The unpersisted records will be lost after this operation.
                Please either persist your records first or store them separately before
                calling #{method}.
              MSG
              scope.#{method}(...)
            else
              scope.#{method}(...).tap { reset }
            end
          end
        RUBY
      end

      delegate_methods = [
        QueryMethods,
        SpawnMethods,
      ].flat_map { |klass|
        klass.public_instance_methods(false)
      } - self.public_instance_methods(false) - [ :select ] + [ :scoping, :values, :load_async ]

      delegate(*delegate_methods, to: :scope)

      private
        def find_nth_with_limit(index, limit)
          load_target if find_from_target?
          super
        end

        def find_nth_from_last(index)
          load_target if find_from_target?
          super
        end

        def null_scope?
          @association.null_scope?
        end

        def find_from_target?
          @association.find_from_target?
        end

        def exec_queries
          load_target
        end
    end
  end
end
