module ActiveStorage::Attached::Model

def attachment_changes # :nodoc:
  @attachment_changes ||= {}
end

def changed_for_autosave? # :nodoc:
  super || attachment_changes.any?
end

def deprecate(action)
  reflection_name = proxy_association.reflection.name
  attached_name = reflection_name.to_s.partition("_").first
  ActiveSupport::Deprecation.warn(<<-MSG.squish)
    Calling `#{action}` from `#{reflection_name}` is deprecated and will be removed in Rails 7.1.
    To migrate to Rails 7.1's behavior call `#{action}` from `#{attached_name}` instead: `#{attached_name}.#{action}`.
  MSG
end

def has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
  validate_service_configuration(name, service)
  generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
    # frozen_string_literal: true
    def #{name}
      @active_storage_attached ||= {}
      @active_storage_attached[:#{name}] ||= ActiveStorage::Attached::Many.new("#{name}", self)
    end
    def #{name}=(attachables)
      attachables = Array(attachables).compact_blank
      if ActiveStorage.replace_on_assign_to_many
        attachment_changes["#{name}"] =
          if attachables.none?
            ActiveStorage::Attached::Changes::DeleteMany.new("#{name}", self)
          else
            ActiveStorage::Attached::Changes::CreateMany.new("#{name}", self, attachables)
          end
      else
        ActiveSupport::Deprecation.warn \
          "config.active_storage.replace_on_assign_to_many is deprecated and will be removed in Rails 7.1. " \
          "Make sure that your code works well with config.active_storage.replace_on_assign_to_many set to true before upgrading. " \
          "To append new attachables to the Active Storage association, prefer using `attach`. " \
          "Using association setter would result in purging the existing attached attachments and replacing them with new ones."
        if attachables.any?
          attachment_changes["#{name}"] =
            ActiveStorage::Attached::Changes::CreateMany.new("#{name}", self, #{name}.blobs + attachables)
        end
      end
    end
  CODE
  has_many :"#{name}_attachments", -> { where(name: name) }, as: :record, class_name: "ActiveStorage::Attachment", inverse_of: :record, dependent: :destroy, strict_loading: strict_loading do
    def purge
      deprecate(:purge)
      each(&:purge)
      reset
    end
    def purge_later
      deprecate(:purge_later)
      each(&:purge_later)
      reset
    end
    private
    def deprecate(action)
      reflection_name = proxy_association.reflection.name
      attached_name = reflection_name.to_s.partition("_").first
      ActiveSupport::Deprecation.warn(<<-MSG.squish)
        Calling `#{action}` from `#{reflection_name}` is deprecated and will be removed in Rails 7.1.
        To migrate to Rails 7.1's behavior call `#{action}` from `#{attached_name}` instead: `#{attached_name}.#{action}`.
      MSG
    end
  end
  has_many :"#{name}_blobs", through: :"#{name}_attachments", class_name: "ActiveStorage::Blob", source: :blob, strict_loading: strict_loading
  scope :"with_attached_#{name}", -> {
    if ActiveStorage.track_variants
      includes("#{name}_attachments": { blob: :variant_records })
    else
      includes("#{name}_attachments": :blob)
    end
  }
  after_save { attachment_changes[name.to_s]&.save }
  after_commit(on: %i[ create update ]) { attachment_changes.delete(name.to_s).try(:upload) }
  reflection = ActiveRecord::Reflection.create(
    :has_many_attached,
    name,
    nil,
    { dependent: dependent, service_name: service },
    self
  )
  yield reflection if block_given?
  ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
end

def has_one_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
  validate_service_configuration(name, service)
  generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
    # frozen_string_literal: true
    def #{name}
      @active_storage_attached ||= {}
      @active_storage_attached[:#{name}] ||= ActiveStorage::Attached::One.new("#{name}", self)
    end
    def #{name}=(attachable)
      attachment_changes["#{name}"] =
        if attachable.nil?
          ActiveStorage::Attached::Changes::DeleteOne.new("#{name}", self)
        else
          ActiveStorage::Attached::Changes::CreateOne.new("#{name}", self, attachable)
        end
    end
  CODE
  has_one :"#{name}_attachment", -> { where(name: name) }, class_name: "ActiveStorage::Attachment", as: :record, inverse_of: :record, dependent: :destroy, strict_loading: strict_loading
  has_one :"#{name}_blob", through: :"#{name}_attachment", class_name: "ActiveStorage::Blob", source: :blob, strict_loading: strict_loading
  scope :"with_attached_#{name}", -> { includes("#{name}_attachment": :blob) }
  after_save { attachment_changes[name.to_s]&.save }
  after_commit(on: %i[ create update ]) { attachment_changes.delete(name.to_s).try(:upload) }
  reflection = ActiveRecord::Reflection.create(
    :has_one_attached,
    name,
    nil,
    { dependent: dependent, service_name: service },
    self
  )
  yield reflection if block_given?
  ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
end

def initialize_dup(*) # :nodoc:
  super
  @active_storage_attached = nil
  @attachment_changes = nil
end

def purge
  deprecate(:purge)
  each(&:purge)
  reset
end

def purge_later
  deprecate(:purge_later)
  each(&:purge_later)
  reset
end

def reload(*) # :nodoc:
  super.tap { @attachment_changes = nil }
end

def validate_service_configuration(association_name, service)
  if service.present?
    ActiveStorage::Blob.services.fetch(service) do
      raise ArgumentError, "Cannot configure service :#{service} for #{name}##{association_name}"
    end
  end
end