# frozen_string_literal: true

module Decidim
  module Admin
    # A command that reorders a collection of content blocks. It also creates
    # the ones that might be missing.
    class ReorderContentBlocks < Decidim::Command
      # Public: Initializes the command.
      #
      # organization - the Organization where the content blocks reside
      # scope - the scope applied to the content blocks
      # order - an Array holding the order of IDs of published content blocks.
      # scoped_resource_id - (optional) The id of the resource the content blocks belongs to.
      def initialize(organization, scope, order, scoped_resource_id = nil)
        @organization = organization
        @scope = scope
        @order = order
        @scoped_resource_id = scoped_resource_id
      end

      # Executes the command. Broadcasts these events:
      #
      # - :ok when everything is valid.
      # - :invalid if the data wasn't valid and we couldn't proceed.
      #
      # Returns nothing.
      def call
        return broadcast(:invalid) if order.blank?

        reorder_steps
        broadcast(:ok)
      end

      private

      attr_reader :organization, :scope, :scoped_resource_id

      def reorder_steps
        transaction do
          reset_weights
          collection.reload
          set_new_weights
          unpublish_removed_content_blocks
          publish_appearing_content_blocks
        end
      end

      def reset_weights
        # rubocop:disable Rails/SkipsModelValidations
        collection.where.not(weight: nil).update_all(weight: nil)
        # rubocop:enable Rails/SkipsModelValidations
      end

      def set_new_weights
        data = order.each_with_index.inject({}) do |hash, (manifest_name, index)|
          hash.update(manifest_name => index + 1)
        end

        data.each do |manifest_name, weight|
          content_block = collection.find { |block| block.manifest_name == manifest_name }
          if content_block.present?
            content_block.update!(weight: weight)
          else
            create_content_block(manifest_name, weight)
          end
        end
      end

      # rubocop:disable Rails/SkipsModelValidations
      def unpublish_removed_content_blocks
        collection.where(weight: nil).update_all(published_at: nil)
      end

      def publish_appearing_content_blocks
        collection.where(published_at: nil).where.not(weight: nil).update_all(published_at: Time.current)
      end
      # rubocop:enable Rails/SkipsModelValidations

      def create_content_block(manifest_name, weight)
        Decidim::ContentBlock.create!(
          organization: organization,
          scope_name: scope,
          scoped_resource_id: scoped_resource_id.presence,
          weight: weight,
          manifest_name: manifest_name
        )
      end

      def order
        return nil unless @order.is_a?(Array) && @order.present?

        @order
      end

      def collection
        @collection ||= Decidim::ContentBlock.for_scope(scope, organization: organization).where(scoped_resource_id: scoped_resource_id)
      end
    end
  end
end