require 'active_record'
require_relative 'postgres/serialized_message'
require_relative 'postgres/advisory_transaction_lock'

require_relative 'postgres/store'
module Messaging
  module Adapters
    # Adapter for using Postgres and Active Record as a message store.
    # @see Messaging::Adapters::Postgres::Store Store - for more information on how to use the message store
    # capabilities provided by this adapter.
    class Postgres
      def self.register!
        return if Adapters.key? :postgres

        Adapters.register(:postgres, memoize: true) { Postgres.new }
        Adapters::Store.register(:postgres, memoize: true) { Store.new }
      end
      private_class_method :register!

      register!

      def create_schema
        connection.execute 'CREATE SCHEMA IF NOT EXISTS messaging'
      end

      def create_id_sequence
        connection.execute 'CREATE SEQUENCE IF NOT EXISTS messaging.messages_id_seq'
      end

      def create_messages_table
        sql = <<~SQL
          CREATE TABLE messaging.messages (
            id bigint DEFAULT nextval('messaging.messages_id_seq'::regclass) NOT NULL,
            uuid uuid NOT NULL,
            stream character varying NOT NULL,
            stream_position bigint NOT NULL,
            message_type character varying NOT NULL,
            data jsonb,
            created_at timestamp without time zone NOT NULL,
            updated_at timestamp without time zone NOT NULL,
            stream_category character varying,
            stream_id character varying
          )
          PARTITION BY LIST (stream_category);

          CREATE INDEX messages_id_idx ON ONLY messaging.messages USING btree (id);
          CREATE INDEX messages_stream_category_id_idx ON ONLY messaging.messages USING btree (stream_category, id);
          CREATE INDEX messages_stream_category_stream_id_stream_position_idx ON ONLY messaging.messages USING btree (stream_category, stream_id, stream_position);
        SQL
        connection.execute sql
      end

      def create_category(category_name)
        table_name = category_name.parameterize(separator: '_')
        sql = <<~SQL
          CREATE TABLE messaging.#{table_name}
          PARTITION OF messaging.messages FOR VALUES IN ('#{category_name}');
        SQL
        connection.execute sql
      end

      def drop_category(category_name)
        table_name = category_name.parameterize(separator: '_')
        sql = <<~SQL
          drop TABLE messaging.#{table_name}
        SQL
        connection.execute sql
      end

      def connection
        ActiveRecord::Base.connection
      end
    end
  end
end