# frozen_string_literal: true

module RailsFailover
  module ActiveRecord
    class Railtie < ::Rails::Railtie
      initializer "rails_failover.init", after: "active_record.initialize_database" do |app|

        # AR 6.0 / 6.1 compat
        config =
          if ::ActiveRecord::Base.respond_to? :connection_db_config
            ::ActiveRecord::Base.connection_db_config.configuration_hash
          else
            ::ActiveRecord::Base.connection_config
          end

        app.config.active_record_rails_failover = false

        if !!(config[:replica_host] && config[:replica_port])
          app.config.active_record_rails_failover = true

          ::ActiveSupport.on_load(:active_record) do
            Handler.instance

            # We are doing this manually for now since we're awaiting Rails 6.1 to be released which will
            # have more stable ActiveRecord APIs for handling multiple databases with different roles.
            ::ActiveRecord::Base.connection_handlers[::ActiveRecord::Base.reading_role] =
              ::ActiveRecord::ConnectionAdapters::ConnectionHandler.new

            ::ActiveRecord::Base.connection_handlers[::ActiveRecord::Base.writing_role].connection_pools.each do |connection_pool|
              if connection_pool.respond_to?(:db_config)
                config = connection_pool.db_config.configuration_hash
              else
                config = connection_pool.spec.config
              end
              RailsFailover::ActiveRecord.establish_reading_connection(
                ::ActiveRecord::Base.connection_handlers[::ActiveRecord::Base.reading_role],
                config
              )
            end

            begin
              ::ActiveRecord::Base.connection
            rescue ::ActiveRecord::NoDatabaseError
              # Do nothing since database hasn't been created
            rescue ::PG::Error, ::ActiveRecord::ConnectionNotEstablished
              Handler.instance.verify_primary(::ActiveRecord::Base.writing_role)
              ::ActiveRecord::Base.connection_handler = ::ActiveRecord::Base.lookup_connection_handler(:reading)
            end
          end
        end
      end

      initializer "rails_failover.insert_middleware" do |app|
        if app.config.active_record_rails_failover
          ActionDispatch::DebugExceptions.register_interceptor do |request, exception|
            RailsFailover::ActiveRecord::Interceptor.handle(request, exception)
          end

          if !skip_middleware?(app.config)
            app.middleware.unshift(::RailsFailover::ActiveRecord::Middleware)
          end
        end
      end

      def skip_middleware?(config)
        return false if !config.respond_to?(:skip_rails_failover_active_record_middleware)
        config.skip_rails_failover_active_record_middleware
      end
    end
  end
end