class Multiwoven::Integrations::Source::Postgresql::Client

def check_connection(connection_config)
  connection_config = connection_config.with_indifferent_access
  create_connection(connection_config)
  ConnectionStatus.new(
    status: ConnectionStatusType["succeeded"]
  ).to_multiwoven_message
rescue PG::Error => e
  ConnectionStatus.new(
    status: ConnectionStatusType["failed"], message: e.message
  ).to_multiwoven_message
end

def create_connection(connection_config)
  raise "Unsupported Auth type" unless connection_config[:credentials][:auth_type] == "username/password"
  PG.connect(
    host: connection_config[:host],
    dbname: connection_config[:database],
    user: connection_config[:credentials][:username],
    password: connection_config[:credentials][:password],
    port: connection_config[:port]
  )
end

def create_streams(records)
  group_by_table(records).map do |r|
    Multiwoven::Integrations::Protocol::Stream.new(name: r[:tablename], action: StreamAction["fetch"], json_schema: convert_to_json_schema(r[:columns]))
  end
end

def discover(connection_config)
  connection_config = connection_config.with_indifferent_access
  query = "SELECT table_name, column_name,
           CASE WHEN data_type = 'USER-DEFINED' THEN udt_name ELSE data_type END
           AS data_type,
           is_nullable
           FROM information_schema.columns
           WHERE table_schema = '#{connection_config[:schema]}' AND table_catalog = '#{connection_config[:database]}'
           ORDER BY table_name, ordinal_position;"
  db = create_connection(connection_config)
  records = db.exec(query) do |result|
    result.map do |row|
      row
    end
  end
  catalog = Catalog.new(streams: create_streams(records))
  catalog.to_multiwoven_message
rescue StandardError => e
  handle_exception(e, {
                     context: "POSTGRESQL:DISCOVER:EXCEPTION",
                     type: "error"
                   })
ensure
  db&.close
end

def group_by_table(records)
  records.group_by { |entry| entry["table_name"] }.map do |table_name, columns|
    {
      tablename: table_name,
      columns: columns.map do |column|
        {
          column_name: column["column_name"],
          type: column["data_type"],
          optional: column["is_nullable"] == "YES"
        }
      end
    }
  end
end

def query(connection, query)
  connection.exec(query) do |result|
    result.map do |row|
      RecordMessage.new(data: row, emitted_at: Time.now.to_i).to_multiwoven_message
    end
  end
end

def read(sync_config)
  connection_config = sync_config.source.connection_specification
  connection_config = connection_config.with_indifferent_access
  query = sync_config.model.query
  query = batched_query(query, sync_config.limit, sync_config.offset) unless sync_config.limit.nil? && sync_config.offset.nil?
  db = create_connection(connection_config)
  query(db, query)
rescue StandardError => e
  handle_exception(e, {
                     context: "POSTGRESQL:READ:EXCEPTION",
                     type: "error",
                     sync_id: sync_config.sync_id,
                     sync_run_id: sync_config.sync_run_id
                   })
ensure
  db&.close
end