class Multiwoven::Integrations::Source::Bigquery::Client

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

def create_connection(connection_config)
  Google::Cloud::Bigquery.new(
    project: connection_config["project_id"],
    credentials: connection_config["credentials_json"]
  )
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
  bigquery = create_connection(connection_config)
  target_dataset_id = connection_config["dataset_id"]
  records = bigquery.datasets.flat_map do |dataset|
    next unless dataset.dataset_id == target_dataset_id
    dataset.tables.flat_map do |table|
      table.schema.fields.map do |field|
        {
          table_name: table.table_id,
          column_name: field.name,
          data_type: field.type,
          is_nullable: field.mode == "NULLABLE"
        }
      end
    end
  end
  catalog = Catalog.new(streams: create_streams(records))
  catalog.to_multiwoven_message
rescue StandardError => e
  handle_exception(e, {
                     context: "BIGQUERY:DISCOVER:EXCEPTION",
                     type: "error"
                   })
end

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

def query(connection, query)
  records = []
  results = connection.query(query) || []
  results.each do |row|
    records << RecordMessage.new(data: row, emitted_at: Time.now.to_i).to_multiwoven_message
  end
  records
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?
  bigquery = create_connection(connection_config)
  query(bigquery, query)
rescue StandardError => e
  handle_exception(e, {
                     context: "BIGQUERY:READ:EXCEPTION",
                     type: "error",
                     sync_id: sync_config.sync_id,
                     sync_run_id: sync_config.sync_run_id
                   })
end