# Copyright 2023 Google LLC All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Classes for representing Async aggregation queries for the Google Cloud Firestore API.

A :class:`~google.cloud.firestore_v1.async_aggregation.AsyncAggregationQuery` can be created directly from
a :class:`~google.cloud.firestore_v1.async_collection.AsyncCollection` and that can be
a more common way to create an aggregation query than direct usage of the constructor.
"""
from __future__ import annotations

from google.api_core import gapic_v1
from google.api_core import retry as retries

from typing import List, Union, AsyncGenerator


from google.cloud.firestore_v1.base_aggregation import (
    AggregationResult,
    _query_response_to_result,
    BaseAggregationQuery,
)


class AsyncAggregationQuery(BaseAggregationQuery):
    """Represents an aggregation query to the Firestore API."""

    def __init__(
        self,
        nested_query,
    ) -> None:
        super(AsyncAggregationQuery, self).__init__(nested_query)

    async def get(
        self,
        transaction=None,
        retry: Union[
            retries.Retry, None, gapic_v1.method._MethodDefault
        ] = gapic_v1.method.DEFAULT,
        timeout: float | None = None,
    ) -> List[AggregationResult]:
        """Runs the aggregation query.

        This sends a ``RunAggregationQuery`` RPC and returns a list of aggregation results in the stream of ``RunAggregationQueryResponse`` messages.

        Args:
            transaction
                (Optional[:class:`~google.cloud.firestore_v1.transaction.Transaction`]):
                An existing transaction that this query will run in.
                If a ``transaction`` is used and it already has write operations
                added, this method cannot be used (i.e. read-after-write is not
                allowed).
            retry (google.api_core.retry.Retry): Designation of what errors, if any,
                should be retried.  Defaults to a system-specified policy.
            timeout (float): The timeout for this request.  Defaults to a
                system-specified value.

        Returns:
            list: The aggregation query results

        """
        stream_result = self.stream(
            transaction=transaction, retry=retry, timeout=timeout
        )
        result = [aggregation async for aggregation in stream_result]
        return result  # type: ignore

    async def stream(
        self,
        transaction=None,
        retry: Union[
            retries.Retry, None, gapic_v1.method._MethodDefault
        ] = gapic_v1.method.DEFAULT,
        timeout: float | None = None,
    ) -> Union[AsyncGenerator[List[AggregationResult], None]]:
        """Runs the aggregation query.

        This sends a ``RunAggregationQuery`` RPC and then returns an iterator which
        consumes each document returned in the stream of ``RunAggregationQueryResponse``
        messages.

        If a ``transaction`` is used and it already has write operations
        added, this method cannot be used (i.e. read-after-write is not
        allowed).

        Args:
            transaction
                (Optional[:class:`~google.cloud.firestore_v1.transaction.Transaction`]):
                An existing transaction that this query will run in.
            retry (google.api_core.retry.Retry): Designation of what errors, if any,
                should be retried.  Defaults to a system-specified policy.
            timeout (float): The timeout for this request.  Defaults to a
                system-specified value.

        Yields:
            :class:`~google.cloud.firestore_v1.base_aggregation.AggregationResult`:
            The result of aggregations of this query
        """
        request, kwargs = self._prep_stream(
            transaction,
            retry,
            timeout,
        )

        response_iterator = await self._client._firestore_api.run_aggregation_query(
            request=request,
            metadata=self._client._rpc_metadata,
            **kwargs,
        )

        async for response in response_iterator:
            result = _query_response_to_result(response)
            yield result