# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

"""
The daemon connection module contains low-level APIs for sending requests to the Pyre daemon.
This module is responsible for the communication with the Pyre daemon, which is
at the layer as low as the direct socket connection. The socket connection is used
to send a string form request to the daemon and returns the response in string form.

This module is NOT responsible for any kind of processing that happens to the request/response,
which is left to the higher layers.
"""


from __future__ import annotations

import asyncio
import contextlib
import dataclasses
import logging
from pathlib import Path
from typing import AsyncIterator, Union

from .. import dataclasses_json_extensions as json_mixins, log
from . import connections


LOG: logging.Logger = logging.getLogger(__name__)


@dataclasses.dataclass(frozen=True)
class DaemonConnectionFailure(json_mixins.CamlCaseAndExcludeJsonMixin):
    error_message: str


def send_raw_request(socket_path: Path, raw_request: str) -> str:
    with connections.connect(socket_path) as (
        input_channel,
        output_channel,
    ):
        LOG.debug(f"Sending `{log.truncate(raw_request, 400)}`")
        output_channel.write(f"{raw_request}\n")
        raw_response = input_channel.readline().strip()
        LOG.debug(f"Received `{log.truncate(raw_response, 400)}`")
        return raw_response


@dataclasses.dataclass(frozen=True)
class AsyncConnection:
    reader: connections.AsyncTextReader
    writer: connections.AsyncTextWriter

    async def _send_request_no_logging(
        self,
        request: str,
    ) -> str:
        await self.writer.write(f"{request}\n")
        return await self.reader.read_until(separator="\n")

    async def send_request(
        self,
        request: str,
    ) -> str:
        LOG.debug(f"Sending `{log.truncate(request, 400)}`")
        response = await self._send_request_no_logging(request)
        LOG.info(f"Received: `{log.truncate(response, 400).strip()}`")
        return response

    @staticmethod
    @contextlib.asynccontextmanager
    async def create(
        socket_path: Path,
    ) -> AsyncIterator[AsyncConnection]:
        async with connections.connect_async(socket_path) as (reader, writer):
            yield AsyncConnection(reader, writer)


async def send_async_raw_request(
    socket_path: Path,
    request: str,
) -> str:
    async with AsyncConnection.create(socket_path) as connection:
        return await connection.send_request(request)


async def attempt_send_async_raw_request(
    socket_path: Path,
    request: str,
) -> Union[DaemonConnectionFailure, str]:
    try:
        return await send_async_raw_request(
            socket_path,
            request,
        )
    except (
        connections.ConnectionFailure,
        asyncio.IncompleteReadError,
        ConnectionError,
    ) as error:
        return DaemonConnectionFailure(
            "Could not establish connection with an existing Pyre server "
            f"at {socket_path}: {error}"
        )
