"""ZMQ клиент к FFmpeg's `zmq` filter.

FFmpeg zmq filter принимает строки формата:
    `target command [args]`

Например для cuda_grid в filter graph:
    `cuda_grid@livingroom_tv set_layout quad`

См. https://ffmpeg.org/ffmpeg-filters.html#zmq_002c-azmq
"""

from __future__ import annotations

import structlog
import zmq
import zmq.asyncio

log = structlog.get_logger()


class FFmpegZmqClient:
    """REQ-socket к FFmpeg zmq filter. Один client = один FFmpeg pipeline."""

    def __init__(self, endpoint: str, request_timeout_ms: int = 2000) -> None:
        self.endpoint = endpoint
        self.request_timeout_ms = request_timeout_ms
        self._ctx = zmq.asyncio.Context.instance()
        self._sock: zmq.asyncio.Socket | None = None

    async def connect(self) -> None:
        if self._sock is not None:
            return
        self._sock = self._ctx.socket(zmq.REQ)
        self._sock.setsockopt(zmq.LINGER, 0)
        self._sock.setsockopt(zmq.RCVTIMEO, self.request_timeout_ms)
        self._sock.setsockopt(zmq.SNDTIMEO, self.request_timeout_ms)
        self._sock.connect(self.endpoint)
        log.info("zmq.connected", endpoint=self.endpoint)

    async def send_command(self, target: str, command: str, args: str | None = None) -> str:
        """Отправить команду filter'у. Возвращает ответ от ffmpeg ('0 Success' / error string)."""
        if self._sock is None:
            await self.connect()
        assert self._sock is not None

        cmd_str = f"{target} {command}"
        if args:
            cmd_str = f"{cmd_str} {args}"

        log.debug("zmq.send", endpoint=self.endpoint, cmd=cmd_str)
        try:
            await self._sock.send_string(cmd_str)
            reply = await self._sock.recv_string()
            log.debug("zmq.reply", reply=reply)
            return reply
        except zmq.error.Again:
            log.warning("zmq.timeout", endpoint=self.endpoint, cmd=cmd_str)
            # Reset REQ socket state — после timeout REQ нельзя re-use
            self._sock.close(linger=0)
            self._sock = None
            raise TimeoutError(f"zmq command timeout: {cmd_str}")

    async def close(self) -> None:
        if self._sock is not None:
            self._sock.close(linger=0)
            self._sock = None