#!/usr/bin/env python3

from abc import abstractmethod
import time
import argparse
import asyncio
import contextlib
import json
import uuid
import logging
from dataclasses import dataclass, field
from typing import Any, TYPE_CHECKING

# aiortc and its dependencies have lots of internal warnings :(
import warnings
warnings.filterwarnings("ignore", category=DeprecationWarning)
warnings.filterwarnings("ignore", category=RuntimeWarning) # TODO: remove this when google-crc32c publish a python3.12 wheel

import capnp
from aiohttp import web
if TYPE_CHECKING:
  from aiortc.rtcdatachannel import RTCDataChannel

from openpilot.system.webrtc.schema import generate_field
from cereal import messaging, log


class AsyncTaskRunner:
  def __init__(self):
    self.is_running = False
    self.task = None
    self.logger = logging.getLogger("webrtcd")

  def start(self):
    assert self.task is None
    self.task = asyncio.create_task(self.run())

  async def stop(self):
    if self.task is None:
      return
    task = self.task
    self.task = None
    if task.done():
      return
    task.cancel()
    with contextlib.suppress(asyncio.CancelledError):
      await task

  @abstractmethod
  async def run(self):
    pass


class CerealOutgoingMessageProxy(AsyncTaskRunner):
  def __init__(self, sm: messaging.SubMaster):
    super().__init__()
    self.sm = sm
    self.channels: list[RTCDataChannel] = []

  def add_channel(self, channel: 'RTCDataChannel'):
    self.channels.append(channel)

  def to_json(self, msg_content: Any):
    if isinstance(msg_content, capnp._DynamicStructReader):
      msg_dict = msg_content.to_dict()
    elif isinstance(msg_content, capnp._DynamicListReader):
      msg_dict = [self.to_json(msg) for msg in msg_content]
    elif isinstance(msg_content, bytes):
      msg_dict = msg_content.decode()
    else:
      msg_dict = msg_content

    return msg_dict

  def update(self):
    # this is blocking in async context...
    self.sm.update(0)
    for service, updated in self.sm.updated.items():
      if not updated:
        continue
      msg_dict = self.to_json(self.sm[service])
      mono_time, valid = self.sm.logMonoTime[service], self.sm.valid[service]
      outgoing_msg = {"type": service, "logMonoTime": mono_time, "valid": valid, "data": msg_dict}
      encoded_msg = json.dumps(outgoing_msg).encode()
      for channel in self.channels:
        channel.send(encoded_msg)

  async def run(self):
    from aiortc.exceptions import InvalidStateError

    while True:
      try:
        self.update()
      except InvalidStateError:
        self.logger.warning("Cereal outgoing proxy invalid state (connection closed)")
        break
      except Exception:
        self.logger.exception("Cereal outgoing proxy failure")
      await asyncio.sleep(0.01)


class CerealIncomingMessageProxy:
  def __init__(self, pm: messaging.PubMaster):
    self.pm = pm

  def send(self, message: bytes):
    msg_json = json.loads(message)
    msg_type, msg_data = msg_json["type"], msg_json["data"]
    size = None
    if not isinstance(msg_data, dict):
      size = len(msg_data)

    msg = messaging.new_message(msg_type, size=size)
    setattr(msg, msg_type, msg_data)
    self.pm.send(msg_type, msg)


class DynamicPubMaster(messaging.PubMaster):
  def __init__(self, *args, **kwargs):
    super().__init__(*args, **kwargs)
    self.lock = asyncio.Lock()

  async def add_services_if_needed(self, services):
    async with self.lock:
      for service in services:
        if service not in self.sock:
          self.sock[service] = messaging.pub_sock(service)


class StreamSession:
  shared_pub_master = DynamicPubMaster([])

  def __init__(self, sdp: str, init_camera: str, incoming_services: list[str], outgoing_services: list[str], debug_mode: bool = False):
    from aiortc.mediastreams import VideoStreamTrack
    from openpilot.system.webrtc.device.video import LiveStreamVideoStreamTrack
    from teleoprtc import WebRTCAnswerBuilder

    builder = WebRTCAnswerBuilder(sdp)

    self.video_track = LiveStreamVideoStreamTrack(init_camera) if not debug_mode else VideoStreamTrack()
    builder.add_video_stream(init_camera, self.video_track)

    self.stream = builder.stream()
    self.identifier = str(uuid.uuid4())

    self.incoming_bridge: CerealIncomingMessageProxy | None = None
    self.incoming_bridge_services = incoming_services
    self.outgoing_bridge: CerealOutgoingMessageProxy | None = None
    if len(incoming_services) > 0:
      self.incoming_bridge = CerealIncomingMessageProxy(self.shared_pub_master)
    if len(outgoing_services) > 0:
      self.outgoing_bridge = CerealOutgoingMessageProxy(messaging.SubMaster(outgoing_services))

    self.run_task: asyncio.Task | None = None
    self._cleanup_lock = asyncio.Lock()
    self._cleanup_done = False
    self.logger = logging.getLogger("webrtcd")
    self.logger.info(
      "New stream session (%s), init camera %s, incoming services %s, outgoing services %s",
      self.identifier, init_camera, incoming_services, outgoing_services,
    )

  def start(self):
    self.run_task = asyncio.create_task(self.run())

  async def stop(self):
    if self.run_task is not None and not self.run_task.done() and self.run_task is not asyncio.current_task():
      self.run_task.cancel()
      with contextlib.suppress(asyncio.CancelledError):
        await self.run_task
    self.run_task = None
    await self.post_run_cleanup()

  async def get_answer(self):
    return await self.stream.start()

  def message_handler(self, message: bytes):
    assert self.incoming_bridge is not None
    try:
      payload = json.loads(message) if isinstance(message, (bytes, str)) else None
      if isinstance(payload, dict):
        msg_type = payload.get("type")

        if msg_type == "livestreamCameraSwitch":
          self.video_track.switch_camera(payload["data"]["camera"])
          return

        if msg_type == "clockSync":
          data = payload.get("data", {})
          pong = json.dumps({"type": "clockSync", "data": {
            "action": "pong", "browserSendTime": data.get("browserSendTime"), "deviceTime": time.time() * 1000, # noqa: TID251
          }})
          self.stream.get_messaging_channel().send(pong)
          return

        if msg_type == "enableTimingSei":
          enabled = bool(payload.get("data", {}).get("enabled"))
          if hasattr(self.video_track, 'timing_sei_enabled'):
            self.video_track.timing_sei_enabled = enabled
          return

      if payload.get("type") not in self.incoming_bridge_services:
        return
      self.incoming_bridge.send(message)
    except Exception:
      self.logger.exception("Cereal incoming proxy failure")

  async def run(self):
    try:
      await self.stream.wait_for_connection()
      if self.stream.has_messaging_channel():
        if self.incoming_bridge is not None:
          await self.shared_pub_master.add_services_if_needed(self.incoming_bridge_services)
          self.stream.set_message_handler(self.message_handler)
        if self.outgoing_bridge is not None:
          channel = self.stream.get_messaging_channel()
          self.outgoing_bridge.add_channel(channel)
          self.outgoing_bridge.start()
      self.logger.info("Stream session (%s) connected", self.identifier)

      await self.stream.wait_for_disconnection()

      self.logger.info("Stream session (%s) ended", self.identifier)
    except Exception:
      self.logger.exception("Stream session failure")
    finally:
      await self.post_run_cleanup()

  async def post_run_cleanup(self):
    async with self._cleanup_lock:
      if self._cleanup_done:
        return
      self._cleanup_done = True
      if self.outgoing_bridge is not None:
        await self.outgoing_bridge.stop()
      await self.stream.stop()


@dataclass
class StreamRequestBody:
  sdp: str
  initCamera: str
  bridge_services_in: list[str] = field(default_factory=list)
  bridge_services_out: list[str] = field(default_factory=list)


async def get_stream(request: 'web.Request'):
  stream_dict, debug_mode = request.app['streams'], request.app['debug']
  raw_body = await request.json()
  body = StreamRequestBody(**raw_body)

  async with request.app['stream_lock']:
    # Fully disconnect any other active stream before starting the replacement.
    for sid, s in list(stream_dict.items()):
      if s.run_task and not s.run_task.done():
        try:
          ch = s.stream.get_messaging_channel()
          ch.send(json.dumps({"type": "connectionReplaced", "data": "Another device has connected, closing this session."}))
        except Exception:
          pass
      await s.stop()
      del stream_dict[sid]

    session = StreamSession(body.sdp, body.initCamera, body.bridge_services_in, body.bridge_services_out, debug_mode)
    try:
      answer = await session.get_answer()
    except ValueError as e:
      await session.stop()
      raise web.HTTPBadRequest(
        text=json.dumps({"error": "invalid_sdp", "message": str(e)}),
        content_type="application/json",
      ) from e
    except Exception:
      await session.stop()
      raise
    session.start()

    stream_dict[session.identifier] = session

  return web.json_response({"sdp": answer.sdp, "type": answer.type})


async def get_schema(request: 'web.Request'):
  services = request.query["services"].split(",")
  services = [s for s in services if s]
  assert all(s in log.Event.schema.fields and not s.endswith("DEPRECATED") for s in services), "Invalid service name"
  schema_dict = {s: generate_field(log.Event.schema.fields[s]) for s in services}
  return web.json_response(schema_dict)


async def post_notify(request: 'web.Request'):
  try:
    payload = await request.json()
  except Exception as e:
    raise web.HTTPBadRequest(text="Invalid JSON") from e

  for session in list(request.app.get('streams', {}).values()):
    try:
      ch = session.stream.get_messaging_channel()
      ch.send(json.dumps(payload))
    except Exception:
      continue

  return web.Response(status=200, text="OK")


async def on_shutdown(app: 'web.Application'):
  for session in app['streams'].values():
    await session.stop()
  del app['streams']


def webrtcd_thread(host: str, port: int, debug: bool):
  logging.basicConfig(level=logging.CRITICAL, handlers=[logging.StreamHandler()])
  logging_level = logging.DEBUG if debug else logging.INFO
  logging.getLogger("WebRTCStream").setLevel(logging_level)
  logging.getLogger("webrtcd").setLevel(logging_level)

  app = web.Application()

  app['streams'] = dict()
  app['stream_lock'] = asyncio.Lock()
  app['debug'] = debug
  app.on_shutdown.append(on_shutdown)
  app.router.add_post("/stream", get_stream)
  app.router.add_post("/notify", post_notify)
  app.router.add_get("/schema", get_schema)

  web.run_app(app, host=host, port=port)


def main():
  parser = argparse.ArgumentParser(description="WebRTC daemon")
  parser.add_argument("--host", type=str, default="0.0.0.0", help="Host to listen on")
  parser.add_argument("--port", type=int, default=5001, help="Port to listen on")
  parser.add_argument("--debug", action="store_true", help="Enable debug mode")
  args = parser.parse_args()

  webrtcd_thread(args.host, args.port, args.debug)


if __name__=="__main__":
  main()