"""
双路流管理器

独立管理全景和球机两路视频流，每路使用独立线程和独立锁，
互不阻塞。提供统一帧获取接口、健康监控、自动重连。

关键改进：
- 两路流完全独立，一路卡住不影响另一路
- 每路有自己的锁（per-camera lock），不再用全局 FFmpeg 锁
- 超时读帧 + 自动重连 + 健康状态监控
- 帧新鲜度追踪：确保读到的是最近帧而非缓冲区中的旧帧
"""

import os
os.environ['OPENCV_FFMPEG_CAPTURE_OPTIONS'] = 'threads;1'

import cv2
import threading
import time
import queue
import logging
from typing import Optional, Dict, Tuple, Callable
from dataclasses import dataclass, field

from video_lock import safe_read, safe_is_opened, get_stream_health, CameraLockManager

logger = logging.getLogger(__name__)


@dataclass
class StreamConfig:
    """流配置"""
    camera_id: str
    rtsp_url: str
    camera_type: str = "panorama"  # "panorama" 或 "ptz"
    buffer_size: int = 2            # 帧缓冲大小（保持低延迟）
    reconnect_interval: float = 5.0  # 重连间隔(秒)
    max_consecutive_errors: int = 50 # 最大连续错误数
    read_timeout: float = 2.0       # 读帧超时(秒)
    fps_target: float = 25.0        # 目标帧率


@dataclass
class StreamStatus:
    """流状态"""
    is_running: bool = False
    is_connected: bool = False
    consecutive_errors: int = 0
    total_frames: int = 0
    total_errors: int = 0
    last_frame_time: float = 0.0
    avg_read_time_ms: float = 0.0
    reconnect_count: int = 0
    fps_actual: float = 0.0


class StreamWorker:
    """单路视频流工作线程"""
    
    def __init__(self, config: StreamConfig):
        self.config = config
        self._cap = None
        self._current_frame = None
        self._frame_lock = threading.Lock()
        self._frame_queue = queue.Queue(maxsize=config.buffer_size)
        self._running = False
        self._thread = None
        self._status = StreamStatus()
        self._status_lock = threading.Lock()
        self._last_fps_time = time.time()
        self._fps_frame_count = 0
    
    @property
    def status(self) -> StreamStatus:
        with self._status_lock:
            return StreamStatus(
                is_running=self._status.is_running,
                is_connected=self._status.is_connected,
                consecutive_errors=self._status.consecutive_errors,
                total_frames=self._status.total_frames,
                total_errors=self._status.total_errors,
                last_frame_time=self._status.last_frame_time,
                avg_read_time_ms=self._status.avg_read_time_ms,
                reconnect_count=self._status.reconnect_count,
                fps_actual=self._status.fps_actual
            )
    
    def start(self) -> bool:
        """启动视频流"""
        if self._running:
            logger.warning(f"[{self.config.camera_id}] 流已在运行")
            return True
        
        if not self._connect():
            logger.error(f"[{self.config.camera_id}] 初始连接失败")
            # 不返回False，启动重连线程
            self._status.is_running = True
            self._status.is_connected = False
        else:
            self._status.is_running = True
            self._status.is_connected = True
        
        self._running = True
        self._thread = threading.Thread(target=self._stream_loop, daemon=True)
        self._thread.start()
        logger.info(f"[{self.config.camera_id}] 流工作线程已启动")
        return True
    
    def stop(self):
        """停止视频流"""
        self._running = False
        if self._thread:
            self._thread.join(timeout=3)
            self._thread = None
        
        if self._cap is not None:
            try:
                self._cap.release()
            except Exception:
                pass
            self._cap = None
        
        with self._status_lock:
            self._status.is_running = False
            self._status.is_connected = False
        
        logger.info(f"[{self.config.camera_id}] 流已停止")
    
    def get_frame(self) -> Optional[cv2.Mat]:
        """获取最新帧（线程安全副本）"""
        with self._frame_lock:
            if self._current_frame is not None:
                return self._current_frame.copy()
            return None
    
    def get_frame_from_queue(self, timeout: float = 0.1) -> Optional[cv2.Mat]:
        """从帧队列获取帧"""
        try:
            return self._frame_queue.get(timeout=timeout)
        except queue.Empty:
            return None
    
    def _connect(self) -> bool:
        """建立RTSP连接"""
        if self._cap is not None:
            try:
                self._cap.release()
            except Exception:
                pass
            self._cap = None
        
        try:
            self._cap = cv2.VideoCapture(self.config.rtsp_url, cv2.CAP_FFMPEG)
            if not self._cap.isOpened():
                # 尝试 GStreamer 后端
                try:
                    self._cap = cv2.VideoCapture(self.config.rtsp_url, cv2.CAP_GSTREAMER)
                    if self._cap.isOpened():
                        logger.info(f"[{self.config.camera_id}] 使用 GStreamer 后端连接成功")
                        self._cap.set(cv2.CAP_PROP_BUFFERSIZE, 1)
                        return True
                except Exception:
                    pass
                
                logger.error(f"[{self.config.camera_id}] 无法打开RTSP流")
                self._cap = None
                return False
            
            self._cap.set(cv2.CAP_PROP_BUFFERSIZE, 1)
            logger.info(f"[{self.config.camera_id}] RTSP流连接成功")
            return True
            
        except Exception as e:
            logger.error(f"[{self.config.camera_id}] 连接异常: {e}")
            self._cap = None
            return False
    
    def _stream_loop(self):
        """流工作主循环"""
        import signal
        if hasattr(signal, 'pthread_sigmask'):
            try:
                signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGINT})
            except (AttributeError, OSError):
                pass
        
        logger.info(f"[{self.config.camera_id}] 流循环开始")
        
        while self._running:
            try:
                # 如果未连接，尝试重连
                if self._cap is None or not safe_is_opened(self._cap, self.config.camera_id):
                    self._reconnect()
                    continue
                
                # 读帧（使用独立锁+超时）
                start_time = time.time()
                ret, frame = safe_read(self._cap, self.config.camera_id, self.config.read_timeout)
                
                if not ret or frame is None:
                    self._on_read_error()
                    continue
                
                self._on_read_success(frame, start_time)
                
            except Exception as e:
                err_str = str(e)
                if 'async_lock' in err_str or 'Assertion' in err_str:
                    logger.warning(f"[{self.config.camera_id}] FFmpeg内部错误，重建连接: {e}")
                    self._reconnect()
                else:
                    logger.error(f"[{self.config.camera_id}] 流错误: {e}")
                    time.sleep(0.5)
    
    def _on_read_success(self, frame, start_time: float):
        """读帧成功处理"""
        read_time_ms = (time.time() - start_time) * 1000
        
        with self._frame_lock:
            self._current_frame = frame.copy()
        
        # 非阻塞写入帧队列，满则丢弃旧帧
        try:
            # 先清空队列确保只保留最新帧
            while not self._frame_queue.empty():
                try:
                    self._frame_queue.get_nowait()
                except queue.Empty:
                    break
            self._frame_queue.put(frame.copy(), block=False)
        except queue.Full:
            pass
        
        with self._status_lock:
            self._status.consecutive_errors = 0
            self._status.total_frames += 1
            self._status.last_frame_time = time.time()
            self._status.is_connected = True
            alpha = 0.1
            self._status.avg_read_time_ms = alpha * read_time_ms + (1 - alpha) * self._status.avg_read_time_ms
            
            # FPS 计算
            self._fps_frame_count += 1
            elapsed = time.time() - self._last_fps_time
            if elapsed >= 1.0:
                self._status.fps_actual = self._fps_frame_count / elapsed
                self._fps_frame_count = 0
                self._last_fps_time = time.time()
    
    def _on_read_error(self):
        """读帧错误处理"""
        with self._status_lock:
            self._status.consecutive_errors += 1
            self._status.total_errors += 1
            
            if self._status.consecutive_errors > self.config.max_consecutive_errors:
                logger.warning(f"[{self.config.camera_id}] 连续{self._status.consecutive_errors}次读帧失败，触发重连")
        
        time.sleep(0.01)
    
    def _reconnect(self):
        """重连"""
        with self._status_lock:
            self._status.reconnect_count += 1
            self._status.is_connected = False
        
        logger.info(f"[{self.config.camera_id}] 尝试重连...")
        
        if self._cap is not None:
            try:
                self._cap.release()
            except Exception:
                pass
            self._cap = None
        
        time.sleep(self.config.reconnect_interval)
        
        if self._connect():
            logger.info(f"[{self.config.camera_id}] 重连成功")
        else:
            logger.warning(f"[{self.config.camera_id}] 重连失败，{self.config.reconnect_interval}秒后重试")
    
    @property
    def is_healthy(self) -> bool:
        """流是否健康"""
        s = self.status
        if not s.is_running:
            return False
        if s.consecutive_errors > 10:
            return False
        if s.last_frame_time > 0 and (time.time() - s.last_frame_time) > 5.0:
            return False
        return True


class DualStreamManager:
    """
    双路流管理器
    
    管理全景和球机两路视频流，提供统一的帧获取接口。
    每路流使用独立线程和独立锁，互不阻塞。
    """
    
    PANORAMA_ID = "panorama"
    PTZ_ID = "ptz"
    
    def __init__(self):
        self._workers: Dict[str, StreamWorker] = {}
        self._running = False
    
    def add_stream(self, config: StreamConfig) -> StreamWorker:
        """添加一路视频流"""
        if config.camera_id in self._workers:
            logger.warning(f"流 {config.camera_id} 已存在，将先停止")
            self._workers[config.camera_id].stop()
        
        worker = StreamWorker(config)
        self._workers[config.camera_id] = worker
        return worker
    
    def start_stream(self, camera_id: str) -> bool:
        """启动指定流"""
        if camera_id not in self._workers:
            logger.error(f"流 {camera_id} 未注册")
            return False
        return self._workers[camera_id].start()
    
    def stop_stream(self, camera_id: str):
        """停止指定流"""
        if camera_id in self._workers:
            self._workers[camera_id].stop()
    
    def start_all(self) -> bool:
        """启动所有流"""
        success = True
        for camera_id, worker in self._workers.items():
            if not worker.start():
                logger.error(f"启动流 {camera_id} 失败")
                success = False
            else:
                logger.info(f"流 {camera_id} 启动中...")
        self._running = True
        return success
    
    def stop_all(self):
        """停止所有流"""
        for camera_id, worker in self._workers.items():
            worker.stop()
        self._running = False
    
    def get_frame(self, camera_id: str) -> Optional[cv2.Mat]:
        """获取指定摄像头的最新帧"""
        if camera_id not in self._workers:
            return None
        return self._workers[camera_id].get_frame()
    
    def get_panorama_frame(self) -> Optional[cv2.Mat]:
        """获取全景摄像头最新帧"""
        return self.get_frame(self.PANORAMA_ID)
    
    def get_ptz_frame(self) -> Optional[cv2.Mat]:
        """获取球机最新帧"""
        return self.get_frame(self.PTZ_ID)
    
    def get_status(self, camera_id: str) -> Optional[StreamStatus]:
        """获取指定流的状态"""
        if camera_id not in self._workers:
            return None
        return self._workers[camera_id].status
    
    def get_all_status(self) -> Dict[str, StreamStatus]:
        """获取所有流的状态"""
        return {cid: w.status for cid, w in self._workers.items()}
    
    def is_healthy(self, camera_id: str) -> bool:
        """检查指定流是否健康"""
        if camera_id not in self._workers:
            return False
        return self._workers[camera_id].is_healthy
    
    def wait_for_frames(self, timeout: float = 15.0) -> Dict[str, bool]:
        """
        等待所有流就绪（获取到至少一帧）
        
        Returns:
            Dict[camera_id, 是否有帧]
        """
        start_time = time.time()
        ready = {cid: False for cid in self._workers}
        
        while time.time() - start_time < timeout:
            all_ready = True
            for cid in self._workers:
                if not ready[cid]:
                    frame = self.get_frame(cid)
                    if frame is not None:
                        ready[cid] = True
                        logger.info(f"[{cid}] 帧就绪 ({frame.shape})")
                if not ready[cid]:
                    all_ready = False
            
            if all_ready:
                break
            
            time.sleep(0.5)
        
        for cid, r in ready.items():
            if not r:
                logger.warning(f"[{cid}] 等待帧超时({timeout}s)")
        
        return ready
    
    def get_stream_health(self, camera_id: str):
        """获取流健康详情（来自video_lock模块）"""
        return get_stream_health(camera_id)
    
    @property
    def panorama_worker(self) -> Optional[StreamWorker]:
        """获取全景流工作线程"""
        return self._workers.get(self.PANORAMA_ID)
    
    @property
    def ptz_worker(self) -> Optional[StreamWorker]:
        """获取球机流工作线程"""
        return self._workers.get(self.PTZ_ID)
    
    @staticmethod
    def build_rtsp_url(config: dict) -> str:
        """从配置构建RTSP URL"""
        if 'rtsp_url' in config and config['rtsp_url']:
            return config['rtsp_url']
        
        channel = config.get('channel', 0)
        return (f"rtsp://{config['username']}:{config['password']}"
                f"@{config['ip']}:{config.get('rtsp_port', 554)}"
                f"/cam/realmonitor?channel={channel + 1}&subtype=1")


def create_dual_stream_manager(panorama_config: dict, ptz_config: dict) -> DualStreamManager:
    """
    便捷函数：根据摄像头配置创建双路流管理器
    
    Args:
        panorama_config: 全景摄像头配置
        ptz_config: 球机配置
    
    Returns:
        已配置的 DualStreamManager 实例
    """
    manager = DualStreamManager()
    
    pan_rtsp = DualStreamManager.build_rtsp_url(panorama_config)
    ptz_rtsp = DualStreamManager.build_rtsp_url(ptz_config)
    
    manager.add_stream(StreamConfig(
        camera_id=DualStreamManager.PANORAMA_ID,
        rtsp_url=pan_rtsp,
        camera_type="panorama"
    ))
    
    manager.add_stream(StreamConfig(
        camera_id=DualStreamManager.PTZ_ID,
        rtsp_url=ptz_rtsp,
        camera_type="ptz"
    ))
    
    return manager