# base_frame_processor.py
# 通用帧处理工作线程基类
# 统一异步POST、告警去重、抽帧控制等公共逻辑

import cv2
import base64
import time
import threading
import queue
import requests
from typing import Dict, Any, Callable
from concurrent.futures import ThreadPoolExecutor

from common.constants import ALERT_PUSH_URL
from utils.logger import get_logger

logger = get_logger(__name__)

# 告警推送频率限制（秒）
ALERT_PUSH_INTERVAL = 5.0


class BaseFrameProcessorWorker(threading.Thread):
    """
    通用帧处理工作线程基类
    
    功能：
    - 统一异步POST（线程池）
    - 统一告警去重逻辑
    - 统一抽帧控制
    - 统一异常处理
    
    子类仅需提供：
    - DETECTOR_FACTORY: 检测器工厂函数
    - POST_TYPE: POST请求的type值
    - TARGET_FPS: 目标帧率
    """
    
    # ========== 子类必须重写的类常量 ==========
    DETECTOR_FACTORY: Callable = None  # 检测器工厂函数
    POST_TYPE: int = 2                 # POST type
    TARGET_FPS: float = 10.0           # 目标帧率
    
    def __init__(self,
                 raw_queue: queue.Queue,
                 ws_queue: queue.Queue,
                 stop_event: threading.Event,
                 cameras=None,
                 post_workers: int = 4):
        super().__init__(daemon=True)
        self.raw_queue = raw_queue
        self.ws_queue = ws_queue
        self.stop_event = stop_event
        # 将摄像头列表转换为字典，key为id，方便通过camera_id快速查找
        self.cameras = {cam.id: cam for cam in cameras} if cameras is not None else {}
        
        self.last_ts: Dict[int, float] = {}
        
        # 检测器实例缓存
        self.detectors: Dict[int, Any] = {}
        
        # 告警去重记录 {camera_id: {action: last_push_time}}
        self.last_alert_push_time: Dict[int, Dict[str, float]] = {}
        
        # 异步POST线程池
        self.post_executor = ThreadPoolExecutor(
            max_workers=post_workers,
            thread_name_prefix="alert_post"
        )
    
    def _encode_image_to_base64(self, img) -> str:
        """图像编码为 Base64"""
        ok, buf = cv2.imencode(".jpg", img)
        if not ok:
            raise RuntimeError("Failed to encode image to JPEG")
        return base64.b64encode(buf.tobytes()).decode("ascii")
    
    def _post_alert(self, msg: dict):
        """异步发送告警 POST 请求（在线程池中执行）"""
        try:
            response = requests.post(ALERT_PUSH_URL, json=msg, timeout=5.0)
            if response.status_code == 200:
                print(f"[INFO] POST alert sent successfully for actions: {msg.get('result_type')}")
            else:
                print(f"[WARN] POST alert failed with status: {response.status_code}")
        except Exception as e:
            print(f"[ERROR] POST alert request failed: {e}")
    
    def _create_detector(self, params):
        """创建检测器实例"""
        # 使用 type(self) 访问类属性，避免 lambda 被绑定 self 参数
        factory = type(self).DETECTOR_FACTORY
        if factory is None:
            raise NotImplementedError("子类必须提供 DETECTOR_FACTORY")
        return factory(params)
    
    def _filter_duplicate_alerts(self, cam_id: int, alerts: list, current_time: float) -> list:
        """
        过滤5秒内重复的告警
        
        Args:
            cam_id: 摄像头ID
            alerts: 当前帧的告警列表
            current_time: 当前时间戳
            
        Returns:
            符合推送条件的action列表
        """
        if cam_id not in self.last_alert_push_time:
            self.last_alert_push_time[cam_id] = {}
        
        push_actions = []
        for alert in alerts:
            action = alert['action']
            last_push = self.last_alert_push_time[cam_id].get(action, 0)
            # 检查是否超过推送间隔
            if current_time - last_push >= ALERT_PUSH_INTERVAL:
                push_actions.append(action)
                # 更新该action的最后推送时间
                self.last_alert_push_time[cam_id][action] = current_time
        
        return push_actions
    
    def run(self):
        """主循环 - 模板方法"""
        target_interval = 1.0 / self.TARGET_FPS
        
        while not self.stop_event.is_set():
            try:
                item = self.raw_queue.get(timeout=0.5)
            except queue.Empty:
                continue

            try:
                cam_id = item["camera_id"]
                ts = item["timestamp"]
                frame = item["frame"]

                # 抽帧控制
                if ts - self.last_ts.get(cam_id, 0) < target_interval:
                    continue
                self.last_ts[cam_id] = ts

                # 获取或创建检测器实例
                if cam_id not in self.detectors:
                    camera_config = self.cameras.get(cam_id)
                    params = camera_config.params if camera_config else None
                    self.detectors[cam_id] = self._create_detector(params)
                detector = self.detectors[cam_id]

                # 执行检测
                result = detector.process_frame(frame.copy(), cam_id, ts)
                result_img = result["image"]
                result_alerts = result["alerts"]

                # 过滤重复告警
                push_actions = self._filter_duplicate_alerts(
                    cam_id, result_alerts, time.time()
                )

                # 编码图像
                try:
                    img_b64 = self._encode_image_to_base64(result_img)
                except Exception as e:
                    logger.error(f"[ERROR] Encode image failed: {e}")
                    img_b64 = None

                # 推送结果
                if img_b64 is not None:
                    msg = {
                        "msg_type": "frame",
                        "camera_id": item["camera_index"],
                        "timestamp": ts,
                        "result_type": push_actions,
                        "image_base64": img_b64,
                    }
                    try:
                        self.ws_queue.put(msg, timeout=1.0)
                        if push_actions and len(push_actions) > 0:
                            # 异步发送 POST 请求（提交到线程池）
                            post_msg = msg.copy()
                            post_msg['type'] = self.POST_TYPE
                            self.post_executor.submit(self._post_alert, post_msg)
                    except queue.Full:
                        logger.warning("[WARN] ws_send_queue full, drop frame message")

            except Exception as e:
                logger.error(
                    f"[ERROR] Frame processing failed for camera {cam_id if 'cam_id' in locals() else 'unknown'}: {e}")
                logger.exception("Exception details:")
            finally:
                self.raw_queue.task_done()

        # 线程退出时关闭线程池
        self.post_executor.shutdown(wait=False)