"""
告警上报 Worker

独立线程运行，从 Redis 队列消费告警：
1. BRPOP 取待上报告警
2. 上传截图到腾讯云 COS
3. HTTP POST 上报告警元数据到云端
4. 失败重试 / 死信队列

Redis Key 设计：
  local:alarm:pending  - 待上报告警队列
  local:alarm:retry    - 重试告警队列
  local:alarm:dead     - 死信告警队列
"""

import json
import logging
import threading
import time
from datetime import datetime, timezone
from typing import Any, Dict, Optional

import redis
import requests

from config.settings import get_settings
from core.result_reporter import (
    REDIS_KEY_ALARM_PENDING,
    REDIS_KEY_ALARM_RETRY,
    REDIS_KEY_ALARM_DEAD,
)

logger = logging.getLogger(__name__)


class AlarmUploadWorker:
    """告警上报 Worker

    在独立线程中运行，从本地 Redis 消费告警数据，
    上传截图到 COS，再 HTTP 上报告警元数据到云端。
    """

    def __init__(self):
        self._settings = get_settings()
        self._logger = logging.getLogger("alarm_upload_worker")

        self._redis: Optional[redis.Redis] = None
        self._cos_client = None  # 懒初始化

        self._thread: Optional[threading.Thread] = None
        self._stop_event = threading.Event()

        self._stats = {
            "processed": 0,
            "cos_uploaded": 0,
            "http_reported": 0,
            "retried": 0,
            "dead_lettered": 0,
            "errors": 0,
        }

    def start(self):
        """启动 worker 线程"""
        if self._thread and self._thread.is_alive():
            self._logger.warning("AlarmUploadWorker 已在运行")
            return

        # 初始化 Redis 连接
        redis_cfg = self._settings.local_redis
        try:
            self._redis = redis.Redis(
                host=redis_cfg.host,
                port=redis_cfg.port,
                db=redis_cfg.db,
                password=redis_cfg.password,
                decode_responses=True,
                socket_connect_timeout=5,
            )
            self._redis.ping()
            self._logger.info(f"Worker Redis 连接成功: {redis_cfg.host}:{redis_cfg.port}/{redis_cfg.db}")
        except Exception as e:
            self._logger.error(f"Worker Redis 连接失败: {e}")
            return

        # 启动时验证云端 API 可达性
        self._check_cloud_api()

        self._stop_event.clear()
        self._thread = threading.Thread(
            target=self._worker_loop,
            name="AlarmUploadWorker",
            daemon=True,
        )
        self._thread.start()
        self._logger.info("AlarmUploadWorker 已启动")

    def _check_cloud_api(self):
        """启动时检查云端 API 是否可达（仅记录日志，不阻断启动）"""
        upload_cfg = self._settings.alarm_upload
        base_url = upload_cfg.cloud_api_url.rstrip("/")
        health_url = f"{base_url}/health"
        report_url = f"{base_url}/api/ai/alert/edge/report"

        self._logger.info(f"云端 API 地址: {base_url}")
        self._logger.info(f"告警上报端点: {report_url}")

        try:
            resp = requests.get(health_url, timeout=5)
            if resp.status_code == 200:
                self._logger.info(f"云端健康检查通过: {health_url}")
            else:
                self._logger.warning(
                    f"云端健康检查异常: {health_url}, status={resp.status_code}"
                )
        except requests.ConnectionError:
            self._logger.warning(f"云端不可达: {health_url}，请确认服务已启动")
        except Exception as e:
            self._logger.warning(f"云端健康检查失败: {e}")

    def stop(self):
        """停止 worker"""
        if not self._thread or not self._thread.is_alive():
            return

        self._logger.info("正在停止 AlarmUploadWorker...")
        self._stop_event.set()

        # 等待线程退出（BRPOP 有超时，所以不会永远阻塞）
        self._thread.join(timeout=10)

        if self._redis:
            try:
                self._redis.close()
            except Exception:
                pass

        self._logger.info("AlarmUploadWorker 已停止")

    def _worker_loop(self):
        """主循环：消费待上报告警"""
        self._logger.info("Worker 主循环开始")

        while not self._stop_event.is_set():
            try:
                # 先检查重试队列
                self._process_retry_queue()

                # BRPOP 阻塞等待新告警（超时 2 秒，便于检查 stop 信号）
                result = self._redis.brpop(REDIS_KEY_ALARM_PENDING, timeout=2)
                if result is None:
                    continue

                _, alarm_json = result
                self._process_alarm(alarm_json)

            except redis.ConnectionError as e:
                self._logger.error(f"Redis 连接断开: {e}")
                time.sleep(5)
                self._reconnect_redis()
            except Exception as e:
                self._logger.error(f"Worker 主循环异常: {e}")
                self._stats["errors"] += 1
                time.sleep(1)

        self._logger.info("Worker 主循环退出")

    def _process_alarm(self, alarm_json: str):
        """处理单条告警"""
        try:
            alarm_data = json.loads(alarm_json)
        except json.JSONDecodeError as e:
            self._logger.error(f"告警 JSON 解析失败: {e}")
            return

        # 如果是 resolve 事件，走单独的处理逻辑
        if alarm_data.get("_type") == "resolve":
            self._process_resolve(alarm_data)
            return

        alarm_id = alarm_data.get("alarm_id", "unknown")
        retry_count = alarm_data.get("_retry_count", 0)

        self._logger.info(f"开始处理告警: {alarm_id} (retry={retry_count})")

        # Step 1: 上传截图到 COS（从 base64 解码后直接上传字节流）
        snapshot_b64 = alarm_data.get("snapshot_b64")
        object_key = None

        if snapshot_b64:
            try:
                import base64
                image_bytes = base64.b64decode(snapshot_b64)
                object_key = self._upload_snapshot_to_cos(
                    image_bytes,
                    alarm_id,
                    alarm_data.get("device_id", "unknown"),
                )
                if object_key is None:
                    # COS 上传失败，进入重试
                    self._handle_retry(alarm_json, "COS 上传失败")
                    return
            except Exception as e:
                self._logger.error(f"截图解码/上传失败: {e}")
                self._handle_retry(alarm_json, f"截图处理失败: {e}")
                return

        # Step 2: HTTP 上报告警元数据（不含截图二进制数据）
        report_data = {
            "alarm_id": alarm_data.get("alarm_id"),
            "alarm_type": alarm_data.get("alarm_type"),
            "device_id": alarm_data.get("device_id"),
            "scene_id": alarm_data.get("scene_id"),
            "event_time": alarm_data.get("event_time"),
            "alarm_level": alarm_data.get("alarm_level"),
            "snapshot_url": object_key or "",  # COS object_key
            "algorithm_code": alarm_data.get("algorithm_code"),
            "confidence_score": alarm_data.get("confidence_score"),
            "ext_data": alarm_data.get("ext_data", {}),
        }

        success = self._report_alarm_http(report_data)

        if success:
            self._stats["processed"] += 1
            self._logger.info(f"告警上报成功: {alarm_id}")
        else:
            # HTTP 上报失败，进入重试
            self._handle_retry(alarm_json, "HTTP 上报失败")

    def _process_resolve(self, resolve_data: dict):
        """处理告警结束事件 - HTTP POST 到云端"""
        upload_cfg = self._settings.alarm_upload
        base_url = upload_cfg.cloud_api_url.rstrip("/")
        url = f"{base_url}/api/ai/alert/edge/resolve"

        headers = {"Content-Type": "application/json"}
        if upload_cfg.edge_token:
            headers["Authorization"] = f"Bearer {upload_cfg.edge_token}"

        payload = {
            "alarm_id": resolve_data.get("alarm_id"),
            "duration_ms": resolve_data.get("duration_ms"),
            "last_frame_time": resolve_data.get("last_frame_time"),
            "resolve_type": resolve_data.get("resolve_type"),
        }

        try:
            response = requests.post(url, json=payload, headers=headers, timeout=10)
            if response.status_code == 200:
                body = response.json()
                if body.get("code") == 0:
                    self._logger.info(f"告警结束上报成功: {resolve_data.get('alarm_id')}")
                else:
                    self._logger.warning(f"告警结束上报业务错误: {body}")
            else:
                self._logger.warning(f"告警结束上报失败: status={response.status_code}")
        except Exception as e:
            self._logger.warning(f"告警结束上报异常: {e}")

    def _upload_snapshot_to_cos(
        self, image_bytes: bytes, alarm_id: str, device_id: str
    ) -> Optional[str]:
        """
        上传截图到腾讯云 COS（直接从内存字节流上传）

        Args:
            image_bytes: JPEG 图片字节
            alarm_id: 告警ID
            device_id: 设备ID

        Returns:
            COS object_key，失败返回 None
        """
        cos_cfg = self._settings.cos
        if not cos_cfg.secret_id or not cos_cfg.bucket:
            self._logger.error("COS 未配置（缺少 secret_id 或 bucket），无法上传截图")
            return None

        # 懒初始化 COS 客户端
        if self._cos_client is None:
            try:
                from qcloud_cos import CosConfig, CosS3Client

                config = CosConfig(
                    Region=cos_cfg.region,
                    SecretId=cos_cfg.secret_id,
                    SecretKey=cos_cfg.secret_key,
                    Scheme="https",
                )
                self._cos_client = CosS3Client(config)
                self._logger.info(f"COS 客户端初始化成功: bucket={cos_cfg.bucket}")
            except Exception as e:
                self._logger.error(f"COS 客户端初始化失败: {e}")
                return None

        # 生成 Object Key: alarms/{device_id}/{yyyy-MM-dd}/{alarm_id}.jpg
        date_str = datetime.now(timezone.utc).strftime("%Y-%m-%d")
        object_key = f"alarms/{device_id}/{date_str}/{alarm_id}.jpg"

        try:
            self._cos_client.put_object(
                Bucket=cos_cfg.bucket,
                Body=image_bytes,
                Key=object_key,
                ContentType="image/jpeg",
            )
            self._stats["cos_uploaded"] += 1
            self._logger.info(f"COS 上传成功: {object_key}")
            return object_key

        except Exception as e:
            self._logger.error(f"COS 上传失败: {e}")
            return None

    def _report_alarm_http(self, alarm_data: Dict[str, Any]) -> bool:
        """
        HTTP POST 上报告警元数据到云端

        Args:
            alarm_data: 告警元数据

        Returns:
            是否上报成功
        """
        upload_cfg = self._settings.alarm_upload
        base_url = upload_cfg.cloud_api_url.rstrip("/")
        url = f"{base_url}/api/ai/alert/edge/report"

        headers = {
            "Content-Type": "application/json",
        }
        if upload_cfg.edge_token:
            headers["Authorization"] = f"Bearer {upload_cfg.edge_token}"

        # 过滤掉内部字段（以 _ 开头的控制字段不发送到云端）
        report_data = {k: v for k, v in alarm_data.items() if not k.startswith("_")}

        self._logger.debug(f"HTTP 上报 URL: {url}")
        self._logger.debug(f"HTTP 上报数据: {report_data}")

        try:
            response = requests.post(
                url,
                json=report_data,
                headers=headers,
                timeout=10,
            )

            if response.status_code == 200:
                body = response.json()
                if body.get("code") == 0:
                    self._stats["http_reported"] += 1
                    return True
                else:
                    self._logger.warning(
                        f"云端返回业务错误: code={body.get('code')}, msg={body.get('msg')}"
                    )
                    return False
            else:
                # 记录详细的错误信息便于排查
                resp_text = ""
                try:
                    resp_text = response.text[:500]
                except Exception:
                    pass
                self._logger.warning(
                    f"HTTP 上报失败: url={url}, status={response.status_code}, "
                    f"body={resp_text}"
                )
                return False

        except requests.Timeout:
            self._logger.warning(f"HTTP 上报超时: {url}")
            return False
        except requests.ConnectionError as e:
            self._logger.warning(f"HTTP 上报连接失败: {url}, error={e}")
            return False
        except Exception as e:
            self._logger.error(f"HTTP 上报异常: {url}, error={e}")
            return False

    def _handle_retry(self, alarm_json: str, error: str):
        """处理重试逻辑"""
        try:
            alarm_data = json.loads(alarm_json)
        except json.JSONDecodeError:
            return

        retry_count = alarm_data.get("_retry_count", 0) + 1
        max_retry = self._settings.alarm_upload.retry_max

        if retry_count > max_retry:
            # 超过最大重试次数，写入死信队列
            alarm_data["_dead_reason"] = error
            alarm_data["_dead_at"] = datetime.now(timezone.utc).isoformat()
            dead_json = json.dumps(alarm_data, ensure_ascii=False)
            self._redis.lpush(REDIS_KEY_ALARM_DEAD, dead_json)
            self._stats["dead_lettered"] += 1
            self._logger.warning(
                f"告警进入死信队列: {alarm_data.get('alarm_id')}, "
                f"reason={error}, retries={retry_count - 1}"
            )
            return

        # 指数退避：base_interval * 2^(retry_count-1)
        base_interval = self._settings.alarm_upload.retry_interval
        delay = base_interval * (2 ** (retry_count - 1))

        alarm_data["_retry_count"] = retry_count
        alarm_data["_retry_at"] = (
            datetime.now(timezone.utc).timestamp() + delay
        )
        retry_json = json.dumps(alarm_data, ensure_ascii=False)

        self._redis.lpush(REDIS_KEY_ALARM_RETRY, retry_json)
        self._stats["retried"] += 1

        self._logger.info(
            f"告警将重试: {alarm_data.get('alarm_id')}, "
            f"retry={retry_count}/{max_retry}, delay={delay}s, reason={error}"
        )

    def _process_retry_queue(self):
        """检查重试队列中到期的告警"""
        if not self._redis:
            return

        try:
            queue_len = self._redis.llen(REDIS_KEY_ALARM_RETRY)
            if queue_len == 0:
                return

            now = datetime.now(timezone.utc).timestamp()

            # 逐条检查（FIFO: RPOP 取最早的）
            checked = 0
            while checked < queue_len:
                item = self._redis.rpop(REDIS_KEY_ALARM_RETRY)
                if item is None:
                    break

                checked += 1

                try:
                    data = json.loads(item)
                    retry_at = data.get("_retry_at", 0)

                    if now >= retry_at:
                        # 到期，放回 pending 队列重新处理
                        self._redis.lpush(REDIS_KEY_ALARM_PENDING, item)
                        self._logger.debug(
                            f"重试告警回归 pending: {data.get('alarm_id')}"
                        )
                    else:
                        # 未到期，放回 retry 队列头部
                        self._redis.lpush(REDIS_KEY_ALARM_RETRY, item)
                except json.JSONDecodeError:
                    pass

        except Exception as e:
            self._logger.error(f"处理重试队列异常: {e}")

    def _reconnect_redis(self):
        """重连 Redis"""
        redis_cfg = self._settings.local_redis
        try:
            self._redis = redis.Redis(
                host=redis_cfg.host,
                port=redis_cfg.port,
                db=redis_cfg.db,
                password=redis_cfg.password,
                decode_responses=True,
                socket_connect_timeout=5,
            )
            self._redis.ping()
            self._logger.info("Redis 重连成功")
        except Exception as e:
            self._logger.error(f"Redis 重连失败: {e}")
            self._redis = None

    def get_statistics(self) -> Dict[str, Any]:
        """获取 Worker 统计"""
        stats = self._stats.copy()
        stats["running"] = self._thread is not None and self._thread.is_alive()
        return stats