#!/usr/bin/env python3
"""
padsleep Web Monitor
====================
通过 Unix Socket 从 padsleep 守护进程读取全量状态（含 GPIO 实时电平），
通过 WebSocket 推送到浏览器实时展示。不与守护进程竞争硬件资源。

用法:
    # 先启动 padsleep 守护进程
    python padsleep.py

    # 再启动 Web 监控（新终端）
    python padsleep_web.py

    # 浏览器打开 http://树莓派IP:31400

依赖:
    pip install flask flask-socketio

配置项（环境变量）:
    PORT=31400         Web 端口
"""

import json
import os
import socket
import threading
import time

from flask import Flask, render_template
from flask_socketio import SocketIO, emit

# ── 配置 ────────────────────────────────────────────
PORT = int(os.environ.get("PORT", "31400"))
SOCKET_PATH = "/tmp/padsleep.sock"
POLL_FAST_S = 0.2      # GPIO 电平轮询间隔（200ms，跟随守护进程 50ms 更新）
POLL_SLOW_S = 1         # 其他状态轮询间隔


# ═══════════════════════════════════════════════════════════════════
#  IpcClient — 与 padsleep 守护进程通信（Unix Socket）
# ═══════════════════════════════════════════════════════════════════

class IpcClient:
    """Unix Socket JSON 行协议客户端（每次 send 新建连接）。"""

    def __init__(self, socket_path=SOCKET_PATH):
        self.socket_path = socket_path
        self.last_error = ""

    def _connect(self) -> socket.socket | None:
        try:
            sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
            sock.settimeout(2)
            sock.connect(self.socket_path)
            return sock
        except (socket.error, OSError) as e:
            self.last_error = str(e)
            return None

    def send(self, cmd: str, **kwargs) -> dict:
        """发送命令，每次新建连接（守护进程每请求关闭连接）。"""
        sock = self._connect()
        if sock is None:
            return {"ok": False, "error": f"未连接: {self.last_error}"}
        req = {"cmd": cmd, **kwargs}
        try:
            sock.sendall((json.dumps(req) + "\n").encode("utf-8"))
            resp = sock.recv(65536)
            return json.loads(resp.decode("utf-8").strip())
        except (socket.error, json.JSONDecodeError) as e:
            return {"ok": False, "error": str(e)}
        finally:
            try:
                sock.close()
            except Exception:
                pass


# ═══════════════════════════════════════════════════════════════════
#  Flask 应用
# ═══════════════════════════════════════════════════════════════════

app = Flask(__name__)
app.config["SECRET_KEY"] = os.urandom(16).hex()
socketio = SocketIO(app, cors_allowed_origins="*")

ipc = IpcClient()

# ── 全局缓存（供不同频率的轮询线程共享）──
_data_lock = threading.Lock()
_cached = {
    "gpio_level": -1,
    "gpio_time": "--",
    "status": None,
}


# ── 路由 ─────────────────────────────────────────────

@app.route("/")
def index():
    return render_template("index.html")


# ── 后台线程：高频轮询 GPIO 电平 ────────────────────

def poll_gpio():
    """通过 IPC 高频读取 GPIO 电平，变化时 WebSocket 广播。"""
    last_val = -1
    while True:
        r = ipc.send("status")
        if r.get("ok"):
            level = r["data"].get("gpio_level", -1)
            now = time.strftime("%H:%M:%S") + f".{int(time.time() * 1000) % 1000:03d}"
            if level != -1 and level != last_val:
                socketio.emit("gpio_update", {
                    "value": level,
                    "time": now,
                })
                last_val = level
            # 更新缓存（补上 connected 字段，前端据此判断连接状态）
            r["data"]["connected"] = True
            with _data_lock:
                _cached["gpio_level"] = level
                _cached["gpio_time"] = now
                _cached["status"] = r["data"]
        socketio.sleep(POLL_FAST_S)


# ── 后台线程：慢速轮询全量状态 ──────────────────────

def poll_status():
    """定期查询守护进程全量状态，通过 WebSocket 广播。"""
    while True:
        with _data_lock:
            status = _cached.get("status")
        if status:
            socketio.emit("status_update", status)
        socketio.sleep(POLL_SLOW_S)


# ── WebSocket 事件 ──────────────────────────────────

@socketio.on("connect")
def on_connect(auth=None):
    print("[WS] 客户端已连接")
    # 推送初始状态
    r = ipc.send("status")
    if r.get("ok"):
        data = r["data"]
        data["connected"] = True
        level = data.get("gpio_level", -1)
        now = time.strftime("%H:%M:%S") + f".{int(time.time() * 1000) % 1000:03d}"
        with _data_lock:
            _cached["gpio_level"] = level
            _cached["gpio_time"] = now
            _cached["status"] = data
        socketio.emit("gpio_update", {"value": level, "time": now})
        socketio.emit("status_update", data)
    else:
        socketio.emit("status_update", {
            "connected": False,
            "error": r.get("error", "无法连接守护进程"),
        })


@socketio.on("disconnect")
def on_disconnect():
    print("[WS] 客户端已断开")


# ── 入口 ─────────────────────────────────────────────

def main():
    print("╔══════════════════════════════════════════╗")
    print("║   padsleep Web Monitor                  ║")
    print("║   （通过 IPC 读取守护进程状态）          ║")
    print("╠══════════════════════════════════════════╣")
    print(f"║  监听地址:  http://0.0.0.0:{PORT}")
    print(f"║  数据源:    {SOCKET_PATH}")
    print(f"║  GPIO 轮询: {POLL_FAST_S*1000:.0f}ms — 跟随守护进程 50ms 线程")
    print(f"║  状态轮询:  {POLL_SLOW_S}s")
    print(f"║  请先启动 padsleep.py 守护进程")
    print(f"║  按 Ctrl+C 停止                          ║")
    print("╚══════════════════════════════════════════╝")

    # 启动后台线程
    socketio.start_background_task(poll_gpio)
    socketio.start_background_task(poll_status)

    try:
        socketio.run(app, host="0.0.0.0", port=PORT, allow_unsafe_werkzeug=True)
    except KeyboardInterrupt:
        pass
    finally:
        print("👋 已退出")


if __name__ == "__main__":
    main()