"""
3D Printer STM32 MQTT Web Control Panel
========================================
Broker:    mqtt.beihong.wang:1883
Subscribe: /3D/message/put  (STM32 responses)
Publish:   /3D/message      (commands to STM32)
"""

import json
import time
import threading
import queue
from flask import Flask, render_template, jsonify, request, Response
import paho.mqtt.client as mqtt

app = Flask(__name__)

# --- MQTT Config ---
MQTT_BROKER = "mqtt.beihong.wang"
MQTT_PORT = 1883
MQTT_USER = "3D_Stm32"
MQTT_PASS = "123456"
MQTT_CLIENT_ID = "3D_WebPanel"
MQTT_TOPIC_PUB = "/3D/message"
MQTT_TOPIC_SUB = "/3D/message/put"

# --- Message queue for SSE ---
msg_queue = queue.Queue()

# --- MQTT connection state ---
mqtt_state = {"connected": False}


def on_connect(client, userdata, flags, reason_code, properties=None):
    if reason_code == 0:
        mqtt_state["connected"] = True
        client.subscribe(MQTT_TOPIC_SUB, qos=1)
        print(f"[MQTT] Connected, subscribed to {MQTT_TOPIC_SUB}")
    else:
        mqtt_state["connected"] = False
        print(f"[MQTT] Connect failed, code={reason_code}")


def on_disconnect(client, userdata, reason_code, properties=None):
    mqtt_state["connected"] = False
    print(f"[MQTT] Disconnected, code={reason_code}")


def on_message(client, userdata, msg):
    try:
        payload = msg.payload.decode("utf-8", errors="replace")
        print(f"[MQTT] << {msg.topic}: {payload}")
        msg_queue.put({"topic": msg.topic, "payload": payload, "time": time.strftime("%H:%M:%S")})
    except Exception as e:
        print(f"[MQTT] Message decode error: {e}")


def mqtt_loop():
    client = mqtt.Client(callback_api_version=mqtt.CallbackAPIVersion.VERSION2,
                         client_id=MQTT_CLIENT_ID)
    client.username_pw_set(MQTT_USER, MQTT_PASS)
    client.on_connect = on_connect
    client.on_disconnect = on_disconnect
    client.on_message = on_message

    while True:
        try:
            print(f"[MQTT] Connecting to {MQTT_BROKER}:{MQTT_PORT} ...")
            client.connect(MQTT_BROKER, MQTT_PORT, keepalive=60)
            client.loop_forever()
        except Exception as e:
            print(f"[MQTT] Error: {e}, retrying in 5s ...")
            mqtt_state["connected"] = False
            time.sleep(5)


# --- Flask routes ---

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


@app.route("/api/status")
def api_status():
    return jsonify({"connected": mqtt_state["connected"]})


@app.route("/api/send", methods=["POST"])
def api_send():
    data = request.get_json(force=True, silent=True)
    if not data:
        return jsonify({"ok": False, "msg": "invalid json"}), 400

    if not mqtt_state["connected"]:
        return jsonify({"ok": False, "msg": "mqtt disconnected"}), 503

    try:
        payload = json.dumps(data, separators=(',', ':'), ensure_ascii=False)
        # Publish to MQTT broker
        mqtt_client.publish(MQTT_TOPIC_PUB, payload, qos=1)
        print(f"[MQTT] >> {MQTT_TOPIC_PUB}: {payload}")
        return jsonify({"ok": True})
    except Exception as e:
        return jsonify({"ok": False, "msg": str(e)}), 500


@app.route("/api/stream")
def api_stream():
    """Server-Sent Events endpoint for real-time messages"""
    def generate():
        while True:
            try:
                msg = msg_queue.get(timeout=25)
                yield f"data: {json.dumps(msg, ensure_ascii=False)}\n\n"
            except queue.Empty:
                yield ": keepalive\n\n"

    resp = Response(generate(), mimetype="text/event-stream")
    resp.headers["Cache-Control"] = "no-cache"
    resp.headers["X-Accel-Buffering"] = "no"
    return resp


@app.route("/api/poll")
def api_poll():
    """轮询获取新消息"""
    try:
        msg = msg_queue.get_nowait()
        return jsonify(msg)
    except queue.Empty:
        return jsonify({"msg": None})


# --- Global MQTT client reference ---
mqtt_client = None


@app.before_request
def ensure_mqtt_client():
    global mqtt_client
    if mqtt_client is None:
        # Create a client just for publishing (the loop thread has its own)
        mqtt_client = mqtt.Client(callback_api_version=mqtt.CallbackAPIVersion.VERSION2,
                                  client_id=MQTT_CLIENT_ID + "_pub")
        mqtt_client.username_pw_set(MQTT_USER, MQTT_PASS)
        try:
            mqtt_client.connect(MQTT_BROKER, MQTT_PORT, keepalive=60)
            mqtt_client.loop_start()
        except Exception:
            pass


if __name__ == "__main__":
    # Start MQTT background thread
    t = threading.Thread(target=mqtt_loop, daemon=True)
    t.start()
    # Start Flask web server
    app.run(host="127.0.0.1", port=3000, debug=False)