# pip install paho-mqtt
import json
import re
import time
from paho.mqtt import client as mqtt

# ========= 使用者設定 =========
BROKER_HOST = "169.254.11.130"
BROKER_PORT = 1886
TOPIC       = "topic_plc_and_py_for_AXIS"
QOS         = 1   # 建議測試用 1
# ============================

# 全域狀態（方便觀察最新值）
state = {
    "BUTTON_Y": None,
    "Forward_RPM": None,
    "UPDown_RPM": None,
}

def _robust_json_parse(raw: str):
    """
    將 PLC 端常見的非標準 JSON 嘗試修正後解析為 dict。
    例：'{Forward_RPM:1500,UPDown_RPM:800}' -> {'Forward_RPM':1500,'UPDown_RPM':800}
    也會把 TRUE/FALSE -> true/false
    """
    s = raw.strip()

    # 去掉最外層引號（若有）
    if (s.startswith("'") and s.endswith("'")) or (s.startswith('"') and s.endswith('"')):
        s = s[1:-1].strip()

    # PLC 常見布林大寫 -> JSON 規範小寫
    s = s.replace("TRUE", "true").replace("FALSE", "false")

    # 自動補 key 的雙引號：{key: -> {"key":
    s = re.sub(r'([{,]\s*)([A-Za-z_]\w*)\s*:', r'\1"\2":', s)

    # 轉單引號為雙引號（若 payload 用了單引號包字串）
    # 放在補 key 後，避免 key 的引號再被替換
    s = s.replace("'", '"')

    return json.loads(s)

def on_connect(client: mqtt.Client, userdata, flags, reason_code, properties=None):
    """
    連上 Broker 後自動訂閱 Topic。
    paho-mqtt 2.x 的 on_connect 第四個參數是 reason_code（非 rc），名稱略有不同。
    """
    if reason_code == 0:
        print(f"✅ 已連線到 MQTT Broker {BROKER_HOST}:{BROKER_PORT}")
        client.subscribe(TOPIC, qos=QOS)
        print(f"📡 已訂閱 Topic: {TOPIC}（QoS={QOS}）")
    else:
        print(f"❌ 連線失敗，reason_code={reason_code}")

def on_message(client: mqtt.Client, userdata, msg: mqtt.MQTTMessage):
    payload_raw = msg.payload.decode("utf-8", errors="replace")
    print(f"\n📥 收到原始訊息：{payload_raw}")

    # 先試標準 JSON，失敗再用容錯解析
    try:
        data = json.loads(payload_raw)
    except json.JSONDecodeError:
        try:
            data = _robust_json_parse(payload_raw)
        except Exception as e:
            print(f"❌ 無法解析為 JSON：{payload_raw} ；錯誤：{e}")
            return

    # 只更新我們關心的欄位（有傳才改）
    for key in ("BUTTON_Y", "Forward_RPM", "UPDown_RPM"):
        if key in data:
            state[key] = data[key]

    print(
        f"✅ 解析後資料：{data}\n"
        f"📊 目前狀態：BUTTON_Y={state['BUTTON_Y']}, "
        f"Forward_RPM={state['Forward_RPM']}, UPDown_RPM={state['UPDown_RPM']}"
    )

def on_disconnect(client: mqtt.Client, userdata, reason_code, properties=None):
    print(f"🔌 已斷線，reason_code={reason_code}")

def sub_to_plc(broker_host: str, broker_port: int, topic: str):
    client = mqtt.Client(client_id="py_sub_plc_test", protocol=mqtt.MQTTv311)

    # 如需帳密或 TLS，在這裡設定
    # client.username_pw_set("user", "pass")
    # client.tls_set(ca_certs="ca.pem")

    # 自動重連延遲（paho-mqtt 2.x）
    client.reconnect_delay_set(min_delay=1, max_delay=10)

    client.on_connect = on_connect
    client.on_message = on_message
    client.on_disconnect = on_disconnect

    # 先連線，再進入 loop
    client.connect(broker_host, broker_port, keepalive=60)

    try:
        # loop_forever 會阻塞執行緒，內建自動重連
        client.loop_forever()
    except KeyboardInterrupt:
        print("\n🛑 收到中斷訊號，準備斷線...")
    finally:
        try:
            client.disconnect()
        except Exception:
            pass

if __name__ == "__main__":
    print("🚀 啟動 MQTT 訂閱器...")
    print(f"Broker={BROKER_HOST}:{BROKER_PORT}, Topic={TOPIC}, QoS={QOS}")
    sub_to_plc(BROKER_HOST, BROKER_PORT, TOPIC)