from machine import UART, Pin, reset
import time
import network
from umqtt.simple import MQTTClient
# ====================== 巴法云配置 ======================
SECRET_KEY = "369ba69d230e49bc9ad9825f0f4b1894"  # 你的巴法云秘钥
MQTT_SERVER = "mqtt.bemfa.com"                # 巴法云 MQTT 服务器
MQTT_PORT = 9501                              # 端口号
TOPIC_LED = "led001"                          # LED控制主题名

# ====================== WiFi 配置 ======================
WIFI_SSID = "Wokwi-GUEST"                     # WiFi 名称
WIFI_PASSWORD = ""                            # WiFi 密码

# ====================== 硬件初始化 ======================
uart = UART(1, baudrate=115200, tx=1, rx=3)   # 初始化 UART
led = Pin(15, Pin.OUT, value=0)               # 初始化 LED

# ====================== 全局变量 ======================
mqtt_client = None       # MQTT 客户端对象
wifi_connected = False   # WiFi 连接状态
mqtt_connected = False   # MQTT 连接状态
reconnect_interval = 5   # 重连间隔（秒）
last_attempt_time = 0    # 上次连接尝试时间

# ====================== WiFi 连接函数 ======================
def connect_wifi():
    global wifi_connected
    wlan = network.WLAN(network.STA_IF)
    
    # 检查是否已连接
    if wlan.isconnected():
        wifi_connected = True
        return True
    
    wlan.active(True)
    wlan.disconnect()
    
    print(f"正在连接 WiFi：{WIFI_SSID}...")
    uart.write(f"\rConnecting to WiFi: {WIFI_SSID}...\n")
    wlan.connect(WIFI_SSID, WIFI_PASSWORD)
    
    # 等待连接成功或超时（30秒）
    timeout = 30
    while timeout > 0 and not wlan.isconnected():
        time.sleep(1)
        timeout -= 1
        print(f"剩余连接时间：{timeout} 秒")
    
    if wlan.isconnected():
        print(f"WiFi 连接成功！IP：{wlan.ifconfig()[0]}")
        uart.write("\rWiFi connected successfully!\n")
        wifi_connected = True
        return True
    else:
        print("WiFi 连接失败！")
        uart.write("\rWiFi connection failed!\n")
        wifi_connected = False
        return False

# ====================== MQTT 连接函数 ======================
def connect_mqtt():
    global mqtt_client, mqtt_connected
    if not wifi_connected:
        print("WiFi未连接，无法连接MQTT！")
        uart.write("\rWiFi not connected, cannot connect to MQTT!\n")
        return False
    
    try:
        # 客户端 ID 固定为秘钥
        mqtt_client = MQTTClient(SECRET_KEY, MQTT_SERVER, port=MQTT_PORT)
        mqtt_client.set_callback(mqtt_callback)
        mqtt_client.connect()
        mqtt_client.subscribe(TOPIC_LED)
        print("MQTT 连接到巴法云成功！")
        uart.write("\rMQTT connected to BafaCloud successfully!\n")
        mqtt_connected = True
        return True
    except Exception as e:
        print(f"MQTT 连接失败：{e}")
        uart.write(f"\rMQTT connection failed: {e}\n")
        mqtt_connected = False
        return False

# ====================== MQTT 回调函数 ======================
def mqtt_callback(topic, msg):
    print(f"收到MQTT消息 - 主题: {topic.decode()}, 消息: {msg.decode()}")
    uart.write(f"\rMQTT message received: {msg.decode()}\n")
    
    if msg.decode() == 'on':
        led.value(1)
        uart.write("\rLED is ON.\n")
        update_led_status()  # 同步状态
    elif msg.decode() == 'off':
        led.value(0)
        uart.write("\rLED is OFF.\n")
        update_led_status()  # 同步状态
    else:
        uart.write("\rInvalid MQTT command!\n")

# ====================== 更新LED状态到巴法云 ======================
def update_led_status():
    if not mqtt_connected or not mqtt_client:
        return
    
    try:
        status = "on" if led.value() else "off"
        mqtt_client.publish(TOPIC_LED, status)
        print(f"已更新LED状态到巴法云: {status}")
    except Exception as e:
        print(f"发布LED状态失败: {e}")
        check_connection()  # 检查连接状态

# ====================== 检查连接状态并尝试重连 ======================
def check_connection():
    global last_attempt_time
    current_time = time.time()
    
    # 避免频繁尝试重连
    if current_time - last_attempt_time < reconnect_interval:
        return
    
    last_attempt_time = current_time
    
    # 检查WiFi连接
    wlan = network.WLAN(network.STA_IF)
    if not wlan.isconnected():
        print("WiFi连接丢失，尝试重连...")
        connect_wifi()
    
    # 检查MQTT连接
    if wifi_connected and (not mqtt_connected or not mqtt_client):
        print("MQTT连接丢失，尝试重连...")
        connect_mqtt()

# ====================== 处理串口输入 ======================
def handle_uart_input():
    if uart.any():
        data = uart.read().decode().strip()
        print(f"收到串口输入: {data}")
        
        if data == '1':
            led.value(1)
            uart.write("\rUART: LED is ON.\n")
            update_led_status()  # 更新状态到巴法云
        elif data == '0':
            led.value(0)
            uart.write("\rUART: LED is OFF.\n")
            update_led_status()  # 更新状态到巴法云
        elif data.lower() == 'status':
            status = "ON" if led.value() else "OFF"
            uart.write(f"\rLED Status: {status}\n")
        else:
            uart.write("\r无效输入! 请输入1/0控制LED，或输入status查看状态.\n")

# ====================== 主程序 ======================
if __name__ == "__main__":
    uart.write("\rLED Control System Started.\n")
    uart.write("Enter 1 to turn ON LED, 0 to turn OFF, status to check status.\n")
    
    try:
        # 初始连接
        connect_wifi()
        if wifi_connected:
            connect_mqtt()
        
        while True:
            try:
                # 处理串口输入
                handle_uart_input()
                
                # 检查MQTT消息
                if mqtt_connected and mqtt_client:
                    mqtt_client.check_msg()
                
                # 定期检查连接状态
                check_connection()
                
                # 短暂延时，避免CPU占用过高
                time.sleep(0.1)
                
            except Exception as e:
                print(f"主循环异常: {e}")
                time.sleep(1)
    
    except KeyboardInterrupt:
        print("\n程序停止，断开连接...")
        uart.write("\rProgram stopped.\n")
        if mqtt_client:
            try:
                mqtt_client.disconnect()
            except:
                pass
        led.value(0)  # 确保LED关闭