from machine import UART, Pin, SoftI2C, Timer
import time
import network
from ssd1306 import SSD1306_I2C
from umqtt.simple import MQTTClient
import dht

# 硬件配置
# OLED 引脚
OLED_SDA_PIN = 23  
OLED_SCL_PIN = 18  
# DHT22 引脚
DHT22_PIN = 4
# 串口配置（使用串口1，TX: GPIO1, RX: GPIO3 ，根据实际硬件确认）
UART_PORT = 1
UART_BAUDRATE = 115200
UART_TX_PIN = 1
UART_RX_PIN = 3
# LED 引脚（状态指示）
LED_PIN = 15  

# 网络配置（需替换为实际 WiFi 信息）
WIFI_SSID = "Wokwi-GUEST"  
WIFI_PASSWORD = ""  

# 巴法云 MQTT 配置
MQTT_BROKER = "bemfa.com"  
MQTT_PORT = 9501  
MQTT_CLIENT_ID = "531335e94ce44795a9834be0a956119a"   
MQTT_TEMP_TOPIC = "temp"  
MQTT_HUMI_TOPIC = "humity"    
ONLINE_STATUS = "on"  
OFFLINE_STATUS = "off" 

# 全局变量
dht_sensor = None      
oled = None             # OLED显示屏
uart = None             # 串口对象
led = None              # LED对象
wifi_connected = False  # WiFi连接状态
mqtt_client = None      # MQTT客户端
timer = None            # 定时器对象
last_online_publish = 0  # 上次发布在线状态的时间
online_publish_interval = 60  # 在线状态发布间隔(秒)
last_connection_attempt = 0  # 上次连接尝试时间
connection_backoff = 5  # 初始重连等待时间(秒)
max_connection_backoff = 60  # 最大重连等待时间(秒)
last_dht_read = 0       # 上次读取DHT22的时间
dht_read_interval = 2   # DHT22读取间隔(秒)
temperature = 0.0       # 温度值
humidity = 0.0          # 湿度值

def connect_wifi():
    """连接WiFi网络"""
    global wifi_connected
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if not wlan.isconnected():
        print("正在连接WiFi...")
        wlan.connect(WIFI_SSID, WIFI_PASSWORD)
        max_wait = 10
        while max_wait > 0:
            if wlan.isconnected():
                break
            max_wait -= 1
            time.sleep(1)
        if wlan.isconnected():
            print(f"WiFi连接成功，网络配置: {wlan.ifconfig()}")
            wifi_connected = True
            return True
        else:
            print("WiFi连接失败")
            wifi_connected = False
            return False
    else:
        print(f"已连接WiFi，网络配置: {wlan.ifconfig()}")
        wifi_connected = True
        return True

def setup_hardware():
    """初始化硬件组件：OLED、DHT22、串口、LED"""
    global oled, uart, led, dht_sensor
    
    # 初始化OLED
    i2c = SoftI2C(sda=Pin(OLED_SDA_PIN), scl=Pin(OLED_SCL_PIN))
    oled = SSD1306_I2C(128, 64, i2c)
    
    # 初始化DHT22传感器
    dht_sensor = dht.DHT22(Pin(DHT22_PIN))
    
    # 初始化串口
    uart = UART(UART_PORT, baudrate=UART_BAUDRATE, tx=Pin(UART_TX_PIN), rx=Pin(UART_RX_PIN))
    
    # 初始化LED
    led = Pin(LED_PIN, Pin.OUT)
    led.value(0)  # 默认关闭LED
    
    return oled, uart, led, dht_sensor

def display_status():
    """在OLED上显示温湿度、WiFi连接状态和MQTT连接状态"""
    global oled, temperature, humidity, wifi_connected, mqtt_client
    
    oled.fill(0)  # 清屏
    
    # 显示温湿度
    oled.text("Temp: {:.1f} C".format(temperature), 0, 0, 1)
    oled.text("Humi: {:.1f} %".format(humidity), 0, 15, 1)
    
    # 显示WiFi状态
    wifi_text = "WiFi: Connected" if wifi_connected else "WiFi: Disconnected"
    oled.text(wifi_text, 0, 30, 1)
    
    # 显示MQTT状态
    mqtt_text = "MQTT: Connected" if mqtt_client else "MQTT: Disconnected"
    oled.text(mqtt_text, 0, 45, 1)
    
    oled.show()  # 更新显示

def read_dht_sensor():
    """读取DHT22传感器数据"""
    global dht_sensor, temperature, humidity, last_dht_read
    
    current_time = time.time()
    
    # 检查是否到了读取时间
    if current_time - last_dht_read < dht_read_interval:
        return False
    
    last_dht_read = current_time
    
    try:
        dht_sensor.measure()
        temperature = dht_sensor.temperature()
        humidity = dht_sensor.humidity()
        print(f"读取DHT22: 温度={temperature}°C, 湿度={humidity}%")
        
        # 在串口显示
        uart.write(f"\r温度: {temperature}°C, 湿度: {humidity}%\n")
        
        return True
    except Exception as e:
        print(f"读取DHT22失败: {e}")
        return False

def connect_mqtt():
    """连接巴法云MQTT服务器"""
    global mqtt_client, last_connection_attempt, connection_backoff
    
    current_time = time.time()
    
    # 避免过于频繁地尝试连接
    if current_time - last_connection_attempt < connection_backoff:
        time.sleep(connection_backoff)
        return False
    
    last_connection_attempt = current_time
    
    try:
        # 如果已有客户端，先断开
        if mqtt_client:
            try:
                mqtt_client.disconnect()
            except:
                pass
            mqtt_client = None
        
        # 创建新的MQTT客户端连接
        mqtt_client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, MQTT_PORT)
        mqtt_client.connect()
        print("已连接到巴法云MQTT服务器")
        
        # 重置重连等待时间
        connection_backoff = 5
        return True
    except Exception as e:
        print(f"连接MQTT服务器失败: {e}")
        mqtt_client = None
        # 增加重连等待时间，但不超过最大值
        connection_backoff = min(connection_backoff * 2, max_connection_backoff)
        return False

def publish_sensor_data():
    """发布传感器数据到巴法云MQTT服务器"""
    global mqtt_client, temperature, humidity
    
    if not mqtt_client:
        return False
    
    try:
        # 发布温度数据
        mqtt_client.publish(MQTT_TEMP_TOPIC, "{:.1f}".format(temperature))
        print(f"已发布温度: {temperature}°C 到主题: {MQTT_TEMP_TOPIC}")
        
        # 发布湿度数据
        mqtt_client.publish(MQTT_HUMI_TOPIC, "{:.1f}".format(humidity))
        print(f"已发布湿度: {humidity}% 到主题: {MQTT_HUMI_TOPIC}")
        
        return True
    except Exception as e:
        print(f"发布传感器数据失败: {e}")
        return False

def check_mqtt_connection():
    """检查MQTT连接状态，如果断开则重新连接"""
    global mqtt_client, wifi_connected
    
    if not wifi_connected:
        wifi_connected = connect_wifi()
        if not wifi_connected:
            return False
    
    if mqtt_client is None:
        print("MQTT客户端未初始化，尝试连接...")
        return connect_mqtt()
    
    try:
        # 使用ping检查连接是否活跃
        mqtt_client.ping()
        return True
    except Exception as e:
        print(f"MQTT ping失败，连接已断开: {e}")
        mqtt_client = None
        return connect_mqtt()

def main():
    """主程序逻辑：读取DHT22数据、OLED显示、MQTT上传数据"""
    global wifi_connected, mqtt_client, timer
    
    # 连接WiFi
    wifi_connected = connect_wifi()
    if not wifi_connected:
        print("WiFi连接失败，程序退出")
        return
    
    # 初始化硬件
    oled, uart, led, dht_sensor = setup_hardware()
    
    # 连接MQTT服务器
    if not connect_mqtt():
        print("MQTT连接失败，程序退出")
        return
    
    # 欢迎信息
    uart.write(b"\rDHT22温湿度监控系统已启动\n")
    uart.write(b"------------------------\n")
    
    try:
        while True:
            # 检查MQTT连接
            if not check_mqtt_connection():
                time.sleep(5)  # 连接失败后等待一段时间再重试
                continue
            
            # 读取DHT22传感器数据
            if read_dht_sensor():
                # 发布传感器数据到MQTT
                publish_sensor_data()
                
                # 更新OLED显示
                display_status()
            
            # 处理串口数据
            if uart.any():
                data = uart.read()
                print("串口收到:", data)
                
                if data == b'?':
                    uart.write(b"\r可用命令:\n")
                    uart.write(b"  ? - 显示帮助信息\n")
                    uart.write(b"  r - 立即读取传感器数据\n")
                    uart.write(b"  s - 显示当前状态\n")
                
                elif data == b'r':
                    if read_dht_sensor():
                        publish_sensor_data()
                        display_status()
                
                elif data == b's':
                    display_status()
            
            time.sleep(0.1)  # 适当延时，减少CPU使用率
    
    except KeyboardInterrupt:
        print("程序被用户中断")
    finally:
        # 清理资源
        if mqtt_client:
            try:
                mqtt_client.disconnect()
            except:
                pass
        print("程序已停止")

if __name__ == "__main__":
    main()