from machine import Pin, ADC, SoftI2C
import time
from ssd1306 import SSD1306_I2C
from umqtt.simple import MQTTClient
import network
import ujson

# 网络配置
WIFI_SSID = "Wokwi-GUEST"
WIFI_PASSWORD = ""

# 巴法云配置
BAFA_SERVER = "bemfa.com"
BAFA_PORT = 9501
CLIENT_ID = "ee7ca1783cfe4cd4bcf27ea0700fe3f9"  # 替换为巴法云私钥
TOPIC = "MQ2"  # MQTT主题
PASSWORD = "ee7ca1783cfe4cd4bcf27ea0700fe3f9"  # 替换为巴法云API密钥

# MQ2传感器配置
MQ2_PIN = 34  # ADC引脚GP34
VOLTAGE_REF = 3.3  # 参考电压3.3V
MQ2_RL = 10  # 负载电阻10kΩ

# 气体浓度阈值
GAS_ALARM_LOW = 200  # 低浓度报警
GAS_ALARM_HIGH = 1000  # 高浓度报警

# OLED屏幕配置
OLED_WIDTH = 128
OLED_HEIGHT = 64
i2c = SoftI2C(sda=Pin(23), scl=Pin(18))  # Wokwi中默认I2C引脚
oled = SSD1306_I2C(OLED_WIDTH, OLED_HEIGHT, i2c)

# 全局变量
mqtt_client = None
retry_count = 0
sta_if = None

# 初始化函数
def setup():
    global gas_adc
    gas_adc = ADC(Pin(MQ2_PIN))
    gas_adc.atten(ADC.ATTN_11DB)  # 11dB衰减
    
    # 初始化OLED
    oled.fill(0)
    oled.text("MQ2 Gas Monitor", 0, 0)
    oled.text("Connecting WiFi...", 0, 20)
    oled.show()
    
    # 连接WiFi
    global sta_if
    sta_if = network.WLAN(network.STA_IF)
    if not sta_if.isconnected():
        sta_if.active(True)
        sta_if.connect(WIFI_SSID, WIFI_PASSWORD)
        while not sta_if.isconnected():
            pass
    print('WiFi已连接，IP地址:', sta_if.ifconfig()[0])
    
    # 初始化MQTT
    init_mqtt()
    
    # 控制台标题
    print("=" * 50)
    print("  Wokwi MQ2气体传感器监测系统")
    print("=" * 50)
    print("ADC值\t电压(mV)\t浓度(ppm)\t状态\t\tMQTT状态")
    print("-" * 50)

# 初始化MQTT连接
def init_mqtt():
    global mqtt_client
    try:
        mqtt_client = MQTTClient(CLIENT_ID, BAFA_SERVER, BAFA_PORT, "", PASSWORD)
        mqtt_client.set_callback(mqtt_callback)
        mqtt_client.connect()
        mqtt_client.subscribe(TOPIC)
        print("已连接到巴法云MQTT服务器")
        update_oled_status("MQTT: 已连接")
    except Exception as e:
        print(f"MQTT连接失败: {e}")
        update_oled_status("MQTT: 连接失败")
        mqtt_client = None

# MQTT回调函数
def mqtt_callback(topic, msg):
    print(f"收到来自主题 {topic.decode()} 的消息: {msg.decode()}")

# 计算电压值（mV）
def get_voltage(adc_value):
    voltage = (adc_value / 4095) * VOLTAGE_REF
    return round(voltage * 1000, 2)

# 计算气体浓度（ppm）
def get_gas_concentration(adc_value):
    if adc_value > 3500:
        return 0
    elif adc_value < 1000:
        return 2000
    else:
        return round((3500 - adc_value) * 2000 / 2500, 2)

# 判断气体状态
def get_gas_status(concentration):
    if concentration == 0:
        return "清洁空气"
    elif concentration < GAS_ALARM_LOW:
        return "低浓度"
    elif concentration < GAS_ALARM_HIGH:
        return "中浓度"
    else:
        return "高浓度! 报警!"

# 更新OLED显示
def update_oled(adc_value, voltage, concentration, status, mqtt_status):
    oled.fill(0)  # 清屏
    
    # 显示标题
    oled.text("MQ2 Gas Sensor", 0, 0)
    
    # 显示ADC值和电压
    oled.text(f"ADC: {adc_value}", 0, 16)
    oled.text(f"Volt: {voltage}mV", 0, 32)
    
    # 显示浓度和状态
    oled.text(f"Gas: {concentration}ppm", 0, 48)
    oled.text(status, 0, 60)
    
    # 显示MQTT状态
    oled.text(f"MQTT: {mqtt_status}", 0, 52)
    
    # 报警指示
    if "报警" in status:
        oled.fill_rect(0, 56, OLED_WIDTH, 8, 1)  # 红色警告条
    
    oled.show()  # 更新显示

# 更新OLED上的MQTT状态
def update_oled_status(status):
    oled.fill_rect(0, 52, OLED_WIDTH, 12, 0)  # 清除旧状态
    oled.text(f"MQTT: {status}", 0, 52)
    oled.show()

# 重连MQTT
def reconnect_mqtt():
    global retry_count, mqtt_client
    retry_count += 1
    wait_time = min(30, 2 ** retry_count)  # 指数退避
    print(f"MQTT重连尝试 {retry_count}，{wait_time}秒后重试...")
    time.sleep(wait_time)
    init_mqtt()

# 发布数据到MQTT
def publish_to_mqtt(adc_value, voltage, concentration, status):
    global mqtt_client
    if mqtt_client:
        try:
            data = {
                "adc": adc_value,
                "voltage": voltage,
                "concentration": concentration,
                "status": status,
                "timestamp": time.time()
            }
            mqtt_client.publish(TOPIC, ujson.dumps(data))
            mqtt_client.check_msg()
        except Exception as e:
            print(f"MQTT发布失败: {e}")
            mqtt_client = None
            reconnect_mqtt()

# 主循环
def loop():
    try:
        while True:
            adc_value = gas_adc.read()
            voltage = get_voltage(adc_value)
            concentration = get_gas_concentration(adc_value)
            status = get_gas_status(concentration)
            
            # MQTT状态
            mqtt_status = "已连接" if mqtt_client else "断开中"
            
            # 控制台输出
            print(f"{adc_value}\t{voltage}\t{concentration}\t{status}\t{mqtt_status}")
            if concentration >= GAS_ALARM_HIGH:
                print("!" * 50)
            
            # OLED显示
            update_oled(adc_value, voltage, concentration, status, mqtt_status)
            
            # 发布到MQTT
            publish_to_mqtt(adc_value, voltage, concentration, status)
            
            time.sleep(0.5)  # 500ms更新一次
            
    except KeyboardInterrupt:
        print("\n" + "-" * 50)
        print("程序已停止")
        oled.fill(0)
        oled.text("System Stopped", 0, 32)
        oled.show()
        if mqtt_client:
            mqtt_client.disconnect()

# 程序入口
if __name__ == '__main__':
    setup()
    loop()