#include <Wire.h>                   // I2C 通信库
#include <Adafruit_GFX.h>           // OLED 图形库
#include <Adafruit_SSD1306.h>       // SSD1306 驱动库
#include <DHT.h>                    // DHT22 温湿度库

// SSD1306 OLED 参数
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// DHT22 配置
#define DHTPIN 2                   
#define DHTTYPE DHT22              
DHT dht(DHTPIN, DHTTYPE);

// 模块引脚定义
const int smokePin = A0;           // MQ-2 烟雾传感器
const int buzzerPin = 3;           // 蜂鸣器
const int ledPin = 4;              // LED 指示灯
const int stopAlarmPin = 6;        // 停止报警按钮
const int setThresholdPin = 7;     // 设置阈值按钮

// 报警阈值
float tempThreshold = 30.0;        
float humiThreshold = 60.0;        
int smokeThreshold = 300;          

// 状态变量
bool isAlarmActive = false;
bool alarmManuallyDisabled = false;
bool currentButtonState = HIGH;
bool lastButtonState = HIGH;
unsigned long lastAlarmTime = 0;    // 记录上次报警时间
const unsigned long ALARM_INTERVAL = 100;  // 报警间隔100ms（0.1秒）
bool buzzerState = false;          // 蜂鸣器当前状态

// 函数声明
String getCurrentTime();
void checkSensors();
void updateDisplay(float temp, float humi, int smoke);
void handleThresholdButton();
void handleStopAlarmButton();
void updateAlarm();

void setup() {
  Serial.begin(9600);
  dht.begin();  

  // 初始化 OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 初始化失败！"));
    for(;;); 
  }
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(1);

  // 设置引脚模式
  pinMode(smokePin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(stopAlarmPin, INPUT_PULLUP);
  pinMode(setThresholdPin, INPUT_PULLUP);
  
  Serial.println("环境监测系统已启动");
  Serial.print("温度阈值: ");
  Serial.println(tempThreshold);
  Serial.print("湿度阈值: ");
  Serial.println(humiThreshold);
  Serial.print("烟雾阈值: ");
  Serial.println(smokeThreshold);
}

void loop() {
  // 读取传感器数据
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  int smokeValue = analogRead(smokePin);
  
  // 检查传感器数据是否有效
  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("无法从DHT传感器读取数据!");
    temperature = 0;
    humidity = 0;
  }

  // 更新显示（保持原OLED格式不变）
  updateDisplay(temperature, humidity, smokeValue);

  // 检查是否需要触发报警
  if (!alarmManuallyDisabled) {
    bool shouldAlarm = (temperature > tempThreshold || 
                        humidity > humiThreshold || 
                        smokeValue > smokeThreshold);
    
    if (shouldAlarm != isAlarmActive) {
      isAlarmActive = shouldAlarm;
      lastAlarmTime = millis(); // 重置报警计时
    }
  }

  // 处理按钮输入
  handleThresholdButton();
  handleStopAlarmButton();
  
  // 更新报警状态（控制蜂鸣器脉冲）
  updateAlarm();

  // 短暂延时，减少CPU负载
  delay(50); // 缩短延时以确保报警脉冲准确
}

void updateDisplay(float temp, float humi, int smoke) {
  display.clearDisplay();
  
  // 显示时间
  display.setCursor(0, 0);
  display.print("Time: ");
  display.print(getCurrentTime());
  
  // 显示温度
  display.setCursor(0, 10);
  display.print("Temp: ");
  display.print(temp);
  display.print(" C");
  
  // 显示湿度
  display.setCursor(0, 20);
  display.print("Humi: ");
  display.print(humi);
  display.print(" %");
  
  // 显示烟雾值
  display.setCursor(0, 30);
  display.print("Smoke: ");
  display.print(smoke);
  
  // 显示阈值
  display.setCursor(0, 40);
  display.print("Temp Th: ");
  display.print(tempThreshold);
  display.print(" C");
  
  // 显示报警状态
  display.setCursor(0, 50);
  if (isAlarmActive) {
    display.print("ALARM ACTIVE!");
  } else if (alarmManuallyDisabled) {
    display.print("Alarm disabled");
  } else {
    display.print("System OK");
  }
  
  display.display();
}

void handleThresholdButton() {
  // 读取当前按钮状态
  currentButtonState = digitalRead(setThresholdPin);
  
  // 检测按钮按下（从HIGH变为LOW）
  if (currentButtonState == LOW && lastButtonState == HIGH) {
    // 按钮被按下，增加温度阈值
    tempThreshold += 1.0;
    
    // 检查是否超过最大值，如果超过则重置为最小值
    if (tempThreshold > 50.0) {
      tempThreshold = 30.0;
    }
    
    // 打印新的阈值
    Serial.print("新温度阈值: ");
    Serial.println(tempThreshold);
    
    // 短暂延时以避免按键抖动
    delay(200);
  }
  
  // 更新上一次按钮状态
  lastButtonState = currentButtonState;
}

void handleStopAlarmButton() {
  static bool lastStopButtonState = HIGH;
  bool currentStopButtonState = digitalRead(stopAlarmPin);
  
  // 检测按钮按下
  if (currentStopButtonState == LOW && lastStopButtonState == HIGH) {
    // 消抖处理
    delay(50);
    if (digitalRead(stopAlarmPin) == LOW) {
      // 关闭报警状态
      if (isAlarmActive) {
        isAlarmActive = false;
        alarmManuallyDisabled = true;
        digitalWrite(buzzerPin, LOW);
        digitalWrite(ledPin, LOW);
        Serial.println("报警已手动关闭");
      } else {
        // 重置手动禁用状态
        alarmManuallyDisabled = false;
        Serial.println("报警检测已恢复");
      }
    }
  }
  
  // 更新上一次按钮状态
  lastStopButtonState = currentStopButtonState;
}

void updateAlarm() {
  if (isAlarmActive) {
    // 每100ms切换蜂鸣器状态
    unsigned long currentTime = millis();
    if (currentTime - lastAlarmTime >= ALARM_INTERVAL) {
      lastAlarmTime = currentTime;
      buzzerState = !buzzerState;
      digitalWrite(buzzerPin, buzzerState);
      digitalWrite(ledPin, buzzerState); // LED同步闪烁
    }
  } else {
    // 非报警状态时关闭蜂鸣器和LED
    digitalWrite(buzzerPin, LOW);
    digitalWrite(ledPin, LOW);
  }
}

String getCurrentTime() {
  // 这里应该添加获取当前时间的代码
  // 例如：使用RTC模块或系统时间
  
  // 模拟时间（实际应用中替换为真实时间）
  unsigned long seconds = millis() / 1000;
  int hours = (seconds / 3600) % 24;
  int minutes = (seconds / 60) % 60;
  int secs = seconds % 60;
  
  String timeStr = "";
  if (hours < 10) timeStr += "0";
  timeStr += String(hours) + ":";
  if (minutes < 10) timeStr += "0";
  timeStr += String(minutes) + ":";
  if (secs < 10) timeStr += "0";
  timeStr += String(secs);
  
  return timeStr;
}