#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h>

// 定义引脚连接
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET    -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define DHTPIN 3     // Digital pin connected to the DHT sensor
#define DHTTYPE DHT22   // DHT 22  (AM2302)
DHT dht(DHTPIN, DHTTYPE);

#define MQ2_A_PIN A0    // MQ2模拟输出引脚
#define MQ2_D_PIN 2     // MQ2数字输出引脚
#define LED_PIN 4       // LED引脚
#define BUZZER_PIN 5    // 蜂鸣器引脚
#define SWITCH_PIN 6    // 开关引脚
#define TEMP_THRESHOLD_PIN A1  // 温度阈值调节电位器
#define SMOKE_THRESHOLD_PIN A2 // 烟雾阈值调节电位器

// 全局变量
float temperature = 0;
float humidity = 0;
float smokeLevel = 0;
float tempThreshold = 30.0; // 默认温度阈值(°C)
float smokeThreshold = 300; // 默认烟雾阈值(模拟值)
bool alarmActive = false;
unsigned long alarmStartTime = 0;
float maxTemp = 0;
float maxHumidity = 0;

void setup() {
  Serial.begin(9600);
  
  // 初始化OLED显示屏
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Fire Alarm System");
  display.println("Initializing...");
  display.display();
  
  // 初始化传感器和外设
  dht.begin();
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(SWITCH_PIN, INPUT_PULLUP);
  pinMode(MQ2_D_PIN, INPUT);
  
  // 初始化蜂鸣器和LED
  digitalWrite(LED_PIN, LOW);
  digitalWrite(BUZZER_PIN, LOW);
  
  delay(2000); // 初始化延时
}

void loop() {
  // 读取传感器数据
  readSensors();
  
  // 读取阈值设置
  readThresholds();
  
  // 检查是否需要触发报警
  checkAlarm();
  
  // 处理手动解除报警
  handleSwitch();
  
  // 更新显示
  updateDisplay();
  
  delay(1000); // 主循环延时
}

void readSensors() {
  // 读取DHT22传感器数据
  humidity = dht.readHumidity();
  temperature = dht.readTemperature();
  
  // 检查读取是否成功
  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  
  // 更新历史最高值
  if (temperature > maxTemp) maxTemp = temperature;
  if (humidity > maxHumidity) maxHumidity = humidity;
  
  // 读取MQ2传感器数据
  smokeLevel = analogRead(MQ2_A_PIN);
}

void readThresholds() {
  // 读取温度阈值(0-50°C)
  int tempValue = analogRead(TEMP_THRESHOLD_PIN);
  tempThreshold = map(tempValue, 0, 1023, 10, 60);
  
  // 读取烟雾阈值(0-1023)
  int smokeValue = analogRead(SMOKE_THRESHOLD_PIN);
  smokeThreshold = map(smokeValue, 0, 1023, 100, 800);
}

void checkAlarm() {
  // 检查是否超过阈值
  bool tempAlarm = temperature > tempThreshold;
  bool smokeAlarm = smokeLevel > smokeThreshold;
  
  if (tempAlarm || smokeAlarm) {
    if (!alarmActive) {
      // 启动报警
      alarmActive = true;
      alarmStartTime = millis();
      Serial.println("ALARM TRIGGERED!");
    }
    
    // 执行报警动作
    triggerAlarm();
  } else {
    // 关闭报警
    alarmActive = false;
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  }
}

void triggerAlarm() {
  // 声光报警逻辑
  unsigned long currentTime = millis();
  unsigned long alarmDuration = currentTime - alarmStartTime;
  
  // 每500ms切换LED状态
  if ((alarmDuration % 500) < 250) {
    digitalWrite(LED_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
  }
  
  // 蜂鸣器发出警笛声
  if ((alarmDuration % 1000) < 500) {
    // 高音
    tone(BUZZER_PIN, 1000);
  } else {
    // 低音
    tone(BUZZER_PIN, 500);
  }
}

void handleSwitch() {
  // 检查开关状态(低电平表示按下)
  if (digitalRead(SWITCH_PIN) == LOW) {
    // 延时去抖
    delay(50);
    if (digitalRead(SWITCH_PIN) == LOW) {
      // 手动关闭报警
      alarmActive = false;
      digitalWrite(LED_PIN, LOW);
      noTone(BUZZER_PIN);
      Serial.println("Alarm manually disabled");
      
      // 等待开关释放
      while (digitalRead(SWITCH_PIN) == LOW);
    }
  }
}

void updateDisplay() {
  display.clearDisplay();
  display.setCursor(0, 0);
  
  // 显示标题
  display.setTextSize(1);
  display.println("Fire Alarm System");
  
  // 显示温度和湿度
  display.setTextSize(2);
  display.print("Temp: ");
  display.print(temperature);
  display.print(" C");
  display.setCursor(0, 20);
  
  display.print("Humi: ");
  display.print(humidity);
  display.println(" %");
  
  // 显示烟雾浓度
  display.setTextSize(1);
  display.print("Smoke: ");
  display.print(smokeLevel);
  display.println(" ppm");
  
  // 显示阈值
  display.print("Temp Threshold: ");
  display.print(tempThreshold);
  display.println(" C");
  
  display.print("Smoke Threshold: ");
  display.print(smokeThreshold);
  display.println(" ppm");
  
  // 显示历史最高值
  display.print("Max Temp: ");
  display.print(maxTemp);
  display.print(" C  ");
  
  display.print("Max Humi: ");
  display.print(maxHumidity);
  display.println(" %");
  
  // 显示报警状态
  display.setTextSize(2);
  display.setCursor(0, 50);
  if (alarmActive) {
    display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // 反色显示
    display.println("ALARM!");
    display.setTextColor(SSD1306_WHITE);
  } else {
    display.println("Normal");
  }
  
  display.display();
}