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

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

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

#define BUZZER_PIN 3
#define LED_PIN 4
#define MQ2_PIN A0

#define ALARM_OFF_BTN 5
#define SET_MODE_BTN 6
#define CONFIRM_BTN 7

// 默认阈值
float tempThreshold = 50.0;
float humThreshold = 20.0;
int gasThreshold = 600;

// 报警状态
bool alarmActive = false;
bool alarmSilenced = false;
bool conditionsMet = false; // 跟踪当前是否满足报警条件

// 设置模式
bool settingMode = false;
byte settingItem = 0; // 0:温度, 1:湿度, 2:气体

// 时间变量
int hours = 10;
int minutes = 26;

// 报警历史记录
const int maxHistory = 5;
String alarmHistory[maxHistory];
int historyIndex = 0;

// 按钮状态跟踪
bool lastAlarmOffState = HIGH;
bool lastSetModeState = HIGH;
bool lastConfirmState = HIGH;
unsigned long lastDebounceTime = 0;

void setup() {
  Serial.begin(9600);
  
  // 初始化OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  
  dht.begin();
  
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  
  pinMode(ALARM_OFF_BTN, INPUT_PULLUP);
  pinMode(SET_MODE_BTN, INPUT_PULLUP);
  pinMode(CONFIRM_BTN, INPUT_PULLUP);
  
  // 从EEPROM加载阈值
  EEPROM.get(0, tempThreshold);
  EEPROM.get(sizeof(float), humThreshold);
  EEPROM.get(2*sizeof(float), gasThreshold);
  
  // 初始化报警历史
  for(int i=0; i<maxHistory; i++) {
    alarmHistory[i] = "";
  }
  
  display.clearDisplay();
  display.display();
}

void loop() {
  static unsigned long lastUpdate = 0;
  static unsigned long lastMinute = 0;
  static unsigned long lastAlarmCheck = 0;
  static unsigned long lastButtonCheck = 0;
  
  unsigned long currentMillis = millis();
  
  // 每分钟更新时间
  if(currentMillis - lastMinute >= 60000) {
    lastMinute = currentMillis;
    minutes++;
    if(minutes >= 60) {
      minutes = 0;
      hours++;
      if(hours >= 24) {
        hours = 0;
      }
    }
  }
  
  // 每2秒更新传感器数据
  if(currentMillis - lastUpdate >= 2000 || lastUpdate == 0) {
    lastUpdate = currentMillis;
    
    float temp = dht.readTemperature();
    float hum = dht.readHumidity();
    int gasValue = analogRead(MQ2_PIN);
    
    // 检查报警条件
    conditionsMet = (temp > tempThreshold || hum < humThreshold || gasValue > gasThreshold);
    
    if(conditionsMet) {
      if(!alarmSilenced) {
        alarmActive = true;
      }
      
      // 记录报警历史
      String record = String(hours) + ":" + (minutes < 10 ? "0" + String(minutes) : String(minutes)) + " ";
      record += "T:" + String(temp) + " H:" + String(hum) + " G:" + String(gasValue);
      alarmHistory[historyIndex] = record;
      historyIndex = (historyIndex + 1) % maxHistory;
    } else {
      // 环境参数恢复正常，重置报警状态
      alarmActive = false;
      alarmSilenced = false;
    }
    
    // 显示信息
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(WHITE);
    
    if(settingMode) {
      displaySettingScreen();
    } else {
      displayNormalScreen(temp, hum, gasValue);
    }
    
    display.display();
  }
  
  // 处理报警
  if(alarmActive && !alarmSilenced) {
    if(currentMillis - lastAlarmCheck >= 100) {
      lastAlarmCheck = currentMillis;
      triggerAlarm();
    }
  } else {
    noTone(BUZZER_PIN);
    digitalWrite(LED_PIN, LOW);
  }
  
  // 每100ms检查按钮状态
  if(currentMillis - lastButtonCheck >= 100) {
    lastButtonCheck = currentMillis;
    checkButtons();
  }
}

void displayNormalScreen(float temp, float hum, int gasValue) {
  // 显示时间
  display.setCursor(0, 0);
  display.print("Time: ");
  display.print(hours);
  display.print(":");
  if(minutes < 10) display.print("0");
  display.print(minutes);
  
  // 显示温度
  display.setCursor(0, 16);
  display.print("Temp: ");
  display.print(temp);
  display.print("C");
  display.print(" (");
  display.print(tempThreshold);
  display.print(")");
  
  // 显示湿度
  display.setCursor(0, 28);
  display.print("Hum:  ");
  display.print(hum);
  display.print("%");
  display.print(" (");
  display.print(humThreshold);
  display.print(")");
  
  // 显示气体浓度
  display.setCursor(0, 40);
  display.print("Gas:  ");
  display.print(gasValue);
  display.print(" (");
  display.print(gasThreshold);
  display.print(")");
  
  // 显示报警状态
  display.setCursor(0, 52);
  if(alarmActive) {
    if(alarmSilenced) {
      display.print("Alarm silenced");
    } else {
      display.print("ALARM ACTIVE!");
    }
  } else {
    display.print("System normal");
  }
}

void displaySettingScreen() {
  display.setCursor(0, 0);
  display.print("SETTING MODE");
  
  // 显示当前设置项指示器
  display.setCursor(110, 0);
  display.print(settingItem + 1);
  display.print("/3");
  
  // 确保显示位置正确
  display.setCursor(0, 16);
  display.print("Temp Threshold:");
  display.setCursor(0, 26);
  display.print(tempThreshold);
  display.print("C");
  
  display.setCursor(0, 36);
  display.print("Hum Threshold:");
  display.setCursor(0, 46);
  display.print(humThreshold);
  display.print("%");
  
  display.setCursor(0, 56);
  display.print("Gas Threshold:");
  display.setCursor(0, 66);
  display.print(gasThreshold);
  
  // 高亮当前设置项
  switch(settingItem) {
    case 0:
      display.fillRect(0, 26, 50, 8, WHITE);
      display.setTextColor(BLACK);
      display.setCursor(0, 26);
      display.print(tempThreshold);
      display.print("C");
      display.setTextColor(WHITE);
      break;
    case 1:
      display.fillRect(0, 46, 50, 8, WHITE);
      display.setTextColor(BLACK);
      display.setCursor(0, 46);
      display.print(humThreshold);
      display.print("%");
      display.setTextColor(WHITE);
      break;
    case 2:
      display.fillRect(0, 66, 50, 8, WHITE);
      display.setTextColor(BLACK);
      display.setCursor(0, 66);
      display.print(gasThreshold);
      display.setTextColor(WHITE);
      break;
  }
}

void triggerAlarm() {
  static int blinkCount = 0;
  static bool buzzerState = false;
  
  // LED闪烁模式：快速闪烁3次
  if(blinkCount < 6) {
    digitalWrite(LED_PIN, blinkCount % 2 == 0);
    blinkCount++;
  } else {
    digitalWrite(LED_PIN, LOW);
    blinkCount = 0;
  }
  
  // 蜂鸣器警报音
  buzzerState = !buzzerState;
  if(buzzerState) {
    tone(BUZZER_PIN, 1000);
  } else {
    tone(BUZZER_PIN, 1500);
  }
}

void checkButtons() {
  // 读取当前按钮状态
  bool alarmOffState = digitalRead(ALARM_OFF_BTN);
  bool setModeState = digitalRead(SET_MODE_BTN);
  bool confirmState = digitalRead(CONFIRM_BTN);
  
  // 报警关闭/开启按钮处理
  if(alarmOffState == LOW && lastAlarmOffState == HIGH && millis() - lastDebounceTime > 300) {
    lastDebounceTime = millis();
    // 切换报警静音状态
    alarmSilenced = !alarmSilenced;
    Serial.println(alarmSilenced ? "Alarm silenced" : "Alarm enabled");
  }
  lastAlarmOffState = alarmOffState;
  
  // 设置模式按钮处理
  if(setModeState == LOW && lastSetModeState == HIGH && millis() - lastDebounceTime > 300) {
    lastDebounceTime = millis();
    settingMode = !settingMode;
    if(settingMode) {
      settingItem = 0; // 进入设置模式时重置为第一个设置项
    } else {
      // 保存阈值到EEPROM
      EEPROM.put(0, tempThreshold);
      EEPROM.put(sizeof(float), humThreshold);
      EEPROM.put(2*sizeof(float), gasThreshold);
    }
  }
  lastSetModeState = setModeState;
  
  // 确认/调整按钮处理
  if(confirmState == LOW && lastConfirmState == HIGH && millis() - lastDebounceTime > 300) {
    lastDebounceTime = millis();
    
    if(settingMode) {
      // 短按调整参数值
      switch(settingItem) {
        case 0: // 温度阈值
          tempThreshold += 1.0;
          if(tempThreshold > 100.0) tempThreshold = 0.0;
          break;
        case 1: // 湿度阈值
          humThreshold += 1.0;
          if(humThreshold > 100.0) humThreshold = 0.0;
          break;
        case 2: // 气体阈值
          gasThreshold += 10;
          if(gasThreshold > 1023) gasThreshold = 0;
          break;
      }
      // 立即更新显示
      displaySettingScreen();
      display.display();
    }
  }
  lastConfirmState = confirmState;
  
  // 在设置模式下，长按确认按钮切换设置项
  if(settingMode && confirmState == LOW && millis() - lastDebounceTime > 1000) {
    settingItem = (settingItem + 1) % 3;
    lastDebounceTime = millis();
    // 立即更新显示
    displaySettingScreen();
    display.display();
  }
}