#include <Wire.h>
#include <LiquidCrystal_I2C_Hangul.h>

// 定義I2C地址，通常是0x27或0x3F，請根據您的LCD型號進行調整
#define I2C_ADDR 0x27

// 建立LiquidCrystal_I2C物件
LiquidCrystal_I2C_Hangul lcd(I2C_ADDR, 16, 2); // 16列，2行

const int buttonPin = 2;     //計時按鈕
const int ledPin = 13;       //ＬＥＤ燈
const int buzzerPin = 9;     //蜂鳴器
boolean buttonState = 0;     //按鈕的目前狀態，預設值為0表示沒按下
boolean lastButtonState = 0; //記錄上一次按鈕的狀態
unsigned long startTime;     //開始時間
const unsigned long interval = 180000;    //三分鐘

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);

  // 初始化LCD
  lcd.init();                      // 初始化LCD
  lcd.backlight();                 // 開啟背光
  lcd.setCursor(0, 0);
  lcd.print("Time: ");
}

void loop() {
  buttonState = digitalRead(buttonPin);

  if (buttonState == HIGH && lastButtonState == LOW) {
    startTime = millis();
  }

  if (buttonState == HIGH && (millis() - startTime >= interval)) {
    digitalWrite(ledPin, HIGH);
    tone(buzzerPin, 1000);
    lcd.setCursor(6, 0);
    lcd.print("3:00");
  } else {
    digitalWrite(ledPin, LOW);
    noTone(buzzerPin);
    lcd.setCursor(6, 0);
    unsigned long elapsedTime = (millis() - startTime) / 1000;
    int minutes = elapsedTime / 60;
    int seconds = elapsedTime % 60;
    lcd.print(minutes);
    lcd.print(":");
    if (seconds < 10) {
      lcd.print("0");
    }
    lcd.print(seconds);
  }

  lastButtonState = buttonState;
}