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

#define SCREEN_WIDTH 128 // OLED width,  in pixels
#define SCREEN_HEIGHT 64 // OLED height, in pixels

// create an OLED display object connected to I2C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

unsigned long startTime;
unsigned long countdownSeconds = 0.5 * 24 * 60 * 60; // ใส่จำนวนวัน
String selectedVegetable = ""; // ใส่ชื่อผักที่เลือก


void setup() {
  Serial.begin(115200);
  
  Wire.begin();
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.clearDisplay();
  display.setTextColor(WHITE);
  
  startTime = millis();
}

void loop() {
  // ตรวจสอบว่ามีข้อมูลใหม่จาก Serial หรือไม่ (จำลองการรับข้อมูลจากแอพฯ)
  if (Serial.available()) {
    selectedVegetable = Serial.readStringUntil('\n');
    selectedVegetable.trim();
    Serial.println("Received: " + selectedVegetable);
    startTime = millis(); // รีเซ็ตเวลาเริ่มต้นเมื่อได้รับชื่อผักใหม่
  }

  unsigned long currentTime = millis();
  unsigned long elapsedSeconds = (currentTime - startTime) / 1000;
  
  if (elapsedSeconds < countdownSeconds) {
    unsigned long remainingSeconds = countdownSeconds - elapsedSeconds;
    unsigned long days = remainingSeconds / 86400;
    unsigned long hours = (remainingSeconds % 86400) / 3600;
    unsigned long minutes = (remainingSeconds % 3600) / 60;
    unsigned long seconds = remainingSeconds % 60;
    
    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(0, 0);
    
    if (selectedVegetable != "") {
      display.println(selectedVegetable);
    } else {
      display.println("Waiting for selection");
    }
    
    display.setTextSize(2);
    display.setCursor(0, 16);
    char timeStr[20];
    sprintf(timeStr, "%02ld : %02ld : %02ld : %02ld", days, hours, minutes, seconds);
    display.println(timeStr);
    
    display.display();
    
    Serial.print("Time left: ");
    Serial.println(timeStr);
  } else {
    display.clearDisplay();
    display.setTextSize(2);
    display.setCursor(0, 24);
    display.println("Time's up!");
    display.display();
    
    Serial.println("Time's up!");
  }
  
  delay(1000);
}