#include <Wire.h>
#include <U8g2lib.h>

#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)
#define SCREEN_ADDRESS 0x3C // I2C address for the OLED

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset= */ OLED_RESET);

unsigned long startTime = 0;
const unsigned long duration = 30000; // 30 seconds in milliseconds

void setup() {
  // Initialize the OLED display
  u8g2.begin();

  // Start the timer
  startTime = millis();
}

void loop() {
  // Calculate remaining time
  unsigned long currentTime = millis();
  unsigned long elapsedTime = currentTime - startTime;
  unsigned long remainingTime = max(0, duration - elapsedTime);
  unsigned int secondsRemaining = remainingTime / 1000;

  // Calculate progress
  float progress = (float)elapsedTime / duration;
  // Ensure progress does not exceed 1.0
  progress = min(progress, 1.0);

  // Display on the OLED
  u8g2.firstPage();
  do {
    // Display "RC LUDO FUEL PUMP" in small font, centered
    u8g2.setFont(u8g2_font_profont10_tf);
    u8g2.drawStr(2, 7, "RC LUDO FUEL PUMP");

    // Display "FILL START" in medium font, centered
    u8g2.setFont(u8g2_font_profont22_tf);
    int textWidth = u8g2.getStrWidth("FILL START");
    u8g2.drawStr((SCREEN_WIDTH - textWidth) / 2, 28, "FILL START");

    // Display the remaining seconds on the second line
    u8g2.setFont(u8g2_font_profont22_tf);
    char secondsString[15]; // Adjusted size to accommodate the largest possible string
    snprintf(secondsString, sizeof(secondsString), "Timer %us", (unsigned int)secondsRemaining);
    textWidth = u8g2.getStrWidth(secondsString);
    u8g2.drawStr((SCREEN_WIDTH - textWidth) / 2, 47, secondsString);

    // Draw the progress bar frame
    u8g2.drawFrame(10, 54, SCREEN_WIDTH - 20, 10);

    // Draw the progress bar
    int barWidth = (SCREEN_WIDTH - 20 - 2) * progress;
    u8g2.drawBox(12, 56, barWidth, 6);
  } while (u8g2.nextPage());

  // If 30 seconds elapsed, reset the timer
  if (elapsedTime >= duration) {
    startTime = currentTime;
  }

  // Update every 100 milliseconds
  delay(100);
}