/*
 * ============================================================
 *  OLED 0.96" 128×64 I2C Display (SSD1306) — Sample Sketch
 *  Tishvi Electronics | guide.tishvi.com
 * ============================================================
 *  Wiring (I2C):
 *    OLED GND → Arduino GND
 *    OLED VCC → Arduino 5V
 *    OLED SCL → Arduino A5
 *    OLED SDA → Arduino A4
 *
 *  I2C Address: 0x3C  (default for most SSD1306 modules)
 *
 *  Libraries required — install via Arduino IDE Library Manager:
 *    1. Adafruit SSD1306        (search: "Adafruit SSD1306")
 *    2. Adafruit GFX Library   (search: "Adafruit GFX")
 *
 *  What this sketch does:
 *    1. Initialises the OLED display
 *    2. Shows a Tishvi welcome screen with border
 *    3. After 2 seconds, shows a live counter (counts up every second)
 *    4. Also demonstrates text size, cursor positioning, and clearing
 * ============================================================
 */

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

// ── Display Configuration ────────────────────────────────────
#define SCREEN_WIDTH  128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1        // No reset pin on 4-pin I2C modules
#define OLED_ADDRESS  0x3C     // Default I2C address

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// ── Counter variable ─────────────────────────────────────────
unsigned long counter = 0;

void setup() {
  Serial.begin(9600);

  // ── Initialise display ──────────────────────────────────
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
    Serial.println("ERROR: OLED not found at 0x3C!");
    Serial.println("Check wiring: SDA → A4, SCL → A5, VCC → 5V");
    while (true);  // Stop if display not found
  }

  Serial.println("OLED initialised successfully.");

  // ── Welcome Screen ──────────────────────────────────────
  display.clearDisplay();

  // Draw a border
  display.drawRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, SSD1306_WHITE);

  // Title
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(14, 10);
  display.println("TISHVI");

  // Subtitle
  display.setTextSize(1);
  display.setCursor(18, 32);
  display.println("OLED Ready!");

  // Small note
  display.setCursor(12, 46);
  display.println("guide.tishvi.com");

  display.display();   // Push buffer to screen
  delay(2500);         // Show welcome for 2.5 seconds
}

void loop() {
  // ── Counting Screen ─────────────────────────────────────
  display.clearDisplay();

  // Header
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("  Tishvi OLED Sample");
  display.drawLine(0, 10, SCREEN_WIDTH, 10, SSD1306_WHITE);

  // Label
  display.setCursor(0, 18);
  display.setTextSize(1);
  display.println("Counter:");

  // Large counter value
  display.setCursor(0, 32);
  display.setTextSize(3);
  display.println(counter);

  // Footer
  display.setTextSize(1);
  display.setCursor(0, 56);
  display.print("SSD1306  128x64");

  display.display();   // Push to screen

  Serial.print("Counter: ");
  Serial.println(counter);

  counter++;
  delay(1000);         // Increment every second
}