#include "SPI.h"
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"

#define TFT_DC 48
#define TFT_CS 53
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);


#define RED     0xc086
#define WHITE   0xffff
#define BLUE    0x010d

void setup() {
 
  tft.begin();
  tft.setRotation(3);

}

// --- Random RGB565 color generator ---
uint16_t randomRGB565() {
    
  uint8_t r = random(0, 32);   // 5-bit red
  uint8_t g = random(0, 64);   // 6-bit green
  uint8_t b = random(0, 32);   // 5-bit blue

  return (r << 11) | (g << 5) | b;

}

void loop(void) {

    uint16_t randomUS      = randomRGB565();
    uint16_t randomUK      = randomRGB565();
    uint16_t randomStripes = randomRGB565();
    uint16_t randomBox     = randomRGB565();
    uint16_t randomStars   = randomRGB565();
    uint16_t randomScot    = randomRGB565();
    uint16_t randomEng     = randomRGB565();


    tft.fillScreen(randomUS);

    // draw stripes
    for (int y = 0; y <= 222; y += 37) {
        drawStripe(y, randomStripes);
    }

    // draw box
    tft.fillRect(0, 0, 174, 129, randomBox);
    
    // draw stars
    for (int j = 3; j <= 107; j += 26) {
        
        for (int i = 3; i <= 155; i += 30) {
            drawStar(i, j, randomStars);
        }

        if (j < 107) {
            for (int i = 18; i <= 140; i += 30) {
                drawStar(i, j + 13, randomStars);
            }
        }
    }

    delay(1000);

    tft.fillScreen(randomUK);
    
    // draw white diagonals
    tft.fillTriangle(0, 0, 0, 31, 279, 239, randomScot);
    tft.fillTriangle(0, 0, 319, 239, 279, 239, randomScot);
    tft.fillTriangle(0, 0, 36, 0, 319, 239, randomScot);
    tft.fillTriangle(36, 0, 319, 239, 319, 208, randomScot);

    tft.fillTriangle(0, 239, 0, 209, 279, 0, randomScot);
    tft.fillTriangle(0, 239, 279, 0, 319, 0, randomScot);
    tft.fillTriangle(0, 239, 319, 0, 319, 30, randomScot);
    tft.fillTriangle(319, 30, 0, 239, 40, 239, randomScot);

    // draw white cross
    tft.fillRect(120, 0, 80, 240, randomScot);
    tft.fillRect(0, 79, 320, 80, randomScot);

    // draw red cross
    tft.fillRect(136, 0, 48, 240, randomEng);
    tft.fillRect(0, 96, 320, 48, randomEng);

     // draw red diagonals
    tft.fillTriangle(0, 0, 108, 79, 78, 79, randomEng);
    tft.fillTriangle(0, 0, 0, 20, 78, 79, randomEng);

    tft.fillTriangle(200, 69, 200, 79, 294, 0, randomEng);
    tft.fillTriangle(200, 79, 294, 0, 319, 0, randomEng);
    tft.fillTriangle(319, 0, 214, 79, 200, 79, randomEng);

    tft.fillTriangle(210, 159, 319, 239, 319, 220, randomEng);
    tft.fillTriangle(319, 220, 237, 159, 210, 159, randomEng);

    tft.fillTriangle(0, 239, 107, 159, 120, 159, randomEng);
    tft.fillTriangle(120, 159, 0, 239, 26, 239, randomEng);
    tft.fillTriangle(26, 239, 120, 159, 120, 169, randomEng);

    delay(1000);
}

void drawStar(int x, int y, uint16_t color) {
    tft.fillTriangle(x + 7, y + 0, x + 9, y + 6, x + 5, y + 6, color);
    tft.fillTriangle(x + 14, y + 5, x + 6, y + 11, x + 5, y + 5, color);
    tft.fillTriangle(x + 12, y + 14, x + 4, y + 8, x + 9, y + 6, color);
    tft.fillTriangle(x + 2, y + 14, x + 5, y + 6, x + 10, y + 8, color);
    tft.fillTriangle(x + 0, y + 5, x + 9, y + 5, x + 8, y + 11, color);
}

void drawStripe(int y, uint16_t color) {
    tft.fillRect(0, y, 320, 18, color);

}