#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>

#define TFT_CS 10
#define TFT_DC 9
#define SCREEN_HEIGHT 240
#define SCREEN_WIDTH 320

#define SCREEN_REFRESH_RATE 100

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

#define arrSize(X) sizeof(X) / sizeof(X[0])

int course = 310;
int target = 27;

int circleRadius = 50;

void drawBearing(int angle, uint16_t colour) { 
    tft.drawLine(
    tft.width() / 2,
    tft.height() / 2,
    tft.width() / 2 + circleRadius * sin(angle * M_PI / 180.),
    tft.height() / 2 - circleRadius * cos(angle * M_PI / 180.),
    colour);
}

void erasePreviousBearingLines() {
  drawBearing(course, ILI9341_BLUE);
  drawBearing(target, ILI9341_BLUE);
}

void printNewBearingLines() {
  drawBearing(course, ILI9341_GREEN);
  drawBearing(target, ILI9341_RED);
}

void setup() {
  Serial.begin(9600);
  randomSeed(analogRead(0));
  tft.begin();
  tft.setRotation(1);
  tft.fillScreen(ILI9341_BLACK);

  tft.fillCircle(tft.width() / 2, tft.height() / 2, circleRadius, ILI9341_BLUE);
}

void loop() { 
static uint32_t timeCapture;
  if ((millis() - timeCapture) > SCREEN_REFRESH_RATE) {
    timeCapture = millis();
    erasePreviousBearingLines();
    course = random(360);
    target = random(360);
    printNewBearingLines();
  }
}