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

#define TFT_DC 9
#define TFT_CS 10
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

void setup() {
  tft.begin();
  tft.setCursor(26, 120);
  tft.setTextColor(ILI9341_RED);
  tft.setTextSize(3);
  tft.println("Hello, TFT!");

  tft.setCursor(20, 160);
  tft.setTextColor(ILI9341_GREEN);
  tft.setTextSize(2);
  tft.println("I can has colors?");

  Serial.begin(115200);
  pinMode(A0, INPUT);
}

void loop() { 
  int inputValue = analogRead(A0);
  drawProgressBar(0, 10, 128, 20, 0, 1023, inputValue, 0, 100);
  drawDial(64, 72, 30, 0, 1023, inputValue, 0, 100);
  Serial.println(inputValue);
  delay(100);
}

void drawDial(int x, int y, int radius, int inputMin, int inputMax, int inputValue, int guageMin, int guageMax){
  // 270 sets travel angle of guage needle.
  int DIAL_TRAVEL_DEGS = 270;
  // -225 sets start position of guage needle.
  int DIAL_START_POSITION = -225;

  int progress = getGuageValue(inputMin, inputMax, inputValue, guageMin, guageMax);
  progress = DIAL_TRAVEL_DEGS / guageMax * progress;
  
  int angle = progress + DIAL_START_POSITION;
  float radAngle = radians(angle);
  
  int endX = x + (cos(radAngle) * (radius-3));
  int endY = y + (sin(radAngle) * (radius-3));

  tft.drawLine(x, y, endX, endY, ILI9341_RED);
  tft.drawCircle(x, y, radius, 255);
}

void drawProgressBar(int x, int y, int w, int h, float inputMin, float inputMax, float inputValue, float guageMin, float guageMax){
  int margin = 5;
  tft.drawRect(x, y, w, h, ILI9341_RED);
  int progress = getGuageValue(inputMin, inputMax, inputValue, guageMin, guageMax);
  progress = map(progress, guageMin, guageMax, 0, w-(2*margin)); // Use the map function for scaling
  tft.fillRect(x+margin, y+margin, progress, h-(margin*2), ILI9341_BLUE);  
}

int getGuageValue(float inputMin, float inputMax, float inputValue, float guageMin, float guageMax) {
  float value = inputValue;
  value = value / (inputMax - inputMin);
  return int(value * (guageMax - guageMin));
}