// Demo using arcFill to draw ellipses and a segmented elipse
//#include <TFT_eSPI.h> // Hardware-specific library
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"
#include <SPI.h>

//TFT_eSPI tft = TFT_eSPI();       // Invoke custom library
#define TFT_DC 21
#define TFT_CS 22
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

#define DEG2RAD 0.0174532925
#define LOOP_DELAY 10 // Loop delay to slow things down

#define ENCODER_CLK 14
#define ENCODER_DT  12
#define ENCODER_SW  13

#define RED2RED 0
#define GREEN2GREEN 1
#define BLUE2BLUE 2
#define BLUE2RED 3
#define GREEN2RED 4
#define RED2GREEN 5


int counter = 0;

byte inc = 0;
unsigned int col = 0;

byte red = 31; // Red is the top 5 bits of a 16 bit colour value
byte green = 0;// Green is the middle 6 bits
byte blue = 0; // Blue is the bottom 5 bits
byte state = 0;

int tempValue = 0;

void setup(void) {

  pinMode(ENCODER_CLK, INPUT);
  pinMode(ENCODER_DT, INPUT);
  pinMode(ENCODER_SW, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(ENCODER_CLK), readEncoder, FALLING);

  tft.begin();
  tft.setRotation(1);
//  tft.fillScreen(TFT_BLACK);
  tft.fillScreen(ILI9341_BLACK);
}


void loop() {

  tempValue = getCounter();
//  fillArc(160, 120, tempValue * 6, 1, 120, 120, 10, rainbow(col));
  ringMeter(tempValue*5,0,200, 40, 5, 120," C",GREEN2RED); // Draw analogue meter
  
/*
  // Continuous elliptical arc drawing
  //fillArc(160, 120, inc * 6, 1, 140, 100, 10, rainbow(col));

  // Continuous segmented (inc*2) elliptical arc drawing
  //fillArc(160, 120, ((inc * 2) % 60) * 6, 1, 120, 80, 30, rainbow(col));
  fillArc(160, 120, ((inc * 3) % 60) * 6, 1, 120, 120, 10, rainbow(col));

  // Circle drawing using arc with arc width = radius
  //fillArc(160, 120, inc * 6, 1, 42, 42, 42, rainbow(col));

  inc++;
  col += 1;
  if (col > 191) col = 0;
  if (inc > 59) inc = 0;

  delay(LOOP_DELAY);
*/
}

void readEncoder() {
  int dtValue = digitalRead(ENCODER_DT);
  if (dtValue == HIGH) {
    counter++; // Clockwise
  }
  if (dtValue == LOW) {
    counter--; // Counterclockwise
  }
}

// Get the counter value, disabling interrupts.
// This make sure readEncoder() doesn't change the value
// while we're reading it.
int getCounter() {
  int result;
  noInterrupts();
  result = counter;
  interrupts();
  return result;
}

void resetCounter() {
  noInterrupts();
  counter = 0;
  interrupts();
}


// #########################################################################
// Draw a circular or elliptical arc with a defined thickness
// #########################################################################

// x,y == coords of centre of arc
// start_angle = 0 - 359
// seg_count = number of 6 degree segments to draw (60 => 360 degree arc)
// rx = x axis outer radius
// ry = y axis outer radius
// w  = width (thickness) of arc in pixels
// colour = 16 bit colour value
// Note if rx and ry are the same then an arc of a circle is drawn

void fillArc(int x, int y, int start_angle, int seg_count, int rx, int ry, int w, unsigned int colour)
{

  byte seg = 6; // Segments are 3 degrees wide = 120 segments for 360 degrees
  byte inc = 6; // Draw segments every 3 degrees, increase to 6 for segmented ring

  // Calculate first pair of coordinates for segment start
  float sx = cos((start_angle - 90) * DEG2RAD);
  float sy = sin((start_angle - 90) * DEG2RAD);
  uint16_t x0 = sx * (rx - w) + x;
  uint16_t y0 = sy * (ry - w) + y;
  uint16_t x1 = sx * rx + x;
  uint16_t y1 = sy * ry + y;

  // Draw colour blocks every inc degrees
  for (int i = start_angle; i < start_angle + seg * seg_count; i += inc) {

    // Calculate pair of coordinates for segment end
    float sx2 = cos((i + seg - 90) * DEG2RAD);
    float sy2 = sin((i + seg - 90) * DEG2RAD);
    int x2 = sx2 * (rx - w) + x;
    int y2 = sy2 * (ry - w) + y;
    int x3 = sx2 * rx + x;
    int y3 = sy2 * ry + y;

    tft.fillTriangle(x0, y0, x1, y1, x2, y2, colour);
    tft.fillTriangle(x1, y1, x2, y2, x3, y3, colour);

    // Copy segment end to sgement start for next segment
    x0 = x2;
    y0 = y2;
    x1 = x3;
    y1 = y3;
  }
}

// #########################################################################
// Return the 16 bit colour with brightness 0-100%
// #########################################################################
unsigned int brightness(unsigned int colour, int brightness)
{
  byte red   = colour >> 11;
  byte green = (colour & 0x7E0) >> 5;
  byte blue  = colour & 0x1F;

  blue =  (blue * brightness) / 100;
  green = (green * brightness) / 100;
  red =   (red * brightness) / 100;

  return (red << 11) + (green << 5) + blue;
}

// #########################################################################
// Return a 16 bit rainbow colour
// #########################################################################
unsigned int rainbow1(byte value)
{
  // Value is expected to be in range 0-127
  // The value is converted to a spectrum colour from 0 = blue through to 127 = red

  switch (state) {
    case 0:
      green ++;
      if (green == 64) {
        green = 63;
        state = 1;
      }
      break;
    case 1:
      red--;
      if (red == 255) {
        red = 0;
        state = 2;
      }
      break;
    case 2:
      blue ++;
      if (blue == 32) {
        blue = 31;
        state = 3;
      }
      break;
    case 3:
      green --;
      if (green == 255) {
        green = 0;
        state = 4;
      }
      break;
    case 4:
      red ++;
      if (red == 32) {
        red = 31;
        state = 5;
      }
      break;
    case 5:
      blue --;
      if (blue == 255) {
        blue = 0;
        state = 0;
      }
      break;
  }
  return red << 11 | green << 5 | blue;
}

// #########################################################################
//  Draw the meter on the screen, returns x coord of righthand side
// #########################################################################
int ringMeter(int value, int vmin, int vmax, int x, int y, int r, char *units, byte scheme)
{
  // Minimum value of r is about 52 before value text intrudes on ring
  // drawing the text first is an option
  
  x += r; y += r;   // Calculate coords of centre of ring

  int w = r / 12;    // Width of outer ring is 1/4 of radius
  
  int angle = 150;  // Half the sweep angle of meter (300 degrees)

  int text_colour = 0; // To hold the text colour

  int v = map(value, vmin, vmax, -angle, angle); // Map the value to an angle v

  byte seg = 10; // Segments are 5 degrees wide = 60 segments for 300 degrees
  byte inc = 12; // Draw segments every 5 degrees, increase to 10 for segmented ring

  // Draw colour blocks every inc degrees
  for (int i = -angle; i < angle; i += inc) {

    // Choose colour from scheme
    int colour = 0;
    switch (scheme) {
      case 0: colour = ILI9341_RED; break; // Fixed colour
      case 1: colour = ILI9341_GREEN; break; // Fixed colour
      case 2: colour = ILI9341_BLUE; break; // Fixed colour
      case 3: colour = rainbow(map(i, -angle, angle, 0, 127)); break; // Full spectrum blue to red
      case 4: colour = rainbow(map(i, -angle, angle, 85, 127)); break; // Green to red (high temperature etc)
      case 5: colour = rainbow(map(i, -angle, angle, 127, 63)); break; // Red to green (low battery etc)
      default: colour = ILI9341_BLUE; break; // Fixed colour
    }

    // Calculate pair of coordinates for segment start
    float sx = cos((i - 90) * 0.0174532925);
    float sy = sin((i - 90) * 0.0174532925);
    uint16_t x0 = sx * (r - w) + x;
    uint16_t y0 = sy * (r - w) + y;
    uint16_t x1 = sx * r + x;
    uint16_t y1 = sy * r + y;

    // Calculate pair of coordinates for segment end
    float sx2 = cos((i + seg - 90) * 0.0174532925);
    float sy2 = sin((i + seg - 90) * 0.0174532925);
    int x2 = sx2 * (r - w) + x;
    int y2 = sy2 * (r - w) + y;
    int x3 = sx2 * r + x;
    int y3 = sy2 * r + y;

    if (i < v) { // Fill in coloured segments with 2 triangles
      tft.fillTriangle(x0, y0, x1, y1, x2, y2, colour);
      tft.fillTriangle(x1, y1, x2, y2, x3, y3, colour);
      text_colour = colour; // Save the last colour drawn
    }
    else // Fill in blank segments
    {
      tft.fillTriangle(x0, y0, x1, y1, x2, y2, 128);
      tft.fillTriangle(x1, y1, x2, y2, x3, y3, 128);
    }
  }

  // Convert value to a string
  char buf[10];
  byte len = 4; if (value > 999) len = 5;
  dtostrf(value, len, 0, buf);

  // Set the text colour to default
  //tft.setTextColor(ILI9341_WHITE, ILI9341_BLACK);
  // Uncomment next line to set the text colour to the last segment value!
  // tft.setTextColor(text_colour, ILI9341_BLACK);
  
  // Print value, if the meter is large then use big font 6, othewise use 4
  //if (r > 84) tft.drawCentreString(buf, x - 5, y - 20, 6); // Value in middle
  //else tft.drawCentreString(buf, x - 5, y - 20, 4); // Value in middle

  // Print units, if the meter is large then use big font 4, othewise use 2
  //tft.setTextColor(ILI9341_WHITE, ILI9341_BLACK);
  //if (r > 84) tft.drawCentreString(units, x, y + 30, 4); // Units display
  //else tft.drawCentreString(units, x, y + 5, 2); // Units display

  // Calculate and return right hand side x coordinate
  return x + r;
}

// #########################################################################
// Return a 16 bit rainbow colour
// #########################################################################
unsigned int rainbow(byte value)
{
  // Value is expected to be in range 0-127
  // The value is converted to a spectrum colour from 0 = blue through to 127 = red

  byte red = 0; // Red is the top 5 bits of a 16 bit colour value
  byte green = 0;// Green is the middle 6 bits
  byte blue = 0; // Blue is the bottom 5 bits

  byte quadrant = value / 32;

  if (quadrant == 0) {
    blue = 31;
    green = 2 * (value % 32);
    red = 0;
  }
  if (quadrant == 1) {
    blue = 31 - (value % 32);
    green = 63;
    red = 0;
  }
  if (quadrant == 2) {
    blue = 0;
    green = 63;
    red = value % 32;
  }
  if (quadrant == 3) {
    blue = 0;
    green = 63 - 2 * (value % 32);
    red = 31;
  }
  return (red << 11) + (green << 5) + blue;
}

// #########################################################################
// Return a value in range -1 to +1 for a given phase angle in degrees
// #########################################################################
float sineWave(int phase) {
  return sin(phase * 0.0174532925);
}