/*
  ESP32 HTTPClient Jokes API Example

  https://wokwi.com/projects/342032431249883731

  Copyright (C) 2022, Uri Shaked
*/

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

#define TFT_DC 2
#define TFT_CS 15
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

// Meter colour schemes
#define RED2RED 0
#define GREEN2GREEN 1
#define BLUE2BLUE 2
#define BLUE2RED 3
#define GREEN2RED 4
#define RED2GREEN 5
#define ILI9341_GREY 0x2104 // Dark grey 16 bit colour


uint32_t runTime = -99999;       // time for next update

int reading = 0; // Value to be displayed
int d = 1; // Variable used for the sinewave test waveform


void setup() {
  tft.begin();
  tft.fillScreen(ILI9341_BLACK);
  tft.setRotation(1);
  tft.setTextColor(ILI9341_WHITE);
  tft.setTextSize(2);
}

void loop() {
//  tft.drawRoundRect(10, 10, 60, 20, 5, 0xFFE0);
//  delay(1);
    if (millis() - runTime >= 1000L) { // Execute every 2s
    runTime = millis();
/*
    // Test with a slowly changing value from a Sine function
    d += 1; if (d >= 360) d = 0;

    // Set the the position, gap between meters, and inner radius of the meters
    int xpos = 0, ypos = 5, gap = 4, radius = 52;

    // Draw meter and get back x position of next meter

    // Test with Sine wave function, normally reading will be from a sensor
    reading = 250 + 250 * sineWave(d+0);
    xpos = gap + ringMeter(reading, 0, 500, xpos, ypos, radius, "mA", GREEN2RED); // Draw analogue meter

    reading = 20 + 30 * sineWave(d+60);
    xpos = gap + ringMeter(reading, -10, 50, xpos, ypos, radius, "degC", BLUE2RED); // Draw analogue meter

    reading = 50 + 50 * sineWave(d + 120);
    ringMeter(reading, 0, 100, xpos, ypos, radius, "%RH", BLUE2BLUE); // Draw analogue meter


    // Draw two more larger meters
    xpos = 20, ypos = 115, gap = 24, radius = 64;

    reading = 1000 + 150 * sineWave(d + 90);
    xpos = gap + ringMeter(reading, 850, 1150, xpos, ypos, radius, "mb", BLUE2RED); // Draw analogue meter

    reading = 15 + 15 * sineWave(d + 150);
    xpos = gap + ringMeter(reading, 0, 30, xpos, ypos, radius, "Volts", GREEN2GREEN); // Draw analogue meter

    // Draw a large meter
    xpos = 40, ypos = 5, gap = 15, radius = 120;
    reading = 175;
*/
    // Comment out above meters, then uncomment the next line to show large meter
    ringMeter(175,0,200, 40,5,120," Watts",GREEN2RED); // Draw analogue meter
    }
}

// #########################################################################
//  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 / 4;    // Width of outer ring is 1/4 of radius
  
  int angle = 120;  // 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 = 1; // Segments are 5 degrees wide = 60 segments for 300 degrees
  byte inc = 10; // 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, 63, 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, ILI9341_GREY);
      tft.fillTriangle(x1, y1, x2, y2, x3, y3, ILI9341_GREY);
    }
  }

  // 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);
}