/*
==================================================
  EPD 2.9" DISPLAY DEMO FOR ARDUINO IDE
  SIMULATES E-PAPER GRAPHICS
  BY ARVIND
==================================================

  HARDWARE:
  Arduino UNO / NANO
  Waveshare 2.9" EPD

  LIBRARIES:
  GxEPD2
  Adafruit GFX

  INSTALL:
  Arduino IDE ->
  Library Manager ->
  Install:
    - GxEPD2
    - Adafruit GFX

==================================================
  CONNECTIONS
==================================================

EPD MODULE        ARDUINO UNO

VCC      -------> 3.3V
GND      -------> GND
DIN      -------> D11
CLK      -------> D13
CS       -------> D10
DC       -------> D9
RST      -------> D8
BUSY     -------> D7

==================================================
*/

#include <GxEPD2_BW.h>
#include <Adafruit_GFX.h>
#include <Fonts/FreeMonoBold12pt7b.h>

// ------------------------------------------------
// DISPLAY DRIVER
// ------------------------------------------------
// 2.9 inch 296x128 display

GxEPD2_BW<GxEPD2_290, GxEPD2_290::HEIGHT> display(
  GxEPD2_290(
    10,   // CS
    9,    // DC
    8,    // RST
    7     // BUSY
  )
);

// ------------------------------------------------
// VARIABLES
// ------------------------------------------------
unsigned long lastChange = 0;
int screenIndex = 0;

// ------------------------------------------------
// SCREEN 1
// ------------------------------------------------
void screen1()
{
  display.setFullWindow();
  display.firstPage();

  do
  {
    display.fillScreen(GxEPD_WHITE);

    display.setTextColor(GxEPD_BLACK);
    display.setFont(&FreeMonoBold12pt7b);

    display.setCursor(20, 35);
    display.println("HELLO");

    display.setCursor(20, 70);
    display.println("ARVIND");

    display.drawLine(10, 85, 280, 85, GxEPD_BLACK);

    display.setCursor(20, 115);
    display.println("EPD 2.9 DEMO");

  } while (display.nextPage());
}

// ------------------------------------------------
// SCREEN 2
// ------------------------------------------------
void screen2()
{
  display.setFullWindow();
  display.firstPage();

  do
  {
    display.fillScreen(GxEPD_WHITE);

    display.drawRect(20, 20, 100, 60, GxEPD_BLACK);

    display.drawCircle(220, 50, 30, GxEPD_BLACK);

    display.fillCircle(220, 50, 10, GxEPD_BLACK);

    display.setCursor(30, 110);
    display.println("GRAPHICS TEST");

  } while (display.nextPage());
}

// ------------------------------------------------
// SCREEN 3
// ------------------------------------------------
void screen3()
{
  display.setFullWindow();
  display.firstPage();

  do
  {
    display.fillScreen(GxEPD_WHITE);

    for (int i = 0; i < 296; i += 20)
    {
      display.drawLine(i, 0, 296 - i, 127, GxEPD_BLACK);
    }

    display.setCursor(25, 65);
    display.println("ARDUINO");

    display.setCursor(25, 95);
    display.println("+ EPD");

  } while (display.nextPage());
}

// ------------------------------------------------
// SCREEN 4
// ------------------------------------------------
void screen4()
{
  display.setFullWindow();
  display.firstPage();

  do
  {
    display.fillScreen(GxEPD_WHITE);

    display.setCursor(20, 30);
    display.println("TEMP : 28C");

    display.setCursor(20, 65);
    display.println("HUM  : 65%");

    display.setCursor(20, 100);
    display.println("STATUS OK");

    // Battery Icon
    display.drawRect(220, 20, 45, 20, GxEPD_BLACK);
    display.fillRect(265, 26, 5, 8, GxEPD_BLACK);
    display.fillRect(225, 25, 30, 10, GxEPD_BLACK);

  } while (display.nextPage());
}

// ------------------------------------------------
// SETUP
// ------------------------------------------------
void setup()
{
  Serial.begin(115200);

  display.init();

  display.setRotation(1);

  screen1();

  lastChange = millis();
}

// ------------------------------------------------
// LOOP
// ------------------------------------------------
void loop()
{
  if (millis() - lastChange > 5000)
  {
    screenIndex++;

    if (screenIndex > 3)
      screenIndex = 0;

    switch (screenIndex)
    {
      case 0:
        screen1();
        break;

      case 1:
        screen2();
        break;

      case 2:
        screen3();
        break;

      case 3:
        screen4();
        break;
    }

    lastChange = millis();
  }
}