#include <Arduino.h>
#include <Wire.h>               // specify use of Wire.h library for use of I2C communication
#include <U8g2lib.h>            // OLED display library (controller SSD1306, etc.)
// #include <qrcodegen.h>
// HARDWARE PINS ASSIGNMENTS
uint16_t WD_LED = 2;
uint16_t WD_state = 1;
int SDA_1  = 13;  // I2C interface pin SDA
int SCL_1  = 16;  // I2C interface pin SCL
U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE, SCL_1, SDA_1 );
String _s;
char char_arr[64];
uint8_t qrcodeArray[60][60];
const uint8_t qrcodeSize = 25;

void OLED_setup();
void OLED_print(int x, int y, int clear, const char* txt);
void OLED_barcode();

void setup() {
  Serial.begin(115200);
  delay(200);
  pinMode(WD_LED, OUTPUT);     // Watch dog LED  pin init
  WD_state = 1;
  digitalWrite(WD_LED, WD_state);

  Wire.begin(SDA_1, SCL_1);    // define pins for I2C
  OLED_setup();                // OLED display setup
  // OLED_print(0,37,1,"Controller boot...");
  delay(1000);
  Serial.println("Making buffer...");
  makeBuffer();
  delay(1000);
  OLED_pixel_test();
  delay(2000);
}

void loop() {
  if (WD_state == 1) {
    WD_state = 0;
  } else {
    WD_state = 1;
  }
  digitalWrite(WD_LED, WD_state);
  Serial.print("WD_state = "); Serial.println(WD_state);
  if (WD_state == 1) {
    _s = "WD state: " + String(WD_state);
    _s.toCharArray(char_arr, 22);
    OLED_print(0,37,1,char_arr);
  } else {
    // OLED_print(0,37,1,"QR code");

    OLED_barcode();

  }
  delay(10000);
}

void OLED_setup() {
  u8g2.begin();             // OLED display init
  u8g2.enableUTF8Print();   // OLED display init
  u8g2.clearBuffer();			  // clear the OLED display internal memory
  u8g2.setFont(u8g2_font_6x13_t_cyrillic);
}

void OLED_print(int x, int y, int clear, const char* txt) {    
  if (clear == 1) u8g2.clearDisplay();
  u8g2.setFont(u8g2_font_6x13_t_cyrillic);  // u8g2.setFont(u8g2_font_6x13_t_cyrillic);
  u8g2.drawStr(x,y,txt);
  u8g2.sendBuffer();
}

void OLED_pixel_test() {
  u8g2.clearDisplay();
  u8g2.setDrawColor(1);
  for (uint8_t i = 0; i < 100; i++) {
    u8g2.drawPixel(i, 10);
  }
  u8g2.display();
  u8g2.setDrawColor(2);
  for (uint8_t i = 0; i < 100; i++) {
    u8g2.drawPixel(i, 20);
  }
  u8g2.sendBuffer();

}

void OLED_barcode() {
  uint8_t _dot;
  u8g2.clearDisplay();
  for (uint8_t y = 0; y < qrcodeSize*2; y++)
  {
    for (uint8_t x = 0; x < qrcodeSize*2; x++)
    {
      _dot = qrcodeArray[y][x];
      if (_dot == 1) {
        u8g2.setDrawColor(1);          
      } else {
        u8g2.setDrawColor(0);
      }
      u8g2.drawPixel(x, y);
    }  
  }
  u8g2.sendBuffer();
}

void makeBuffer() {
  uint8_t qrcodeSample[25][25] =
  {
    {1,1,1,1,1,1,1,0,1,0,0,0,0,1,1,0,1,0,1,1,1,1,1,1,1},  // 1
    {1,0,0,0,0,0,1,0,1,0,0,1,1,1,1,0,1,0,1,0,0,0,0,0,1},  // 2
    {1,0,1,1,1,0,1,0,1,1,0,0,1,0,1,1,1,0,1,0,1,1,1,0,1},  // 3
    {1,0,1,1,1,0,1,0,1,1,1,0,0,0,1,1,1,0,1,0,1,1,1,0,1},  // 4
    {1,0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1},  // 5
    {1,0,0,0,0,0,1,0,1,1,1,0,1,0,1,0,0,0,1,0,0,0,0,0,1},  // 6
    {1,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1},  // 7
    {0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,1,1,0,0,0,0,0,0,0,0},  // 8
    {1,1,0,0,1,1,1,0,0,0,1,0,1,1,0,0,0,0,0,1,0,1,1,1,1},  // 9 
    {1,0,0,1,1,0,0,0,1,0,0,0,0,1,1,1,0,1,0,0,1,1,1,0,1},  // 10
    {1,0,1,1,1,0,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,0,0},  // 11
    {1,0,0,1,0,0,0,0,1,1,0,0,1,0,0,0,1,0,1,1,0,1,1,1,1},  // 12
    {0,0,1,0,0,0,1,0,0,0,0,0,1,1,0,1,1,0,1,0,0,0,1,0,1},  // 13
    {1,0,0,0,1,0,0,1,1,1,1,0,0,1,1,1,0,0,0,0,1,1,1,0,1},  // 14
    {0,0,1,1,1,0,1,1,1,1,0,1,1,1,0,1,0,0,1,0,1,0,1,0,0},  // 15
    {0,0,1,0,0,1,0,0,0,1,0,1,1,0,1,1,0,0,0,0,0,0,1,1,0},  // 16
    {1,1,0,0,0,1,1,0,0,0,0,0,1,1,0,1,1,1,1,1,1,0,0,1,0},  // 17
    {0,0,0,0,0,0,0,0,1,1,0,0,0,1,1,0,1,0,0,0,1,1,1,0,1},  // 18
    {1,1,1,1,1,1,1,0,0,1,0,1,1,1,0,1,1,0,1,0,1,0,1,0,0},  // 19
    {1,0,0,0,0,0,1,0,1,0,1,1,1,0,1,0,1,0,0,0,1,0,1,1,0},  // 20
    {1,0,1,1,1,0,1,0,1,0,0,0,1,1,0,0,1,1,1,1,1,0,1,1,0},  // 21
    {1,0,1,1,1,0,1,0,0,1,1,0,0,1,1,0,1,1,1,1,0,1,1,1,1},
    {1,0,1,1,1,0,1,0,0,1,0,1,0,0,1,0,1,1,0,1,0,0,0,1,0},
    {1,0,0,0,0,0,1,0,1,1,1,1,1,0,0,0,1,0,1,0,0,0,1,1,0},
    {1,1,1,1,1,1,1,0,1,1,1,0,1,1,0,1,0,0,1,0,1,0,1,1,1}
  };
  uint8_t _pixel = 0;
  for (uint8_t y = 0; y < qrcodeSize; y++)
  {
    for (uint8_t x = 0; x < qrcodeSize; x++)
    {
      _pixel = qrcodeSample[y][x]; 
      qrcodeArray[y*2][x*2]     = _pixel;
      qrcodeArray[y*2][x*2+1]   = _pixel;
      qrcodeArray[y*2+1][x*2]   = _pixel;
      qrcodeArray[y*2+1][x*2+1] = _pixel;
    }  
  }
}

/*
void makeBuffer() {
  uint8_t _pixel = 0;
  for (uint8_t y = 0; y < qrcodeSize; y++)
  {
    for (uint8_t x = 0; x < qrcodeSize; x++)
    {
      qrcodeArray[y*2][x*2]     = _pixel;
      qrcodeArray[y*2][x*2+1]   = _pixel;
      qrcodeArray[y*2+1][x*2]   = _pixel;
      qrcodeArray[y*2+1][x*2+1] = _pixel;
      if (_pixel == 1) {
        _pixel = 0;
      } else {
        _pixel = 1;
      }
    }  
  }
}
*/