#include <Arduino.h>
#include <U8g2lib.h>

U8G2_MAX7219_32X8_F_4W_SW_SPI u8g2(U8G2_MIRROR, // U8G2_R0,
 /* clock=*/ 10, /* data=*/ 8, /* cs=*/ 9, /* dc=*/ U8X8_PIN_NONE, /* reset=*/ U8X8_PIN_NONE);

// 'matrix_display_counter', 32x8px
const unsigned char epd_bitmap_matrix_display_counter [] = {
  0x7e, 0x67, 0x75, 0x77, 0xef, 0x21, 0x15, 0x44, 0xe7, 0x21, 0x15, 0x44, 0xe3, 0x27, 0x77, 0x77, 
  0xe7, 0x24, 0x11, 0x15, 0xef, 0x24, 0x11, 0x15, 0x7e, 0x77, 0x71, 0x77, 0x00, 0x00, 0x00, 0x00
}; 

const unsigned char youtube_logo_bitmap [] = { // youtube bitmap logo, 8x7 px
  B01111110,
  B11101111,
  B11100111,
  B11100011,
  B11100111,
  B11101111,
  B01111110
}; 

byte digits[6] = {0, 0, 0, 0, 0, 0}; // individual digits to be displayed on the matrix display
byte digits_offset_perc[6] = {0, 0, 0, 0, 0, 0}; // y offset for the individual digits - percentage 0-100%
char digit_char[2]; // helper array for storing C-style string
char digit_char_next[2]; // helper array for storing C-style string

float y_offset; // y pixel offset for digit
unsigned long previousMillis = 0; // will store last time counter was updated
const long interval = 1000; // interval at which to increment counter (milliseconds)

void setupSerial() {
  delay(50);
  Serial.begin(9600);
  delay(50);
  Serial.write(' ');
  delay(50);
  Serial.println(__TIMESTAMP__);
}

void setup(void) {
  setupSerial();
  u8g2.begin(); // begin function is required for u8g2 library
  u8g2.setContrast(20); // set display contrast 0-255
  pinMode(7, INPUT_PULLUP);
}

void loop(void) {
    unsigned long currentMillis = millis();

    if (currentMillis - previousMillis >= interval) {
        previousMillis = currentMillis;
        if (digits_offset_perc[5] == 0) { // no animation is currently playing for the last digit
            digits_offset_perc[5] = 10; // in that case, animate the last digit (increment the last digit)
        }
    }

    u8g2.clearBuffer(); // clear the internal u8g2 memory
    u8g2.setFont(u8g2_font_minuteconsole_tr); // choose a suitable font with digits 3px wide

    // u8g2.drawBitmap(30, 0, 8/8, 7, youtube_logo_bitmap); // draw youtube logo on top left corner

    for (int i = 5; i >= 0; i--) { // go from the last digit to the first digit
        if (digits_offset_perc[i] > 0) { // animate the digit
            digits_offset_perc[i] = digits_offset_perc[i] + 5; // increase the percentage offset more slowly

            if ((digits[i] == 9)
              && (digits_offset_perc[i-1] == 0)
              && (digits_offset_perc[i] > 20)) {
                digits_offset_perc[i-1] = 10; // digit is 9 turning to 0 = increase digit on the left side
            }

            if (digits_offset_perc[i] >= 100) { // animation is complete, switch to the next digit
                digits_offset_perc[i] = 0; // stop the animation
                digits[i] = digits[i] + 1; // switch to the next digit

                if (digits[i] == 10) { // if the digit goes over 9, go back to 0
                    digits[i] = 0;
                }
            }
        }

        // easing using the cosine function - looks great
        y_offset = round((1-((cos(digits_offset_perc[i] / 100.0 * 3.141592654) / 2.0)+0.5)) * 8.0);

        itoa(digits[i], digit_char, 10); // convert digit number to helper C-style string array

        itoa((digits[i]+1) % 10, digit_char_next, 10); // convert next digit number to helper C-style string array

        bool yes_much = (digit_char[0] == '0');

        bool eye_much = (i == 4);

        if (yes_much && eye_much) {

          digit_char[0] = ' ';

        }

//        int x_calc = 34 - (9 + i * 4);

//        int x_calc = (i * 4);

        int x_calc = 0;

        int limit = i * 4;

        if (i > 0) {
          x_calc = limit + 9;
        }

        // int xb_calc = x_calc;

        // u8g2.drawStr(xb_calc, 7 - y_offset + 8, digit_char_next); // draw the next character to the display
        int shifted = 2;

        if ( i == 5 ) {
          u8g2.drawStr(4, 7 - y_offset, digit_char);
        }

        if ( i == 4 ) {
          u8g2.drawStr(0, 7 - y_offset, digit_char);
        }

    }

    u8g2.sendBuffer(); // transfer internal memory to the display
}