// Example: https://wokwi.com/projects/289186888566178317
// FontGen: https://pjrp.github.io/MDParolaFontEditor
// Examples: https://github.com/MajicDesigns/MD_Parola/tree/main/examples

// Header file includes
#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include "Font.h"

// LEDs
#define HARDWARE_TYPE MD_MAX72XX::PAROLA_HW
#define MAX_DEVICES 3 // Define the number of displays connected
#define CLK_PIN    13 // CLK or SCK
#define DATA_PIN   11 // DATA or MOSI
#define CS_PIN     10 // CS or SS

// Fonts
#define CHAR_SPACING 1

// Hardware SPI connection
MD_MAX72XX mx = MD_MAX72XX(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

char message[64] = "1234";

void setup() {
  mx.begin();
  mx.setFont(compact);
}

void loop() {
  printText(0, MAX_DEVICES - 1, message);
}



// Functions

void printText(uint8_t modStart, uint8_t modEnd, char *pMsg)
// Print the text string to the LED matrix modules specified.
// Message area is padded with blank columns after printing.
{
  uint8_t   state = 0;
  uint8_t   curLen;
  uint16_t  showLen;
  uint8_t   cBuf[8];
  int16_t   col = ((modEnd + 1) * COL_SIZE) - 1;

  mx.control(modStart, modEnd, MD_MAX72XX::UPDATE, MD_MAX72XX::OFF);

  do     // finite state machine to print the characters in the space available
  {
    switch(state)
    {
      case 0: // Load the next character from the font table
        // if we reached end of message, reset the message pointer
        if (*pMsg == '\0')
        {
          showLen = col - (modEnd * COL_SIZE);  // padding characters
          state = 2;
          break;
        }

        // retrieve the next character form the font file
        showLen = mx.getChar(*pMsg++, sizeof(cBuf)/sizeof(cBuf[0]), cBuf);
        curLen = 0;
        state++;
        // !! deliberately fall through to next state to start displaying

      case 1: // display the next part of the character
        mx.setColumn(col--, cBuf[curLen++]);

        // done with font character, now display the space between chars
        if (curLen == showLen)
        {
          showLen = CHAR_SPACING;
          state = 2;
        }
        break;

      case 2: // initialize state for displaying empty columns
        curLen = 0;
        state++;
        // fall through

      case 3:	// display inter-character spacing or end of message padding (blank columns)
        mx.setColumn(col--, 0);
        curLen++;
        if (curLen == showLen)
          state = 0;
        break;

      default:
        col = -1;   // this definitely ends the do loop
    }
  } while (col >= (modStart * COL_SIZE));

  mx.control(modStart, modEnd, MD_MAX72XX::UPDATE, MD_MAX72XX::ON);
}