#include <MD_Parola.h>
#include <MD_MAX72xx.h>

MD_Parola P = MD_Parola( MD_MAX72XX::PAROLA_HW, 12, 4 );

struct Substitute
{
	char const * const utf8;
	uint8_t const sub;
};

Substitute substitutes[] =
{
  { "Å", 0xC5 },
  { "Ä", 0xC4 },
  { "Ö", 0xD6 },
  { "å", 0xE5 },
  { "ä", 0xE4 },
  { "ö", 0xF6 },
};

size_t const substitutes_count = sizeof( substitutes ) / sizeof ( substitutes[0] );

char * replace_utf8( char * const str )
{
	char *p = str;

  while ( *p )
  {
    if ( (*p & 0xFF) > 127 )
    {
      for ( size_t i = 0; i < substitutes_count; ++i )
      {
        size_t len = strlen( substitutes[i].utf8 );

        if ( !strncmp( p, substitutes[i].utf8, len ) )
        {
          *p = substitutes[i].sub;
          strcpy( p + 1, p + len );
          break;
        }
      }
    }

    ++p;
  }
  
  return str;
}

uint8_t const smiley[] =
{
  4,
  0b00100100,
  0b01000000,
  0b01000000,
  0b00100100,
};

void setup()
{
  P.begin();
  P.addChar( 0xF6, smiley );

  char str[] = "ÅÄÖåäö";
  P.print( replace_utf8( str ) );
}

void loop()
{
}