// --------------------------------------------------------------------------
// Sym-1 Notepad
//
// Wayne Parham
//
// wayne@parhamdata.com
// --------------------------------------------------------------------------
//
// Note:  This program requires RAM memory in locations 0xE000 - 0xEFFF
//        Alternatively,  the tape I/O buffer location and size can  be
//        changed by altering the defined TAPIO values below.
//
// --------------------------------------------------------------------------

#include <symio.h>;
#include <stdlib.h>;
#include <string.h>;

#define     TAPIO_ADDRESS      0xE000
#define     TAPIO_MAX_SIZE     0x0FFF

void main(void) {
   char  c                 =   0x00;
   int   l                 =   0x00;
   int   p                 =   0x00;
   int   error             =   0x00;
   int   running           =   0x01;
   int   writing           =   0x01;
   int instruction_needed  =   0x01;
   int   heap_size         =   0x00;
   char* tapio  = (char*) TAPIO_ADDRESS;
   char* buffer;

   heap_size = _heapmaxavail();

   if( heap_size > TAPIO_MAX_SIZE ) {  // No need to malloc more than
      heap_size = TAPIO_MAX_SIZE;      // the interface allows
   }

   buffer   = malloc( heap_size );
   memset( buffer, 0x00, heap_size );

   if( buffer == 0x00 ) {
      puts( "Memory full." );
      running = 0;
   }

   tapio[0] = 0x00;                    // Check tape interface memory
   if( tapio[0] != 0x00 )
      error = 1;

   tapio[0] = 0xFF;
   if( tapio[0] != 0xFF )
      error = 1;

   tapio[TAPIO_MAX_SIZE] = 0x00;
   if( tapio[TAPIO_MAX_SIZE] != 0x00 )
      error = 1;

   tapio[TAPIO_MAX_SIZE] = 0xFF;
   if( tapio[TAPIO_MAX_SIZE] != 0xFF )
      error = 1;

   if( error ) {
      printf( "\nNo memory at location %p, aborting.\n", tapio );
      running = 0;
   }
   else {
      memset( tapio, 0, TAPIO_MAX_SIZE );
   }	   


   while( running ) {

      putchar( '\r' );
      for( l = 0; l < 25; l++ ) {
         putchar( '\n' );
      }

      puts( "===================== Sym-1 Notepad ====================" );

      if( instruction_needed ) {
         puts( "Enter  text  and you can save it to tape  for  reloading" );
         puts( "later.  There are four special 'command' characters:\n" );
         puts( "   Control-S   Save to tape" );
         puts( "   Control-L   Load from tape" );
         puts( "   Control-C   Clear memory" );
         puts( "   Control-X   Exit" );
         puts( "========================================================\n" );
      }

      while( writing ) {

         c = getchar();

         if( c == 0x08 ) {             // Backspace
            if( p > 0 ) {
               buffer[p] = 0x00;
               p--;
            }
         }
         else if( c == 0x13 ) {        // Save
            puts( "\n========================= Save =========================" );
            puts( "\nPress any key to save." );
            c = getchar();
            for( l = 0; l <= p; l++ ) {
               tapio[l] = buffer[l];
            }
            l++;
            tapio[l] = 0x00;
            puts( "Saving to tape." );
            error = dumpt( 'N', (int) tapio, (int) tapio+p );
            if( error ) {
               puts( "\nTape error." );
            }
            else
            {
               putchar( '\r' );
               for( l = 0; l < 25; l++ ) {
                  putchar( '\n' );
               }
            }
            puts( "===================== Sym-1 Notepad ====================\n" );
            for( l = 0; l <= p; l++ ) {
               putchar( buffer[l] );
               if( buffer[l] == '\r' ) {
                  putchar( '\n' );
               }
            }
         }
         else if( c == 0x0C ) {        // Load
            p = 0;
            puts( "\nLoading from tape." );
            memset( buffer, 0, heap_size );
            memset( tapio, 0, TAPIO_MAX_SIZE );
            error = loadt( 'N' );
            if( error ) {
               puts( "\nTape error." );
               puts( "===================== Sym-1 Notepad ====================\n" );
            }
            else
            {
               for( l = 0; l <= heap_size; l++ ) {
                  buffer[l] = tapio[l];
               }

	       p = strlen( buffer );

               putchar( '\r' );
               for( l = 0; l < 25; l++ ) {
                  putchar( '\n' );
               }
               puts( "===================== Sym-1 Notepad ====================\n" );

               for( l = 0; l <= p; l++ ) {
                  putchar( buffer[l] );
                  if( buffer[l] == '\r' ) {
                     putchar( '\n' );
                  }
               }
            }
         }
         else if( c == 0x03 ) {        // Clear
            p = 0;
            memset( buffer, 0, heap_size );
            putchar( '\r' );
            for( l = 0; l < 25; l++ ) {
               putchar( '\n' );
            }
            puts( "===================== Sym-1 Notepad ====================\n" );
         }
         else if( c == 0x18 ) {        // Exit
            writing = 0;
            running = 0;
         }
         else {
            if( p >= heap_size - 1 ) {
               puts( "\n========================= End  =========================" );
               puts( "Buffer full." );
            }
            else {
               if( c == '\r' ) {
                  putchar( '\n' );
               }
               buffer[p] = c;
               putchar( c );
            }
            p++;
         }
      }
   }

   free( buffer );

   puts( "\nEnjoy your day!\n" );

   return;
}