//SPDX-FileCopyrightText: 2025 Ethan Masse <guitaristocrat@aol.com>
//
//SPDX-License-Identifier: CC-BY-SA-4.0 OR AGPL-3.0-or-later

/*
 * WS4TOTXT: a converter from WordStar 4.0 files
 * to pleasant .TXT files. Strips the high bit
 * and inserts newlines.
 *
 * Copyright (C) 2025  Ethan Masse
 *
 * This program is free software: you can redistribute
 * it and/or modify it under the terms of the GNU
 * Affero General Public License as published by the
 * Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Affero General Public License for more details.
 *
 * You should have received a copy of the GNU
 * Affero General Public License along with this
 * program.  If not, see
 * <https://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <assert.h>
#include <stdlib.h>

int
debug_convert_ws4_and_print(FILE* input_file)
{
  int current_byte = EOF; /*Maybe not actually be a byte?*/
  int stripped_byte = 0;

  do
  {
    if (input_file == NULL)
    {
      (void)(fprintf(stderr, "Conversion failed.\n"));
      return 1;
    }

    current_byte = fgetc(input_file);

    if (ferror(input_file) != 0)
    {
      (void)(fprintf(stderr, "Error reading file\n"));
      return 1;
    }

    if (current_byte != EOF)
    {
      stripped_byte = current_byte & 0x7F;

      if (stripped_byte != current_byte)
      {
        (void)(printf("\{"));
      }

      if ((stripped_byte & 0x1F) == stripped_byte)
      {
        (void)(printf("\<%d\>", stripped_byte));
      }
      else
      {
	(void)(printf("%c", stripped_byte));
      }

      if (stripped_byte != current_byte)
      {
        (void)(printf("\}"));
      }

      if ((stripped_byte == 13) ||
	  (stripped_byte == 10))
      {
	(void)(printf("\n"));
      }
    }
  } while (current_byte != EOF);

  return 0;
}

int
convert_ws4_and_print(FILE* input_file)
{
  int current_byte = EOF;

  int stripped_byte = 0;

  do
  {
    if (input_file == NULL)
    {
      (void)(fprintf(stderr, "Conversion failed.\n"));
      return 1;
    }

    current_byte = fgetc(input_file);

    if (ferror(input_file) != 0)
    {
      (void)(fprintf(stderr, "Error reading file\n"));
      return 1;
    }

    if (current_byte != EOF)
    {
      stripped_byte = current_byte & 0x7F;

      if (stripped_byte == 13)
      {
        current_byte = fgetc(input_file);

	if (ferror(input_file) != 0)
	{
	  (void)(fprintf(stderr, "Error reading file\n"));
	  return 1;
	}

	if (current_byte == EOF)
	{
	  return 0;
	}

	stripped_byte = current_byte & 0x7F;
	if (stripped_byte == 10)
	{
	  (void)(printf("\n"));
	}
      }
      else
      {
        if ((stripped_byte & 0x1F) != stripped_byte)
        {
	  (void)(printf("%c", stripped_byte));
        }
      }
    }
  } while (current_byte != EOF);

  return 0;
}

int
main(int argc, char** argv)
{
  FILE* current_input_file = NULL;
  int index = 1;
  char* current_file_name = NULL;
  const int debug_flag = 0;

  for (; index < argc; index++)
  {
    current_file_name = argv[index];

    if (current_file_name == NULL)
    {
      (void)(fprintf(stderr, "Error: CLI argument %d invalid\n", index));
    }

    (void)(assert(current_file_name != NULL));

    current_input_file = fopen(current_file_name, "rb");

    if (current_input_file == NULL)
    {
      (void)(fprintf(stderr, "Error: file %s not found\n", current_file_name));
    }

    (void)(assert(current_input_file != NULL));

    (void)(printf("Printing file %s as txt:\n\n", current_file_name));

    if (debug_flag != 0)
    {
      if (debug_convert_ws4_and_print(current_input_file) != 0)
      {
        (void)(fprintf(stderr, "Error: debug conversion failed on %s\n", current_file_name));
      }
    }

    else
    {
      if (convert_ws4_and_print(current_input_file) != 0)
      {
        (void)(fprintf(stderr, "Error: txt conversion failed on %s\n", current_file_name));
      }
    }

    (void)(assert(current_input_file != NULL));

    if (fclose(current_input_file) != 0)
    {
      (void)(fprintf(stderr, "Error: couldn't close file %s\n", current_file_name));
      return 1;
    }

    current_input_file = NULL;
  }

  return 0;
}