/*
 * Mimas conversion tools
 *
 * Copyright (C) 2010 Benjamin Moody
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

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

#include "output.h"
#include "utils.h"

ti8x_file *ti8x_file_new(const char *name)
{
  ti8x_file *f;

  f = xnew(ti8x_file, 1);
  f->name = xstrdup(name);
  f->num_vars = 0;
  f->vars = NULL;
  return f;
}

void ti8x_file_free(ti8x_file *f)
{
  int i;

  if (!f)
    return;

  if (f->vars) {
    for (i = 0; i < f->num_vars; i++) {
      if (f->vars[i]) {
	xfree(f->vars[i]->data);
	xfree(f->vars[i]);
      }
    }
  }

  xfree(f->name);
  xfree(f->vars);
  xfree(f);
}

ti8x_var_entry *ti8x_file_add_var(ti8x_file *f,
				  unsigned int type,
				  const char *name,
				  int archived)
{
  ti8x_var_entry *v;

  f->num_vars++;
  f->vars = xrenew(ti8x_var_entry *, f->vars, f->num_vars);
  f->vars[f->num_vars - 1] = v = xnew(ti8x_var_entry, 1);

  v->type = type;
  v->archived = archived;
  strncpy(v->name, name, 8);
  v->name[8] = 0;
  v->length = 0;
  v->length_a = 0;
  v->data = NULL;
  return v;
}

void ti8x_var_append_data(ti8x_var_entry *var,
			  const unsigned char *data,
			  unsigned int length)
{
  if (var->length + length > var->length_a) {
    var->length_a = var->length + length + 1024;
    var->data = xrenew(unsigned char, var->data, var->length_a);
  }

  if (data)
    memcpy(var->data + var->length, data, length);
  else
    memset(var->data + var->length, 0, length);

  var->length += length;
}

static unsigned int checksum(const unsigned char *data, unsigned int length)
{
  unsigned int n;
  n = 0;
  while (length != 0) {
    n += *data;
    data++;
    length--;
  }
  return n;
}

int ti8x_file_write(FILE *outf, ti8x_file *f)
{
  unsigned char hdr[55];
  unsigned int total_size;
  int i;
  unsigned int sum;

  total_size = 0;
  for (i = 0; i < f->num_vars; i++)
    total_size += 2 + 13 + 2 + f->vars[i]->length;

  if (total_size >= 0x10000) {
    fprintf(stderr, "Cannot write %s: contents too large (%u)",
	    f->name, total_size);
    return 1;
  }

  memset(hdr, 0, sizeof(hdr));
  memcpy(hdr, "**TI83F*\032\012", 11);

  hdr[53] = total_size;
  hdr[54] = total_size >> 8;

  if (fwrite(hdr, 1, 55, outf) != 55) {
    fprintf(stderr, "Error writing %s\n", f->name);
    return 1;
  }

  sum = 0;

  for (i = 0; i < f->num_vars; i++) {
    /* var header */
    hdr[0] = 13;
    hdr[1] = 0;
    hdr[2] = f->vars[i]->length;
    hdr[3] = f->vars[i]->length >> 8;
    hdr[4] = f->vars[i]->type;
    strncpy((char *) &hdr[5], f->vars[i]->name, 8);
    hdr[13] = 0;
    hdr[14] = f->vars[i]->archived ? 0x80 : 0;

    /* length of var data */
    hdr[15] = f->vars[i]->length;
    hdr[16] = f->vars[i]->length >> 8;

    if (fwrite(hdr, 1, 17, outf) != 17
	|| (fwrite(f->vars[i]->data, 1, f->vars[i]->length, outf)
	    != f->vars[i]->length)) {
      fprintf(stderr, "Error writing %s\n", f->name);
      return 1;
    }

    sum += checksum(hdr, 17) + checksum(f->vars[i]->data, f->vars[i]->length);
  }

  hdr[0] = sum;
  hdr[1] = sum >> 8;
  if (fwrite(hdr, 1, 2, outf) != 2) {
    fprintf(stderr, "Error writing %s\n", f->name);
    return 1;
  }

  return 0;
}