/* savegame.c - save/load game etc
 *
 * 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 2 of the License, or (at your option) any later version.
 */
#include <gtk/gtk.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <time.h>
#include <stdlib.h>

#include "game.h"

gint parse_save_game(gchar *sgame, gchar **rules, gint *score, gint **board, gint **next)
{
   struct stat buf;
   gchar  *sdata, *psdata, *srules;
   FILE   *f;
   gint   i, val;
   gint rw, rh, rc, rn, rd, rlen;

   if (stat(sgame, &buf) != 0 || !S_ISREG(buf.st_mode) || buf.st_size < 20 || (f = fopen(sgame, "r")) == NULL) {
      return 0;
   }

   sdata = g_malloc(buf.st_size);

   if (fread(sdata, 1, buf.st_size, f) != (size_t) buf.st_size) {
      g_free (sdata);
      return 0;
   }

   fclose(f);

   rlen = rules_get_str_len();
   srules = g_malloc(rlen + 1);
   srules[rlen] = 0;
   memcpy(srules, sdata, rlen);

   if (!rules_get_from_str(srules, &rw, &rh, &rc, &rn, &rd) ||
      sscanf(sdata + rlen, "%010u", score) != 1 ||
      buf.st_size != rlen + 10 + rw * rh * 2 + rn * 2) {
      printf("[%s]\n", srules);
      g_free (srules);
      g_free (sdata);
      return 0;
   }

   g_free (srules);

   *board = g_malloc(rw * rh * sizeof(gint));
   *next = g_malloc(rn * sizeof(gint));

   psdata = sdata + rlen + 10;
   for (i = 0; i < rw * rh; i++, psdata += 2) {
      if (sscanf(psdata, "%02d", &val) != 1 || val < 0 || val > rc) {
         g_free (*next);
         g_free (*board);
         g_free (sdata);
         return 0;
      }
      (*board)[i] = val;
   }

   for (i = 0; i < rn; i++, psdata += 2) {
      if (sscanf(psdata, "%02d", &val) != 1 || val < 0 || val > rc) {
         g_free (*next);
         g_free (*board);
         g_free (sdata);
         return 0;
      }
      (*next)[i] = val;
   }

   *rules = g_strndup(sdata, rlen);
   g_free (sdata);

   return 1;
}


/* check that save game name is in form YYYY-MM-DD-HHMMSS.sav and have correct content
   return string "DD.MM.YYYY HH:MM:SS (score)" on success, NULL on failure */
gchar *is_valid_save_game(gchar *name, gchar *path)
{
   guint i, y, m, d, h, min, s;
   gint score, *board, *next;
   gchar *sgame;
   gchar *rules;

   if ((i = sscanf(name, "%04u-%02u-%02u-%02u%02u%02u", &y, &m, &d, &h, &min, &s)) != 6 ||
      !m || m > 12 || !d || d > 31 || h > 23 || min > 59 || s > 61 ||
      (strcmp(name + strlen(name) - 4, ".sav") != 0)) {
         return NULL;
   }

   sgame=g_strconcat(path, G_DIR_SEPARATOR_S, name, NULL);

   i = parse_save_game(sgame, &rules, &score, &board, &next);
   g_free (sgame);

   if (!i) return NULL;

   g_free (rules);
   g_free (board);
   g_free (next);

   return g_strdup_printf("%02d.%02d.%04d %02d:%02d:%02d (%d)",
                     d, m, y, h, min, s, score);
/* FIXME: return rules back
        return g_strdup_printf("%02d.%02d.%04d %02d:%02d:%02d (%d [%dx%d %d %d %d])",
                     d, m, y, h, min, s, score,
                     rules.xsize, rules.ysize, rules.colors, rules.next, rules.destroy);
*/
}


gint get_saved_games(gchar ***gamelist)
{
   gchar  *datapath;
   struct stat buf;
   struct dirent *dir_entry;
   DIR    *directory;
   gchar  **games = NULL, *game;
   gint   num = 0;

   datapath = g_strconcat(getenv("HOME"), G_DIR_SEPARATOR_S, ".gtkballs", NULL);
   if (stat(datapath, &buf) != 0) { /* no ~/.gtkballs */
      if (mkdir(datapath, 0700) != 0) { /* and cannot create it... */
         g_free (datapath);
         return -1;
      }
   } else if (!S_ISDIR(buf.st_mode)) { /* ~/.gtkballs is not a directory */
      g_free (datapath);
      return -1;
   }
   if ((directory = opendir(datapath)))
   {
      while ((dir_entry = readdir(directory))) {
         if ((game = is_valid_save_game(dir_entry->d_name, datapath)) != NULL) {
            num++;
            games = g_realloc(games, sizeof(gchar *) * num * 2);
            games[(num - 1) * 2] = game;
            games[(num - 1) * 2 + 1] = g_strdup_printf("%s%s%s", datapath, G_DIR_SEPARATOR_S, dir_entry->d_name);
         }
      }
      closedir(directory);
   }
   g_free (datapath);
   *gamelist = games;
   return num;
}


gchar *save_game(gchar *rules, gint score, gint *board, gint *nextcolors)
{
   FILE *f;
   gchar *fname;
   time_t nowtime;
   gchar  ftime[]="0000-00-00-000000";
   gint i;

   nowtime = time(NULL);
   strftime(ftime, sizeof(ftime), "%Y-%m-%d-%H%M%S", localtime(&nowtime));
   fname = g_strconcat(getenv("HOME"), G_DIR_SEPARATOR_S, ".gtkballs",
                       G_DIR_SEPARATOR_S, ftime, ".sav", NULL);
   if ((f = fopen(fname, "w")) != NULL) {
      chmod(fname, 0600);
      /* TODO: check for errors ! */
      fprintf(f, rules);
      fprintf(f, "%010d", score);
      for (i = 0; i < rules_get_width() * rules_get_height(); i++) {
         fprintf(f, "%02d", board[i]);
      }
      for (i = 0; i < rules_get_next(); i++) {
         fprintf(f, "%02d", nextcolors[i]);
      }
      fclose(f);
   } else {
      return fname;
   }

   g_free (fname);

   return NULL;
}