/*  SSNES - A Super Nintendo Entertainment System (SNES) Emulator frontend for libsnes.
 *  Copyright (C) 2010-2011 - Hans-Kristian Arntzen
 *
 *  Some code herein may be based on code found in BSNES.
 * 
 *  SSNES 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 Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  SSNES 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 SSNES.
 *  If not, see <http://www.gnu.org/licenses/>.
 */


#include "config_file.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include "../strl.h"

#if !defined(_WIN32) && !defined(__CELLOS_LV2__)
#include <sys/param.h> // MAXPATHLEN
#elif defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif

#ifndef MAXPATHLEN
#ifdef PATH_MAX
#define MAXPATHLEN PATH_MAX
#else
#define MAXPATHLEN 512
#endif
#endif

#define MAX_INCLUDE_DEPTH 16

struct entry_list
{
   bool readonly; // If we got this from an #include, do not allow write.
   char *key;
   char *value;
   struct entry_list *next;
};

struct include_list
{
   char *path;
   struct include_list *next;
};

struct config_file
{
   char *path;
   struct entry_list *entries;
   struct entry_list *tail;
   unsigned include_depth;

   struct include_list *includes;
};

static config_file_t *config_file_new_internal(const char *path, unsigned depth);

static char *getaline(FILE *file)
{
   char *newline = malloc(9);
   size_t cur_size = 8;
   size_t index = 0;

   int in = getc(file);
   while (in != EOF && in != '\n')
   {
      if (index == cur_size)
      {
         cur_size *= 2;
         newline = realloc(newline, cur_size + 1);
      }

      newline[index++] = in;
      in = getc(file);
   }
   newline[index] = '\0';
   return newline; 
}

static char *extract_value(char *line, bool is_value)
{
   if (is_value)
   {
      while (isspace(*line))
         line++;

      // If we don't have an equal sign here, we've got an invalid string...
      if (*line != '=')
         return false;

      line++;
   }

   while (isspace(*line))
      line++;

   // We have a full string. Read until next ".
   if (*line == '"')
   {
      line++;
      char *tok = strtok(line, "\"");
      if (!tok)
         return false;
      return strdup(tok);
   }
   else if (*line == '\0') // Nothing :(
      return NULL;
   else // We don't have that... Read till next space.
   {
      char *tok = strtok(line, " \n\t\f\r\v");
      if (tok)
         return strdup(tok);
      else
         return NULL;
   }
}

static void set_list_readonly(struct entry_list *list)
{
   while (list)
   {
      list->readonly = true;
      list = list->next;
   }
}

// Move semantics? :)
static void add_child_list(config_file_t *parent, config_file_t *child)
{
   if (parent->entries)
   {
      struct entry_list *head = parent->entries;
      while (head->next)
         head = head->next;

      set_list_readonly(child->entries);
      head->next = child->entries;
   }
   else
   {
      set_list_readonly(child->entries);
      parent->entries = child->entries;
   }

   child->entries = NULL;

   // Rebase tail.
   if (parent->entries)
   {
      struct entry_list *head = parent->entries;
      while (head->next)
         head = head->next;
      parent->tail = head;
   }
   else
      parent->tail = NULL;
}

static void add_include_list(config_file_t *conf, const char *path)
{
   struct include_list *head = conf->includes;
   struct include_list *node = calloc(1, sizeof(*node));
   node->path = strdup(path);

   if (head)
   {
      while (head->next)
         head = head->next;

      head->next = node;
   }
   else
      conf->includes = node;
}

static void add_sub_conf(config_file_t *conf, char *line)
{
   char *path = extract_value(line, false);
   if (!path)
      return;

   add_include_list(conf, path);

   char real_path[MAXPATHLEN];

#ifdef _WIN32
   // Accomodate POSIX systems on Win32.
   bool is_full_path = *path == '/';

   if (is_full_path)
      strlcpy(real_path, path, sizeof(real_path));
   else
      GetFullPathNameA(path, sizeof(real_path), real_path, NULL);

   if (strcmp(path, real_path) != 0)
   {
      strlcpy(real_path, conf->path, sizeof(real_path));
      char *split = strrchr(real_path, '/');
      if (!split)
         split = strrchr(real_path, '\\');

      split[1] = '\0';
      strlcat(real_path, path, sizeof(real_path));
   }
#else
   if (*path == '/')
   {
      strlcpy(real_path, path, sizeof(real_path));
   }
#ifndef __CELLOS_LV2__
   else if (*path == '~')
   {
      const char *home = getenv("HOME");
      strlcpy(real_path, home ? home : "/", sizeof(real_path));
      strlcat(real_path, path + 1, sizeof(real_path));
   }
#endif
   else
   {
      strlcpy(real_path, conf->path, sizeof(real_path));
      char *split = strrchr(real_path, '/');
      if (split)
      {
         split[1] = '\0';
         strlcat(real_path, path, sizeof(real_path));
      }
      else
         strlcpy(real_path, path, sizeof(real_path));
   }
#endif

   config_file_t *sub_conf = config_file_new_internal(real_path, conf->include_depth + 1);
   if (!sub_conf)
   {
      free(path);
      return;
   }

   // Pilfer internal list! :D
   add_child_list(conf, sub_conf);
   config_file_free(sub_conf);
   free(path);
}

static bool parse_line(config_file_t *conf, struct entry_list *list, char *line)
{
   // Remove everything after comment.
   char *comment = strchr(line, '#');
   if (comment)
      *comment = '\0';

   // Starting line with # and include includes config files. :)
   if ((comment == line) && (conf->include_depth < MAX_INCLUDE_DEPTH))
   {
      comment++;
      if (strstr(comment, "include ") == comment)
      {
         add_sub_conf(conf, comment + strlen("include "));
         return false;
      }
   }
   else if (conf->include_depth >= MAX_INCLUDE_DEPTH)
      fprintf(stderr, "!!! #include depth exceeded for config! Might be a cycle.\n");

   // Skips to first character.
   while (isspace(*line))
      line++;

   char *key = malloc(9);
   size_t cur_size = 8;
   size_t index = 0;

   while (isgraph(*line))
   {
      if (index == cur_size)
      {
         cur_size *= 2;
         key = realloc(key, cur_size + 1);
      }

      key[index++] = *line++;
   }
   key[index] = '\0';
   list->key = key;

   list->value = extract_value(line, true);
   if (!list->value)
   {
      list->key = NULL;
      free(key);
      return false;
   }

   return true;
}

static config_file_t *config_file_new_internal(const char *path, unsigned depth)
{
   struct config_file *conf = calloc(1, sizeof(*conf));
   if (!conf)
      return NULL;

   if (!path)
      return conf;

   conf->path = strdup(path);
   if (!conf->path)
   {
      free(conf);
      return NULL;
   }

   conf->include_depth = depth;

   FILE *file = fopen(path, "r");
   if (!file)
   {
      free(conf->path);
      free(conf);
      return NULL;
   }

   while (!feof(file))
   {
      struct entry_list *list = calloc(1, sizeof(*list));
      char *line = getaline(file);

      if (line)
      {
         if (parse_line(conf, list, line))
         {
            if (conf->entries)
            {
               conf->tail->next = list;
               conf->tail = list;
            }
            else
            {
               conf->entries = list;
               conf->tail = list;
            }
         }

         free(line);
      }

      if (list != conf->tail)
         free(list);
   }
   fclose(file);

   return conf;
}

config_file_t *config_file_new(const char *path)
{
   return config_file_new_internal(path, 0);
}

void config_file_free(config_file_t *conf)
{
   if (!conf)
      return;

   struct entry_list *tmp = conf->entries;
   while (tmp)
   {
      free(tmp->key);
      free(tmp->value);
      struct entry_list *hold = tmp;
      tmp = tmp->next;
      free(hold);
   }

   struct include_list *inc_tmp = conf->includes;
   while (inc_tmp)
   {
      free(inc_tmp->path);
      struct include_list *hold = inc_tmp;
      inc_tmp = inc_tmp->next;
      free(hold);
   }

   free(conf->path);
   free(conf);
}

bool config_get_double(config_file_t *conf, const char *key, double *in)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         *in = strtod(list->value, NULL);
         return true;
      }
      list = list->next;
   }
   return false;
}

bool config_get_int(config_file_t *conf, const char *key, int *in)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         errno = 0;
         int val = strtol(list->value, NULL, 0);
         if (errno == 0)
         {
            *in = val;
            return true;
         }
         return
            false;
      }
      list = list->next;
   }
   return false;
}

bool config_get_hex(config_file_t *conf, const char *key, unsigned *in)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         errno = 0;
         unsigned val = strtoul(list->value, NULL, 16);
         if (errno == 0)
         {
            *in = val;
            return true;
         }
         else
            return false;
      }
      list = list->next;
   }
   return false;
}

bool config_get_char(config_file_t *conf, const char *key, char *in)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         if (list->value[0] && list->value[1])
            return false;
         *in = *list->value;
         return true;
      }
      list = list->next;
   }
   return false;
}

bool config_get_string(config_file_t *conf, const char *key, char **str)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         *str = strdup(list->value);
         return true;
      }
      list = list->next;
   }
   return false;
}

bool config_get_array(config_file_t *conf, const char *key, char *buf, size_t size)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         strlcpy(buf, list->value, size);
         return true;
      }
      list = list->next;
   }
   return false;
}

bool config_get_bool(config_file_t *conf, const char *key, bool *in)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(key, list->key) == 0)
      {
         if (strcasecmp(list->value, "true") == 0)
            *in = true;
         else if (strcasecmp(list->value, "1") == 0)
            *in = true;
         else if (strcasecmp(list->value, "false") == 0)
            *in = false;
         else if (strcasecmp(list->value, "0") == 0)
            *in = false;
         else
            return false;

         return true;
      }
      list = list->next;
   }
   return false;
}

void config_set_string(config_file_t *conf, const char *key, const char *val)
{
   struct entry_list *list = conf->entries;
   struct entry_list *last = list;
   while (list)
   {
      if (!list->readonly && (strcmp(key, list->key) == 0))
      {
         free(list->value);
         list->value = strdup(val);
         return;
      }

      last = list;
      list = list->next;
   }

   struct entry_list *elem = calloc(1, sizeof(*elem));
   elem->key = strdup(key);
   elem->value = strdup(val);

   if (last)
      last->next = elem;
   else
      conf->entries = elem;
}

void config_set_double(config_file_t *conf, const char *key, double val)
{
   char buf[128];
   snprintf(buf, sizeof(buf), "%lf", val);
   config_set_string(conf, key, buf);
}

void config_set_int(config_file_t *conf, const char *key, int val)
{
   char buf[128];
   snprintf(buf, sizeof(buf), "%d", val);
   config_set_string(conf, key, buf);
}

void config_set_char(config_file_t *conf, const char *key, char val)
{
   char buf[2];
   snprintf(buf, sizeof(buf), "%c", val);
   config_set_string(conf, key, buf);
}

void config_set_bool(config_file_t *conf, const char *key, bool val)
{
   config_set_string(conf, key, val ? "true" : "false");
}

bool config_file_write(config_file_t *conf, const char *path)
{
   FILE *file;

   if (path)
   {
      file = fopen(path, "w");
      if (!file)
         return false;
   }
   else
      file = stdout;

   config_file_dump(conf, file);

   if (path)
      fclose(file);

   return true;
}

void config_file_dump(config_file_t *conf, FILE *file)
{
   struct include_list *includes = conf->includes;
   while (includes)
   {
      fprintf(file, "#include \"%s\"\n", includes->path);
      includes = includes->next;
   }

   struct entry_list *list = conf->entries;
   while (list)
   {
      if (!list->readonly)
         fprintf(file, "%s = \"%s\"\n", list->key, list->value);
      list = list->next;
   }
}

void config_file_dump_all(config_file_t *conf, FILE *file)
{
   struct include_list *includes = conf->includes;
   while (includes)
   {
      fprintf(file, "#include \"%s\"\n", includes->path);
      includes = includes->next;
   }

   struct entry_list *list = conf->entries;
   while (list)
   {
      fprintf(file, "%s = \"%s\" %s\n", list->key, list->value, list->readonly ? "(included)" : "");
      list = list->next;
   }
}

bool config_entry_exists(config_file_t *conf, const char *entry)
{
   struct entry_list *list = conf->entries;

   while (list)
   {
      if (strcmp(entry, list->key) == 0)
         return true;
      list = list->next;
   }

   return false;
}