/*

 * compl.c      -- Completion system

 * 

 * Copyright (C) 2005 Mikael Berthe <bmikael@lists.lilotux.net>

 *

 * 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.

 *

 * 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, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307

 * USA

 */

/*  Usage, basically:

 * - new_completion();      // 1.   Initialization

 * - complete();            // 2.   1st completion

 * - cancel_completion();   // 3a.  2nd completion / cancel previous

 * - complete();            // 3b.  2nd completion / complete

 *   ...

 * - done_completion();     // n.   finished -- free allocated areas

 *

 */

#include <string.h>

#include "compl.h"

// Completion structure

typedef struct {

  GSList *list;         // list of matches

  guint len_prefix;     // length of text already typed by the user

  guint len_compl;      // length of the last completion

  GSList *next;         // pointer to next completion to try

} compl;

// Category structure

typedef struct {

  guint flag;

  GSList *words;

} category;

static GSList *Categories;

static compl *InputCompl;

//  new_completion(prefix, compl_cat)

// . prefix    = beginning of the word, typed by the user

// . compl_cat = pointer to a completion category list (list of *char)

// Returns a pointer to an allocated compl structure.  This structure should

// be freed by the caller when not used anymore.

void new_completion(char *prefix, GSList *compl_cat)

{

  compl *c;

  GSList *sl_cat;

  int len = strlen(prefix);

  if (InputCompl) { // This should not happen, but hey...

    cancel_completion();

  }

  c = g_new0(compl, 1);

  // Build the list of matches

  for (sl_cat=compl_cat; sl_cat; sl_cat = g_slist_next(sl_cat)) {

    char *word = sl_cat->data;

    if (!strncasecmp(prefix, word, len)) {

      if (strlen(word) != len)

        c->list = g_slist_append(c->list, g_strdup(word+len)); // TODO sort

    }

  }

  c->next = c->list;

  InputCompl = c;

}

//  done_completion();

void done_completion(void)

{

  if (!InputCompl)  return;

  // TODO free everything

  g_slist_free(InputCompl->list);

  g_free(InputCompl);

  InputCompl = NULL;

}

//  cancel_completion()

// Returns the number of chars to delete to cancel the completion

//guint cancel_completion(compl *c)

guint cancel_completion(void)

{

  if (!InputCompl)  return 0;

  return InputCompl->len_compl;

}

// Returns pointer to text to insert, NULL if no completion.

const char *complete()

{

  compl* c = InputCompl;

  char *r;

  if (!InputCompl)  return NULL;

  if (!c->next) {

    c->next = c->list;  // back to the beginning

    c->len_compl = 0;

    return NULL;

  }

  r = (char*)c->next->data;

  c->next = g_slist_next(c->next);

  c->len_compl = strlen(r);

  return r;

}

/* Categories functions */

//  compl_add_category_word(categ, command)

// Adds a keyword as a possible completion in category categ.

void compl_add_category_word(guint categ, const char *word)

{

  GSList *sl_cat;

  category *cat;

  char *nword;

  // Look for category

  for (sl_cat=Categories; sl_cat; sl_cat = g_slist_next(sl_cat)) {

    if (categ == ((category*)sl_cat->data)->flag)

      break;

  }

  if (!sl_cat) {   // Category not found, let's create it

    cat = g_new0(category, 1);

    cat->flag = categ;

    Categories = g_slist_append(Categories, cat);

  } else

    cat = (category*)sl_cat->data;

  // If word is not space-terminated, we add one trailing space

  for (nword = (char*)word; *nword; nword++)

    ;

  if (nword > word) nword--;

  if (*nword != ' ') {  // Add a space

    nword = g_new(char, strlen(word)+2);

    strcpy(nword, word);

    strcat(nword, " ");

  } else {              // word is fine

    nword = g_strdup(word);

  }

  // TODO Check word does not already exist

  cat->words = g_slist_append(cat->words, nword); // TODO sort

}

//  compl_get_category_list()

// Returns a slist of all words in the categories specified by the given flags

GSList *compl_get_category_list(guint cat_flags)

{

  GSList *sl_cat;

  // Look for category

  // XXX Actually that's not that simple... cat_flags can be a combination

  // of several flags!

  for (sl_cat=Categories; sl_cat; sl_cat = g_slist_next(sl_cat)) {

    if (cat_flags == ((category*)sl_cat->data)->flag)

      break;

  }

  if (sl_cat)       // Category was found, easy...

    return ((category*)sl_cat->data)->words;

  return NULL;

}