/* 
 * prof_autocomplete.c
 *
 * Copyright (C) 2012 James Booth <boothj5@gmail.com>
 * 
 * This file is part of Profanity.
 *
 * Profanity 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.
 *
 * Profanity 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 Profanity.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

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

#include <glib.h>

#include "common.h"
#include "prof_autocomplete.h"

struct p_autocomplete_t {
    GSList *items;
    GSList *last_found;
    gchar *search_str;
    PStrFunc str_func;
    PCopyFunc copy_func;
    GDestroyNotify free_func;
};

static gchar * _search_from(PAutocomplete ac, GSList *curr);
static const char *_str_func_default(const char *orig);
static const char *_copy_func_default(const char *orig);

PAutocomplete p_autocomplete_new(void)
{
    return p_obj_autocomplete_new(NULL, NULL, NULL);
}

PAutocomplete p_obj_autocomplete_new(PStrFunc str_func, PCopyFunc copy_func, 
    GDestroyNotify free_func)
{
    PAutocomplete new = malloc(sizeof(struct p_autocomplete_t));
    new->items = NULL;
    new->last_found = NULL;
    new->search_str = NULL;

    if (str_func)
        new->str_func = str_func;
    else
        new->str_func = (PStrFunc)_str_func_default;

    if (copy_func)
        new->copy_func = copy_func;
    else
        new->copy_func = (PCopyFunc)_copy_func_default;

    if (free_func)
        new->free_func = free_func;
    else
        new->free_func = (GDestroyNotify)free;

    return new;
}

void p_autocomplete_clear(PAutocomplete ac)
{
    g_slist_free_full(ac->items, ac->free_func);
    ac->items = NULL;

    p_autocomplete_reset(ac);
}

void p_autocomplete_reset(PAutocomplete ac)
{
    ac->last_found = NULL;
    if (ac->search_str != NULL) {
        free(ac->search_str);
        ac->search_str = NULL;
    }
}

gboolean p_autocomplete_add(PAutocomplete ac, void *item)
{
    if (ac->items == NULL) {
        ac->items = g_slist_append(ac->items, item);
        return TRUE;
    } else {
        GSList *curr = ac->items;
        
        while(curr) {
            
            // insert
            if (g_strcmp0(ac->str_func(curr->data), ac->str_func(item)) > 0) {
                ac->items = g_slist_insert_before(ac->items,
                    curr, item);
                return TRUE;
            
            // update
            } else if (g_strcmp0(ac->str_func(curr->data), ac->str_func(item)) == 0) {
                ac->free_func(curr->data);
                curr->data = item;
                return TRUE;
            }
            
            curr = g_slist_next(curr);
        }

        // hit end, append
        ac->items = g_slist_append(ac->items, item);

        return TRUE;
    }
}

gboolean p_autocomplete_remove(PAutocomplete ac, const char * const item)
{
    // reset last found if it points to the item to be removed
    if (ac->last_found != NULL)
        if (g_strcmp0(ac->str_func(ac->last_found->data), item) == 0)
            ac->last_found = NULL;

    if (!ac->items) {
        return FALSE;
    } else {
        GSList *curr = ac->items;
        
        while(curr) {
            if (g_strcmp0(ac->str_func(curr->data), item) == 0) {
                void *current_item = curr->data;
                ac->items = g_slist_remove(ac->items, curr->data);
                ac->free_func(current_item);
                
                return TRUE;
            }

            curr = g_slist_next(curr);
        }

        return FALSE;
    }
}

GSList * p_autocomplete_get_list(PAutocomplete ac)
{
    GSList *copy = NULL;
    GSList *curr = ac->items;

    while(curr) {
        copy = g_slist_append(copy, ac->copy_func(curr->data));
        curr = g_slist_next(curr);
    }

    return copy;
}

gchar * p_autocomplete_complete(PAutocomplete ac, gchar *search_str)
{
    gchar *found = NULL;

    // no items to search
    if (!ac->items)
        return NULL;

    // first search attempt
    if (ac->last_found == NULL) {
        ac->search_str = 
            (gchar *) malloc((strlen(search_str) + 1) * sizeof(gchar));
        strcpy(ac->search_str, search_str);

        found = _search_from(ac, ac->items);
        return found;

    // subsequent search attempt    
    } else {
        // search from here+1 tp end
        found = _search_from(ac, g_slist_next(ac->last_found));
        if (found != NULL)
            return found;

        // search from beginning
        found = _search_from(ac, ac->items);
        if (found != NULL)
            return found;
    
        // we found nothing, reset search
        p_autocomplete_reset(ac);
        return NULL;
    }
}

static gchar * _search_from(PAutocomplete ac, GSList *curr)
{
    while(curr) {
        
        // match found
        if (strncmp(ac->str_func(curr->data),
                ac->search_str,
                strlen(ac->search_str)) == 0) {
            gchar *result = 
                (gchar *) malloc((strlen(ac->str_func(curr->data)) + 1) * sizeof(gchar));
            
            // set pointer to last found
            ac->last_found = curr;

            // return the string, must be free'd by caller
            strcpy(result, ac->str_func(curr->data));
            return result;
        }

        curr = g_slist_next(curr);
    }

    return NULL;
}

static const char *_str_func_default(const char *orig) 
{
    return orig;
}

static const char *_copy_func_default(const char *orig)
{
    return strdup(orig);
}