/*
 * pluma-taglist-plugin-parser.c
 * This file is part of pluma
 *
 * Copyright (C) 2002-2005 - Paolo Maggi
 *
 * 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., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

/*
 * Modified by the pluma Team, 2002-2005. See the AUTHORS file for a
 * list of people on the pluma Team.
 * See the ChangeLog files for a list of changes.
 *
 * $Id$
 */

/* FIXME: we should rewrite the parser to avoid using DOM */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>
#include <libxml/parser.h>
#include <glib.h>
#include <glib/gi18n.h>

#include <pluma/pluma-debug.h>

#include "pluma-taglist-plugin-parser.h"

#define USER_PLUMA_TAGLIST_PLUGIN_LOCATION "pluma/taglist/"

TagList* taglist = NULL;
static gint taglist_ref_count = 0;

static gboolean	 parse_tag (Tag *tag, xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur);
static gboolean	 parse_tag_group (TagGroup *tg, const gchar *fn,
				  xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur,
				  gboolean sort);
static TagGroup* get_tag_group (const gchar* filename, xmlDocPtr doc,
				xmlNsPtr ns, xmlNodePtr cur);
static TagList* lookup_best_lang (TagList *taglist, const gchar *filename,
				xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur);
static TagList 	*parse_taglist_file (const gchar* filename);
static TagList  *parse_taglist_dir (const gchar *dir);

static void	 free_tag (Tag *tag);
static void	 free_tag_group (TagGroup *tag_group);

static gboolean
parse_tag (Tag *tag, xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur)
{
	/*
	pluma_debug_message (DEBUG_PLUGINS, "  Tag name: %s", tag->name);
	*/
	/* We don't care what the top level element name is */
	cur = cur->xmlChildrenNode;

	while (cur != NULL)
	{
		if ((!xmlStrcmp (cur->name, (const xmlChar *)"Begin")) &&
		    (cur->ns == ns))
		{
			tag->begin = xmlNodeListGetString (doc, cur->xmlChildrenNode, 1);
			/*
			pluma_debug_message (DEBUG_PLUGINS, "    - Begin: %s", tag->begin);
			*/
		}

		if ((!xmlStrcmp (cur->name, (const xmlChar *)"End")) &&
		    (cur->ns == ns))
		{
			tag->end = xmlNodeListGetString (doc, cur->xmlChildrenNode, 1);
			/*
			pluma_debug_message (DEBUG_PLUGINS, "    - End: %s", tag->end);
			*/
		}

		cur = cur->next;
	}

	if ((tag->begin == NULL) && (tag->end == NULL))
		return FALSE;

	return TRUE;
}

static gint
tags_cmp (gconstpointer a, gconstpointer b)
{
	gchar *tag_a = (gchar*)((Tag *)a)->name;
	gchar *tag_b = (gchar*)((Tag *)b)->name;

	return g_utf8_collate (tag_a, tag_b);
}

static gboolean
parse_tag_group (TagGroup *tg, const gchar* fn, xmlDocPtr doc,
		 xmlNsPtr ns, xmlNodePtr cur, gboolean sort)
{
	pluma_debug_message (DEBUG_PLUGINS, "Parse TagGroup: %s", tg->name);

	/* We don't care what the top level element name is */
    	cur = cur->xmlChildrenNode;

	while (cur != NULL)
	{
		if (xmlStrcmp (cur->name, (const xmlChar *) "comment") == 0)
		{
			cur = cur->next;
		}

		if ((xmlStrcmp (cur->name, (const xmlChar *) "Tag")) || (cur->ns != ns))
		{
			g_warning ("The tag list file '%s' is of the wrong type, "
				   "was '%s', 'Tag' expected.", fn, cur->name);

			return FALSE;
		}
		else
		{
			Tag *tag;

			tag = g_new0 (Tag, 1);

			/* Get Tag name */
			tag->name = (xmlChar*)gettext((const char*)xmlGetProp (cur, (const xmlChar *) "name"));

			if (tag->name == NULL)
			{
				/* Error: No name */
				g_warning ("The tag list file '%s' is of the wrong type, "
				   "Tag without name.", fn);

				g_free (tag);

				return FALSE;
			}
			else
			{
				/* Parse Tag */
				if (parse_tag (tag, doc, ns, cur))
				{
					/* Prepend Tag to TagGroup */
					tg->tags = g_list_prepend (tg->tags, tag);
				}
				else
				{
					/* Error parsing Tag */
					g_warning ("The tag list file '%s' is of the wrong type, "
			   		   	   "error parsing Tag '%s' in TagGroup '%s'.",
					   	   fn, tag->name, tg->name);

					free_tag (tag);

					return FALSE;
				}
			}
		}

		cur = cur->next;
	}

	if (sort)
		tg->tags = g_list_sort (tg->tags, tags_cmp);
	else
		tg->tags = g_list_reverse (tg->tags);

	return TRUE;
}

static TagGroup*
get_tag_group (const gchar* filename, xmlDocPtr doc,
		 xmlNsPtr ns, xmlNodePtr cur)
{
	TagGroup *tag_group;
	xmlChar *sort_str;
	gboolean sort = FALSE;

	tag_group = g_new0 (TagGroup, 1);

	/* Get TagGroup name */
	tag_group->name = (xmlChar*)gettext((const char*)xmlGetProp (cur, (const xmlChar *) "name"));

	sort_str = xmlGetProp (cur, (const xmlChar *) "sort");

	if ((sort_str != NULL) &&
	    ((xmlStrcasecmp (sort_str, (const xmlChar *) "yes") == 0) ||
	     (xmlStrcasecmp (sort_str, (const xmlChar *) "true") == 0) ||
	     (xmlStrcasecmp (sort_str, (const xmlChar *) "1") == 0)))
	{
		sort = TRUE;
	}

	xmlFree(sort_str);

	if (tag_group->name == NULL)
	{
		/* Error: No name */
		g_warning ("The tag list file '%s' is of the wrong type, "
		   "TagGroup without name.", filename);

		g_free (tag_group);
	}
	else
	{
		/* Name found */
		gboolean exists = FALSE;
		GList *t = taglist->tag_groups;

		/* Check if the tag group already exists */
		while (t && !exists)
		{
			gchar *tgn = (gchar*)((TagGroup*)(t->data))->name;

			if (strcmp (tgn, (gchar*)tag_group->name) == 0)
			{
				pluma_debug_message (DEBUG_PLUGINS,
					     "Tag group '%s' already exists.", tgn);

				exists = TRUE;

				free_tag_group (tag_group);
			}

			t = g_list_next (t);
		}

		if (!exists)
		{
			/* Parse tag group */
			if (parse_tag_group (tag_group, filename, doc, ns, cur, sort))
			{
				return tag_group;
			}
			else
			{
				/* Error parsing TagGroup */
				g_warning ("The tag list file '%s' is of the wrong type, "
		   			   "error parsing TagGroup '%s'.",
					   filename, tag_group->name);

				free_tag_group (tag_group);
			}
		}
	}
	return NULL;
}

static gint
groups_cmp (gconstpointer a, gconstpointer b)
{
	gchar *g_a = (gchar *)((TagGroup *)a)->name;
	gchar *g_b = (gchar *)((TagGroup *)b)->name;

	return g_utf8_collate (g_a, g_b);
}

/*
 *  tags file is localized by intltool-merge below.
 *
 *      <pluma:TagGroup name="XSLT - Elements">
 *      </pluma:TagGroup>
 *      <pluma:TagGroup xml:lang="am" name="LOCALIZED TEXT">
 *      </pluma:TagGroup>
 *      <pluma:TagGroup xml:lang="ar" name="LOCALIZED TEXT">
 *      </pluma:TagGroup>
 *      .....
 *      <pluma:TagGroup name="XSLT - Functions">
 *      </pluma:TagGroup>
 *      .....
 *  Therefore need to pick up the best lang on the current locale.
 */
static TagList*
lookup_best_lang (TagList *taglist, const gchar *filename,
		xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur)
{

	TagGroup *best_tag_group = NULL;
	TagGroup *tag_group;
	gint best_lanking = -1;

	/*
	 * Walk the tree.
	 *
	 * First level we expect a list TagGroup
	 */
	cur = cur->xmlChildrenNode;

	while (cur != NULL)
     	{
		if ((xmlStrcmp (cur->name, (const xmlChar *) "TagGroup")) || (cur->ns != ns))
		{
			g_warning ("The tag list file '%s' is of the wrong type, "
				   "was '%s', 'TagGroup' expected.", filename, cur->name);
			xmlFreeDoc (doc);

			return taglist;
		}
		else
		{
			const char * const *langs_pointer;
			gchar *lang;
			gint cur_lanking;
			gint i;

			langs_pointer = g_get_language_names ();

			lang = (gchar*) xmlGetProp (cur, (const xmlChar*) "lang");
			cur_lanking = 1;

			/*
			 * When found a new TagGroup, prepend the best
			 * tag_group to taglist. In the current intltool-merge,
			 * the first section is the default lang NULL.
			 */
			if (lang == NULL) {
				if (best_tag_group != NULL) {
					taglist->tag_groups =
					g_list_prepend (taglist->tag_groups, best_tag_group);
				}

				best_tag_group = NULL;
				best_lanking = -1;
			}

			/*
			 * If already find the best TagGroup on the current
			 * locale, ignore the logic.
			 */
			if (best_lanking != -1 && best_lanking <= cur_lanking) {
				cur = cur->next;
				continue;
			}

			/* try to find the best lang */
			for (i = 0; langs_pointer[i] != NULL; i++)
			{
				const gchar *best_lang = langs_pointer[i];

				/*
				 * if launch on C, POSIX locale or does
				 * not find the best lang on the current locale,
				 * this is called.
				 * g_get_language_names returns lang
				 * lists with C locale.
				 */
				if (lang == NULL &&
				    (!g_ascii_strcasecmp (best_lang, "C") ||
				     !g_ascii_strcasecmp (best_lang, "POSIX")))
				{
					tag_group = get_tag_group (filename, doc, ns, cur);
					if (tag_group != NULL)
					{
						if (best_tag_group !=NULL)
							free_tag_group (best_tag_group);
						best_lanking = cur_lanking;
						best_tag_group = tag_group;
					}
				}

				/* if it is possible the best lang is not C */
				else if (lang == NULL)
				{
					cur_lanking++;
					continue;
				}

				/* if the best lang is found */
				else if (!g_ascii_strcasecmp (best_lang, lang))
				{
					tag_group = get_tag_group (filename, doc, ns, cur);
					if (tag_group != NULL)
					{
						if (best_tag_group !=NULL)
							free_tag_group (best_tag_group);
						best_lanking = cur_lanking;
						best_tag_group = tag_group;
					}
				}

				cur_lanking++;
			}

			if (lang) g_free (lang);
		} /* End of else */

		cur = cur->next;
    	} /* End of while (cur != NULL) */

	/* Prepend TagGroup to TagList */
	if (best_tag_group != NULL) {
		taglist->tag_groups =
			g_list_prepend (taglist->tag_groups, best_tag_group);
	}

	taglist->tag_groups = g_list_sort (taglist->tag_groups, groups_cmp);

	return taglist;
}

static TagList *
parse_taglist_file (const gchar* filename)
{
	xmlDocPtr doc;

	xmlNsPtr ns;
	xmlNodePtr cur;

	pluma_debug_message (DEBUG_PLUGINS, "Parse file: %s", filename);

	xmlKeepBlanksDefault (0);

	/*
	* build an XML tree from a the file;
	*/
	doc = xmlParseFile (filename);
	if (doc == NULL)
	{
		g_warning ("The tag list file '%s' is empty.", filename);

		return taglist;
	}

	/*
	* Check the document is of the right kind
	*/

	cur = xmlDocGetRootElement (doc);

	if (cur == NULL)
	{
		g_warning ("The tag list file '%s' is empty.", filename);
		xmlFreeDoc(doc);
		return taglist;
	}

	ns = xmlSearchNsByHref (doc, cur,
			(const xmlChar *) "http://pluma.sourceforge.net/some-location");

	if (ns == NULL)
	{
		g_warning ("The tag list file '%s' is of the wrong type, "
			   "pluma namespace not found.", filename);
		xmlFreeDoc (doc);

		return taglist;
	}

    	if (xmlStrcmp(cur->name, (const xmlChar *) "TagList"))
	{
		g_warning ("The tag list file '%s' is of the wrong type, "
			   "root node != TagList.", filename);
		xmlFreeDoc (doc);

		return taglist;
	}

	/*
	 * If needed, allocate taglist
	 */

	if (taglist == NULL)
		taglist = g_new0 (TagList, 1);

	taglist = lookup_best_lang (taglist, filename, doc, ns, cur);

	xmlFreeDoc (doc);

	pluma_debug_message (DEBUG_PLUGINS, "END");

	return taglist;
}

static void
free_tag (Tag *tag)
{
	/*
	pluma_debug_message (DEBUG_PLUGINS, "Tag: %s", tag->name);
	*/
	g_return_if_fail (tag != NULL);

	free (tag->name);

	if (tag->begin != NULL)
		free (tag->begin);

	if (tag->end != NULL)
		free (tag->end);

	g_free (tag);
}

static void
free_tag_group (TagGroup *tag_group)
{
	GList *l;

	pluma_debug_message (DEBUG_PLUGINS, "Tag group: %s", tag_group->name);

	g_return_if_fail (tag_group != NULL);

	free (tag_group->name);

	for (l = tag_group->tags; l != NULL; l = g_list_next (l))
	{
		free_tag ((Tag *) l->data);
	}

	g_list_free (tag_group->tags);
	g_free (tag_group);

	pluma_debug_message (DEBUG_PLUGINS, "END");
}

void free_taglist(void)
{
	GList* l;

	pluma_debug_message(DEBUG_PLUGINS, "ref_count: %d", taglist_ref_count);

	if (taglist == NULL)
	{
		return;
	}

	g_return_if_fail(taglist_ref_count > 0);

	--taglist_ref_count;

	if (taglist_ref_count > 0)
	{
		return;
	}

	for (l = taglist->tag_groups; l != NULL; l = g_list_next (l))
	{
		free_tag_group ((TagGroup*) l->data);
	}

	g_list_free (taglist->tag_groups);
	g_free (taglist);
	taglist = NULL;

	pluma_debug_message (DEBUG_PLUGINS, "Really freed");
}

static TagList* parse_taglist_dir(const gchar* dir)
{
	GError* error = NULL;
	GDir* d;
	const gchar* dirent;

	pluma_debug_message(DEBUG_PLUGINS, "DIR: %s", dir);

	d = g_dir_open(dir, 0, &error);

	if (!d)
	{
		pluma_debug_message(DEBUG_PLUGINS, "%s", error->message);
		g_error_free (error);
		return taglist;
	}

	while ((dirent = g_dir_read_name(d)))
	{
		if (g_str_has_suffix(dirent, ".tags") || g_str_has_suffix(dirent, ".tags.gz"))
		{
			gchar* tags_file = g_build_filename(dir, dirent, NULL);
			parse_taglist_file(tags_file);
			g_free (tags_file);
		}
	}

	g_dir_close (d);

	return taglist;
}

TagList* create_taglist(const gchar* data_dir)
{
	gchar* pdir;

	pluma_debug_message(DEBUG_PLUGINS, "ref_count: %d", taglist_ref_count);

	if (taglist_ref_count > 0)
	{
		++taglist_ref_count;

		return taglist;
	}

	const gchar* home;

	/* load user's taglists */

	home = g_get_home_dir ();
	if (home != NULL)
	{
		pdir = g_build_filename(home, ".config", USER_PLUMA_TAGLIST_PLUGIN_LOCATION, NULL);
		parse_taglist_dir(pdir);
		g_free (pdir);
	}

	/* load system's taglists */
	parse_taglist_dir(data_dir);

	++taglist_ref_count;
	g_return_val_if_fail(taglist_ref_count == 1, taglist);

	return taglist;
}