/*
 * Copyright (C) 2010 Collabora Ltd.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Authors: Xavier Claessens <xclaesse@gmail.com>
 */

#include <config.h>

#include <string.h>

#include "empathy-string-parser.h"
#include "empathy-smiley-manager.h"
#include "empathy-ui-utils.h"

#define SCHEMES           "([a-zA-Z\\+]+)"
#define INVALID_CHARS     "\\s\"<>"
#define INVALID_CHARS_EXT INVALID_CHARS "\\[\\](){},;:"
#define INVALID_CHARS_FULL INVALID_CHARS_EXT "?'"
#define BODY              "([^"INVALID_CHARS_FULL"])([^"INVALID_CHARS_EXT"]*)"
#define BODY_END          "([^"INVALID_CHARS"]*)[^"INVALID_CHARS_FULL".]"
#define URI_REGEX         "("SCHEMES"://"BODY_END")" \
		          "|((www|ftp)\\."BODY_END")" \
		          "|((mailto:)?"BODY"@"BODY"\\."BODY_END")"

static GRegex *
uri_regex_dup_singleton (void)
{
	static GRegex *uri_regex = NULL;

	/* We intentionally leak the regex so it's not recomputed */
	if (!uri_regex) {
		GError *error = NULL;

		uri_regex = g_regex_new (URI_REGEX, 0, 0, &error);
		if (uri_regex == NULL) {
			g_warning ("Failed to create reg exp: %s", error->message);
			g_error_free (error);
			return NULL;
		}
	}

	return g_regex_ref (uri_regex);
}

void
empathy_string_parser_substr (const gchar *text,
			      gssize len,
			      EmpathyStringParser *parsers,
			      gpointer user_data)
{
	if (parsers != NULL && parsers[0].match_func != NULL) {
		parsers[0].match_func (text, len,
				       parsers[0].replace_func, parsers + 1,
				       user_data);
	}
}

void
empathy_string_match_link (const gchar *text,
			   gssize len,
			   EmpathyStringReplace replace_func,
			   EmpathyStringParser *sub_parsers,
			   gpointer user_data)
{
	GRegex     *uri_regex;
	GMatchInfo *match_info;
	gboolean    match;
	gint        last = 0;

	uri_regex = uri_regex_dup_singleton ();
	if (uri_regex == NULL) {
		empathy_string_parser_substr (text, len, sub_parsers, user_data);
		return;
	}

	match = g_regex_match_full (uri_regex, text, len, 0, 0, &match_info, NULL);
	if (match) {
		gint s = 0, e = 0;

		do {
			g_match_info_fetch_pos (match_info, 0, &s, &e);

			if (s > last) {
				/* Append the text between last link (or the
				 * start of the message) and this link */
				empathy_string_parser_substr (text + last,
							      s - last,
							      sub_parsers,
							      user_data);
			}

			replace_func (text + s, e - s, NULL, user_data);

			last = e;
		} while (g_match_info_next (match_info, NULL));
	}

	empathy_string_parser_substr (text + last, len - last,
				      sub_parsers, user_data);

	g_match_info_free (match_info);
	g_regex_unref (uri_regex);
}

void
empathy_string_match_smiley (const gchar *text,
			     gssize len,
			     EmpathyStringReplace replace_func,
			     EmpathyStringParser *sub_parsers,
			     gpointer user_data)
{
	guint last = 0;
	EmpathySmileyManager *smiley_manager;
	GSList *hits, *l;

	smiley_manager = empathy_smiley_manager_dup_singleton ();
	hits = empathy_smiley_manager_parse_len (smiley_manager, text, len);

	for (l = hits; l; l = l->next) {
		EmpathySmileyHit *hit = l->data;

		if (hit->start > last) {
			/* Append the text between last smiley (or the
			 * start of the message) and this smiley */
			empathy_string_parser_substr (text + last,
						      hit->start - last,
						      sub_parsers, user_data);
		}

		replace_func (text + hit->start, hit->end - hit->start,
			      hit, user_data);

		last = hit->end;

		empathy_smiley_hit_free (hit);
	}
	g_slist_free (hits);
	g_object_unref (smiley_manager);

	empathy_string_parser_substr (text + last, len - last,
				      sub_parsers, user_data);
}

void
empathy_string_match_all (const gchar *text,
			  gssize len,
			  EmpathyStringReplace replace_func,
			  EmpathyStringParser *sub_parsers,
			  gpointer user_data)
{
	replace_func (text, len, NULL, user_data);
}

void
empathy_string_replace_link (const gchar *text,
                             gssize len,
                             gpointer match_data,
                             gpointer user_data)
{
	GString *string = user_data;
	gchar *real_url;
	gchar *title;
	gchar *markup;

	real_url = empathy_make_absolute_url_len (text, len);

	/* Need to copy manually, because g_markup_printf_escaped does not work
	 * with string precision pitfalls. */
	title = g_strndup (text, len);

	/* Append the link inside <a href=""></a> tag */
	markup = g_markup_printf_escaped ("<a href=\"%s\">%s</a>",
			real_url, title);

	g_string_append (string, markup);

	g_free (real_url);
	g_free (title);
	g_free (markup);
}

void
empathy_string_replace_escaped (const gchar *text,
				gssize len,
				gpointer match_data,
				gpointer user_data)
{
	GString *string = user_data;
	gchar *escaped;
	guint i;
	gsize escaped_len, old_len;

	escaped = g_markup_escape_text (text, len);
	escaped_len = strlen (escaped);

	/* Allocate more space to string (we really need a g_string_extend...) */
	old_len = string->len;
	g_string_set_size (string, old_len + escaped_len);
	g_string_truncate (string, old_len);

	/* Remove '\r' */
	for (i = 0; i < escaped_len; i++) {
		if (escaped[i] != '\r')
			g_string_append_c (string, escaped[i]);
	}

	g_free (escaped);
}

gchar *
empathy_add_link_markup (const gchar *text)
{
	EmpathyStringParser parsers[] = {
		{empathy_string_match_link, empathy_string_replace_link},
		{empathy_string_match_all, empathy_string_replace_escaped},
		{NULL, NULL}
	};
	GString *string;

	g_return_val_if_fail (text != NULL, NULL);

	string = g_string_sized_new (strlen (text));
	empathy_string_parser_substr (text, -1, parsers, string);

	return g_string_free (string, FALSE);
}