/*
 * HTML document generation
 *
 * Copyright (C) 2017  Patrick McDermott
 *
 * This file is part of Marquee.
 *
 * Marquee 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.
 *
 * Marquee 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 Marquee.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "html.h"

#include <stdarg.h>
#include <string.h>

#include <glib.h>
#include <gtk/gtk.h>

static const gchar *styles =
	/*
	 * General styles
	 */
	"* {\n"
		"margin: 6px;\n"
		"padding: 0;\n"
		"background: none;\n"
		"border: 0 none;\n"
	"}\n"
	"html {\n"
		"margin: 0;\n"
	"}\n"
	"body {\n"
		"margin: 18px;\n"
		"background-color: #AFAFAF;\n"
		"font-family: sans-serif;\n"
	"}\n"
	"h1, h2, h3, h4, h5, h6, p {\n"
		"text-align: center;\n"
	"}\n"
	/*
	 * Horizontal notebook
	 */
	"div.notebook-h {\n"
		"clear: left;\n"
		"position: relative;\n"
		"padding: 0;\n"
	"}\n"
	"div.notebook-h > input {\n"
		"display: none;\n"
	"}\n"
	"div.notebook-h > label {\n"
		"display: block;\n"
		"background-color: #9F9F9F;\n"
		"color: #5F5F5F;\n"
		"float: left;\n"
		"margin: 6px 3px 0 0;\n"
		"border-width: 1px 1px 0 1px;\n"
		"border-style: solid;\n"
		"border-color: #8F8F8F;\n"
		"border-radius: 3px 3px 0 0;\n"
		"padding: 6px;\n"
		"font-weight: bold;\n"
		"position: relative;\n"
		"top: 3px;\n"
	"}\n"
	"div.notebook-h > input:checked + label {\n"
		"background-color: #CFCFCF;\n"
		"color: #000000;\n"
		"padding: 6px 6px 7px 6px;\n"
		"border-color: #9F9F9F;\n"
		"position: relative;\n"
		"top: 0;\n"
		"z-index: 1;\n"
	"}\n"
	"div.notebook-h > div {\n"
		"display: none;\n"
		"background-color: #CFCFCF;\n"
		"clear: left;\n"
		"border: 1px solid #9F9F9F;\n"
		"border-radius: 0 0 3px 3px;\n"
		"position: relative;\n"
		"top: -1px;\n"
		"margin: 0;\n"
	"}\n"
	/*
	 * Vertical notebook
	 */
	"div.notebook-v {\n"
		"position: relative;\n"
		/* Why are these weird margin and padding numbers necessary? */
		"margin: 6px 5px 6px 0;\n"
		"padding: 6px 0 0 0;\n"
	"}\n"
	"div.notebook-v > input {\n"
		"display: none;\n"
	"}\n"
	"div.notebook-v > label {\n"
		"display: block;\n"
		"background-color: #9F9F9F;\n"
		"color: #5F5F5F;\n"
		"float: left;\n"
		"clear: left;\n"
		"margin: 0 0 3px 6px;\n"
		"border-width: 1px 0 1px 1px;\n"
		"border-style: solid;\n"
		"border-color: #8F8F8F;\n"
		"border-radius: 3px 0 0 3px;\n"
		"padding: 6px;\n"
		"font-weight: bold;\n"
		"position: relative;\n"
		"left: 3px;\n"
	"}\n"
	"div.notebook-v > input:checked + label {\n"
		"background-color: #CFCFCF;\n"
		"color: #000000;\n"
		"padding: 6px 7px 6px 6px;\n"
		"border-color: #9F9F9F;\n"
		"position: relative;\n"
		"left: 0;\n"
		"z-index: 1;\n"
	"}\n"
	"div.notebook-v > div {\n"
		"display: none;\n"
		"background-color: #CFCFCF;\n"
		"border: 1px solid #9F9F9F;\n"
		"border-radius: 0 3px 3px 0;\n"
		"position: relative;\n"
		"left: -1px;\n"
		"margin: 0;\n"
		"overflow: hidden;\n"
	"}\n"
	/*
	 * Form elements
	 */
	"form {\n"
		"margin: 0;\n"
	"}\n"
	"form input, form select {\n"
		"border: 1px solid #9F9F9F;\n"
		"border-radius: 3px;\n"
		"background-color: #EFEFEF;\n"
		"padding: 6px;\n"
		"color: #000000;\n"
		"transition: all 250ms ease-in-out 0s;\n"
		"-moz-transition: all 250ms ease-in-out 0s;\n"
		"-wekbit-transition: all 250ms ease-in-out 0s;\n"
		"-o-transition: all 250ms ease-in-out 0s;\n"
	"}\n"
	"div.dialog-buttonbox {\n"
		"margin: 0;\n"
		"float: right;\n"
	"}\n"
	"form label {\n"
		"display: block;\n"
	"}\n"
	"form label span {\n"
		"display: inline-block;\n"
		"width: calc(50% - 6px);\n"
		"text-align: right;\n"
	"}\n"
	"form input[type=submit], form input[type=reset] {\n"
		"background-color: #DFDFDF;\n"
	"}\n"
	"form input:hover, form select:hover,\n"
	"form input:focus, form select:focus {\n"
		"border: 1px solid #4F8FCF;\n"
		"outline: 0;\n"
	"}\n"
	"form input[type=submit]:hover, form input[type=reset]:hover,\n"
	"form input[type=submit]:focus, form input[type=reset]:focus {\n"
		"background-color: #EFEFEF;\n"
	"}\n"
	"iframe {\n"
		"width: calc(100% - 12px);\n"
		"height: 400px;\n"
	"}\n"
	;

gchar *
mq_html_document(const gchar *title, ...)
{
	gsize    len;
	va_list  ap;
	gchar   *child;
	gchar   *document;
	gchar   *ptr;

	/* Calculate length. */
	len = strlen("<!doctype html>\n<html dir=\"");
	len += 3;  /* "ltr" or "rtl" */
	len += strlen("\">\n<head>\n<meta charset=\"utf-8\">\n<title>");
	len += strlen(title);
	len += strlen("</title>\n<style>\n");
	len += strlen(styles);
	len += strlen("</style>\n</head>\n<body>\n");
	va_start(ap, title);
	while ((child = va_arg(ap, gchar *))) {
		len += strlen(child);
	}
	va_end(ap);
	len += strlen("</body>\n</html>\n");
	++len;  /* NUL byte */

	/* Build string. */
	document = g_new(gchar, len);
	ptr = g_stpcpy(document, "<!doctype html>\n<html dir=\"");
	ptr = g_stpcpy(ptr, gtk_widget_get_default_direction() ==
		GTK_TEXT_DIR_RTL ? "rtl" : "ltr");
	ptr = g_stpcpy(ptr, "\">\n<head>\n<meta charset=\"utf-8\">\n<title>");
	ptr = g_stpcpy(ptr, title);
	ptr = g_stpcpy(ptr, "</title>\n<style>\n");
	ptr = g_stpcpy(ptr, styles);
	ptr = g_stpcpy(ptr, "</style>\n</head>\n<body>\n");
	va_start(ap, title);
	while ((child = va_arg(ap, gchar *))) {
		ptr = g_stpcpy(ptr, child);
		g_free(child);
	}
	va_end(ap);
	ptr = g_stpcpy(ptr, "</body>\n</html>\n");  /* g_stpcpy() adds NUL. */

	return document;
}

#define TEXT_ELEMENT(ELEM) \
	gchar * \
	mq_html_##ELEM(const gchar *text) \
	{ \
		return g_strconcat("<" #ELEM ">", text, "</" #ELEM ">\n", \
			NULL); \
	} \
	gchar * \
	mq_html_##ELEM##_free(gchar *text) \
	{ \
		gchar *e; \
		e = g_strconcat("<" #ELEM ">", text, "</" #ELEM ">\n", NULL); \
		g_free(text); \
		return e; \
	}
TEXT_ELEMENT(h1)
TEXT_ELEMENT(h2)
TEXT_ELEMENT(h3)
TEXT_ELEMENT(h4)
TEXT_ELEMENT(h5)
TEXT_ELEMENT(h6)
TEXT_ELEMENT(p)
#undef TEXT_ELEMENT

gchar *
mq_html_list(const gchar *type, GDestroyNotify destroy, ...)
{
	gsize    len;
	va_list  ap;
	gchar   *child;
	gchar   *list;
	gchar   *ptr;

	/* TODO: Doesn't support specification of <ol> list types. */

	/* Calculate length. */
	len = strlen("<ul>\n");
	va_start(ap, destroy);
	while ((child = va_arg(ap, gchar *))) {
		len += strlen("<li>\n");
		len += strlen(child);
		len += strlen("</li>\n");
	}
	va_end(ap);
	len += strlen("</ul>\n");
	++len;  /* NUL byte */

	/* Build string. */
	list = g_new(gchar, len);
	if (type && type[0]) {
		ptr = g_stpcpy(list, "<ol>\n");
	} else {
		ptr = g_stpcpy(list, "<ul>\n");
	}
	va_start(ap, destroy);
	while ((child = va_arg(ap, gchar *))) {
		ptr = g_stpcpy(ptr, "<li>\n");
		ptr = g_stpcpy(ptr, child);
		if (destroy) {
			destroy(child);
		}
		ptr = g_stpcpy(ptr, "</li>\n");
	}
	va_end(ap);
	ptr = g_stpcpy(ptr, "</ul>\n");  /* g_stpcpy() adds the NUL. */

	return list;
}

gchar *
mq_html_list_v(const gchar *type, gchar **children)
{
	gsize  len;
	gsize  i;
	gchar *list;
	gchar *ptr;

	/* TODO: Doesn't support specification of <ol> list types. */

	/* Calculate length. */
	len = strlen("<ul>\n");
	for (i = 0; children && children[i]; ++i) {
		len += strlen("<li>\n");
		len += strlen(children[i]);
		len += strlen("</li>\n");
	}
	len += strlen("</ul>\n");
	++len;  /* NUL byte */

	/* Build string. */
	list = g_new(gchar, len);
	if (type && type[0]) {
		ptr = g_stpcpy(list, "<ol>\n");
	} else {
		ptr = g_stpcpy(list, "<ul>\n");
	}
	for (i = 0; children && children[i]; ++i) {
		ptr = g_stpcpy(ptr, "<li>\n");
		ptr = g_stpcpy(ptr, children[i]);
		ptr = g_stpcpy(ptr, "</li>\n");
	}
	ptr = g_stpcpy(ptr, "</ul>\n");  /* g_stpcpy() adds the NUL. */

	return list;
}

gchar *
mq_html_container(const gchar *element, const gchar *classes, ...)
{
	gsize    len;
	va_list  ap;
	gchar   *child;
	gchar   *container;
	gchar   *ptr;

	/* Calculate length. */
	len = strlen("<");
	len += strlen(element);
	if (classes && classes[0]) {
		len += strlen(" class=\"");
		len += strlen(classes);
		len += strlen("\"");
	}
	len += strlen(">\n");
	va_start(ap, classes);
	while ((child = va_arg(ap, gchar *))) {
		len += strlen(child);
	}
	va_end(ap);
	len += strlen("</");
	len += strlen(element);
	len += strlen(">\n");
	++len;  /* NUL byte */

	/* Build string. */
	container = g_new(gchar, len);
	ptr = g_stpcpy(container, "<");
	ptr = g_stpcpy(ptr, element);
	if (classes && classes[0]) {
		ptr = g_stpcpy(ptr, " class=\"");
		ptr = g_stpcpy(ptr, classes);
		ptr = g_stpcpy(ptr, "\"");
	}
	ptr = g_stpcpy(ptr, ">\n");
	va_start(ap, classes);
	while ((child = va_arg(ap, gchar *))) {
		ptr = g_stpcpy(ptr, child);
		g_free(child);
	}
	va_end(ap);
	ptr = g_stpcpy(ptr, "</");
	ptr = g_stpcpy(ptr, element);
	ptr = g_stpcpy(ptr, ">\n");  /* g_stpcpy() adds the NUL. */

	return container;
}

gchar *
mq_html_container_v(const gchar *element, const gchar *classes,
	gchar **children)
{
	gsize  len;
	gsize  i;
	gchar *container;
	gchar *ptr;

	/* Calculate length. */
	len = strlen("<");
	len += strlen(element);
	if (classes && classes[0]) {
		len += strlen(" class=\"");
		len += strlen(classes);
		len += strlen("\"");
	}
	len += strlen(">\n");
	for (i = 0; children && children[i]; ++i) {
		len += strlen(children[i]);
	}
	len += strlen("</");
	len += strlen(element);
	len += strlen(">\n");
	++len;  /* NUL byte */

	/* Build string. */
	container = g_new(gchar, len);
	ptr = g_stpcpy(container, "<");
	ptr = g_stpcpy(ptr, element);
	if (classes && classes[0]) {
		ptr = g_stpcpy(ptr, " class=\"");
		ptr = g_stpcpy(ptr, classes);
		ptr = g_stpcpy(ptr, "\"");
	}
	ptr = g_stpcpy(ptr, ">\n");
	for (i = 0; children && children[i]; ++i) {
		ptr = g_stpcpy(ptr, children[i]);
	}
	ptr = g_stpcpy(ptr, "</");
	ptr = g_stpcpy(ptr, element);
	ptr = g_stpcpy(ptr, ">\n");  /* g_stpcpy() adds the NUL. */

	return container;
}

gchar *
mq_html_notebook(gboolean vertical, const gchar *name, guint current_page, ...)
{
	gsize    name_len;
	gsize    len;
	va_list  ap;
	gsize    i;
	gchar   *child;
	gchar   *tab_label;
	gchar   *i_str;
	gchar   *notebook;
	gchar   *ptr;

	/* Calculate length. */
	name_len = strlen(name);
	len = strlen("<div class=\"notebook-") + 1 + strlen("\">\n");
	va_start(ap, current_page);
	i = 0;
	while ((child = va_arg(ap, gchar *)) &&
			(tab_label = va_arg(ap, gchar *))) {
		i_str = g_strdup_printf("%zu", i);
		len += strlen("<input id=\"_tab_");
		len += name_len;
		len += strlen("_");
		len += strlen(i_str);
		/* len += (gsize) log10(i) + 1; */
		len += strlen("\" type=\"radio\"");
		if (i == current_page) {
			len += strlen(" checked=\"checked\"");
		}
		len += strlen(" name=\"_tabs\"></input>\n");
		len += strlen("<label for=\"_tab_");
		len += name_len;
		len += strlen("_");
		len += strlen(i_str);
		/* len += (gsize) log10(i) + 1; */
		len += strlen("\">");
		len += strlen(tab_label);
		len += strlen("</label>\n");
		++i;
	}
	va_end(ap);
	va_start(ap, current_page);
	while ((child = va_arg(ap, gchar *)) &&
			(tab_label = va_arg(ap, gchar *))) {
		i_str = g_strdup_printf("%zu", i);
		len += strlen("<div id=\"_tab-page_");
		len += name_len;
		len += strlen("_");
		len += strlen(i_str);
		len += strlen("\">\n");
		len += strlen(child);
		len += strlen("</div>\n<style>\ndiv.notebook-") + 1;
		len += strlen(" > input#_tab_");
		len += name_len;
		len += strlen("_");
		len += strlen(i_str);
		len += strlen(":checked ~ div#_tab-page_");
		len += name_len;
		len += strlen("_");
		len += strlen(i_str);
		len += strlen(" {\ndisplay: block;\n}\n</style>\n");
	}
	va_end(ap);
	len += strlen("</div>\n");
	++len;  /* NUL byte */

	/* Build string. */
	notebook = g_new(gchar, len);
	ptr = g_stpcpy(notebook, "<div class=\"notebook-");
	ptr = g_stpcpy(ptr, vertical ? "v" : "h");
	ptr = g_stpcpy(ptr, "\">\n");
	va_start(ap, current_page);
	i = 0;
	while ((child = va_arg(ap, gchar *)) &&
			(tab_label = va_arg(ap, gchar *))) {
		i_str = g_strdup_printf("%zu", i);
		ptr = g_stpcpy(ptr, "<input id=\"_tab_");
		ptr = g_stpcpy(ptr, name);
		ptr = g_stpcpy(ptr, "_");
		ptr = g_stpcpy(ptr, i_str);
		ptr = g_stpcpy(ptr, "\" type=\"radio\"");
		if (i == current_page) {
			ptr = g_stpcpy(ptr, " checked=\"checked\"");
		}
		ptr = g_stpcpy(ptr, " name=\"_tabs\"></input>\n");
		ptr = g_stpcpy(ptr, "<label for=\"_tab_");
		ptr = g_stpcpy(ptr, name);
		ptr = g_stpcpy(ptr, "_");
		ptr = g_stpcpy(ptr, i_str);
		ptr = g_stpcpy(ptr, "\">");
		ptr = g_stpcpy(ptr, tab_label);
		ptr = g_stpcpy(ptr, "</label>\n");
		g_free(i_str);
		++i;
	}
	va_end(ap);
	va_start(ap, current_page);
	i = 0;
	while ((child = va_arg(ap, gchar *)) &&
			(tab_label = va_arg(ap, gchar *))) {
		i_str = g_strdup_printf("%zu", i);
		ptr = g_stpcpy(ptr, "<div id=\"_tab-page_");
		ptr = g_stpcpy(ptr, name);
		ptr = g_stpcpy(ptr, "_");
		ptr = g_stpcpy(ptr, i_str);
		ptr = g_stpcpy(ptr, "\">\n");
		ptr = g_stpcpy(ptr, child);
		g_free(child);
		ptr = g_stpcpy(ptr, "</div>\n<style>\ndiv.notebook-");
		ptr = g_stpcpy(ptr, vertical ? "v" : "h");
		ptr = g_stpcpy(ptr, " > input#_tab_");
		ptr = g_stpcpy(ptr, name);
		ptr = g_stpcpy(ptr, "_");
		ptr = g_stpcpy(ptr, i_str);
		ptr = g_stpcpy(ptr, ":checked ~ div#_tab-page_");
		ptr = g_stpcpy(ptr, name);
		ptr = g_stpcpy(ptr, "_");
		ptr = g_stpcpy(ptr, i_str);
		ptr = g_stpcpy(ptr, " {\ndisplay: block;\n}\n</style>\n");
		++i;
	}
	va_end(ap);
	ptr = g_stpcpy(ptr, "</div>\n");  /* g_stpcpy() adds the NUL. */

	return notebook;
}

gchar *
mq_html_form(const gchar *submit_label, const gchar *reset_label, ...)
{
	gsize    len;
	va_list  ap;
	gchar   *child;
	gchar   *form;
	gchar   *ptr;

	/* Calculate length. */
	len = strlen("<form>\n");
	va_start(ap, reset_label);
	while ((child = va_arg(ap, gchar *))) {
		len += strlen(child);
	}
	va_end(ap);
	len += strlen("<div class=\"dialog-buttonbox\">\n");
	if (reset_label && reset_label[0]) {
		len += strlen("<input type=\"reset\" value=\"");
		len += strlen(reset_label);
		len += strlen("\">\n");
	}
	if (submit_label && submit_label[0]) {
		len += strlen("<input type=\"submit\" value=\"");
		len += strlen(submit_label);
		len += strlen("\">\n");
	}
	len += strlen("</div>\n");
	len += strlen("</form>\n");
	++len;  /* NUL byte */

	/* Build string. */
	form = g_new(gchar, len);
	ptr = g_stpcpy(form, "<form>\n");
	va_start(ap, reset_label);
	while ((child = va_arg(ap, gchar *))) {
		ptr = g_stpcpy(ptr, child);
		g_free(child);
	}
	va_end(ap);
	ptr = g_stpcpy(ptr, "<div class=\"dialog-buttonbox\">\n");
	if (reset_label && reset_label[0]) {
		ptr = g_stpcpy(ptr, "<input type=\"reset\" value=\"");
		ptr = g_stpcpy(ptr, reset_label);
		ptr = g_stpcpy(ptr, "\">\n");
	}
	if (submit_label && submit_label[0]) {
		ptr = g_stpcpy(ptr, "<input type=\"submit\" value=\"");
		ptr = g_stpcpy(ptr, submit_label);
		ptr = g_stpcpy(ptr, "\">\n");
	}
	ptr = g_stpcpy(ptr, "</div>\n");
	ptr = g_stpcpy(ptr, "</form>\n");  /* g_stpcpy() adds the NUL. */

	return form;
}

gchar *
mq_html_input_text(const gchar *name, const gchar *label, const gchar *value)
{
	if (label && label[0]) {
		return g_strdup_printf(
			"<label for=\"%s\">\n<span>%s:</span>\n"
				"<input type=\"text\" name=\"%s\" id=\"%s\" "
					"value=\"%s\">\n"
			"</label>\n",
			name, label, name, name, value ? value : "");
	} else {
		return g_strdup_printf(
			"<input type=\"text\" name=\"%s\" id=\"%s\" "
				"value=\"%s\">\n",
			name, name, value ? value : "");
	}
}

gchar *
mq_html_input_number_i(const gchar *name, const gchar *label,
	gint min, gint step, gint max, gint value)
{
	if (label && label[0]) {
		return g_strdup_printf(
			"<label for=\"%s\">\n<span>%s:</span>\n"
				"<input type=\"number\" name=\"%s\" id=\"%s\" "
					"min=\"%d\" step=\"%d\" max=\"%d\" "
					"value=\"%d\">\n"
			"</label>\n",
			name, label, name, name, min, step, max, value);
	} else {
		return g_strdup_printf(
			"<input type=\"number\" name=\"%s\" id=\"%s\" "
				"min=\"%d\" step=\"%d\" max=\"%d\" "
				"value=\"%d\">\n",
			name, name, min, step, max, value);
	}
}

gchar *
mq_html_input_number_d(const gchar *name, const gchar *label,
	gdouble min, gdouble step, gdouble max, gdouble value)
{
	if (label && label[0]) {
		return g_strdup_printf(
			"<label for=\"%s\">\n<span>%s:</span>\n"
				"<input type=\"number\" name=\"%s\" id=\"%s\" "
					"min=\"%f\" step=\"%f\" max=\"%f\" "
					"value=\"%f\">\n"
			"</label>\n",
			name, label, name, name, min, step, max, value);
	} else {
		return g_strdup_printf(
			"<input type=\"number\" name=\"%s\" id=\"%s\" "
				"min=\"%f\" step=\"%f\" max=\"%f\" "
				"value=\"%f\">\n",
			name, name, min, step, max, value);
	}
}

gchar *
mq_html_input_radio(const gchar *name, const gchar *id, const gchar *label,
	gboolean checked)
{
	if (label && label[0]) {
		return g_strdup_printf(
			"<label for=\"%s\">\n<span>%s:</span>\n"
				"<input type=\"radio\" name=\"%s\" "
					"id=\"%s\"%s>\n"
			"</label>\n",
			id, label, name, id,
			checked ? " checked=\"checked\"" : "");
	} else {
		return g_strdup_printf(
			"<input type=\"radio\" name=\"%s\" id=\"%s\"%s>\n",
			name, id,
			checked ? " checked=\"checked\"" : "");
	}
}

gchar *
mq_html_input_checkbox(const gchar *name, const gchar *label, gboolean checked)
{
	/*
	 * Values of "checkbox"-type <input>s that are not checked are not sent
	 * in queries with form submissions.  The "about:preferences"
	 * query-handling code doesn't handle any preferences that aren't
	 * submitted in the query, so values need to be submitted for unchecked
	 * "checkbox"-type <input>s in order for unchecking to have any effect.
	 *
	 * This function returns two <input>s: one of type "hidden" with a value
	 * of "off" and one of type "checkbox".  If the "checkbox"-type <input>
	 * is checked, both <input> values will be submitted in the query, with
	 * the value of the "checkbox"-type <input> last.  Otherwise, only the
	 * "off" value of the "hidden"-type <input> will be submitted.
	 *
	 * The query-parsing code for "about"-scheme resources iterates through
	 * each "key=value" pair in order, inserting each pair into a
	 * GHashTable.  When keys collide, g_hash_table_insert() replaces the
	 * previous value with the new value.  Thus, the value of the
	 * "checkbox"-type <input> will override that of the "hidden"-type
	 * <input> when the former <input> is checked.
	 */

	if (label && label[0]) {
		return g_strdup_printf(
			"<label for=\"%s\">\n<span>%s:</span>\n"
				"<input type=\"hidden\" name=\"%s\" "
					"value=\"off\">\n"
				"<input type=\"checkbox\" name=\"%s\" "
					"id=\"%s\"%s>\n"
			"</label>\n",
			name, label, name, name, name,
			checked ? " checked=\"checked\"" : "");
	} else {
		return g_strdup_printf(
			"<input type=\"hidden\" name=\"%s\" "
				"value=\"off\">\n"
			"<input type=\"checkbox\" name=\"%s\" "
				"id=\"%s\"%s>\n",
			name, name, name,
			checked ? " checked=\"checked\"" : "");
	}
}

gchar *
mq_html_input_select(const gchar *name, const gchar *label,
	const gchar *selected,
	GDestroyNotify destroy_value, GDestroyNotify destroy_label, ...)
{
	gsize    len;
	va_list  ap;
	gchar   *option_value;
	gchar   *option_label;
	gchar   *select;
	gchar   *ptr;

	g_assert(selected && selected[0]);  /* Would cause buffer overflow */

	/* Calculate length. */
	len = 0;
	if (label && label[0]) {
		len += strlen("<label for=\"");
		len += strlen(name);
		len += strlen("\">\n<span>");
		len += strlen(label);
		len += strlen(":</span>\n");
	}
	len += strlen("<select name=\"");
	len += strlen(name);
	len += strlen("\" id=\"");
	len += strlen(name);
	len += strlen("\">\n");
	va_start(ap, destroy_label);
	while ((option_value = va_arg(ap, gchar *)) && (option_label =
				va_arg(ap, gchar *))) {
		len += strlen("<option value=\"");
		len += strlen(option_value);
		len += strlen("\"");
		len += strlen(">");
		len += strlen(option_label);
		len += strlen("</option>\n");
	}
	va_end(ap);
	len += strlen(" selected=\"selected\"");
	len += strlen("</select>\n");
	if (label && label[0]) {
		len += strlen("</label>\n");
	}
	++len;  /* NUL byte */

	/* Build string. */
	ptr = select = g_new(gchar, len);
	if (label && label[0]) {
		ptr = g_stpcpy(ptr, "<label for=\"");
		ptr = g_stpcpy(ptr, name);
		ptr = g_stpcpy(ptr, "\">\n<span>");
		ptr = g_stpcpy(ptr, label);
		ptr = g_stpcpy(ptr, ":</span>\n");
	}
	ptr = g_stpcpy(ptr, "<select name=\"");
	ptr = g_stpcpy(ptr, name);
	ptr = g_stpcpy(ptr, "\" id=\"");
	ptr = g_stpcpy(ptr, name);
	ptr = g_stpcpy(ptr, "\">\n");
	va_start(ap, destroy_label);
	while ((option_value = va_arg(ap, gchar *)) && (option_label =
				va_arg(ap, gchar *))) {
		ptr = g_stpcpy(ptr, "<option value=\"");
		ptr = g_stpcpy(ptr, option_value);
		ptr = g_stpcpy(ptr, "\"");
		if (g_strcmp0(option_value, selected) == 0) {
			ptr = g_stpcpy(ptr, " selected=\"selected\"");
		}
		ptr = g_stpcpy(ptr, ">");
		ptr = g_stpcpy(ptr, option_label);
		if (destroy_value) {
			destroy_value(option_value);
		}
		if (destroy_label) {
			destroy_label(option_label);
		}
		ptr = g_stpcpy(ptr, "</option>\n");
	}
	va_end(ap);
	ptr = g_stpcpy(ptr, "</select>\n");
	if (label && label[0]) {
		ptr = g_stpcpy(ptr, "</label>\n");  /* g_stpcpy() adds NUL */
	}

	return select;
}

gchar *
mq_html_label(const gchar *for_id, const gchar *label, gboolean add_colon)
{
	return g_strdup_printf(
		"<label for=\"%s\">\n<span>%s%s</span>\n</label>\n",
		for_id, label, add_colon ? ":" : "");
}

gchar *
mq_html_input_iframe(const gchar *src)
{
	return g_strdup_printf("<iframe src=\"%s\"></iframe>", src);
}