/*
 * Application configuration
 *
 * 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 <string.h>
#include <stdlib.h>

#include <glib.h>

#include "config.h"

enum type {
	TYPE_BOOLEAN,
	TYPE_INTEGER,
	TYPE_DOUBLE,
};

union callback {
	void (*boolean_cb)(const gchar *, gboolean, gpointer);
	void (*integer_cb)(const gchar *, gint, gpointer);
	void (*double_cb)(const gchar *, gdouble, gpointer);
};

struct callbacks {
	union callback    cb;
	gpointer          user_data;
	struct callbacks *next;
};

struct item {
	enum type         type;
	struct callbacks *callbacks;
};

static void
set_type_or_run_callbacks(MqConfig *config, const gchar *name, gpointer value,
	enum type type)
{
	struct item      *item;
	struct callbacks *cbs;

	if (!config->types_and_cbs_set) {
		item = g_malloc(sizeof(*item));
		item->type = type;
		item->callbacks = NULL;
		g_hash_table_insert(config->types_and_cbs, g_strdup(name),
			item);
	} else {
		item = g_hash_table_lookup(config->types_and_cbs, name);
		for (cbs = item->callbacks; cbs; cbs = cbs->next) {
			switch (item->type) {
				case TYPE_BOOLEAN:
					cbs->cb.boolean_cb(name,
						*((gboolean *) value),
						cbs->user_data);
					break;
				case TYPE_INTEGER:
					cbs->cb.integer_cb(name,
						*((gint *) value),
						cbs->user_data);
					break;
				case TYPE_DOUBLE:
					cbs->cb.double_cb(name,
						*((gdouble *) value),
						cbs->user_data);
					break;
			}
		}
	}
}

static void
set_defaults(MqConfig *config)
{
	config->types_and_cbs_set = FALSE;


	config->types_and_cbs_set = TRUE;
}

MqConfig *
mq_config_new(const gchar *profile)
{
	MqConfig *config;

	config = malloc(sizeof(*config));

	config->file_name = g_strdup_printf("%s/%s/config",
		g_get_user_config_dir(), profile);
	config->key_file = g_key_file_new();
	config->types_and_cbs = g_hash_table_new(g_str_hash, g_int_equal);
	set_defaults(config);

	return config;
}

gboolean
mq_config_load(MqConfig *config)
{
	/* TODO: Handle parsing and ENOENT errors differently? */
	return g_key_file_load_from_file(config->key_file, config->file_name,
		G_KEY_FILE_KEEP_COMMENTS | G_KEY_FILE_KEEP_TRANSLATIONS, NULL);
}

gboolean
mq_config_save(MqConfig *config)
{
	/* TODO: Handle GFileError? */
	return g_key_file_save_to_file(config->key_file, config->file_name,
		NULL);
}

static void
split_name(const gchar *name, gchar **group, gchar **key)
{
	*group = g_strdup(name);
	*key = strchr(*group, '.');
	*(key[0]) = '\0';
	++*key;
}

gboolean
mq_config_get_boolean(MqConfig *config, const gchar *name)
{
	gchar    *group;
	gchar    *key;
	gboolean  value;

	split_name(name, &group, &key);

	/* TODO: Handle value parsing errors? */
	value = g_key_file_get_boolean(config->key_file, group, key, NULL);

	g_free(group);

	return value;
}

gint
mq_config_get_integer(MqConfig *config, const gchar *name)
{
	gchar *group;
	gchar *key;
	gint   value;

	split_name(name, &group, &key);

	/* TODO: Handle value parsing errors? */
	value = g_key_file_get_integer(config->key_file, group, key, NULL);

	g_free(group);

	return value;
}

gdouble
mq_config_get_double(MqConfig *config, const gchar *name)
{
	gchar   *group;
	gchar   *key;
	gdouble  value;

	split_name(name, &group, &key);

	/* TODO: Handle value parsing errors? */
	value = g_key_file_get_double(config->key_file, group, key, NULL);

	g_free(group);

	return value;
}

void
mq_config_set_boolean(MqConfig *config, const gchar *name, gboolean value)
{
	gchar *group;
	gchar *key;

	split_name(name, &group, &key);

	g_key_file_set_boolean(config->key_file, group, key, value);

	g_free(group);

	set_type_or_run_callbacks(config, name, &value, TYPE_BOOLEAN);
}

void
mq_config_set_integer(MqConfig *config, const gchar *name, gint value)
{
	gchar *group;
	gchar *key;

	split_name(name, &group, &key);

	g_key_file_set_integer(config->key_file, group, key, value);

	g_free(group);

	set_type_or_run_callbacks(config, name, &value, TYPE_INTEGER);
}

void
mq_config_set_double(MqConfig *config, const gchar *name, gdouble value)
{
	gchar *group;
	gchar *key;

	split_name(name, &group, &key);

	g_key_file_set_double(config->key_file, group, key, value);

	g_free(group);

	set_type_or_run_callbacks(config, name, &value, TYPE_DOUBLE);
}

gboolean
mq_config_set(MqConfig *config, const gchar *name, const gchar *value)
{
	struct item *item;
	gint         integer_value;
	gdouble      double_value;
	gchar       *endptr;

	item = g_hash_table_lookup(config->types_and_cbs, name);
	g_assert(item);

	switch (item->type) {
		case TYPE_BOOLEAN:
			/* value is "on" or "off" (as implemented in
			 * mq_html_input_checkbox()). */
			mq_config_set_boolean(config, name,
				value[1] == 'n' ? TRUE : FALSE);
			return TRUE;
		case TYPE_INTEGER:
			integer_value = strtol(value, &endptr, 10);
			if (*endptr != '\0') {
				return FALSE;
			}
			mq_config_set_integer(config, name, integer_value);
			return TRUE;
		case TYPE_DOUBLE:
			double_value = strtod(value, &endptr);
			if (*endptr != '\0') {
				return FALSE;
			}
			mq_config_set_double(config, name, double_value);
			return TRUE;
	}

	g_assert_not_reached();
	return FALSE;
}