/*
 * Copyright (C) 2012 - Juan Ferrer Toribio
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include "sql-object.h"

/**
 * SECTION: sql-object
 * @Short_description: represents an SQL statement or a part of it
 * @Title: SqlObject
 * 
 * The #SqlObject is the base class for all objects in SqlLib.
 **/
G_DEFINE_ABSTRACT_TYPE (SqlObject, sql_object, G_TYPE_INITIALLY_UNOWNED);
 
enum {
	 CHANGED
	,LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = {0};

//+++++++++++++++++++++++++++++++++++++++++++++++++++ Private

static void sql_object_child_changed (SqlObject * child, SqlObject * obj)
{
	sql_object_changed (obj);
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++ Protected

/**
 * sql_object_add:
 * @obj: #SqlObject where the new item will be added
 * @child: #SqlObject the object is added
 *
 * Note that this function is considered a protected method and should only
 * be used in classes that inherit from #SqlObjectClass.
 **/
gpointer sql_object_add (gpointer obj, gpointer child)
{
	if (child)
	{
		g_object_ref_sink (child);
		g_signal_connect (child, "changed",
			G_CALLBACK (sql_object_child_changed), obj);
	}
	
	return child;
}

/**
 * sql_object_remove:
 * @obj: #SqlObject where the new item will be added
 * @child: #SqlObject the object is added
 *
 * Note that this function is considered a protected method and should only
 * be used in classes that inherit from #SqlObjectClass.
 **/
void sql_object_remove (gpointer obj, gpointer child)
{
	if (child)
	{
		g_signal_handlers_disconnect_by_func (child,
			sql_object_child_changed, obj);
		g_object_unref (child);
	}
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++ Public

/**
 * sql_object_render:
 * @obj: a #SqlObject
 * @render: an #SqlRender
 *
 * Renders the object into a SQL string and stores it into the renderer.
 **/
void sql_object_render (SqlObject * obj, SqlRender * render)
{
	g_return_if_fail (SQL_IS_OBJECT (obj));
	g_return_if_fail (SQL_IS_RENDER (render));
	
//	SQL_OBJECT_GET_CLASS (obj)->render (obj, render);
}

/**
 * sql_object_is_ready:
 * @obj: a #SqlObject
 *
 * Checks if @obj and all of its elemens are ready to be rendered.
 * 
 * Return value: %TRUE if ready, %FALSE otherwise.
 **/
gboolean sql_object_is_ready (SqlObject * obj)
{
	SqlObjectClass * klass = SQL_OBJECT_GET_CLASS (obj);

	g_return_val_if_fail (SQL_IS_OBJECT (obj), FALSE);
	
	if (obj->held_objects)
	{
		GList * i;
		GList * held_objects = g_hash_table_get_values (obj->held_objects);
		gboolean is_ready = TRUE;
		
		for (i = held_objects; i; i = i->next)
		if (!sql_object_is_ready (i->data))
		{
			is_ready = FALSE;
			break;
		}
		
		g_list_free (held_objects);
		
		if (!is_ready)
			return FALSE;
	}
	
	if (klass->is_ready)
		return klass->is_ready (obj);
	else
		return TRUE;
}

void sql_object_set (SqlObject * obj, const gchar * property, SqlObject * value)
{
	g_return_if_fail (SQL_IS_OBJECT (obj));
	g_return_if_fail (SQL_IS_OBJECT (value));

	g_object_set (obj, property, value, NULL);
}


SqlObject * sql_object_get (SqlObject * obj, const gchar * property)
{
	SqlObject * value;

	g_return_val_if_fail (SQL_IS_OBJECT (obj), NULL);

	g_object_get (obj, property, &value, NULL);
	return value;
}

void sql_object_add_child (SqlObject * obj, const gchar * property, SqlObject * child)
{
	SqlList * list;

	g_return_if_fail (SQL_IS_OBJECT (obj));
	g_return_if_fail (SQL_IS_OBJECT (child));

	g_object_get (obj, property, &list, NULL);
	sql_list_add (list, child);
}

void sql_object_remove_child (SqlObject * obj, const gchar * property, guint n)
{
	SqlList * list;

	g_return_if_fail (SQL_IS_OBJECT (obj));

	g_object_get (obj, property, &list, NULL);
	sql_list_remove (list, n);
}

/**
 * sql_object_add_held_object:
 * @obj: a #SqlObject
 * @id: the id of the #SqlHolder
 * @held_object: the held object
 *
 * Adds a held object.
 **/
void sql_object_add_held_object (SqlObject * obj, const gchar * id, SqlObject * held_object)
{
	g_return_if_fail (SQL_IS_OBJECT (obj));
	g_return_if_fail (id);
	
	if (!obj->held_objects)
		obj->held_objects = g_hash_table_new_full (
			 g_str_hash
			,g_str_equal
			,g_free
			,g_object_unref
		);
	
	g_signal_connect (held_object, "changed",
		G_CALLBACK (sql_object_child_changed), obj
	);
	g_hash_table_replace (obj->held_objects,
		g_strdup (id), g_object_ref_sink (held_object));
}

/**
 * sql_object_get_held_object:
 * @obj: a #SqlObject
 * @id: the id of the #SqlHolder
 *
 * Gets a held object by its id.
 *
 * Return value: the #SqlObject if an object with that id exists, %NULL otherwise
 **/
SqlObject * sql_object_get_held_object (SqlObject * obj, const gchar * id)
{
	g_return_val_if_fail (SQL_IS_OBJECT (obj), NULL);
	g_return_val_if_fail (id, NULL);
	
	if (obj->held_objects)
		return g_hash_table_lookup (obj->held_objects, id);
	
	return NULL;
}

/**
 * sql_object_changed:
 * @obj: a #SqlObject
 *
 * Emits the changed signal on #SqlObject.
 **/
void sql_object_changed (SqlObject * obj)
{
	g_signal_emit (obj, signals[CHANGED], 0);
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++ Class

static void sql_object_init (SqlObject * obj)
{
	obj->child_groups = NULL;
	obj->held_objects = NULL;
}

static void sql_object_finalize (SqlObject * obj)
{
	if (obj->child_groups)
		g_hash_table_destroy (obj->child_groups);
	if (obj->held_objects)
		g_hash_table_destroy (obj->held_objects);

	G_OBJECT_CLASS (sql_object_parent_class)->finalize (G_OBJECT (obj));
}

static void sql_object_class_init (SqlObjectClass * klass)
{
	G_OBJECT_CLASS (klass)->finalize = (GObjectFinalizeFunc) sql_object_finalize;
	klass->is_ready = NULL;
	klass->render = NULL;

	/** 
	 * SqlObject::changed:
	 * @obj: the object which emit the signal.
	 * 
	 * This signal is emitted every time the statement or one of its attributes
	 * is modified. 
	 */
	signals[CHANGED] = g_signal_new ("changed", SQL_TYPE_OBJECT,
		G_SIGNAL_RUN_FIRST, 0, NULL, NULL,
			g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0
	);
}