/*
 * 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"
#include "sql-value.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);
}

static void sql_object_find_holders (SqlObject * obj, SqlBatch * batch)
{
	guint i;
	guint nparams;
	GParamSpec ** params;

	params = g_object_class_list_properties (G_OBJECT_GET_CLASS (obj), &nparams);

	for (i = 0; i < nparams; i++)
	if (SQL_IS_PARAM_OBJECT (params[i]) || SQL_IS_PARAM_LIST (params[i]))
	{
		SqlObject * child;
		
		g_object_get (obj, params[i]->name, &child, NULL);
		
		if (child)
			sql_object_get_holders (child, batch);
	}

	g_free (params);
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++ 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.
 * 
 * Return value: (transfer full):
 **/
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, SqlBatch * batch)
{
	g_return_if_fail (SQL_IS_OBJECT (obj));
	g_return_if_fail (SQL_IS_RENDER (render));
	g_return_if_fail (SQL_IS_BATCH (batch) || !batch);
	
	SQL_OBJECT_GET_CLASS (obj)->render (obj, render, batch);
}

/**
 * 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)
{
	guint i;
	guint nparams;
	GParamSpec ** params;
	gboolean is_ready = TRUE;
	SqlObjectClass * klass;

	g_return_val_if_fail (SQL_IS_OBJECT (obj), FALSE);
	
	klass = SQL_OBJECT_GET_CLASS (obj);
	params = g_object_class_list_properties (G_OBJECT_CLASS (klass), &nparams);

	for (i = 0; i < nparams && is_ready; i++)
	if (SQL_IS_PARAM_OBJECT (params[i]) || SQL_IS_PARAM_LIST (params[i]))
	{
		SqlObject * child;
		g_object_get (obj, params[i]->name, &child, NULL);
		is_ready = !child || sql_object_is_ready (child);
	}

	g_free (params);
	
	if (klass->is_ready)
		return klass->is_ready (obj);
	else
		return is_ready;
}

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);
}

/**
 * sql_object_get:
 * Return value: (transfer none):
 **/
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_get_holders:
 * @obj: a #SqlObject
 * @batch: an #SqlBatch
 *
 * Gets all identifiers of the contained holders.
 **/
void sql_object_get_holders (SqlObject * obj, SqlBatch * batch)
{
	g_return_if_fail (SQL_IS_OBJECT (obj));
	g_return_if_fail (SQL_IS_BATCH (batch));

	SQL_OBJECT_GET_CLASS (obj)->find_holders (obj, batch);
}

/**
 * sql_object_changed:
 * @obj: a #SqlObject
 *
 * Emits the changed signal on #SqlObject.
 **/
void sql_object_changed (SqlObject * obj)
{
	g_return_if_fail (SQL_IS_OBJECT (obj));

	g_signal_emit (obj, signals[CHANGED], 0);
}

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

static void sql_object_init (SqlObject * obj) {}

static void sql_object_finalize (SqlObject * obj)
{
	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->find_holders = sql_object_find_holders;
	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
	);
}