/*
 * 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-select.h"
#include "sql-field.h"

/**
 * SECTION: sql-select
 * @Short_description: an SQL SELECT statement 
 * @Title: SqlSelect
 * 
 * This object represents a SELECT SQL statement
 **/

typedef struct
{
	SqlExpr * expr;
	gchar * alias;
}
SqlSelectAlias;

typedef struct
{
	SqlExpr * expr;
	SqlOrderWay way;
}
SqlOrder;

G_DEFINE_TYPE (SqlSelect, sql_select, SQL_TYPE_DML);

SqlSelect * sql_select_new ()
{
	return g_object_new (SQL_TYPE_SELECT, NULL);
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++ Private
/*
static const char * SQL_SELECT_TYPE[] =
{
	 NULL
	,"UNION ALL"
	,"UNION ANY"
	,"INTERSECT"
	,"EXCEPT"
};
*/
static void sql_select_render_order (SqlOrder * order, SqlRender * render)
{
	sql_render_add_object (render, order->expr);

	if (order->way == SQL_ORDER_DESC)
		sql_render_add_token (render, "DESC");
}

static void sql_select_render (SqlSelect * obj, SqlRender * render)
{
	if (obj->alias)
	{
		GSList * n;

		sql_render_add_token (render, "SELECT");

		for (n = obj->expr; n; n = n->next)
		{
			GSList * l;

			sql_render_add_object (render, n->data);

			for (l = obj->alias; l; l = l->next)
				if (((SqlSelectAlias *) l->data)->expr == n->data)
				{
					sql_render_add_identifier (render,
						((SqlSelectAlias *) l->data)->alias);
				}

			if (n->next)
				sql_render_append (render, " ,");
		}
	}
	else
		sql_render_add_list (render, T, "SELECT", obj->expr, ",");

	sql_render_add_list (render, F, "FROM", SQL_DML (obj)->target, ",");

	if (SQL_DML (obj)->target)
	{
		sql_render_add_item (render, F, "WHERE", SQL_DML (obj)->where);
		sql_render_add_list (render, F, "GROUP BY", obj->group, ",");
		sql_render_add_item (render, F, "HAVING", obj->having);
		sql_render_add_list_with_func (render, F, "ORDER", obj->order, ",",
			(SqlRenderFunc) sql_select_render_order);
		
		if (obj->limit_count)
			sql_render_printf (render, "LIMIT %u OFFSET %u"
				,obj->limit_count
				,obj->limit_offset
			);
	}
}

static void sql_order_free (SqlOrder * obj)
{
	g_object_unref (obj->expr);
	g_free (obj);
}

static void sql_select_alias_free (SqlSelectAlias * obj)
{
	g_free (obj->alias);
	g_free (obj);
}

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

void sql_select_add_expr (SqlSelect * obj, SqlExpr * expr)
{
	g_return_if_fail (SQL_IS_SELECT (obj));
	g_return_if_fail (SQL_IS_EXPR (expr));

	obj->expr = g_slist_append (obj->expr, g_object_ref_sink (expr));
}

void sql_select_set_alias (SqlSelect * obj, SqlExpr * expr, const gchar * alias)
{
	GSList * list;

	g_return_if_fail (SQL_IS_SELECT (obj));

	list = g_slist_find (obj->expr, expr);

	if (list)
	{
		SqlSelectAlias * as = g_new (SqlSelectAlias, 1);
		as->alias = g_strdup (alias);
		as->expr = expr;
		obj->alias = g_slist_append (obj->alias, as);
	}
}

/*
 * Return the alias of a field and if it's an unaliased SqlField, its name,
 * otherwise returns NULL (uses include of sql-field.h)
 */
gchar * sql_select_get_column_name (SqlSelect * obj, SqlExpr * expr)
{
	gboolean listed = FALSE;
	GSList * n;

	g_return_val_if_fail (SQL_IS_SELECT (obj), NULL);
	g_return_val_if_fail (SQL_IS_EXPR (expr), NULL);

	for (n = obj->expr; n; n = n->next)
	if (expr == n->data)
	{
		listed = TRUE;
		break;
	}

	if (listed)
	for (n = obj->alias; n; n = n->next)
	{
		SqlSelectAlias * as = n->data;

		if (expr == as->expr)
			return g_strdup (as->alias);
	}

	if (SQL_IS_FIELD (expr))
	{
		gchar * name;
		g_object_get (expr, "name", &name, NULL);
		return name;
	}

	return NULL;
}

void sql_select_add_group (SqlSelect * obj, SqlExpr * expr)
{
	g_return_if_fail (SQL_IS_SELECT (obj));
	g_return_if_fail (SQL_IS_EXPR (expr));

	obj->group = g_slist_append (obj->group, g_object_ref_sink (expr));
}

void sql_select_set_having (SqlSelect * obj, SqlExpr * expr)
{
	g_return_if_fail (SQL_IS_SELECT (obj));
	g_return_if_fail (SQL_IS_EXPR (expr));

	g_clear_object (&obj->having);
	obj->having = g_object_ref_sink (expr);
}

void sql_select_add_order (SqlSelect * obj, SqlExpr * expr, SqlOrderWay way)
{
	g_return_if_fail (SQL_IS_SELECT (obj));
	g_return_if_fail (SQL_IS_EXPR (expr));

	SqlOrder * order = g_new (SqlOrder, 1);
	order->expr = g_object_ref_sink (expr);
	order->way = way;

	obj->order = g_slist_append (obj->order, order);
}

void sql_select_set_distinct (SqlSelect * obj, gboolean distinct)
{
	g_return_if_fail (SQL_IS_SELECT (obj));

	obj->distinct = distinct;
}

void sql_select_set_limit (SqlSelect * obj, guint count, guint offset)
{
	g_return_if_fail (SQL_IS_SELECT (obj));

	obj->limit_count = count;
	obj->limit_offset = offset;
}

void sql_select_set_next (SqlSelect * obj, SqlSelect * next, SqlSelectType type)
{
	g_return_if_fail (SQL_IS_SELECT (obj));
	g_return_if_fail (SQL_IS_SELECT (next) || !next);

	g_clear_object (&obj->next);
	
	if (next)
	{
		obj->next = g_object_ref (next);
		obj->type = type;
	}
	else
		obj->type = SQL_SELECT_NONE;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++ Properties

enum
{
	 PROP_DISTINCT = 1
	,PROP_LIMIT_COUNT
	,PROP_LIMIT_OFFSET
	,PROP_HAVING
	,PROP_TYPE
	,PROP_NEXT
};

static void sql_select_set_property (SqlSelect * obj, guint id,
	const GValue * value, GParamSpec * pspec)
{
	switch (id)
	{
		case PROP_DISTINCT:
			obj->distinct = g_value_get_boolean (value);
			break;
		case PROP_LIMIT_COUNT:
			obj->limit_count = g_value_get_uint (value);
			break;
		case PROP_LIMIT_OFFSET:
			obj->limit_offset = g_value_get_uint (value);
			break;
		case PROP_HAVING:
			sql_select_set_having (obj, g_value_get_object (value));
			break;
		case PROP_TYPE:
			obj->type = g_value_get_int (value);
			break;
		case PROP_NEXT:
			sql_select_set_next (obj, g_value_get_object (value), obj->type);
			break;
		default:		
			G_OBJECT_WARN_INVALID_PROPERTY_ID (obj, id, pspec);
	}
}

static void sql_select_get_property (SqlSelect * obj, guint id,
	GValue * value, GParamSpec * pspec)
{	
	switch (id)
	{
		case PROP_DISTINCT:
			 g_value_set_boolean (value, obj->distinct);
			break;
		case PROP_LIMIT_COUNT:
			 g_value_set_uint (value, obj->limit_count);
			break;
		case PROP_LIMIT_OFFSET:
			g_value_set_uint (value, obj->limit_offset);
			break;
		case PROP_HAVING:
			g_value_set_object (value, obj->having);
			break;
		case PROP_TYPE:
			g_value_set_int (value, obj->type);
			break;
		case PROP_NEXT:
			g_value_set_object (value, obj->next);
			break;
		default:		
			G_OBJECT_WARN_INVALID_PROPERTY_ID (obj, id, pspec);
	}
}

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

static void sql_select_init (SqlSelect * obj)
{
	obj->distinct = FALSE;
	obj->expr = NULL;
	obj->alias = NULL;
	obj->group = NULL;
	obj->having = NULL;
	obj->order = NULL;
	obj->next = NULL;
	obj->type = SQL_SELECT_NONE;
}

static void sql_select_finalize (SqlSelect * obj)
{
	g_clear_object (&obj->having);
	g_clear_object (&obj->next);
	g_slist_free_full (obj->expr, g_object_unref);
	g_slist_free_full (obj->group, g_object_unref);
	g_slist_free_full (obj->alias, (GFreeFunc) sql_select_alias_free);
	g_slist_free_full (obj->order, (GFreeFunc) sql_order_free);
	G_OBJECT_CLASS (sql_select_parent_class)->finalize (G_OBJECT (obj));
}

static void sql_select_class_init (SqlSelectClass * k)
{
	GObjectClass * klass = G_OBJECT_CLASS (k);
	klass->finalize = (GObjectFinalizeFunc) sql_select_finalize;
	klass->set_property = (GObjectSetPropertyFunc) sql_select_set_property;
	klass->get_property = (GObjectGetPropertyFunc) sql_select_get_property;
	SQL_OBJECT_CLASS (klass)->render = (SqlRenderFunc) sql_select_render;

	g_object_class_install_property (klass, PROP_LIMIT_COUNT,
		g_param_spec_boolean ("distinct"
			,"Distinct"
			,"Determines if the #SqlSelect uses the DISTINCT clause"
			,FALSE, G_PARAM_READWRITE
	));

	g_object_class_install_property (klass, PROP_LIMIT_COUNT,
		g_param_spec_uint ("limit-count"
			,"Limit count"
			,"The COUNT field of the LIMIT clause"
			,0, G_MAXUINT, 0, G_PARAM_READWRITE
	));

	g_object_class_install_property (klass, PROP_LIMIT_OFFSET,
		g_param_spec_uint ("limit-offset"
			,"Limit offset"
			,"The OFFSET field of the LIMIT clause"
			,0, G_MAXUINT, 0, G_PARAM_READWRITE
	));

	g_object_class_install_property (klass, PROP_HAVING,
		g_param_spec_object ("having"
			,"Having"
			,"The HAVING clause"
			,SQL_TYPE_EXPR,	G_PARAM_READWRITE
	));

	g_object_class_install_property (klass, PROP_TYPE,
		g_param_spec_int ("type"
			,"Type"
			,"One of the possible options of #SqlSelectType"
			,0, SQL_SELECT_COUNT - 1, 0, G_PARAM_READWRITE
	));

	g_object_class_install_property (klass, PROP_NEXT,
		g_param_spec_object ("next"
			,"Next"
			,"The next #SqlSelect in case of a statement with more than one"
			,SQL_TYPE_SELECT, G_PARAM_READWRITE
	));
}