/*
 * 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-batch.h"
#include "sql-value.h"

/**
 * SECTION: sql-batch
 * @Short_description: binds identifiers with #SqlObject
 * @Title: SqlBatch
 * 
 * The #SqlBatch is a collection of identifiers bound to #SqlObject in
 * an SQL statement. These identifiers are replaced by the value represented
 * by the #SqlObject when the statement is renderend.
 **/
G_DEFINE_TYPE (SqlBatch, sql_batch, G_TYPE_INITIALLY_UNOWNED);
 
enum {
	 CHANGED
	,LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = {0};

SqlBatch * sql_batch_new ()
{
	return g_object_new (SQL_TYPE_BATCH, NULL);
}

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

static void sql_batch_item_changed (SqlObject * item, SqlBatch * self)
{
	if (!self->frozen)
		sql_batch_changed (self);
}

static void sql_batch_free_item (SqlBatch * self, SqlObject * item)
{
	if (item)
	{
		g_signal_handlers_disconnect_by_func (item,
			sql_batch_item_changed, self);
		g_object_unref (item);
	}
}

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

/**
 * sql_batch_is_ready:
 * @self: a #SqlBatch
 *
 * Checks if @self and all of its elements are ready to be rendered.
 * 
 * Return value: %TRUE if ready, %FALSE otherwise.
 **/
gboolean sql_batch_is_ready (SqlBatch * self)
{
	gpointer item;
	GHashTableIter iter;

	g_return_val_if_fail (SQL_IS_BATCH (self), FALSE);
	
	g_hash_table_iter_init (&iter, self->items);
	
	while (g_hash_table_iter_next (&iter, NULL, &item))
	if (!item || !sql_object_is_ready (item))
		return FALSE;
	
	return TRUE;
}

/**
 * sql_batch_get:
 * @self: a #SqlBatch
 * @id: the id of the #SqlHolder
 *
 * Gets a held object by its id.
 *
 * Return value: (transfer none): the #SqlObject if an object with that id
 * exists, %NULL otherwise
 **/
SqlObject * sql_batch_get (SqlBatch * self, const gchar * id)
{
	g_return_val_if_fail (SQL_IS_BATCH (self), NULL);
	g_return_val_if_fail (id, NULL);
	
	if (self->items)
		return g_hash_table_lookup (self->items, id);
	
	return NULL;
}

/**
 * sql_batch_add:
 * @self: a #SqlBatch
 * @id: the id of the #SqlHolder
 * @item: the #SqlObject
 *
 * Adds a new item to the batch.
 **/
void sql_batch_add (SqlBatch * self, const gchar * id, SqlObject * item)
{
	g_return_if_fail (SQL_IS_BATCH (self));
	g_return_if_fail (id);
	g_return_if_fail (SQL_IS_OBJECT (item) || !item);
	
	sql_batch_remove (self, id);
	
	if (item)
	{
		g_object_ref_sink (item);
		g_signal_connect (item, "changed",
			G_CALLBACK (sql_batch_item_changed), self);
	}

	g_hash_table_replace (self->items, g_strdup (id), item);
	sql_batch_item_changed (NULL, self);
}

/**
 * sql_batch_add_param:
 * @self: a #SqlBatch
 * @id: the id assigned to the item
 * @param: the parameter
 **/
void sql_batch_add_from_param (SqlBatch * self, const gchar * id, GvnParam * param)
{
	g_return_if_fail (SQL_IS_BATCH (self));
	g_return_if_fail (id);
	g_return_if_fail (GVN_IS_PARAM (param));

	sql_batch_add (self, id, sql_value_new_with_param (param));
}

/**
 * sql_batch_add_value:
 * @self: a #SqlBatch
 * @id: the id assigned to the item
 * @value: the value
 **/
void sql_batch_add_from_value (SqlBatch * self, const gchar * id, const GValue * value)
{
	g_return_if_fail (SQL_IS_BATCH (self));
	g_return_if_fail (id);
	g_return_if_fail (G_IS_VALUE (value));

	sql_batch_add (self, id, sql_value_new_with_value (value));
}

/**
 * sql_batch_remove:
 * @self: a #SqlBatch
 * @id: the id of the #SqlHolder
 *
 * Removes a held object from the batch.
 **/
void sql_batch_remove (SqlBatch * self, const gchar * id)
{
	g_return_val_if_fail (SQL_IS_BATCH (self), NULL);
	g_return_val_if_fail (id, NULL);

	SqlObject * item = sql_batch_get (self, id);
	
	if (item)
	{
		sql_batch_free_item (self, item);
		g_hash_table_remove (self->items, id);
	}
}

/**
 * sql_batch_merge:
 * @self: a #SqlBatch
 * @batch: a #SqlBatch
 *
 * Meges the batch with another batch.
 **/
void sql_batch_merge (SqlBatch * self, SqlBatch * batch)
{
	GHashTableIter iter;
	gpointer key, value;

	g_return_if_fail (SQL_IS_BATCH (self));
	g_return_if_fail (SQL_IS_BATCH (batch) || !batch);
	
	if (!batch)
		return;

	g_hash_table_iter_init (&iter, batch->items);
	
	while (g_hash_table_iter_next (&iter, &key, &value))
		sql_batch_add (self, key, value);
}

/**
 * sql_batch_changed:
 * @self: a #SqlBatch
 *
 * Emits the changed signal on #SqlBatch.
 **/
void sql_batch_changed (SqlBatch * self)
{
	g_return_if_fail (SQL_IS_BATCH (self));

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

/**
 * sql_batch_freeze:
 * @self: a #SqlBatch
 *
 * Freezes the changed signal on #SqlBatch.
 **/
void sql_batch_freeze (SqlBatch * self)
{
	g_return_if_fail (SQL_IS_BATCH (self));

	self->frozen = TRUE;
}

/**
 * sql_batch_unfreeze:
 * @self: a #SqlBatch
 *
 * Unfreezes the changed signal on #SqlBatch.
 **/
void sql_batch_unfreeze (SqlBatch * self)
{
	g_return_if_fail (SQL_IS_BATCH (self));

	self->frozen = FALSE;
}

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

static void sql_batch_init (SqlBatch * self)
{
	self->items = g_hash_table_new_full (
		 g_str_hash
		,g_str_equal
		,g_free
		,NULL
	);
	self->frozen = FALSE;
}

static void sql_batch_finalize (SqlBatch * self)
{
	gpointer item;
	GHashTableIter iter;

	g_hash_table_iter_init (&iter, self->items);

	while (g_hash_table_iter_next (&iter, NULL, &item))
		sql_batch_free_item (self, item);

	g_hash_table_destroy (self->items);

	G_OBJECT_CLASS (sql_batch_parent_class)->finalize (G_OBJECT (self));
}

static void sql_batch_class_init (SqlBatchClass * klass)
{
	G_OBJECT_CLASS (klass)->finalize = (GObjectFinalizeFunc) sql_batch_finalize;

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