/**

 * GMyth Library

 *

 * @file gmyth/gmyth_query.c

 * 

 * @brief <p> GMythQuery class provides a wrapper for accessing

 * the libmysqlclient funtions.

 *

 * Copyright (C) 2006 INdT - Instituto Nokia de Tecnologia.

 * @author Leonardo Sobral Cunha <leonardo.cunha@indt.org.br>

 *

 *//*

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation; either version 2 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 Lesser General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <stdlib.h>

#include <stdio.h>

#include <assert.h>

#include "gmyth_query.h"

#include "gmyth_debug.h"

static void gmyth_query_class_init          (GMythQueryClass *klass);

static void gmyth_query_init                (GMythQuery *object);

static void gmyth_query_dispose  (GObject *object);

static void gmyth_query_finalize (GObject *object);

static void gmyth_query_print_error (MYSQL *conn, char *message);

G_DEFINE_TYPE(GMythQuery, gmyth_query, G_TYPE_OBJECT)

static void

gmyth_query_class_init (GMythQueryClass *klass)

{

    GObjectClass *gobject_class;

    gobject_class = (GObjectClass *) klass;

    gobject_class->dispose  = gmyth_query_dispose;

    gobject_class->finalize = gmyth_query_finalize;	

}

static void

gmyth_query_init (GMythQuery *gmyth_query)

{

    gmyth_query->backend_info = NULL;

    /* initialize connection handler */

    gmyth_query->conn = mysql_init (NULL);

    if (!(gmyth_query->conn))

    	g_warning ("[%s] MSQL structure not initialized", __FUNCTION__);

}

static void

gmyth_query_dispose  (GObject *object)

{

    GMythQuery *gmyth_query = GMYTH_QUERY (object);

    if (gmyth_query->backend_info) {

        g_object_unref (gmyth_query->backend_info);

	//gmyth_query->backend_info = NULL;

    }

    G_OBJECT_CLASS (gmyth_query_parent_class)->dispose (object);

}

static void

gmyth_query_finalize (GObject *object)

{

    g_signal_handlers_destroy (object);

    G_OBJECT_CLASS (gmyth_query_parent_class)->finalize (object);

}

/** Creates a new instance of GMythQuery.

 * 

 * @return a new instance of GMythQuery.

 */

GMythQuery*

gmyth_query_new ()

{

    GMythQuery *sql_query = GMYTH_QUERY (g_object_new(GMYTH_QUERY_TYPE, NULL));

    return sql_query;

}

/** Connects to the Mysql database in the backend. The backend address

 * is loaded from the GMythBackendInfo instance.

 * 

 * @param gmyth_query the GMythEPG instance to be connected.

 * @return true if connection was success, false if failed.

 */

gboolean

gmyth_query_connect (GMythQuery *gmyth_query, GMythBackendInfo *backend_info) 

{

    assert(gmyth_query);

    g_return_val_if_fail (backend_info != NULL, FALSE);

    g_return_val_if_fail (backend_info->hostname != NULL, FALSE);

    g_return_val_if_fail (backend_info->username != NULL, FALSE);

    g_return_val_if_fail (backend_info->password != NULL, FALSE);

    g_return_val_if_fail (backend_info->db_name != NULL, FALSE);

    g_object_ref (backend_info);

    gmyth_query->backend_info = backend_info;

    if (gmyth_query->conn == NULL) {

        gmyth_query_print_error (NULL, "mysql_init() failed (probably out of memory)");

        return FALSE;

    }

    /* connect to server */

    if (mysql_real_connect (gmyth_query->conn, 

	    gmyth_query->backend_info->hostname, 

            gmyth_query->backend_info->username,

	    gmyth_query->backend_info->password,

	    gmyth_query->backend_info->db_name, 

            0, NULL, 0) == NULL) {

        gmyth_query_print_error (gmyth_query->conn, "mysql_real_connect() failed");

		return FALSE;

    }

    gmyth_debug ("[%s] Connection to Mysql server succeeded! (host = %s, user = %s, "\

    			"password = %s, db name = %s)", __FUNCTION__, 

    			gmyth_query->backend_info->hostname, gmyth_query->backend_info->username,

	    		gmyth_query->backend_info->password, gmyth_query->backend_info->db_name );

    return TRUE;

}

/** Disconnects from the Mysql database in the backend.

 * 

 * @param gmyth_query the GMythQuery instance to be disconnected

 * @return true if disconnection was success, false if failed.

 */

gboolean

gmyth_query_disconnect (GMythQuery *gmyth_query) 

{

    assert(gmyth_query);

    /* TODO: Check how to return error */

    gmyth_debug ("[%s] Closing gmyth_query->conn", __FUNCTION__);

    mysql_close (gmyth_query->conn);

	return TRUE;	

}

static void

gmyth_query_print_error (MYSQL *conn, char *message)

{

    g_debug ("%s", message);

    if (conn != NULL) {

#if MYSQL_VERSION_ID >= 40101

        g_debug ("Error %u (%s): %s\n",

                mysql_errno (conn), mysql_sqlstate(conn), mysql_error (conn));

#else

        g_debug ("Error %u: %s\n",

               mysql_errno (conn), mysql_error (conn));

#endif

    }

}

/** Sends the given query to the backend returning the query result as

 * MYSQL_RES pointer.

 * 

 * FIXME: this function is returning NULL whether any error happens

 * or no rows are returned (e.g. UPDATE or REPLACE).

 * 

 * @param gmyth_query the GMythQuery instance.

 * @param stmt_str the query text.

 * @return the MYSQL_RES result pointer or NULL if any error happens.

 */

MYSQL_RES*

gmyth_query_process_statement (GMythQuery *gmyth_query, char *stmt_str)

{

    MYSQL_RES *res_set;

    assert(gmyth_query);

    gmyth_debug ("[%s] Running mysql query %s", __FUNCTION__, stmt_str);

    if (gmyth_query == NULL)

    	return NULL;

    /* the statement failed */

    if (mysql_query (gmyth_query->conn, stmt_str) != 0) {

        gmyth_query_print_error (gmyth_query->conn, "Could not execute statement");

        return NULL;

    }

    /* the statement succeeded; determine whether it returned data */

    res_set = mysql_store_result (gmyth_query->conn);

    if (res_set) {

        return res_set;

    } else if (mysql_field_count (gmyth_query->conn) == 0) {

        gmyth_debug ("%lu rows affected\n",

                (unsigned long) mysql_affected_rows (gmyth_query->conn));

    } else {

        gmyth_query_print_error (gmyth_query->conn, "Could not retrieve result set");

    }

    return NULL;

}