/**

  * 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

  */

 #include <stdlib.h>

 #include <stdio.h>

 #include <assert.h>

 #include "gmyth_query.h"

 #include "gmyth_settings.h"

 #include "gmyth_context.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)

 {

 	GMythSettings *gmyth_settings = gmyth_context_get_settings ();

     gmyth_query->opt_host_name = gmyth_settings_get_backend_hostname(gmyth_settings);

     gmyth_query->opt_user_name = gmyth_settings_get_username(gmyth_settings);

     gmyth_query->opt_password = gmyth_settings_get_password(gmyth_settings);

     gmyth_query->opt_db_name = gmyth_settings_get_dbname(gmyth_settings);

     /* 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);

     /* disconnect from server */

 	gmyth_query_disconnect (gmyth_query);

 	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 GMythSettings 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) 

 {

     char *opt_host_name;

     char *opt_user_name;

     char *opt_password;

     char *opt_db_name;

     assert(gmyth_query);

     opt_host_name   = (gmyth_query->opt_host_name ? gmyth_query->opt_host_name->str : NULL);

     opt_db_name     = (gmyth_query->opt_db_name ? gmyth_query->opt_db_name->str : NULL);

     opt_user_name   = (gmyth_query->opt_user_name ? gmyth_query->opt_user_name->str : NULL);

     opt_password    = (gmyth_query->opt_password ? gmyth_query->opt_password->str : NULL);

     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, opt_host_name, 

             opt_user_name, opt_password, opt_db_name, 

             0, NULL, 0) == NULL) {

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

 		return FALSE;

     }

     g_debug ("[%s] Connection to Mysql server succeeded!", __FUNCTION__);

     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 */

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

     mysql_close (gmyth_query->conn);

 	return TRUE;	

 }

 static void

 gmyth_query_print_error (MYSQL *conn, char *message)

 {

     fprintf (stderr, "%s\n", message);

     if (conn != NULL) {

 #if MYSQL_VERSION_ID >= 40101

         fprintf (stderr, "Error %u (%s): %s\n",

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

 #else

         fprintf (stderr, "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);

     g_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) {

              g_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;

 }