/* File: gr_ryow.c
 * Name: lefred
 * Date: 2017-08-05
 * Description: Read you own write on Group Replication
 *              proof-of-concept using GTID returned in
 *              OK packet
 *
 * Usage: ./gr_ryow [-w <host>] [-r <host>] string
 *
 *  -w:     writer node default is localhost
 *  -r:     reader node default is localhost
 *  string: the value you want to insert 
 *
 *  gr_ryown insert a record with the inserted value and returns the GTID
 *  of the transaction (from the OK packet). Then it reads data from the
 *  table looking for the value entered but only when the write is applied
 *  (consistent read / read your own read)
 *  It also displays how many milisecond the read took.
 *
 * Schema used: sync_test
 * Table definition:
 *       CREATE TABLE `test` (
 *           `id` int(11) NOT NULL AUTO_INCREMENT,
 *           `name` varchar(20) DEFAULT NULL,
 *           PRIMARY KEY (`id`),
 *           KEY `name_idx` (`name`)
 *       ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4  
 */

#include <my_global.h>
#include <mysql.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>


void finish_with_error(MYSQL *mysql)
{
	fprintf(stderr, "%s\n", mysql_error(mysql));
	mysql_close(mysql);
	exit(1);        
}

static struct timeval tm1;

static inline void start()
{
	gettimeofday(&tm1, NULL);
}

static inline void stop()
{
	struct timeval tm2;
	gettimeofday(&tm2, NULL);

	unsigned long long t = 1000 * (tm2.tv_sec - tm1.tv_sec) + (tm2.tv_usec - tm1.tv_usec) / 1000;
	printf("%llu ms\n", t);
}

int main(int argc, char **argv)
{
	char *s_host_w = "localhost";
	char *s_host_r = "localhost";
	char s_query[255];
	char s_gtid[100];
	char *s_value = "";
	int opt;
	MYSQL *mysql = mysql_init(NULL);

	while ((opt = getopt(argc, argv, "r:w:")) != -1)
	{
		switch (opt) 
		{
			case 'w': s_host_w = optarg; break;
			case 'r': s_host_r = optarg; break;
		}
	} 
	//printf("MySQL client version: %s\n", mysql_get_client_info());
	s_value = argv[optind];
	if (mysql == NULL) 
	{
		fprintf(stderr, "%s\n", mysql_error(mysql));
		exit(1);
	}  

	if (mysql_real_connect(mysql, s_host_w, "root", "", 
				"sync_test", 0, NULL, 0) == NULL) 
	{
		finish_with_error(mysql);
	}    

	sprintf(s_query, "INSERT INTO test VALUES(0,'%s');", s_value); 
	if (mysql_query(mysql, s_query)) {
		finish_with_error(mysql);
	}

	MYSQL_RES *result = mysql_store_result(mysql);
	if (result) /* there is a result set to fetch */
	{
		mysql_free_result(result);
	}
	else        /* there is no result set */
	{
		if (mysql_field_count(mysql) != 0)
		{
			fprintf(stderr, "Error %u: %s\n",
					mysql_errno(mysql), mysql_error(mysql));
		}
	}

	/* extract any available session state-change information */
	enum enum_session_state_type type;
	for (type = SESSION_TRACK_BEGIN; type <= SESSION_TRACK_END; type++)
	{
		const char *data;
		size_t length;

		if (mysql_session_track_get_first(mysql, type, &data, &length) == 0)
		{
			sprintf(s_gtid,"%*.*s",
					(int) length, (int) length, data);
			printf("GTID: %s\n", s_gtid);

		}
	} 
	mysql_close(mysql);
	mysql = mysql_init(NULL);
	if (mysql_real_connect(mysql, s_host_r, "root", "", 
				"sync_test", 0, NULL, 0) == NULL) 
	{
		finish_with_error(mysql);
	}    
	sprintf(s_query, "SELECT WAIT_FOR_EXECUTED_GTID_SET('%s') as `ignore`", s_gtid); 
        //printf("DEBUG: %s\n", s_query);
	start();
	if (mysql_query(mysql, s_query)) {
		finish_with_error(mysql);
	}
	result = mysql_store_result(mysql);
	mysql_free_result(result);
	sprintf(s_query, "SELECT id, name FROM test WHERE name = '%s';", s_value); 
	if (mysql_query(mysql, s_query)) {
		finish_with_error(mysql);
	}
	result = mysql_store_result(mysql);
	if (result) /* there is a result set to fetch */
	{
		mysql_free_result(result);
	}
	else        /* there is no result set */
	{
		if (mysql_field_count(mysql) != 0)
		{
			fprintf(stderr, "Error %u: %s\n",
					mysql_errno(mysql), mysql_error(mysql));
		}
	}

	stop();
	mysql_close(mysql);
	exit(0);
}