/* db_mysql.c - Implements accessing a mySQL 3.22+ database. */
/* $Id: db_mysql.c,v 1.11 2004/09/13 14:12:54 tyrspace Exp $ */

#include "copyright.h"
#include "autoconf.h"
#include "config.h"

#include "alloc.h"	/* required by mudconf */
#include "flags.h"	/* required by mudconf */
#include "htab.h"	/* required by mudconf */
#include "mudconf.h"	/* required by code */

#include "db.h"		/* required by externs */
#include "externs.h"	/* required by code */
#include "functions.h"  /* required by code */

#include "mysql.h"
#include "errmsg.h"

/* See db_sql.h for details of what each of these functions do. */


/* Number of times to retry a connection if we fail in the middle of
 * a query.
 */

#define MYSQL_RETRY_TIMES 3

static MYSQL *mysql_struct = NULL;

void sql_shutdown()
{
    MYSQL *mysql;

    if (!mysql_struct)
	return;
    mysql = mysql_struct;
    STARTLOG(LOG_ALWAYS, "SQL", "DISC")
	log_printf("Disconnected from SQL server %s, SQL database selected: %s",
		   mysql->host, mysql->db);
    ENDLOG
    mysql_close(mysql);
    XFREE(mysql, "mysql");
    mysql_struct = NULL;
    mudstate.sql_socket = -1;
}

int sql_init()
{
    MYSQL *mysql, *result;

    /* Make sure we have valid config options. */

    if (!mudconf.sql_host || !*mudconf.sql_host)
	return -1;
    if (!mudconf.sql_db || !*mudconf.sql_db)
	return -1;

    /* If we are already connected, drop and retry the connection, in
     * case for some reason the server went away.
     */

    if (mysql_struct)
	sql_shutdown();

    /* Try to connect to the database host. If we have specified
     * localhost, use the Unix domain socket instead.
     */
    mysql = (MYSQL *) XMALLOC(sizeof(MYSQL), "mysql");
    mysql_init(mysql);

    result =  mysql_real_connect(mysql, mudconf.sql_host,
				 mudconf.sql_username, mudconf.sql_password,
				 mudconf.sql_db, 0, NULL, 0);
    if (!result) {
	STARTLOG(LOG_ALWAYS, "SQL", "CONN")
	     log_printf("Failed connection to SQL server %s: %s",
			mudconf.sql_host, mysql_error(mysql));
	ENDLOG
        XFREE(mysql, "mysql");
	return -1;
    }

    STARTLOG(LOG_ALWAYS, "SQL", "CONN")
	log_printf("Connected to SQL server %s, SQL database selected: %s",
		   mysql->host, mysql->db);
    ENDLOG

    mysql_struct = mysql;
    mudstate.sql_socket = mysql->net.fd;
    return 1;
}

int sql_query(player, q_string, buff, bufc, row_delim, field_delim)
    dbref player;
    char *q_string;
    char *buff;
    char **bufc;
    const Delim *row_delim, *field_delim;
{
    MYSQL_RES *qres;
    MYSQL_ROW row_p;
    MYSQL *mysql;
    int num_rows, got_rows, got_fields;
    int i, j;
    int retries;

    /* If we have no connection, and we don't have auto-reconnect on
     * (or we try to auto-reconnect and we fail), this is an error
     * generating a #-1. Notify the player, too, and set the return code.
     */

    mysql = mysql_struct;
    if ((!mysql) & (mudconf.sql_reconnect != 0)) {
	/* Try to reconnect. */
	retries = 0;
	while ((retries < MYSQL_RETRY_TIMES) && !mysql) {
	    sleep(1);
	    sql_init();
            mysql = mysql_struct;
	    retries++;
	}
    }
    if (!mysql) {
	notify(player, "No SQL database connection.");
	if (buff)
	    safe_str("#-1", buff, bufc);
	return -1;
    }
    if (!q_string || !*q_string)
	return 0;

    /* Send the query. */

    got_rows = mysql_real_query(mysql, q_string, strlen(q_string));
    if ((got_rows) && (mysql_errno(mysql) == CR_SERVER_GONE_ERROR)) {

	/* We got this error because the server died unexpectedly
	 * and it shouldn't have. Try repeatedly to reconnect before
	 * giving up and failing. This induces a few seconds of lag,
	 * depending on number of retries; we put in the sleep() here
	 * to see if waiting a little bit helps.
	 */

	STARTLOG(LOG_PROBLEMS, "SQL", "GONE")
	    log_printf("Connection died to SQL server");
	ENDLOG

	retries = 0;
	sql_shutdown();

	while ((retries < MYSQL_RETRY_TIMES) &&
	       (!mysql)) {
	    sleep(1);
	    sql_init();
            mysql = mysql_struct;
	    retries++;
	}

	if (mysql)
	    got_rows = mysql_real_query(mysql, q_string, strlen(q_string));
    }
    if (got_rows) {
	notify(player, mysql_error(mysql));
	if (buff)
	    safe_str("#-1", buff, bufc);
        return -1;
    }

    /* A number of affected rows greater than 0 means it wasn't a SELECT */

    num_rows = mysql_affected_rows(mysql);
    if (num_rows > 0) {
	notify(player, tprintf("SQL query touched %d %s.",
			       num_rows, (num_rows == 1) ? "row" : "rows"));
	return 0;
    } else if (num_rows == 0) {
	return 0;
    }

    /* Check to make sure we got rows back. */

    qres = mysql_store_result(mysql);
    got_rows = mysql_num_rows(qres);
    if (got_rows == 0) {
	mysql_free_result(qres);
	return 0;
    }

    /* Construct properly-delimited data. */

    if (buff) {
	for (i = 0; i < got_rows; i++) {
	    if (i > 0) {
		print_sep(row_delim, buff, bufc);
	    }
	    row_p = mysql_fetch_row(qres);
	    if (row_p) {
		got_fields = mysql_num_fields(qres);
		for (j = 0; j < got_fields; j++) {
		    if (j > 0) {
			print_sep(field_delim, buff, bufc);
		    }
		    if (row_p[j] && *row_p[j])
			safe_str(row_p[j], buff, bufc);
		}
	    }
	}
    } else {
	for (i = 0; i < got_rows; i++) {
	    row_p = mysql_fetch_row(qres);
	    if (row_p) {
		got_fields = mysql_num_fields(qres);
		for (j = 0; j < got_fields; j++) {
		    if (row_p[j] && *row_p[j]) {
			notify(player, tprintf("Row %d, Field %d: %s",
					       i+1, j+1, row_p[j]));
		    } else {
			notify(player,
			       tprintf("Row %d, Field %d: NULL", i+1, j+1));
		    }
		}
	    } else {
		notify(player, tprintf("Row %d: NULL", i+1));
	    }
	}
    }

    mysql_free_result(qres);
    return 0;
}