/*
 *  SPL - The SPL Programming Language
 *  Copyright (C) 2004, 2005  Clifford Wolf <clifford@clifford.at>
 *
 *  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 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 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
 *
 *  mod_sql_mysql.c: Module for MySQL bindings
 */

/**
 * This module implements the MySQL database driver.
 *
 * Load this module (and the [[sql:]] module) and pass "mysql" as backend
 * driver name to [[sql:sql_connect()]];
 *
 * The string describing the database connection (the 2nd argument to
 * [[sql:sql_connect()]]) is a coma seperated list of the following tokens:
 *
 *	host={hostname}
 *	user={username}
 *	pass={password}
 *	sock={socket_filename}
 *	db={database_name}
 *	port={tcp_port_number}
 *
 *	compress             (set MySQL CLIENT_COMPRESS flag)
 *	ignore_space         (set MySQL CLIENT_IGNORE_SPACE flag)
 *	multi_statements     (set MySQL CLIENT_MULTI_STATEMENTS flag)
 *
 * Whitespaces are not allowed. E.g.:
 *
 *	var db = sql_connect("mysql", "host=dbserver,user=dbuser");
 *
 *	var r = sql(db, "show databases");
 *
 *	foreach i (r)
 *		debug pop r[i];
 *
 */

#include <mysql/mysql.h>
#include <stdlib.h>
#include <unistd.h>

#include "spl.h"
#include "mod_sql.h"

#include "compat.h"

extern void SPL_ABI(spl_mod_sql_mysql_init)(struct spl_vm *vm, struct spl_module *mod, int restore);
extern void SPL_ABI(spl_mod_sql_mysql_done)(struct spl_vm *vm, struct spl_module *mod);

struct mysql_backend_data {
	MYSQL mysql;
};

static struct spl_node *sql_mysql_query_callback(struct spl_task *task, void *backend_data, const char *query)
{
	struct mysql_backend_data *mbd = backend_data;
	struct spl_node *result = spl_get(0);

	MYSQL_ROW row;
	MYSQL_RES *res;
	MYSQL_FIELD *fields;
	unsigned int num_fields;

	if (mysql_query(&mbd->mysql, query))
		goto got_error;

	res = mysql_store_result(&mbd->mysql);

	if (res)
	{
		num_fields = mysql_num_fields(res);
		fields = mysql_fetch_fields(res);

		while ( (row = mysql_fetch_row(res)) )
		{
			struct spl_node *n = spl_get(0);

			for (unsigned int i=0; i < num_fields; i++)
			{
				char *name_base = strrchr(fields[i].name, '.');
				name_base = name_base ? name_base+1 : fields[i].name;

				spl_create(task, n, name_base, row[i] ?
						SPL_NEW_STRING_DUP(row[i]) : spl_get(0), SPL_CREATE_LOCAL);
			}

			spl_create(task, result, NULL, n, SPL_CREATE_LOCAL);
		}

		mysql_free_result(res);
	} else
	if(mysql_field_count(&mbd->mysql) != 0)
		goto got_error;

	return result;

got_error:
	spl_put(task->vm, result);
	spl_clib_exception(task, "SqlEx", "description",
		SPL_NEW_SPL_STRING(spl_string_printf(0, 0, 0,
			"MySQL: SQL Error on '%s': %s!\n",
			query, mysql_error(&mbd->mysql))),
		NULL);
	return 0;
}

static void sql_mysql_close_callback(struct spl_vm UNUSED(*vm), void *backend_data)
{
	struct mysql_backend_data *mbd = backend_data;
	mysql_close(&mbd->mysql);
	free(mbd);
}

static void sql_mysql_open_callback(struct spl_task *task, struct spl_node *node, const char *data)
{
	const char *original_data = data;
	const char *config_host = 0;
	const char *config_user = 0;
	const char *config_pass = 0;
	const char *config_sock = 0;
	const char *config_db = 0;
	int config_port = 0;
	int config_flag = 0;

	while (*data) {
		int tok_name_len = strcspn(data, "=,");
		char *tok_name = my_alloca(tok_name_len+1);
		memcpy(tok_name, data, tok_name_len);
		tok_name[tok_name_len] = 0;
		data += tok_name_len;

		if (*data == '=')
		{
			data++;

			int tok_value_len = strcspn(data, ",");
			char *tok_value = my_alloca(tok_value_len+1);
			memcpy(tok_value, data, tok_value_len);
			tok_value[tok_value_len] = 0;
			data += tok_value_len;

			if (!strcmp("host", tok_name))
				config_host = tok_value;
			else
			if (!strcmp("user", tok_name))
				config_user = tok_value;
			else
			if (!strcmp("pass", tok_name))
				config_pass = tok_value;
			else
			if (!strcmp("sock", tok_name))
				config_sock = tok_value;
			else
			if (!strcmp("db", tok_name))
				config_db = tok_value;
			else
			if (!strcmp("port", tok_name))
				config_port = atoi(tok_value);
			else
				goto parser_error;
		} else
		if (!strcmp("compress", tok_name))
			config_flag |= CLIENT_COMPRESS;
		else
		if (!strcmp("ignore_space", tok_name))
			config_flag |= CLIENT_IGNORE_SPACE;
		else
		if (!strcmp("multi_statements", tok_name))
#ifdef CLIENT_MULTI_STATEMENTS
			config_flag |= CLIENT_MULTI_STATEMENTS;
#else
			config_flag |= 0;
#endif
		else {
parser_error:
			spl_clib_exception(task, "SqlEx", "description",
				SPL_NEW_SPL_STRING(spl_string_printf(0, 0, 0,
					"MySQL: Error parsing database "
					"connection description '%s'!\n",
					original_data)),
				NULL);
			return;
		}

		if (*data == ',')
			data++;
	}

	struct mysql_backend_data *mbd = malloc(sizeof(struct mysql_backend_data));

	mysql_init(&mbd->mysql);
	if (!mysql_real_connect(&mbd->mysql, config_host, config_user,
		config_pass, config_db, config_port, config_sock, config_flag))
	{
		spl_clib_exception(task, "SqlEx", "description",
			SPL_NEW_SPL_STRING(spl_string_printf(0, 0, 0,
				"MySQL: Can't open database %s: %s!\n",
				original_data, mysql_error(&mbd->mysql))),
			NULL);
		mysql_close(&mbd->mysql);
		free(mbd);
		return;
	}

	struct sql_hnode_data *hnd = malloc(sizeof(struct sql_hnode_data));

	hnd->backend_data = mbd;
	hnd->query_callback = sql_mysql_query_callback;
	hnd->close_callback = sql_mysql_close_callback;

	node->hnode_data = hnd;
}

/**
 * This function encodes a string to be used in an MySQL query. I.e. the string
 * will be put in single quotes and special characters inside the string is
 * quoted with backslash sequences.
 *
 * Always use this function instead of [[sql:encode_sql()]] for quoting strings
 * in MySQL queries unless you are running MySQL in the ANSI_QUOTES mode.
 *
 * This function is designed to be used with the encoding/quoting operator (::).
 */
// builtin encode_mysql(text)
static struct spl_node *handler_encode_mysql(struct spl_task *task, void UNUSED(*data))
{
	char *text = spl_clib_get_string(task);
	int text_len = strlen(text);

	char *newtext = malloc(text_len*2+3);
	int newtext_len = mysql_escape_string(newtext+1, text, text_len);
	newtext = realloc(newtext, newtext_len+3);

	newtext[0] = newtext[newtext_len+1] = '\'';
	newtext[newtext_len+2] = 0;

	return SPL_NEW_STRING(newtext);
}

void SPL_ABI(spl_mod_sql_mysql_init)(struct spl_vm *vm, struct spl_module UNUSED(*mod), int restore)
{
	if (!restore) spl_module_load(vm, "sql", 0);
	spl_clib_reg(vm, "encode_mysql", handler_encode_mysql, 0);
	sql_register_backend(vm, "mysql", sql_mysql_open_callback);
}

void SPL_ABI(spl_mod_sql_mysql_done)(struct spl_vm *vm, struct spl_module UNUSED(*mod))
{
	sql_unregister_backend(vm, "mysql");
}