#flag linux -lodbc
#flag linux -lmsodbcsql-17

#include <sql.h>
#include <sqltypes.h>
#include <sqlext.h>

/*
	libodbc should be linked BEFORE
	libmsodbcsql otherwise SQLDriverConnect returns -2
	Some funcs, including SQLDriverConnect, seems
	to be redefined in libmsodbcsql
*/

type SQLChar = byte
type SQLCharPtr = charptr
type SQLInteger = int
type SQLSmallInt = i16
type SQLUSmallInt = u16
type SQLReturn = i16	// SQLSmallInt
type SQLHandle = voidptr
type SQLHenv = voidptr  // SQLHandle
type SQLHstmt = voidptr // SQLHandle
type SQLHdbc = voidptr  // SQLHandle
type SQLPointer = voidptr
type SQLHwnd = voidptr

fn sql_succeded(rc SQLReturn) bool {
	return (rc & ~1) == 0
}

fn C.SQLAllocHandle(SQLSmallInt, SqlHandle, &SQLHenv) SQLReturn
fn C.SQLFreeHandle(SQLSmallInt, &SQLHenv) SQLReturn
fn C.SQLSetEnvAttr(SQLHenv, SQLInteger, SQLPointer, SQLInteger) SQLReturn
fn C.SQLSetConnectAttr(SQLHandle, SQLInteger, SQLPointer, SQLInteger) SQLReturn
fn C.SQLDisconnect(SQLHdbc) SQLReturn
fn C.SQLExecDirect(SQLHdbc, SQLCharPtr, SQLSmallInt) SQLReturn
fn C.SQLBindCol(SQLHstmt, SQLUSmallInt, SQLSmallInt, SQLPointer, C.SQLLEN, &C.SQLLEN) SQLReturn
fn C.SQLFetch(SQLHstmt) SQLReturn
fn C.SQLDriverConnect(
	SQLHandle,
	SQLHwnd,
	SQLCharPtr,
	SQLSmallInt,
	SQLCharPtr,
	SQLSmallInt,
	SQLCharPtr,
	SQLSmallInt,
	&SQLSmallInt,
	SQLUSmallint) SQLReturn
fn C.SQLGetDiagRec(
	SQLSmallInt, 
	SQLHandle, 
	SQLSmallInt, 
	SQLCharPtr,
	&SQLInteger,
	SQLCharPtr,
	SQLSmallInt,
	&SQLSmallInt) SQLReturn

fn check_error(rc SQLReturn, label string) {
	if rc != C.SQL_SUCCESS && rc != C.SQL_SUCCESS_WITH_INFO {
		println('[*] $label: ERROR $rc')
	} else {
		println('[*] $label: SUCCESS')
	}
}

const (
	ResultLength = 256
)

fn main() {
	mut henv := &SQLHandle(C.SQL_NULL_HENV)     // Environment handle
	mut hdbc := &SQLHandle(C.SQL_NULL_HDBC)    	// Connection handle
	mut hstmt := &SQLHandle(C.SQL_NULL_HSTMT)   // Statement handle
	mut rc := 0
	mut str_result := [ResultLength]SQLChar{}
	mut out_str := [1024]SQLChar{}
	mut out_str_len := SQLSmallInt(0)

	rc = C.SQLAllocHandle(C.SQL_HANDLE_ENV, C.SQL_NULL_HANDLE, &henv)
	check_error(rc, 'SQLAllocHandle(SQL_HANDLE_ENV)')

	rc = C.SQLSetEnvAttr(henv, C.SQL_ATTR_ODBC_VERSION, C.SQL_OV_ODBC3, sizeof(int))
	check_error(rc, 'SQLSetEnvAttr(SQL_ATTR_ODBC_VERSION)')

	rc = C.SQLAllocHandle(C.SQL_HANDLE_DBC, henv, &hdbc)
	check_error(rc, 'SQLAllocHandle(SQL_HANDLE_DBC)')

	rc = C.SQLSetConnectAttr(hdbc, C.SQL_LOGIN_TIMEOUT, 5, 0)
	check_error(rc, 'SQLSetConnectAttr(SQL_LOGIN_TIMEOUT)')

	conn_str := 'Driver={ODBC Driver 17 for SQL Server};Server=localhost;Database=TestDB;UID=your_uid;PWD=your_pwd;'

	rc = C.SQLDriverConnect(
		hdbc,
		0,
		conn_str.str,
		C.SQL_NTS,
		0,
		0,
		0,
		C.SQL_DRIVER_NOPROMPT
	)
	check_error(rc, 'SQLDriverConnect()')

	rc = C.SQLAllocHandle(C.SQL_HANDLE_STMT, hdbc, &hstmt)
	check_error(rc, 'SQLAllocHandle(SQL_HANDLE_STMT)')

	query := 'SELECT DB_NAME()'
	rc = C.SQLExecDirect(hstmt, query.str, C.SQL_NTS)
	check_error(rc, 'SQLExecDirect("$query")')

	rc = C.SQLBindCol(hstmt, 1, C.SQL_C_CHAR, &str_result, ResultLength, 0)
	check_error(rc, 'SQLBindCol()')

	mut i := 0
	println('[*] SQLFetch()')
	for {
		rc = C.SQLFetch(hstmt)
		if rc == C.SQL_SUCCESS || rc == C.SQL_SUCCESS_WITH_INFO {
			x := cstring_to_vstring(&str_result)
			println('\t($i) "$x"')
		} else {
			if rc != C.SQL_NO_DATA {
				check_error(rc, 'SQLFetch()')
			} else {
				break
			}
		}
		i = i   1
	}

	if hstmt != C.SQL_NULL_HSTMT {
		rc = C.SQLFreeHandle(C.SQL_HANDLE_STMT, hstmt)
		check_error(rc, 'SQLFreeHandle(SQL_HANDLE_HSTMT)')
	}

	if hdbc != C.SQL_NULL_HDBC {
		rc = C.SQLDisconnect(hdbc)
		check_error(rc, 'SQLDisconnect')
		rc = C.SQLFreeHandle(C.SQL_HANDLE_DBC, hdbc)
		check_error(rc, 'SQLFreeHandle(SQL_HANDLE_DBC)')
	}

	if henv != C.SQL_NULL_HENV {
		rc = C.SQLFreeHandle(C.SQL_HANDLE_ENV, henv)
		check_error(rc, 'SQLFreeHandle(SQL_HANDLE_ENV)')
	}
}