#extern(vm) fn vm_fopen(path: *any, mode: *any): *any;
#extern(vm) fn vm_fclose(f: *any): i32;
#extern(vm) fn vm_fread(buf: *any, sz: usize, n: usize, f: *any): usize;
#extern(vm) fn vm_fwrite(buf: *any, sz: usize, n: usize, f: *any): usize;
#extern(vm) fn vm_fsize(f: *any): usize;
#extern(vm) fn vm_stdin(): *any;
#extern(vm) fn vm_stdout(): *any;
#extern(vm) fn vm_stderr(): *any;
#extern(vm) fn vm_putchar(c: i32): i32;
#extern(vm) fn vm_getchar(): i32;

handle: *any,
type File = @self;

fn stdin(): File  { ret File { .handle = vm_stdin() }; }
fn stdout(): File { ret File { .handle = vm_stdout() }; }
fn stderr(): File { ret File { .handle = vm_stderr() }; }

fn open(path: *u8, mode: *u8): File {
    ret File { .handle = vm_fopen(path as *any, mode as *any) };
}

fn valid(f: *File): bool {
    ret f.handle != null;
}

fn write(f: *File, data: *u8, n: u64): u64 {
    if f.handle == null { ret 0; }
    ret vm_fwrite(data as *any, 1, n, f.handle);
}

fn write_byte(f: *File, b: u8): u64 {
    var tmp: u8 = b;
    ret write(f, &tmp, 1);
}

fn read(f: *File, buf: *u8, n: usize): usize {
    if f.handle == null { ret 0; }
    ret vm_fread(buf as *any, 1, n, f.handle);
}

fn size(f: *File): usize {
    if f.handle == null { ret 0; }
    ret vm_fsize(f.handle);
}

fn close(f: *File): i32 {
    if f.handle == null { ret -1; }
    var r = vm_fclose(f.handle);
    f.handle = null;
    ret r;
}

fn putchar(c: u8) {
    vm_putchar(c as i32);
}

fn getchar(): i32 {
    ret vm_getchar();
}

fn main(): void {
    var out = stdout();
    @assert(out.handle != null, "stdout");
    var msg = "file: ok\n";
    var n = write(&out, msg.ptr, msg.len);
    @assert(n == msg.len, "write");
    putchar(46 as u8);
    putchar(10 as u8);
}