use std::io::{self, Write};
use std::ptr;
use windows_sys::Win32::Foundation::HANDLE;
use windows_sys::Win32::System::Console::{
    GetConsoleMode, ReadConsoleW, SetConsoleMode, GetStdHandle, STD_INPUT_HANDLE,
    ENABLE_ECHO_INPUT, ENABLE_LINE_INPUT,
};

fn main() -> io::Result<()> {
    unsafe {
        let h: HANDLE = GetStdHandle(STD_INPUT_HANDLE);
        if h == std::ptr::null_mut() || h == -1_i32 as HANDLE { return Err(io::Error::last_os_error()); }

        // save current mode
        let mut mode: u32 = 0;
        if GetConsoleMode(h, &mut mode) == 0 { return Err(io::Error::last_os_error()); }

        // disable line input and echo so input is available per-key and not echoed
        let new_mode = mode & !(ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT);
        if SetConsoleMode(h, new_mode) == 0 { return Err(io::Error::last_os_error()); }

        print!("Press keys (q to exit): ");
        io::stdout().flush()?;

        // ReadConsoleW reads UTF-16; we'll read one wchar at a time
        let mut buf: [u16; 1] = [0];
        loop {
            let mut read = 0u32;
            if ReadConsoleW(
                h,
                buf.as_mut_ptr() as *mut _,
                1,
                &mut read,
                ptr::null_mut(),
            ) == 0
            {
                // restore mode on error before returning
                let _ = SetConsoleMode(h, mode);
                return Err(io::Error::last_os_error());
            }

            let ch = std::char::from_u32(buf[0] as u32).unwrap_or('\u{FFFD}');
            if ch == 'q' { break; } // q to exit

            // handle Enter (CR) so output is readable
            if ch == '\r' {
                println!();
            } else {
                // show code point (no automatic console echo)
                print!("[{:?}]", ch);
                io::stdout().flush()?;
            }
        }

        // restore original console mode
        let _ = SetConsoleMode(h, mode);
        println!("\nexited");
    }

    Ok(())
}