use usb_device::prelude::*;
use usbd_midi::{
    message::{Message, Channel, Note},
    UsbMidiClass,
    UsbMidiPacketReader,
};
// Prerequisites, must be setup according to the used board.
let mut led = todo!(); // Must implement `embedded_hal::digital::OutputPin`.
let usb_bus = todo!(); // Must be of type `usb_device::bus::UsbBusAllocator`.
// Create a MIDI class with 1 input and 1 output jack.
let mut midi = UsbMidiClass::new(&usb_bus, 1, 1).unwrap();
let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x5e4))
    .device_class(0)
    .device_sub_class(0)
    .strings(&[StringDescriptors::default()
        .manufacturer("Music Company")
        .product("MIDI Device")
        .serial_number("12345678")])
    .unwrap()
    .build();
loop {
    if !usb_dev.poll(&mut [&mut midi]) {
        continue;
    }
    let mut buffer = [0; 64];
    if let Ok(size) = midi.read(&mut buffer) {
        let packet_reader = UsbMidiPacketReader::new(&buffer, size);
        for packet in packet_reader.into_iter() {
            if let Ok(packet) = packet {
                match Message::try_from(&packet).unwrap() {
                    Message::NoteOn(Channel1, Note::C2, ..) => {
                        led.set_low().unwrap();
                    },
                    Message::NoteOff(Channel1, Note::C2, ..) => {
                        led.set_high().unwrap();
                    },
                    _ => {}
                }
            }
        }
    }
}