//! Makes the pygamer appear as a USB serial port loop back device.
//! Repeats back all characters sent to it, but in upper case.

#![no_std]
#![no_main]

use edgebadge::{entry, hal, pac, Pins};
use panic_halt as _;

use hal::clock::GenericClockController;
use hal::prelude::*;
use pac::{CorePeripherals, Peripherals};
use usb_device::prelude::*;
use usbd_serial::{SerialPort, USB_CLASS_CDC};

#[entry]
fn main() -> ! {
    let mut peripherals = Peripherals::take().unwrap();
    let mut _core = CorePeripherals::take().unwrap();
    let mut clocks = GenericClockController::with_internal_32kosc(
        peripherals.GCLK,
        &mut peripherals.MCLK,
        &mut peripherals.OSC32KCTRL,
        &mut peripherals.OSCCTRL,
        &mut peripherals.NVMCTRL,
    );

    let mut pins = Pins::new(peripherals.PORT).split();

    let usb_bus = pins
        .usb
        .init(peripherals.USB, &mut clocks, &mut peripherals.MCLK);

    let mut serial = SerialPort::new(&usb_bus);
    let mut led = pins.led_pin.into_open_drain_output(&mut pins.port);

    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
        .manufacturer("Fake company")
        .product("Serial port")
        .serial_number("TEST")
        .device_class(USB_CLASS_CDC)
        .build();

    loop {
        if !usb_dev.poll(&mut [&mut serial]) {
            continue;
        }

        let mut buf = [0u8; 64];

        match serial.read(&mut buf) {
            Ok(count) if count > 0 => {
                let _ = led.set_high(); // Turn on

                // Echo back in upper case
                for c in buf[0..count].iter_mut() {
                    if 0x61 <= *c && *c <= 0x7a {
                        *c &= !0x20;
                    }
                }

                let mut write_offset = 0;
                while write_offset < count {
                    match serial.write(&buf[write_offset..count]) {
                        Ok(len) if len > 0 => {
                            write_offset += len;
                        }
                        _ => {}
                    }
                }
            }
            _ => {}
        }

        let _ = led.set_low(); // Turn off
    }
}