#![no_std]
#![no_main]

use core::sync::atomic::{AtomicU8, Ordering};

use defmt::*;
use embassy_executor::Spawner;
use embassy_futures::join::join;
use embassy_stm32::time::Hertz;
use embassy_stm32::usb::Driver;
use embassy_stm32::{Config, bind_interrupts, peripherals, usb};
use embassy_time::Timer;
use embassy_usb::Builder;
use embassy_usb::class::hid::{
    HidBootProtocol, HidProtocolMode, HidSubclass, HidWriter, ReportId, RequestHandler, State,
};
use embassy_usb::control::OutResponse;
use usbd_hid::descriptor::{MouseReport, SerializedDescriptor};
use {defmt_rtt as _, panic_probe as _};

bind_interrupts!(struct Irqs {
    OTG_FS => usb::InterruptHandler<peripherals::USB_OTG_FS>;
});

static HID_PROTOCOL_MODE: AtomicU8 = AtomicU8::new(HidProtocolMode::Boot as u8);

// If you are trying this and your USB device doesn't connect, the most
// common issues are the RCC config and vbus_detection
//
// See https://embassy.dev/book/#_the_usb_examples_are_not_working_on_my_board_is_there_anything_else_i_need_to_configure
// for more information.
#[embassy_executor::main]
async fn main(_spawner: Spawner) {
    let mut config = Config::default();
    {
        use embassy_stm32::rcc::*;
        config.rcc.hse = Some(Hse {
            freq: Hertz(8_000_000),
            mode: HseMode::Bypass,
        });
        config.rcc.pll_src = PllSource::HSE;
        config.rcc.pll = Some(Pll {
            prediv: PllPreDiv::DIV4,
            mul: PllMul::MUL168,
            divp: Some(PllPDiv::DIV2), // 8mhz / 4 * 168 / 2 = 168Mhz.
            divq: Some(PllQDiv::DIV7), // 8mhz / 4 * 168 / 7 = 48Mhz.
            divr: None,
        });
        config.rcc.ahb_pre = AHBPrescaler::DIV1;
        config.rcc.apb1_pre = APBPrescaler::DIV4;
        config.rcc.apb2_pre = APBPrescaler::DIV2;
        config.rcc.sys = Sysclk::PLL1_P;
        config.rcc.mux.clk48sel = mux::Clk48sel::PLL1_Q;
    }
    let p = embassy_stm32::init(config);

    // Create the driver, from the HAL.
    let mut ep_out_buffer = [0u8; 256];
    let mut config = embassy_stm32::usb::Config::default();

    // Do not enable vbus_detection. This is a safe default that works in all boards.
    // However, if your USB device is self-powered (can stay powered on if USB is unplugged), you need
    // to enable vbus_detection to comply with the USB spec. If you enable it, the board
    // has to support it or USB won't work at all. See docs on `vbus_detection` for details.
    config.vbus_detection = false;

    let driver = Driver::new_fs(p.USB_OTG_FS, Irqs, p.PA12, p.PA11, &mut ep_out_buffer, config);

    // Create embassy-usb Config
    let mut config = embassy_usb::Config::new(0xc0de, 0xcafe);
    config.manufacturer = Some("Embassy");
    config.product = Some("HID mouse example");
    config.serial_number = Some("12345678");
    config.composite_with_iads = false;
    config.device_class = 0;
    config.device_sub_class = 0;
    config.device_protocol = 0;

    // Create embassy-usb DeviceBuilder using the driver and config.
    // It needs some buffers for building the descriptors.
    let mut config_descriptor = [0; 256];
    let mut bos_descriptor = [0; 256];
    let mut control_buf = [0; 64];

    let mut request_handler = MyRequestHandler {};

    let mut state = State::new();

    let mut builder = Builder::new(
        driver,
        config,
        &mut config_descriptor,
        &mut bos_descriptor,
        &mut [], // no msos descriptors
        &mut control_buf,
    );

    // Create classes on the builder.
    let config = embassy_usb::class::hid::Config {
        report_descriptor: MouseReport::desc(),
        request_handler: Some(&mut request_handler),
        poll_ms: 60,
        max_packet_size: 8,
        hid_subclass: HidSubclass::Boot,
        hid_boot_protocol: HidBootProtocol::Mouse,
    };

    let mut writer = HidWriter::<_, 5>::new(&mut builder, &mut state, config);

    // Build the builder.
    let mut usb = builder.build();

    // Run the USB device.
    let usb_fut = usb.run();

    // Do stuff with the class!
    let hid_fut = async {
        let mut y: i8 = 5;
        loop {
            Timer::after_millis(500).await;

            y = -y;

            if HID_PROTOCOL_MODE.load(Ordering::Relaxed) == HidProtocolMode::Boot as u8 {
                let buttons = 0u8;
                let x = 0i8;
                match writer.write(&[buttons, x as u8, y as u8]).await {
                    Ok(()) => {}
                    Err(e) => warn!("Failed to send boot report: {:?}", e),
                }
            } else {
                let report = MouseReport {
                    buttons: 0,
                    x: 0,
                    y,
                    wheel: 0,
                    pan: 0,
                };
                match writer.write_serialize(&report).await {
                    Ok(()) => {}
                    Err(e) => warn!("Failed to send report: {:?}", e),
                }
            }
        }
    };

    // Run everything concurrently.
    // If we had made everything `'static` above instead, we could do this using separate tasks instead.
    join(usb_fut, hid_fut).await;
}

struct MyRequestHandler {}

impl RequestHandler for MyRequestHandler {
    fn get_report(&mut self, id: ReportId, _buf: &mut [u8]) -> Option<usize> {
        info!("Get report for {:?}", id);
        None
    }

    fn set_report(&mut self, id: ReportId, data: &[u8]) -> OutResponse {
        info!("Set report for {:?}: {=[u8]}", id, data);
        OutResponse::Accepted
    }

    fn get_protocol(&self) -> HidProtocolMode {
        let protocol = HidProtocolMode::from(HID_PROTOCOL_MODE.load(Ordering::Relaxed));
        info!("The current HID protocol mode is: {}", protocol);
        protocol
    }

    fn set_protocol(&mut self, protocol: HidProtocolMode) -> OutResponse {
        info!("Switching to HID protocol mode: {}", protocol);
        HID_PROTOCOL_MODE.store(protocol as u8, Ordering::Relaxed);
        OutResponse::Accepted
    }

    fn set_idle_ms(&mut self, id: Option<ReportId>, dur: u32) {
        info!("Set idle rate for {:?} to {:?}", id, dur);
    }

    fn get_idle_ms(&mut self, id: Option<ReportId>) -> Option<u32> {
        info!("Get idle rate for {:?}", id);
        None
    }
}
