#![no_main]
#![no_std]


// this imports `beginner/apps/lib.rs` to retrieve our global logger + panicking-behavior
use firmware as _;

#[rtic::app(device = dk, peripherals = false)]
mod app {
    use dk::{
        peripheral::USBD,
        usbd::{self, Event},
    };

    use usb::{Descriptor, Request};

    #[local]
    struct MyLocalResources {
        usbd: USBD,
    }

    #[shared]
    struct MySharedResources {
        
    }

    #[init]
    fn init(_cx: init::Context) -> (MySharedResources, MyLocalResources, init::Monotonics) {
        let board = dk::init().unwrap();

        usbd::init(board.power, &board.usbd);

        (MySharedResources {}, MyLocalResources { usbd: board.usbd }, init::Monotonics())
    }

    #[task(binds = USBD, local = [usbd])]
    fn main(cx: main::Context) {
        let usbd = cx.local.usbd;

        while let Some(event) = usbd::next_event(usbd) {
            on_event(usbd, event)
        }
    }

    fn on_event(_usbd: &USBD, event: Event) {
        defmt::println!("USB: {} @ {}", event, dk::uptime());
    
        match event {
            Event::UsbReset => {
                // nothing to do here at the moment
            }
    
            Event::UsbEp0DataDone => todo!(),
    
            Event::UsbEp0Setup => {
                // TODO read USBD registers
    
                // the BMREQUESTTYPE register contains information about data recipient, transfer type and direction
                let bmrequesttype: u8 = 0;
                // the BREQUEST register stores the type of the current request (e.g. SET_ADDRESS, GET_DESCRIPTOR, ...)
                let brequest: u8 = 0;
                // wLength denotes the number of bytes to transfer (if any)
                // composed of a high register (WLENGTHH) and a low register (WLENGTHL)
                let wlength: u16 = 0;
                // wIndex is a generic index field whose meaning depends on the request type
                // composed of a high register (WINDEXH) and a low register (WINDEXL)
                let windex: u16 = 0;
                // wValue is a generic paremeter field meaning depends on the request type (e.g. contains the device
                // address in SET_ADRESS requests)
                // composed of a high register (WVALUEH) and a low register (WVALUEL)
                let wvalue: u16 = 0;
    
                defmt::println!(
                    "SETUP: bmrequesttype: {}, brequest: {}, wlength: {}, windex: {}, wvalue: {}",
                    bmrequesttype,
                    brequest,
                    wlength,
                    windex,
                    wvalue
                );
    
                let request = Request::parse(bmrequesttype, brequest, wvalue, windex, wlength)
                    .expect("Error parsing request");
                match request {
                    Request::GetDescriptor { descriptor, length }
                        if descriptor == Descriptor::Device =>
                    {
                        // TODO modify `Request::parse()` in `advanced/common/usb/lib.rs`
                        // so that this branch is reached
    
                        defmt::println!("GET_DESCRIPTOR Device [length={}]", length);
    
                        defmt::println!("Goal reached; move to the next section");
                        dk::exit()
                    }
                    Request::SetAddress { .. } => {
                        // On Mac OS you'll get this request before the GET_DESCRIPTOR request so we
                        // need to catch it here. We'll properly handle this request later
                        // but for now it's OK to do nothing.
                    }
                    _ => unreachable!(), // we don't handle any other Requests
                }
            }
        }
    }    
}