use bbqueue::{bbq, BBQueue};
use core::{cell::RefCell, ops::DerefMut};
use cortex_m::{self, interrupt::Mutex};
use log::info;
use nrf52840_hal::target::{interrupt, FICR, RADIO, TIMER0};
use rubble::{
    gatt::BatteryServiceAttrs,
    l2cap::{BleChannelMap, L2CAPState},
    link::{
        ad_structure::AdStructure, queue, AddressKind, DeviceAddress, HardwareInterface, LinkLayer,
        Responder, MIN_PDU_BUF,
    },
    security_manager::NoSecurity,
    time::{Duration, Timer},
};
use rubble_nrf52::{
    radio::{BleRadio, PacketBuffer},
    timer::BleTimer,
};

struct NRF52840 {}
impl HardwareInterface for NRF52840 {
    type Timer = BleTimer<TIMER0>;
    type Tx = BleRadio;
}

type Global<T> = Mutex<RefCell<Option<T>>>;

static BLE_LL: Global<LinkLayer<NRF52840>> = Mutex::new(RefCell::new(None));
static BLE_RADIO: Global<BleRadio> = Mutex::new(RefCell::new(None));

pub fn setup(
    radio: RADIO,
    timer: TIMER0,
    ficr: FICR,
) -> Responder<BleChannelMap<BatteryServiceAttrs, NoSecurity>> {
    // make sure hfclock is started for timer0 to work at the right
    // resolution.
    let ble_timer = BleTimer::init(timer);
    let devaddr_lo: &[u8] = &ficr.deviceaddr[0].read().bits().to_le_bytes();
    let devaddr_hi: &[u8] = &(ficr.deviceaddr[1].read().bits() as u16).to_le_bytes();

    let mut devaddr: [u8; 6] = [0; 6];
    for (i, a) in [devaddr_lo, devaddr_hi]
        .iter()
        .copied()
        .flatten()
        .enumerate()
    {
        devaddr[i] = *a;
    }

    let addrkind = if ficr.deviceaddrtype.read().deviceaddrtype().is_public() {
        AddressKind::Public
    } else {
        AddressKind::Random
    };
    let addr = DeviceAddress::new(devaddr, addrkind);
    info!("my address: {:?}", addr);

    static mut TX_BUF: PacketBuffer = [0; MIN_PDU_BUF];
    static mut RX_BUF: PacketBuffer = [0; MIN_PDU_BUF];

    let (tx_prod, tx_cons) = queue::create(bbq![MIN_PDU_BUF * 2].expect("creating tx queue"));
    let (rx_prod, rx_cons) = queue::create(bbq![MIN_PDU_BUF * 2].expect("creating rx queue"));

    // `responder` used on main loop.
    let resp = Responder::new(
        tx_prod,
        rx_cons,
        L2CAPState::new(BleChannelMap::with_attributes(BatteryServiceAttrs::new())),
    );

    // `ble_radio` and `ll` used on both `timer` and `radio`
    // interrupts.
    // may be able to use ring buffer to avoid sharing?
    let mut ble_radio = unsafe { BleRadio::new(radio, &mut TX_BUF, &mut RX_BUF) };

    let mut ble_ll = LinkLayer::<NRF52840>::new(addr, ble_timer);
    let next_update = ble_ll
        .start_advertise(
            Duration::from_millis(200),
            &[AdStructure::CompleteLocalName("bleusb")],
            &mut ble_radio,
            tx_cons,
            rx_prod,
        )
        .expect("scheduling link layer update");
    ble_ll.timer().configure_interrupt(next_update);

    cortex_m::interrupt::free(|cs| {
        BLE_LL.borrow(cs).replace(Some(ble_ll));
        BLE_RADIO.borrow(cs).replace(Some(ble_radio));
    });

    resp
}

#[interrupt]
fn TIMER0() {
    cortex_m::interrupt::free(|cs| {
        if let (Some(ref mut ble_ll), Some(ref mut ble_radio)) = (
            BLE_LL.borrow(cs).borrow_mut().deref_mut(),
            BLE_RADIO.borrow(cs).borrow_mut().deref_mut(),
        ) {
            if !ble_ll.timer().is_interrupt_pending() {
                return;
            }
            ble_ll.timer().clear_interrupt();

            let cmd = ble_ll.update(ble_radio);
            ble_radio.configure_receiver(cmd.radio);

            ble_ll.timer().configure_interrupt(cmd.next_update);
        }
    })
}

#[interrupt]
fn RADIO() {
    cortex_m::interrupt::free(|cs| {
        if let (Some(ref mut ble_ll), Some(ref mut ble_radio)) = (
            BLE_LL.borrow(cs).borrow_mut().deref_mut(),
            BLE_RADIO.borrow(cs).borrow_mut().deref_mut(),
        ) {
            let next_update = ble_radio.recv_interrupt(ble_ll.timer().now(), ble_ll);
            ble_ll.timer().configure_interrupt(next_update);
        }
    })
}