//! BLE interface.

#![no_std]
#![no_main]

mod ble;
mod i2c;
mod logger;
mod macros;
mod rtc;
mod uarte1;

use clint::HandlerArray;
use core::mem;
use cortex_m::{asm::wfi, peripheral::NVIC};
use cortex_m_rt::{entry, exception, ExceptionFrame};
use log::{info, log, trace, Level as LogLevel, LevelFilter};

#[allow(unused_imports)]
extern crate panic_semihosting;

use nrf52840_mdk_bsp::{
    hal::{
        gpio::{Floating, Input, Level, Output, Pin, PushPull},
        target::{interrupt, Interrupt, UARTE0},
        twis::{self, Twis},
        uarte::{self, Baudrate as UartBaudrate, Parity as UartParity, Uarte},
        Clocks, Rtc,
    },
    Board,
};

const I2C_ADDR: u8 = 4;

// TODO:
//   * bluetooth

// Interrupt handler table.
static HANDLERS: HandlerArray = HandlerArray::new();

#[entry]
fn main() -> ! {
    let nrf52 = Board::take().unwrap();

    let uart_wrapped = logger::WriteWrapper::new(nrf52.cdc);
    let logger = logger::SerialLogger::new(uart_wrapped);
    let logger_ref: &'static logger::SerialLogger<UARTE0> = unsafe { mem::transmute(&logger) };
    log::set_logger(logger_ref).expect("setting logger");
    log::set_max_level(LevelFilter::Trace);

    // TODO: use hal interface for this.
    nrf52
        .CLOCK
        .tasks_hfclkstart
        .write(|w| w.tasks_hfclkstart().set_bit());
    while nrf52
        .CLOCK
        .events_hfclkstarted
        .read()
        .events_hfclkstarted()
        .bit_is_clear()
    {}

    nrf52.RTC0.intenset.write(|w| w.tick().set());

    let mut rtc_handler = rtc::setup(Rtc::new(nrf52.RTC0), Clocks::new(nrf52.CLOCK));
    let (mut twis_reader, mut twis_handler) = i2c::setup(Twis::new(
        I2C_ADDR,
        nrf52.TWIS0,
        twis::Pins {
            scl: nrf52.pins.P0_06.into_floating_input().degrade(),
            sda: nrf52.pins.P0_07.into_floating_input().degrade(),
        },
    ));

    let txp = nrf52
        .pins
        .P0_26
        .into_push_pull_output(Level::High)
        .degrade();
    let rxp = nrf52.pins.P0_25.into_floating_input().degrade();
    let uarte1 = uarte1(nrf52.UARTE1, txp, rxp);
    let (mut uarte1_reader, mut uarte1_handler) = uarte1::setup(uarte1);

    let mut resp = ble::setup(nrf52.RADIO, nrf52.TIMER0, nrf52.FICR);

    HANDLERS.with_overrides(|hs| {
        hs.register(0, &mut rtc_handler);
        hs.register(1, &mut twis_handler);
        hs.register(2, &mut uarte1_handler);

        unsafe {
            NVIC::unmask(Interrupt::RTC0);
            NVIC::unmask(Interrupt::SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);
            NVIC::unmask(Interrupt::UARTE1);
            NVIC::unmask(Interrupt::TIMER0);
            NVIC::unmask(Interrupt::RADIO);
        }

        info!("Bootstrap complete.");

        // Buffer is just scratch space that always gets written to
        // before it's read.
        let mut buf: [u8; 256] =
            unsafe { core::mem::MaybeUninit::<[u8; 256]>::uninit().assume_init() };

        // TODO: there's some kind of weird multi-millisecond latency
        // somewhere. It may be in one of the interrupt handlers, so
        // maybe stick a counter on them for every time they're fired
        // and then spit out stats once/second from here.
        //
        // May need to keep total-time-spent inside the handlers as
        // well. This lag is infuriatingly hidden.
        loop {
            let mut len = twis_reader.shift_into(&mut buf);
            while len > 0 {
                info!("i²c data: {:?}", &buf[0..len]);
                len = twis_reader.shift_into(&mut buf);
            }

            let mut len = uarte1_reader.shift_into(&mut buf);
            while len > 0 {
                log!(target: "usb", LogLevel::Info,
                    "{}",
                    core::str::from_utf8(&buf[0..len]).expect("utf8conv")
                );
                len = uarte1_reader.shift_into(&mut buf);
            }

            if resp.has_work() {
                trace!("ble responder has work");
                resp.process_one().expect("ble response processing");
            }
            wfi();
        }
    });
    unreachable!();
}

fn uarte1<U>(uarte: U, tx: Pin<Output<PushPull>>, rx: Pin<Input<Floating>>) -> Uarte<U>
where
    U: uarte::Instance,
{
    Uarte::new(
        uarte,
        uarte::Pins {
            txd: tx,
            rxd: rx,
            cts: None,
            rts: None,
        },
        UartParity::EXCLUDED,
        UartBaudrate::BAUD115200,
    )
}

#[exception]
fn HardFault(ef: &ExceptionFrame) -> ! {
    log::logger().flush();
    logln_now!("!!! Hard Fault - ef: {:?} !!!", ef);
    logln_now!("flushing log");
    loop {
        log::logger().flush();
        wfi()
    }
}

#[interrupt]
fn RTC0() {
    HANDLERS.call(0);
}

#[interrupt]
fn SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0() {
    HANDLERS.call(1);
}

#[interrupt]
fn UARTE1() {
    HANDLERS.call(2);
}