//! BLE interface.

#![no_std]
#![no_main]

mod i2c;
mod logger;
mod macros;
mod rtc;

use clint::HandlerArray;
use core::fmt::Write;
use core::mem;
use cortex_m::asm::wfi;
use cortex_m_rt::{entry, exception, ExceptionFrame};
use log::{info, trace, 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:
//   * set up serial reader for trinket
//   * set up i²c interface for keyboard reports
//   * and, finally, 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);

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

    let mut nvic = nrf52.NVIC;
    let mut rtc_handler = rtc::setup(Rtc::new(nrf52.RTC0), Clocks::new(nrf52.CLOCK));
    let 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 mut uarte1 = uarte1(nrf52.UARTE1, txp, rxp);

    HANDLERS.with_overrides(|hs| {
        hs.register(0, &mut rtc_handler);
        nvic.enable(Interrupt::RTC0);
        hs.register(1, &mut twis_handler);
        nvic.enable(Interrupt::SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);

        info!("Bootstrap complete.");

        let mut last_tick = rtc::millis();
        last_tick -= last_tick % 1024;
        loop {
            let tick = rtc::millis();
            if tick >= last_tick + 1024 {
                last_tick = tick;
                last_tick -= last_tick % 1024;
                trace!(".");
                write!(uarte1, "!").expect("uarte1 write");
            }

            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);
}