#![no_main]
#![no_std]

use embedded_hal::digital::v2::*;
use embedded_hal::prelude::*;
use msp430_rt::entry;
use msp430fr2x5x_hal::{
    clock::{ClockConfig, DcoclkFreqSel, MclkDiv, SmclkDiv},
    fram::Fram,
    gpio::Batch,
    pmm::Pmm,
    timer::{CapCmp, SubTimer, Timer, TimerConfig, TimerDiv, TimerExDiv, TimerParts3, TimerPeriph},
    watchdog::Wdt,
};
use nb::block;
use panic_msp430 as _;
use void::ResultVoidExt;

// 0.5 second on, 0.5 second off
#[entry]
fn main() -> ! {
    let periph = msp430fr2355::Peripherals::take().unwrap();

    let mut fram = Fram::new(periph.FRCTL);
    Wdt::constrain(periph.WDT_A);

    let pmm = Pmm::new(periph.PMM);
    let p1 = Batch::new(periph.P1)
        .config_pin0(|p| p.to_output())
        .split(&pmm);
    let mut p1_0 = p1.pin0;

    let (_smclk, aclk) = ClockConfig::new(periph.CS)
        .mclk_dcoclk(DcoclkFreqSel::_1MHz, MclkDiv::_1)
        .smclk_on(SmclkDiv::_1)
        .aclk_vloclk()
        .freeze(&mut fram);

    let parts = TimerParts3::new(
        periph.TB0,
        TimerConfig::aclk(&aclk).clk_div(TimerDiv::_2, TimerExDiv::_5),
    );
    let mut timer = parts.timer;
    let mut subtimer = parts.subtimer2;

    set_time(&mut timer, &mut subtimer, 500);
    loop {
        block!(subtimer.wait()).void_unwrap();
        p1_0.set_high().void_unwrap();
        // first 0.5 s of timer countdown expires while subtimer expires, so this should only block
        // for 0.5 s
        block!(timer.wait()).void_unwrap();
        p1_0.set_low().void_unwrap();
    }
}

fn set_time<T: TimerPeriph + CapCmp<C>, C>(
    timer: &mut Timer<T>,
    subtimer: &mut SubTimer<T, C>,
    delay: u16,
) {
    timer.start(delay + delay);
    subtimer.set_count(delay);
}

// The compiler will emit calls to the abort() compiler intrinsic if debug assertions are
// enabled (default for dev profile). MSP430 does not actually have meaningful abort() support
// so for now, we create our own in each application where debug assertions are present.
#[no_mangle]
extern "C" fn abort() -> ! {
    panic!();
}