use gd32vf103xx_hal::prelude::_embedded_hal_timer_CountDown;

use core::convert::Infallible;

use gd32vf103xx_hal::{
    eclic::{self, EclicExt},
    pac::{self, Interrupt},
    time::Hertz,
    timer::{Event, Timer},
};
use nb;

use crate::led::LED;

enum State {
    WaitForTimer,
    ToggleLED,
}

pub struct Task {
    timer: Timer<pac::TIMER6>,
    frequency: Hertz,
    led: LED,
    state: State,
}

impl Task {
    pub fn new(mut timer: Timer<pac::TIMER6>, frequency: Hertz, led: LED) -> Self {
        pac::ECLIC::setup(Interrupt::TIMER6, eclic::TriggerType::RisingEdge, eclic::Level::L0, eclic::Priority::P3);
        unsafe { pac::ECLIC::unmask(Interrupt::TIMER6); }
        if !pac::ECLIC::is_enabled(Interrupt::TIMER6) {
            panic!("timer6 interrupt not enabled");
        }
        timer.listen(Event::Update);

        Self { timer, frequency, led, state: State::ToggleLED }
    }

    pub fn poll(&mut self) -> nb::Result<(), Infallible> {
        match self.state {
            State::WaitForTimer => {
                if let Ok(_) = self.timer.wait() {
                    self.state = State::ToggleLED;
                    // self.timer.unlisten(Event::Update);
                    Ok(())
                } else {
                    Err(nb::Error::WouldBlock)
                }
            },
            State::ToggleLED => {
                self.led.toggle();
                self.timer.start(self.frequency);
                self.state = State::WaitForTimer;
                // self.timer.listen(Event::Update);
                Err(nb::Error::WouldBlock)
            }
        }
    }
}