#![no_std]
#![no_main]

mod blink;
mod led;
mod log;

use gd32vf103xx_hal::{
    afio::AfioExt,
    eclic::{self, EclicExt},
    gpio::GpioExt,
    pac::{self, Peripherals},
    rcu::RcuExt,
    serial::Serial,
    time::Hertz,
    timer::Timer,
};
use riscv::asm::wfi;
use riscv_rt::entry;

use led::LED;

// global_asm!(include_str!("boot.S"));

#[derive(PartialEq)]
pub enum PollResult {
    Ok,
    WouldBlock,
}

#[entry]
fn main(_hartid: usize) -> ! {
    let p = Peripherals::take().expect("couldn't take peripherals");

    pac::ECLIC::set_threshold_level(eclic::Level::L0);
    pac::ECLIC::set_level_priority_bits(eclic::LevelPriorityBits::L3P1);

    let mut rcu = p.RCU.configure().freeze();
    let mut afio = p.AFIO.constrain(&mut rcu);

    let timer = Timer::<pac::TIMER6>::timer6(p.TIMER6, Hertz(1), &mut rcu);
    let gpioa = p.GPIOA.split(&mut rcu);
    let led = LED::new(gpioa.pa7);
    let mut blink = blink::Task::new(timer, Hertz(5), led);

    // TODO: figure out how to use the usb serial on the start board.
    //
    // this version has to be wired up physically.
    let serial = Serial::new(
        p.USART1,
        (gpioa.pa2, gpioa.pa3),
        Default::default(),
        &mut afio,
        &mut rcu,
    );
    let (tx, _rx) = serial.split();
    unsafe { log::new(tx) };

    loop {
        let mut can_sleep = true;

        can_sleep &= blink.poll() == PollResult::WouldBlock;
        unsafe { log::log("hi\r\n") };

        if can_sleep {
            unsafe { wfi() };
        }
    }
}

#[export_name="ExceptionHandler"]
fn exception_handler(_frame: &riscv_rt::TrapFrame) -> ! {
    loop { unsafe { wfi() } };
}

#[export_name="DefaultHandler"]
fn default_handler() -> ! {
    loop { unsafe { wfi() } };
}

#[export_name="MachineTimer"]
fn machine_timer() {
    loop { unsafe { wfi() } };
}

#[panic_handler]
fn panic(info: &core::panic::PanicInfo) -> ! {
    if let Some(loc) = info.location() {
        let _file = loc.file();
        let _line = loc.line();
        if let Some(_msg) = info.payload().downcast_ref::<&str>() {
            loop {}
        }
        loop {}
    }
    loop {}
}