#![no_std]
#![no_main]

use cortex_m_rt::entry;
use embedded_hal::digital::v2::{InputPin, OutputPin};
use stm32f1xx_hal::{delay::Delay, pac, prelude::*};

// Halt the MCU when panic
#[allow(unused_imports)]
use panic_halt;

mod seq;
pub use seq::{LayerSelect, SeqLayer, Sequencer};

#[entry]
fn main() -> ! {
    // Grab handles for the underlying hardware objects
    let dp = pac::Peripherals::take().unwrap();
    let cp = cortex_m::Peripherals::take().unwrap();

    // Initialise GPIOC via the HAL
    let mut rcc = dp.RCC.constrain();
    let mut gpioa = dp.GPIOA.split(&mut rcc.apb2);
    let mut gpiob = dp.GPIOB.split(&mut rcc.apb2);

    // Create an LED output
    let mut led1 = gpioa.pa1.into_push_pull_output(&mut gpioa.crl);
    let mut led2 = gpioa.pa2.into_push_pull_output(&mut gpioa.crl);
    let mut led3 = gpioa.pa3.into_push_pull_output(&mut gpioa.crl);
    let mut led4 = gpioa.pa4.into_push_pull_output(&mut gpioa.crl);

    // Create a button input
    let btn1 = gpiob.pb0.into_pull_down_input(&mut gpiob.crl);
    let btn2 = gpiob.pb1.into_pull_down_input(&mut gpiob.crl);
    let btn3 = gpiob.pb2.into_pull_down_input(&mut gpiob.crl);
    let btn4 = gpiob.pb3.into_pull_down_input(&mut gpiob.crl);

    // Initialize the delay object with the MCU frequency
    let mut flash = dp.FLASH.constrain();
    let clocks = rcc
        .cfgr
        .use_hse(8.mhz())
        .sysclk(48.mhz())
        .pclk1(24.mhz())
        .freeze(&mut flash.acr);
    let mut delay = Delay::new(cp.SYST, clocks);

    // Now go blinkenlights
    loop {
        set_led(&btn1, &mut led1);
        set_led(&btn2, &mut led2);
        set_led(&btn3, &mut led3);
        set_led(&btn4, &mut led4);

        delay.delay_ms(5_u16);
    }
}


fn set_led<'k, I: InputPin, O: OutputPin>(i: &'k I, o: &'k mut O) {
    if let Ok(true) = i.is_high() {
        o.set_low().ok();
    } else {
        o.set_high().ok();
    }
}