use core::mem;

use arduino_hal::{
    hal::port::{PB4, PB5, PC4, PC5, PD2},
    pac::{
        adc::adc::ADC_SPEC,
        tc1::{ocr1a::OCR1A_SPEC, ocr1b::OCR1B_SPEC},
    },
    pins,
    port::{
        mode::{Input, Output, PullUp},
        Pin,
    },
    Peripherals,
};
use avr_device::generic::Reg;

pub struct Setup<'a> {
    pub led: Pin<Output, PB5>,
    pub footswitch: Pin<Input<PullUp>, PB4>,
    pub toggle: Pin<Input<PullUp>, PD2>,
    pub push_button_1: Pin<Input<PullUp>, PC5>,
    pub push_button_2: Pin<Input<PullUp>, PC4>,

    ocr1a: &'a Reg<OCR1A_SPEC>,
    ocr1b: &'a Reg<OCR1B_SPEC>,

    adc: &'a Reg<ADC_SPEC>,
}

impl<'a> Setup<'a> {
    //defining the output PWM parameters
    // pwm frequency - 31.3KHz
    const PWM_FREQ: u16 = 0x00FF;
    // Fast (1) or Phase Correct (0)
    const PWM_MODE: u8 = 0;
    // 2 PWMs in parallel
    const PWM_QTY: u8 = 2;

    pub fn write_output(&self, output: u16) {
        let high_byte = ((output + 0x8000) >> 8) & 0x00FF;
        let low_byte = output & 0x00FF;

        self.ocr1a.write(|w| unsafe { w.bits(high_byte) });
        self.ocr1b.write(|w| unsafe { w.bits(low_byte) });
    }

    pub fn get_input(&self) -> u16 {
        self.adc.read().bits()
    }
}

impl<'a> Default for Setup<'a> {
    fn default() -> Self {
        let dp = Peripherals::take().unwrap();

        // turn on outputs
        dp.PORTB.ddrb.write(|w| unsafe { w.bits(0x02) });

        let pins = pins!(dp);

        // defining harware resources
        let led = pins.d13.into_output();
        let footswitch = pins.d12.into_pull_up_input();
        let toggle = pins.d2.into_pull_up_input();
        let push_button_1 = pins.a5.into_pull_up_input();
        let push_button_2 = pins.a4.into_pull_up_input();

        // setup ADC
        // left adjust, adc0, internal vcc
        dp.ADC.admux.write(|w| unsafe { w.bits(0x60) });
        // turn on adc, ck/32, auto trigger
        dp.ADC.adcsra.write(|w| unsafe { w.bits(0xe5) });
        // t1 capture for trigger
        dp.ADC.adcsrb.write(|w| unsafe { w.bits(0x07) });
        // turn off digital inputs for adc0
        dp.ADC.didr0.write(|w| unsafe { w.bits(0x01) });

        // setup PWM
        dp.TC1.tccr1a.write(|w| unsafe {
            w.bits(((Self::PWM_QTY - 1) << 5) | 0x80 | (Self::PWM_MODE << 1))
        });
        // ck/1
        dp.TC1
            .tccr1b
            .write(|w| unsafe { w.bits((Self::PWM_MODE << 3) | 0x11) });
        // interrupt on capture interrupt
        dp.TC1.timsk1.write(|w| unsafe { w.bits(0x20) });
        dp.TC1.icr1.write(|w| unsafe { w.bits(Self::PWM_FREQ) });

        let ocr1a = &dp.TC1.ocr1a;
        let ocr1b = &dp.TC1.ocr1b;
        let adc = &dp.ADC.adc;

        unsafe { avr_device::interrupt::enable() };

        Self {
            led,
            footswitch,
            toggle,
            push_button_1,
            push_button_2,

            ocr1a: unsafe { mem::transmute(ocr1a as *const _) },
            ocr1b: unsafe { mem::transmute(ocr1b as *const _) },

            adc: unsafe { mem::transmute(adc as *const _) },
        }
    }
}