#![feature(abi_avr_interrupt)]
#![no_std]
#![no_main]

use atmega_hal::{
    clock::MHz8,
    delay::Delay,
    pac::{EXINT, TC1},
    pins,
    port::{self, mode::PullUp, Pin, PB6, PB7, PC0},
    spi::{DataOrder, SerialClockRate, Settings, Spi},
    Peripherals,
};
use avr_device::interrupt;
use core::sync::atomic::{AtomicBool, Ordering};
use embedded_hal::{
    blocking::delay::DelayMs,
    spi::{Mode, Phase, Polarity},
};
use panic_halt as _;

mod assets;
mod eeprom;
mod lcd;
mod rotary;
mod screen;

use rotary::{Direction, Rotary};
use screen::{Screen, Screens};

pub type DefaultClock = MHz8;
pub type I2c = atmega_hal::i2c::I2c<DefaultClock>;

#[used]
#[link_section = ".eeprom"]
static BACKLIGHT: u8 = 0;

#[used]
#[link_section = ".eeprom"]
static CONTRAST: u8 = 8;

pub enum Input {
    Next,
    Previous,
    Select,
    Back,
}

struct ClockGenerator {
    screen: Screen,
    tc1: TC1,
    exint: EXINT,
    encoder: Rotary<Pin<port::mode::Input<PullUp>, PB6>, Pin<port::mode::Input<PullUp>, PB7>>,
    button: Pin<port::mode::Input<PullUp>, PC0>,
    delay: Delay<MHz8>,
}

impl ClockGenerator {
    fn new() -> Self {
        let dp = Peripherals::take().unwrap();
        let pins = pins!(dp);

        // Init SPI
        let (spi, _) = Spi::new(
            dp.SPI,
            pins.pb5.into_output(),
            pins.pb3.into_output(),
            pins.pb4.into_pull_up_input(),
            pins.pb2.into_output(),
            Settings {
                data_order: DataOrder::MostSignificantFirst,
                clock: SerialClockRate::OscfOver2,
                mode: Mode {
                    polarity: Polarity::IdleLow,
                    phase: Phase::CaptureOnFirstTransition,
                },
            },
        );

        Self {
            screen: Screen::new(
                dp.TC0,
                spi,
                pins.pd5.into_output(),
                pins.pb0.into_output(),
                pins.pb1.into_output(),
                I2c::new(
                    dp.TWI,
                    pins.pc4.into_pull_up_input(),
                    pins.pc5.into_pull_up_input(),
                    50000,
                ),
            ),
            tc1: dp.TC1,
            exint: dp.EXINT,
            delay: Delay::<MHz8>::new(),
            encoder: Rotary::new(pins.pb6.into_pull_up_input(), pins.pb7.into_pull_up_input()),
            button: pins.pc0.into_pull_up_input(),
        }
    }

    fn init(&mut self) {
        // Init Timer/Counter1
        self.tc1.ocr1a.write(|w| unsafe { w.bits(65535) });

        // Enable interrupts for encoder, button and timer
        self.exint.pcicr.write(|w| w.pcie().bits(0b0000_0011));
        self.exint.pcmsk0.write(|w| w.pcint().bits(0b1100_0000));
        self.exint.pcmsk1.write(|w| w.pcint().bits(0b0000_0001));
        self.tc1.timsk1.write(|w| w.ocie1a().set_bit());

        // Init screen
        self.screen.init();

        // Show splash screen for a moment
        self.delay.delay_ms(2000_u16);

        // Set home screen
        self.screen.change(Screens::Home(screen::Home::new()));

        // Enable interrupts globally
        unsafe { interrupt::enable() };
    }

    fn update(&mut self) {
        if UPDATE_ENCODER.load(Ordering::SeqCst) {
            interrupt::free(|_cs| {
                self.delay.delay_ms(3_u8);

                match self.encoder.update() {
                    Direction::Clockwise => {
                        self.screen.input(&Input::Next);
                    }
                    Direction::CounterClockwise => {
                        self.screen.input(&Input::Previous);
                    }
                    Direction::None => {}
                }
                UPDATE_ENCODER.store(false, Ordering::SeqCst);
            })
        }

        if UPDATE_TIMER.load(Ordering::SeqCst) {
            self.tc1.tccr1b.write(|w| w.cs1().no_clock());
            self.screen.input(&Input::Back);
            UPDATE_TIMER.store(false, Ordering::SeqCst);
        }

        if UPDATE_BUTTON.load(Ordering::SeqCst) {
            self.delay.delay_ms(2_u8);

            if self.button.is_low() {
                // Press
                if self.tc1.tccr1b.read().cs1().is_no_clock() {
                    self.tc1.tcnt1.write(|w| unsafe { w.bits(0) });
                    self.tc1.tccr1b.write(|w| w.cs1().prescale_64());
                }
            } else {
                // Release
                if self.tc1.tccr1b.read().cs1().is_prescale_64() {
                    self.tc1.tccr1b.write(|w| w.cs1().no_clock());
                    self.screen.input(&Input::Select);
                    self.delay.delay_ms(3_u8);
                }
            }
            UPDATE_BUTTON.store(false, Ordering::SeqCst);
        }
    }
}

static UPDATE_ENCODER: AtomicBool = AtomicBool::new(false);
static UPDATE_BUTTON: AtomicBool = AtomicBool::new(false);
static UPDATE_TIMER: AtomicBool = AtomicBool::new(false);

#[interrupt(atmega328p)]
#[allow(non_snake_case)]
fn PCINT0() {
    interrupt::free(|_cs| {
        UPDATE_ENCODER.store(true, Ordering::SeqCst);
    })
}

#[interrupt(atmega328p)]
#[allow(non_snake_case)]
fn PCINT1() {
    interrupt::free(|_cs| {
        UPDATE_BUTTON.store(true, Ordering::SeqCst);
    })
}

#[interrupt(atmega328p)]
#[allow(non_snake_case)]
fn TIMER1_COMPA() {
    interrupt::free(|_cs| {
        UPDATE_TIMER.store(true, Ordering::SeqCst);
    })
}

#[atmega_hal::entry]
fn main() -> ! {
    let mut cg = ClockGenerator::new();
    cg.init();

    loop {
        cg.update();
    }
}