//! A count, and buttons to change it: the first K-UI app. Tab and the
//! arrows move between the buttons, Enter presses, Escape leaves.

#![no_std]
#![forbid(unsafe_code)]
#![no_main]

extern crate alloc;
extern crate libkos;

use alloc::format;
use k_ui::{App, ButtonVariant, Element, Spacing, TextColour, TextStyle, button, column, row, text};

#[derive(Clone, Copy)]
enum Event {
    Add,
    Subtract,
    Reset,
}

struct Tally(i64);

impl App for Tally {
    type Event = Event;

    fn init() -> Self {
        Tally(0)
    }

    fn update(&mut self, event: Event) {
        match event {
            Event::Add => self.0 += 1,
            Event::Subtract => self.0 -= 1,
            Event::Reset => self.0 = 0,
        }
    }

    fn view(&self) -> Element<Event> {
        let mut buttons = row()
            .gap(Spacing::Md)
            .child(button("Subtract", Event::Subtract))
            .child(button("Add", Event::Add).variant(ButtonVariant::Primary));
        if self.0 != 0 {
            buttons = buttons.child(button("Reset", Event::Reset).variant(ButtonVariant::Destructive));
        }
        column()
            .padding(Spacing::Xl)
            .gap(Spacing::Lg)
            .child(text("Tally").style(TextStyle::Heading))
            .child(text(format!("{}", self.0)).style(TextStyle::Subheading).colour(TextColour::Accent))
            .child(buttons)
            .child(text("Tab moves, Enter presses, Esc leaves").style(TextStyle::Caption).colour(TextColour::Secondary))
            .into()
    }
}

libkos::entry!(main);

fn main() {
    k_ui::run::<Tally>();
}