use std::time::Instant;

use eframe::{
    egui::{self, Frame},
    epaint::Color32,
    Frame as EFrame,
};

use super::{state::*, Timer};
use crate::{MAX_REPAINT, MIN_REPAINT};

const STARTING_COLOR: &[f32; 3] = &[10.0, 4.0, 14.0];
const UNIT_COLOR: &[f32; 3] = &[0.986, 0.154, 0.055]; // [160, 125, 9].normalize()

impl eframe::App for Timer {
    fn update(&mut self, ctx: &egui::Context, frame: &mut EFrame) {
        ctx.request_repaint_after(MAX_REPAINT);
        let height = ctx.input().screen_rect().height();

        let t = self.done.powi(3);
        let color = get_color(t);

        egui::CentralPanel::default()
            .frame(Frame::none().fill(color))
            .show(ctx, |ui| {
                match self.state {
                    TimerState::Unstarted => self.unstarted(ui, height),
                    TimerState::Running(cs) => {
                        let dur = Instant::now() - cs.updated;
                        let dur = MIN_REPAINT.saturating_sub(dur);
                        ctx.request_repaint_after(dur);
                        self.running(ui, height, cs);
                    }
                    TimerState::Paused(cs) => self.paused(ui, height, cs),
                    TimerState::Finished => self.finished(ui, height),
                }
                // check for quit key
                if ui.input().key_pressed(egui::Key::Q) || ui.input().key_pressed(egui::Key::Escape)
                {
                    frame.close();
                }
            });
    }
}

fn get_color(t: f32) -> Color32 {
    let [sr, sg, sb] = STARTING_COLOR;
    let [ur, ug, ub] = UNIT_COLOR;
    let mag = t * 162.0;
    let (r, g, b) = (
        (sr + (mag * ur).round()) as u8,
        (sg + (mag * ug).round()) as u8,
        (sb + (mag * ub).round()) as u8,
    );
    // when t is 1.0, then the final color is roughly 170, 29, 23.
    Color32::from_rgb(r, g, b)
}