//! A theme in message words, as the display hands it to a window
//! (`types::display::window::THEME`). Its name stays behind.

use crate::{Rgba, Theme};

pub const WORDS: usize = types::display::window::THEME_WORDS;

fn colours(t: &Theme) -> [Rgba; 12] {
    [
        t.background,
        t.surface,
        t.surface_raised,
        t.accent,
        t.on_accent,
        t.text_primary,
        t.text_secondary,
        t.destructive,
        t.on_destructive,
        t.focus,
        t.orbs[0],
        t.orbs[1],
    ]
}

pub fn encode(t: &Theme) -> [usize; WORDS] {
    let c = colours(t);
    let mut w = [0usize; WORDS];
    for i in 0..6 {
        w[i] = c[2 * i].to_rgb() as usize | (c[2 * i + 1].to_rgb() as usize) << 32;
    }
    w[6] = t.corner_radius as usize
        | (t.spacing_base as usize) << 8
        | (t.blur_radius as usize) << 16
        | (t.panel_opacity as usize) << 24
        | (t.highlight as usize) << 32
        | (t.duration_fast as usize) << 40;
    w[7] = t.duration_normal as usize
        | (t.spring_stiffness as usize) << 16
        | (t.spring_damping as usize & 0xff) << 32
        | (t.orbs[2].to_rgb() as usize & 0xff_ffff) << 40;
    w
}

pub fn decode(w: [usize; WORDS]) -> Theme {
    let c = |i: usize| Rgba::rgb((w[i / 2] >> (32 * (i % 2))) as u32 & 0xff_ffff);
    let byte = |word: usize, at: u32| (w[word] >> at) as u8;
    let half = |word: usize, at: u32| (w[word] >> at) as u16;
    Theme {
        name: [0; crate::NAME_BYTES],
        name_len: 0,
        background: c(0),
        surface: c(1),
        surface_raised: c(2),
        accent: c(3),
        on_accent: c(4),
        text_primary: c(5),
        text_secondary: c(6),
        destructive: c(7),
        on_destructive: c(8),
        focus: c(9),
        orbs: [c(10), c(11), Rgba::rgb((w[7] >> 40) as u32 & 0xff_ffff)],
        corner_radius: byte(6, 0) as f32,
        spacing_base: byte(6, 8) as f32,
        blur_radius: byte(6, 16),
        panel_opacity: byte(6, 24),
        highlight: byte(6, 32),
        duration_fast: half(6, 40),
        duration_normal: half(7, 0),
        spring_stiffness: half(7, 16),
        // At most 200 (see `parse`): a byte.
        spring_damping: byte(7, 32) as u16,
    }
}