wlr-chooser 1.1.0

//! Colour & font theme. Sensible generic-dark defaults, overridable from
//! `~/.config/wlr-chooser/theme.toml` (or `$XDG_CONFIG_HOME/wlr-chooser/theme.toml`).
//!
//! Colour keys are `#rrggbb` / `#rrggbbaa`; font keys configure the UI font:
//!
//! ```toml
//! accent = "#89b4fa"
//! screen-accent = "#89b4fa"
//! window-accent = "#cba6f7"
//!
//! font = "JetBrains Mono"   # UI font family (resolved via fontconfig)
//! # font-path = "/path/to/Font.ttf"   # …or a direct file
//! # cjk-font = "Noto Sans CJK JP"     # CJK fallback (else auto-detected)
//! font-size = 15.0
//! ```
//!
//! Rendering CJK text (Japanese/Chinese/Korean) needs a CJK font installed; one
//! is auto-detected and used as a fallback.

use egui::Color32;
use serde::Deserialize;

#[derive(Clone)]
pub struct Theme {
    pub backdrop: Color32,      // dimmed overlay behind the card (lock mode)
    pub bg: Color32,            // window background (no-lock)
    pub card: Color32,          // the centred card
    pub tile: Color32,          // tile background
    pub tile_hover: Color32,    // tile background, hovered
    pub tile_selected: Color32, // tile background, selected
    pub thumb: Color32,         // thumbnail letterbox area
    pub text: Color32,          // labels
    pub text_dim: Color32,      // placeholders, secondary
    pub accent: Color32,        // general accent (selection, focus)
    pub screen_accent: Color32, // outline + glyph for OUTPUT tiles
    pub window_accent: Color32, // outline for WINDOW tiles

    pub font: Option<String>, // UI font family (resolved via fontconfig)
    pub font_path: Option<String>, // …or a direct font file
    pub cjk_font: Option<String>, // CJK fallback family (else auto-detected)
    pub font_size: Option<f32>, // base UI text size in points
}

impl Default for Theme {
    fn default() -> Self {
        let c = |r, g, b| Color32::from_rgb(r, g, b);
        Self {
            backdrop: Color32::from_rgba_unmultiplied(0, 0, 0, 140),
            bg: c(0x1e, 0x21, 0x27),
            card: c(0x21, 0x25, 0x2d),
            tile: c(0x18, 0x1b, 0x22),
            tile_hover: c(0x26, 0x2b, 0x33),
            tile_selected: c(0x3b, 0x42, 0x52),
            thumb: c(0x12, 0x14, 0x1a),
            text: c(0xd8, 0xde, 0xe9),
            text_dim: c(0x7a, 0x82, 0x90),
            accent: c(0x88, 0xc0, 0xd0),
            screen_accent: c(0x81, 0xa1, 0xc1), // blue — screens
            window_accent: c(0xb4, 0x8e, 0xad), // purple — windows
            font: None,
            font_path: None,
            cjk_font: None,
            font_size: None,
        }
    }
}

#[derive(Deserialize, Default)]
#[serde(rename_all = "kebab-case", default)]
struct Raw {
    backdrop: Option<String>,
    bg: Option<String>,
    card: Option<String>,
    tile: Option<String>,
    tile_hover: Option<String>,
    tile_selected: Option<String>,
    thumb: Option<String>,
    text: Option<String>,
    text_dim: Option<String>,
    accent: Option<String>,
    screen_accent: Option<String>,
    window_accent: Option<String>,
    font: Option<String>,
    font_path: Option<String>,
    cjk_font: Option<String>,
    font_size: Option<f32>,
}

impl Theme {
    /// Load the theme, applying any overrides from the user config.
    pub fn load() -> Self {
        let mut t = Theme::default();
        let Some(raw) = config_path()
            .and_then(|p| std::fs::read_to_string(p).ok())
            .and_then(|s| toml::from_str::<Raw>(&s).ok())
        else {
            return t;
        };
        let set = |dst: &mut Color32, src: &Option<String>| {
            if let Some(c) = src.as_deref().and_then(parse_hex) {
                *dst = c;
            }
        };
        set(&mut t.backdrop, &raw.backdrop);
        set(&mut t.bg, &raw.bg);
        set(&mut t.card, &raw.card);
        set(&mut t.tile, &raw.tile);
        set(&mut t.tile_hover, &raw.tile_hover);
        set(&mut t.tile_selected, &raw.tile_selected);
        set(&mut t.thumb, &raw.thumb);
        set(&mut t.text, &raw.text);
        set(&mut t.text_dim, &raw.text_dim);
        set(&mut t.accent, &raw.accent);
        set(&mut t.screen_accent, &raw.screen_accent);
        set(&mut t.window_accent, &raw.window_accent);
        t.font = raw.font;
        t.font_path = raw.font_path;
        t.cjk_font = raw.cjk_font;
        t.font_size = raw.font_size;
        t
    }

    /// Apply the palette to egui's global visuals (panels, widgets, selection…).
    pub fn apply(&self, ctx: &egui::Context) {
        let mut v = egui::Visuals::dark();
        v.panel_fill = self.bg;
        v.window_fill = self.card;
        v.extreme_bg_color = self.thumb;
        v.override_text_color = Some(self.text);
        v.selection.bg_fill = self.accent.gamma_multiply(0.4);
        v.selection.stroke = egui::Stroke::new(1.0, self.accent);
        v.hyperlink_color = self.accent;
        v.widgets.hovered.bg_fill = self.tile_hover;
        v.widgets.active.bg_fill = self.tile_selected;
        ctx.set_visuals(v);

        self.install_fonts(ctx);
        if let Some(sz) = self.font_size {
            ctx.style_mut(|s| {
                use egui::{FontFamily, FontId, TextStyle};
                let prop = FontFamily::Proportional;
                s.text_styles
                    .insert(TextStyle::Body, FontId::new(sz, prop.clone()));
                s.text_styles
                    .insert(TextStyle::Button, FontId::new(sz, prop.clone()));
                s.text_styles
                    .insert(TextStyle::Small, FontId::new(sz * 0.85, prop.clone()));
                s.text_styles
                    .insert(TextStyle::Heading, FontId::new(sz * 1.4, prop));
                s.text_styles
                    .insert(TextStyle::Monospace, FontId::new(sz, FontFamily::Monospace));
            });
        }
    }

    /// Build egui's font set: the configured UI font first (if any), then egui's
    /// defaults, then a CJK fallback (so Japanese/Chinese/Korean render when a CJK
    /// font is installed).
    fn install_fonts(&self, ctx: &egui::Context) {
        let mut fonts = egui::FontDefinitions::default();
        let mut db = fontdb::Database::new();
        db.load_system_fonts();

        // Primary UI font: explicit file, or a family resolved via fontconfig.
        let primary = self
            .font_path
            .as_deref()
            .and_then(read_font_file)
            .or_else(|| self.font.as_deref().and_then(|f| load_family(&db, f)));
        if let Some(data) = primary {
            fonts.font_data.insert("ui".into(), data.into());
            for fam in [egui::FontFamily::Proportional, egui::FontFamily::Monospace] {
                fonts
                    .families
                    .entry(fam)
                    .or_default()
                    .insert(0, "ui".into());
            }
        }

        // CJK fallback: configured family, else the first common one installed.
        let cjk = self
            .cjk_font
            .as_deref()
            .and_then(|f| load_family(&db, f))
            .or_else(|| CJK_FAMILIES.iter().find_map(|f| load_family(&db, f)));
        if let Some(data) = cjk {
            fonts.font_data.insert("cjk".into(), data.into());
            for fam in [egui::FontFamily::Proportional, egui::FontFamily::Monospace] {
                fonts.families.entry(fam).or_default().push("cjk".into());
            }
        }

        ctx.set_fonts(fonts);
    }
}

/// Common CJK font families to try when none is configured.
const CJK_FAMILIES: &[&str] = &[
    "Noto Sans CJK JP",
    "Noto Sans CJK SC",
    "Noto Sans CJK KR",
    "Source Han Sans",
    "Sarasa Gothic",
    "WenQuanYi Zen Hei",
];

fn read_font_file(path: &str) -> Option<egui::FontData> {
    let bytes = std::fs::read(path).ok()?;
    Some(egui::FontData::from_owned(bytes))
}

/// Resolve a font family name to its data (handles `.ttc` face indices).
fn load_family(db: &fontdb::Database, family: &str) -> Option<egui::FontData> {
    let query = fontdb::Query {
        families: &[fontdb::Family::Name(family)],
        ..Default::default()
    };
    let id = db.query(&query)?;
    db.with_face_data(id, |bytes, index| {
        let mut data = egui::FontData::from_owned(bytes.to_vec());
        data.index = index;
        data
    })
}

fn config_path() -> Option<std::path::PathBuf> {
    let base = std::env::var_os("XDG_CONFIG_HOME")
        .map(std::path::PathBuf::from)
        .or_else(|| {
            std::env::var_os("HOME").map(|h| std::path::PathBuf::from(h).join(".config"))
        })?;
    Some(base.join("wlr-chooser").join("theme.toml"))
}

/// Parse `#rgb`, `#rrggbb` or `#rrggbbaa`.
fn parse_hex(s: &str) -> Option<Color32> {
    let h = s.trim().strip_prefix('#')?;
    let n = |i: usize| u8::from_str_radix(&h[i..i + 2], 16).ok();
    match h.len() {
        6 => Some(Color32::from_rgb(n(0)?, n(2)?, n(4)?)),
        8 => Some(Color32::from_rgba_unmultiplied(n(0)?, n(2)?, n(4)?, n(6)?)),
        3 => {
            let d = |i: usize| {
                let v = u8::from_str_radix(&h[i..i + 1], 16).ok()?;
                Some(v * 17)
            };
            Some(Color32::from_rgb(d(0)?, d(1)?, d(2)?))
        }
        _ => None,
    }
}