tuitube 0.5.0

//! The icons the UI draws. Plain Unicode symbols come from whatever
//! fallback fonts the system has, each at its own size; terminals with Nerd
//! Font icons built in (Ghostty, kitty, WezTerm) draw those at one size.

use serde::{Deserialize, Serialize};

/// Which icons to draw: `icons` in settings.toml, or `TT_ICONS`.
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum IconMode {
    /// Nerd Font icons in terminals known to have them built in.
    #[default]
    Auto,
    /// Nerd Font icons: the terminal has them built in, or uses a Nerd Font.
    Nerd,
    /// Plain Unicode symbols, which every font setup can show.
    Plain,
}

impl IconMode {
    pub fn parse(s: &str) -> Option<Self> {
        Some(match s.trim().to_ascii_lowercase().as_str() {
            "auto" => Self::Auto,
            "nerd" => Self::Nerd,
            "plain" => Self::Plain,
            _ => return None,
        })
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct Icons {
    pub home: &'static str,
    pub shorts: &'static str,
    pub search: &'static str,
    pub watch_later: &'static str,
    pub jukebox: &'static str,
    pub history: &'static str,
    pub play: &'static str,
    pub pause: &'static str,
    pub back: &'static str,
    pub ahead: &'static str,
    pub next: &'static str,
    pub stop: &'static str,
    pub autoplay: &'static str,
    /// The chapters popup's key in the player bar.
    pub chapters: &'static str,
    /// Subtitles' key in the player bar.
    pub subtitles: &'static str,
    pub sound: &'static str,
    pub loading: &'static str,
    pub refresh: &'static str,
}

/// Font Awesome's, as every Nerd Font has them.
pub const NERD: Icons = Icons {
    home: "\u{f015}",
    shorts: "\u{f144}",
    search: "\u{f002}",
    watch_later: "\u{f017}",
    jukebox: "\u{f0cb}",
    history: "\u{f1da}",
    play: "\u{f04b}",
    pause: "\u{f04c}",
    back: "\u{f04a}",
    ahead: "\u{f04e}",
    next: "\u{f051}",
    stop: "\u{f04d}",
    autoplay: "\u{f01e}",
    chapters: "\u{f03a}",
    subtitles: "\u{f20a}",
    sound: "\u{f001}",
    loading: "\u{f110}",
    refresh: "\u{f021}",
};

pub const PLAIN: Icons = Icons {
    home: "⌂",
    shorts: "▷",
    search: "⌕",
    watch_later: "◷",
    jukebox: "≡",
    history: "↺",
    play: "▶",
    pause: "⏸",
    back: "«",
    ahead: "»",
    next: "⏭",
    stop: "■",
    autoplay: "⟳",
    chapters: "§",
    subtitles: "CC",
    sound: "♪",
    loading: "⋯",
    refresh: "↻",
};

impl Icons {
    /// The icons for `mode`, looking at the environment for `Auto`.
    pub fn pick(mode: IconMode, env: impl Fn(&str) -> Option<String>) -> Self {
        match mode {
            IconMode::Nerd => NERD,
            IconMode::Plain => PLAIN,
            IconMode::Auto if nerd_terminal(&env) => NERD,
            IconMode::Auto => PLAIN,
        }
    }
}

/// The terminal drawing the window has Nerd Font icons built in. Ghostty
/// and WezTerm set variables their child processes keep, even inside tmux
/// or another multiplexer, which passes the characters on to them.
fn nerd_terminal(env: &impl Fn(&str) -> Option<String>) -> bool {
    let set = |name: &str| env(name).filter(|v| !v.is_empty());
    let program = set("TERM_PROGRAM").unwrap_or_default().to_ascii_lowercase();
    program == "ghostty"
        || program == "wezterm"
        || set("TERM").is_some_and(|t| t == "xterm-ghostty" || t == "xterm-kitty")
        || set("KITTY_WINDOW_ID").is_some()
        || set("GHOSTTY_RESOURCES_DIR").is_some()
        || set("WEZTERM_EXECUTABLE").is_some()
}

#[cfg(test)]
mod tests {
    use super::*;
    use unicode_width::UnicodeWidthStr;

    fn env(vars: &'static [(&'static str, &'static str)]) -> impl Fn(&str) -> Option<String> {
        move |name| {
            vars.iter()
                .find(|(k, _)| *k == name)
                .map(|(_, v)| v.to_string())
        }
    }

    #[test]
    fn ghostty_gets_nerd_icons_even_inside_a_multiplexer() {
        let inside = env(&[
            ("TERM_PROGRAM", "tmux"),
            ("GHOSTTY_RESOURCES_DIR", "/Applications/Ghostty.app"),
        ]);
        assert_eq!(Icons::pick(IconMode::Auto, inside), NERD);
        let apple = env(&[("TERM_PROGRAM", "Apple_Terminal")]);
        assert_eq!(Icons::pick(IconMode::Auto, apple), PLAIN);
        let apple = env(&[("TERM_PROGRAM", "Apple_Terminal")]);
        assert_eq!(Icons::pick(IconMode::Nerd, apple), NERD, "the settings win");
        assert_eq!(IconMode::parse("Plain"), Some(IconMode::Plain));
    }

    #[test]
    fn every_icon_takes_one_column() {
        for icons in [NERD, PLAIN] {
            for icon in [
                icons.home,
                icons.shorts,
                icons.search,
                icons.watch_later,
                icons.jukebox,
                icons.history,
                icons.play,
                icons.pause,
                icons.back,
                icons.ahead,
                icons.next,
                icons.stop,
                icons.autoplay,
                icons.chapters,
                icons.sound,
                icons.loading,
                icons.refresh,
            ] {
                assert_eq!(icon.width(), 1, "{icon:?}");
            }
        }
    }
}