ishou-render 0.1.6

//! Fleet-fonts renderer — typed Nix attrset every pleme-io GUI app's
//! home-manager module imports to (a) name the canonical font family
//! and (b) install the underlying nixpkgs package via `home.packages`.
//!
//! Why this exists separately from `stylix_fonts`:
//!
//! - `stylix_fonts` produces the **stylix-shaped** `{ monospace,
//!   sansSerif, serif, emoji }` attrset that foreign apps (GTK,
//!   alacritty, kitty, btop, k9s, …) read via the stylix theme.
//!   Stylix has exactly four font slots.
//!
//! - `fleet_fonts` produces a **GPU-app-shaped** `{ primary, italic,
//!   bold, symbols, emoji, fallback_chain }` attrset that pleme-io's
//!   own terminal emulators (mado today; fumi / kagi / hibiki /
//!   namimado / nami next) consume directly via flake input. It
//!   carries the italic + symbols faces stylix doesn't model, plus
//!   the explicit package reference each HM module needs to
//!   `home.packages = [ … ]` so the underlying font is actually
//!   installed on the operator's machine.
//!
//! The two surfaces are sibling projections of the same typed
//! Typography token — changing `MonoFonts::pleme()` in ishou-tokens
//! is the single source of truth for both. Adding a new font slot
//! is a one-line edit in typography.rs; both renderers regenerate
//! in lockstep.
//!
//! ## Output shape
//!
//! ```nix
//! { pkgs }:
//! {
//!   primary = { name = "JetBrainsMono Nerd Font"; package = pkgs.nerd-fonts.jetbrains-mono; };
//!   italic  = { name = "Iosevka"; style_intent = "calligraphic"; package = pkgs.iosevka; };
//!   bold    = { name = "JetBrainsMono Nerd Font"; package = pkgs.nerd-fonts.jetbrains-mono; };
//!   symbols = { name = "Symbols Nerd Font Mono"; package = pkgs.nerd-fonts.symbols-only; };
//!   emoji   = { name = "Apple Color Emoji"; fallback_name = "Noto Color Emoji"; package = null; };
//!   fallback_chain = [ "Symbols Nerd Font Mono" "FiraCode Nerd Font" … ];
//! }
//! ```
//!
//! ## Consumer pattern
//!
//! Every fleet GUI app's HM module imports this attrset and uses it to
//! (a) name the canonical family in its `font.family` default and
//! (b) install the underlying package(s) declaratively:
//!
//! ```nix
//! let fonts = import inputs.ishou.packages.${system}.fleet-fonts
//!               { inherit pkgs; };
//! in {
//!   options.myapp.font.family = lib.mkOption {
//!     default = fonts.primary.name;
//!   };
//!   config.home.packages = [
//!     fonts.primary.package
//!     fonts.italic.package
//!     fonts.symbols.package
//!   ];
//! }
//! ```

use ishou_tokens::TokenSet;
use ishou_tokens::typography::{ItalicStyle, MonoFonts};

use crate::nix_ast::{AttrEntry, NixExpr, NixFile, attrset, lambda, list, raw, str_};

/// Render the canonical fleet-fonts Nix attrset.
#[must_use]
pub fn render(t: &TokenSet) -> String {
    let mono = &t.typography.mono_fonts;

    let primary = attrset(vec![
        AttrEntry::new("name", str_(mono.primary)),
        AttrEntry::new("package", primary_pkg(mono)),
    ]);

    let italic = attrset(vec![
        AttrEntry::new("name", str_(mono.italic)),
        AttrEntry::new("style_intent", str_(italic_style_name(mono.italic_style))),
        AttrEntry::new("package", italic_pkg(mono)),
    ]);

    let bold = attrset(vec![
        AttrEntry::new("name", str_(mono.bold)),
        AttrEntry::new("package", primary_pkg(mono)),
    ]);

    let symbols = attrset(vec![
        AttrEntry::new("name", str_("Symbols Nerd Font Mono")),
        AttrEntry::new("package", raw("pkgs.nerd-fonts.symbols-only")),
    ]);

    let emoji = attrset(vec![
        AttrEntry::new("name", str_("Apple Color Emoji")),
        AttrEntry::new("fallback_name", str_("Noto Color Emoji")),
        AttrEntry::new("package", NixExpr::Null),
    ]);

    let fallback_chain = list(
        mono.fallback
            .iter()
            .map(|name| str_(*name))
            .collect(),
    );

    let body = attrset(vec![
        AttrEntry::new("primary", primary)
            .with_comment(["Primary monospace family.", "Source of every cell's regular glyph."]),
        AttrEntry::new("italic", italic)
            .with_comment(["Italic face — same family slanted (ghostty's model)."]),
        AttrEntry::new("bold", bold)
            .with_comment(["Bold face — shares the primary package."]),
        AttrEntry::new("symbols", symbols)
            .with_comment(["Nerd Font icons (powerline / starship / atuin)."]),
        AttrEntry::new("emoji", emoji)
            .with_comment([
                "macOS uses Apple Color Emoji at the OS layer;",
                "Linux substitutes Noto Color Emoji (operator-installed).",
            ]),
        AttrEntry::new("fallback_chain", fallback_chain)
            .with_comment(["Ordered fallback list cosmic-text walks for missing codepoints."]),
    ]);

    let file = NixFile::new(
        [
            "Generated by ishou-render::fleet_fonts — DO NOT EDIT",
            "Source of truth: pleme-io/ishou/crates/ishou-tokens/src/typography.rs",
            "Architecture:    pleme-io/theory/THEME-ARCHITECTURE.md",
            "",
            "Consumed as `let fonts = import this { inherit pkgs; }; in …`",
            "by every pleme-io GPU app's HM module (mado, ghostty, fumi, …).",
        ],
        lambda(vec!["pkgs"], body),
    );

    file.render()
}

fn primary_pkg(mono: &MonoFonts) -> NixExpr {
    match mono.nerd_font_package_attr {
        Some(attr) => raw(format!("pkgs.nerd-fonts.{attr}")),
        None => NixExpr::Null,
    }
}

fn italic_pkg(mono: &MonoFonts) -> NixExpr {
    match mono.italic_package_attr {
        Some(attr) => raw(format!("pkgs.{attr}")),
        None => NixExpr::Null,
    }
}

fn italic_style_name(s: ItalicStyle) -> &'static str {
    match s {
        ItalicStyle::MatchesPrimary => "matches_primary",
        ItalicStyle::Calligraphic => "calligraphic",
        ItalicStyle::Cursive => "cursive",
    }
}

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

    #[test]
    fn output_is_deterministic() {
        let t = TokenSet::pleme();
        assert_eq!(render(&t), render(&t));
    }

    #[test]
    fn output_contains_all_canonical_slots() {
        let out = render(&TokenSet::pleme());
        for slot in ["primary", "italic", "bold", "symbols", "emoji", "fallback_chain"] {
            assert!(out.contains(&format!("{slot} = ")), "missing slot {slot}\n{out}");
        }
    }

    #[test]
    fn primary_pins_jetbrains_mono_nerd_font_with_correct_package() {
        let out = render(&TokenSet::pleme());
        assert!(out.contains("name = \"JetBrainsMono Nerd Font\""));
        assert!(out.contains("package = pkgs.nerd-fonts.jetbrains-mono"));
    }

    #[test]
    fn italic_carries_style_intent() {
        let out = render(&TokenSet::pleme());
        // Italics now slant the same JetBrainsMono face (ghostty's
        // model), so the intent is `matches_primary`, not a separate
        // calligraphic typeface.
        assert!(out.contains("style_intent = \"matches_primary\""));
    }

    #[test]
    fn symbols_slot_points_at_symbols_only_nerd_font() {
        let out = render(&TokenSet::pleme());
        assert!(out.contains("package = pkgs.nerd-fonts.symbols-only"));
    }

    #[test]
    fn header_documents_provenance() {
        let out = render(&TokenSet::pleme());
        assert!(out.contains("ishou-render::fleet_fonts"));
        assert!(out.contains("typography.rs"));
    }

    #[test]
    fn fallback_chain_is_emitted_in_order() {
        let out = render(&TokenSet::pleme());
        let ts = TokenSet::pleme();
        for name in ts.typography.mono_fonts.fallback {
            assert!(out.contains(&format!("\"{name}\"")), "missing fallback {name}");
        }
    }

    #[test]
    fn output_starts_with_pkgs_lambda() {
        let out = render(&TokenSet::pleme());
        // After the comment header, the first non-comment line should
        // be the lambda. Lambda printer renders `{ pkgs }:`.
        let body = out
            .lines()
            .find(|l| !l.starts_with('#'))
            .unwrap_or("");
        assert_eq!(body, "{ pkgs }:");
    }
}