//! Theme and colour palette. //! //! Two themes are provided — one for light terminal backgrounds //! and one for dark — per NFR-7. The palette is intentionally //! small for the walking skeleton; it grows as more views are //! added. Contrast is chosen against the target background so //! that foreground text meets WCAG-AA (NFR-5) on both variants. //! //! Per-token-class colours (the `tok_*` fields) drive ambient //! typing assistance (ADR-0022 §3). Each token class has a //! distinct colour so the user can tell keywords from //! identifiers from string literals at a glance, with punct and //! identifier intentionally close to `fg` to keep the surface //! quiet for the dominant content. The `tok_error` colour //! reuses the existing error palette so lex-error tokens and //! parse-error overlays read consistently with `[error]` //! lines elsewhere. use ratatui::style::Color; use crate::dsl::grammar::HighlightClass; #[derive(Debug, Clone, Copy, PartialEq, Eq)] pub enum Background { Light, Dark, } #[derive(Debug, Clone)] pub struct Theme { pub background: Background, pub bg: Color, pub fg: Color, pub muted: Color, pub border: Color, pub border_advanced: Color, pub mode_simple: Color, pub mode_advanced: Color, pub system: Color, pub error: Color, /// Validity-indicator WARNING colour (ADR-0027 §4) — an /// amber distinct from `error`'s red. Drives the `[WRN]` /// label; `[ERR]` reuses `error`. pub warning: Color, // ---- Per-token-class colours (ADR-0022 §3) ------------------- pub tok_keyword: Color, pub tok_identifier: Color, pub tok_number: Color, pub tok_string: Color, pub tok_punct: Color, pub tok_flag: Color, pub tok_error: Color, } impl Theme { #[must_use] pub const fn dark() -> Self { Self { background: Background::Dark, bg: Color::Rgb(0x18, 0x1B, 0x22), fg: Color::Rgb(0xE6, 0xE6, 0xE6), muted: Color::Rgb(0x8B, 0x90, 0x9A), border: Color::Rgb(0x4A, 0x52, 0x65), border_advanced: Color::Rgb(0xE0, 0x60, 0x60), mode_simple: Color::Rgb(0x6E, 0xC4, 0xFF), mode_advanced: Color::Rgb(0xFF, 0x9E, 0x6B), system: Color::Rgb(0x9F, 0xD8, 0x91), error: Color::Rgb(0xFF, 0x6B, 0x6B), warning: Color::Rgb(0xF5, 0xA9, 0x4B), // amber // Token classes — distinct enough to tell apart at a // glance, quiet enough that 80-char lines don't read // like a Christmas tree. Identifier and punct sit // close to `fg`/`muted` so the dominant content // remains restful; literals and flags get warm // accent tones; keyword takes a cool accent tone // distinct from the mode-banner blue. tok_keyword: Color::Rgb(0xC7, 0x92, 0xEA), // muted purple tok_identifier: Color::Rgb(0x56, 0xB6, 0xC2), // cyan-teal — identifiers are the user's content, deserve a vivid distinct colour tok_number: Color::Rgb(0xF7, 0x8C, 0x6C), // warm orange tok_string: Color::Rgb(0xC3, 0xE8, 0x8D), // soft green tok_punct: Color::Rgb(0x8B, 0x90, 0x9A), // == muted tok_flag: Color::Rgb(0xFF, 0xCB, 0x6B), // amber tok_error: Color::Rgb(0xFF, 0x6B, 0x6B), // == error } } #[must_use] pub const fn light() -> Self { Self { background: Background::Light, bg: Color::Rgb(0xFA, 0xFA, 0xF7), fg: Color::Rgb(0x1A, 0x1F, 0x2C), muted: Color::Rgb(0x60, 0x66, 0x73), border: Color::Rgb(0xB6, 0xBC, 0xC8), border_advanced: Color::Rgb(0xC2, 0x3A, 0x3A), mode_simple: Color::Rgb(0x21, 0x69, 0xC7), mode_advanced: Color::Rgb(0xB0, 0x4A, 0x12), system: Color::Rgb(0x2E, 0x7C, 0x3C), error: Color::Rgb(0xC0, 0x39, 0x2B), warning: Color::Rgb(0xA6, 0x5A, 0x00), // burnt amber // Light-theme token palette: same intent as dark — // identifier/punct close to fg/muted; warm tones for // literals + flags; cool accent for keyword. tok_keyword: Color::Rgb(0x6F, 0x42, 0xC1), // royal purple tok_identifier: Color::Rgb(0x0F, 0x6B, 0x76), // deep teal — same role as dark variant: identifiers stand out tok_number: Color::Rgb(0xBC, 0x4F, 0x1F), // burnt orange tok_string: Color::Rgb(0x22, 0x86, 0x3A), // forest green tok_punct: Color::Rgb(0x60, 0x66, 0x73), // == muted tok_flag: Color::Rgb(0xB0, 0x88, 0x00), // mustard tok_error: Color::Rgb(0xC0, 0x39, 0x2B), // == error } } /// Map a walker `HighlightClass` to its display colour /// (ADR-0024 §architecture, Phase F). This is the walker-side /// equivalent of `token_color` — the renderer consumes /// `walker::highlight_runs` output, which produces /// `HighlightClass` per byte range, and looks up colours /// through this method. #[must_use] pub const fn highlight_class_color(&self, class: HighlightClass) -> Color { match class { HighlightClass::Keyword => self.tok_keyword, HighlightClass::Identifier => self.tok_identifier, HighlightClass::Number => self.tok_number, HighlightClass::String => self.tok_string, HighlightClass::Punct => self.tok_punct, HighlightClass::Flag => self.tok_flag, HighlightClass::Error => self.tok_error, } } } impl Default for Theme { fn default() -> Self { Self::dark() } } #[cfg(test)] mod tests { use super::*; #[test] fn dark_theme_token_colours_differ_from_background() { let t = Theme::dark(); for (name, c) in [ ("tok_keyword", t.tok_keyword), ("tok_number", t.tok_number), ("tok_string", t.tok_string), ("tok_flag", t.tok_flag), ("tok_error", t.tok_error), ("warning", t.warning), ] { assert_ne!( c, t.bg, "{name} must contrast against bg in dark theme", ); } } #[test] fn light_theme_token_colours_differ_from_background() { let t = Theme::light(); for (name, c) in [ ("tok_keyword", t.tok_keyword), ("tok_number", t.tok_number), ("tok_string", t.tok_string), ("tok_flag", t.tok_flag), ("tok_error", t.tok_error), ("warning", t.warning), ] { assert_ne!( c, t.bg, "{name} must contrast against bg in light theme", ); } } #[test] fn highlight_class_color_maps_each_variant() { let t = Theme::dark(); assert_eq!(t.highlight_class_color(HighlightClass::Keyword), t.tok_keyword); assert_eq!(t.highlight_class_color(HighlightClass::Identifier), t.tok_identifier); assert_eq!(t.highlight_class_color(HighlightClass::Number), t.tok_number); assert_eq!(t.highlight_class_color(HighlightClass::String), t.tok_string); assert_eq!(t.highlight_class_color(HighlightClass::Punct), t.tok_punct); assert_eq!(t.highlight_class_color(HighlightClass::Flag), t.tok_flag); assert_eq!(t.highlight_class_color(HighlightClass::Error), t.tok_error); } }