dirge-agent 0.7.3

//! UI color theme.
//!
//! Centralizes semantic color choices (agent, tool, error, accent, …)
//! so the whole UI can swap palettes without rewriting call sites.
//! The active theme is selected at startup via `ui::theme::init` (from
//! the user's `theme = "..."` config) and read everywhere else through
//! the helper functions exposed at the bottom of this file.
//!
//! Currently shipping presets:
//! - `phosphor` (default) — CRT-green 80s-hacker palette. Errors stay
//!   red and warnings stay yellow so semantic urgency isn't sacrificed
//!   for aesthetics.
//! - `plain` — the pre-theme look (white assistant text, cyan accents).
//!   Use this if green-on-black hurts your eyes or clashes with your
//!   terminal background.
//!
//! ## Custom themes via `<name>.theme.json`
//!
//! Users can define their own palette by dropping a JSON file at
//! `~/.config/dirge/<name>.theme.json` and setting `theme = "<name>"`
//! in `config.json`. All theme fields are optional — fields not
//! present fall back to the phosphor preset, so a minimal override
//! file like `{"agent": "blue"}` works.
//!
//! Color values accept:
//! - Named colors: `"green"`, `"darkgreen"`, `"red"`, … (every
//!   crossterm `Color::<Name>` is accepted, case-insensitive).
//! - Hex RGB: `"#1a2b3c"`.
//! - 256-color palette index as a number: `42` (0..=255).
//!
//! Adding a built-in preset means appending a `pub const fn`-style
//! preset here and matching its name in `init` — no other code
//! changes needed.

use std::sync::OnceLock;

use crossterm::style::Color;
use serde::Deserialize;

/// Semantic colors for every role in the UI. Concrete colors are
/// chosen by the active preset; call sites should reach for the helper
/// functions below (`agent()`, `error()`, …) rather than poking the
/// struct directly so future additions stay backwards-compatible.
#[derive(Debug, Clone, Copy)]
pub struct Theme {
    /// Assistant chat text.
    pub agent: Color,
    /// User-message prefix (and prompt indicator).
    pub user: Color,
    /// System/info messages — context loaded, compactions, etc.
    pub system: Color,
    /// Tool execution headers (`bash:`, `read:`, …).
    pub tool: Color,
    /// Permission prompts. Stays loud (yellow/red family) because the
    /// user must notice — never go subtle here.
    pub perm: Color,
    /// Secondary result text (slash command output, tool stdout dim).
    pub result: Color,
    /// In-loop critic's review voice. Distinct from `user` so critic
    /// follow-ups aren't mistaken for the user's own messages.
    pub critic: Color,
    /// The agent's "thinking" register — the suppressed-reasoning
    /// placeholder, the (Ctrl+R) live reasoning stream, and the Ctrl+O
    /// expansion. Deliberately soft/recessive: it's transient, low-priority
    /// context that must never compete with the agent's actual prose.
    pub thinking: Color,
    /// Hard errors. Always red-family; theme can choose the exact red
    /// but must keep it semantically distinct from everything else.
    pub error: Color,
    /// Warnings. Yellow-family; same rule as `error`.
    pub warn: Color,
    /// Headers, focused picker rows, banner accent. The "look at this"
    /// color.
    pub accent: Color,
    /// Dim auxiliary text — placeholders, separators, low-noise hints.
    pub dim: Color,
    /// Panel headers in the right-hand info panel.
    pub header: Color,
    /// Horizontal divider line color.
    pub divider: Color,
    /// Welcome-banner primary stroke.
    pub banner_primary: Color,
    /// Welcome-banner secondary stroke (border, decorations).
    pub banner_secondary: Color,
    /// Terminal background fill. Painted behind every cell (foregrounds
    /// preserved). `Color::Reset` keeps the terminal's own default background
    /// (no fill) — the right choice for `plain` and for users on a custom
    /// terminal palette who don't want dirge overriding it.
    pub background: Color,
    /// Human-readable name surfaced in the banner ("PHOSPHOR", "PLAIN").
    pub label: &'static str,
}

impl Theme {
    /// 80s-CRT phosphor green — a modern, cohesive take. Anchored on the
    /// bright phosphor green of the agent's prose, with a low-saturation
    /// surface around it. Two axes carry meaning so the log is readable at
    /// a glance:
    ///   - HUE = action type, so peripheral vision recognizes a message's
    ///     kind without reading it: green = the agent, cyan = you, teal =
    ///     tools, lavender = the critic, amber = needs-you (perms/warnings),
    ///     red = errors.
    ///   - BRIGHTNESS = importance, so the eye is pulled to what matters:
    ///     the loud warm signals (error/perm) and the agent's answer are
    ///     brightest; supporting detail (tool output, system/thinking
    ///     notes) is muted; chrome (dim/divider) barely registers.
    ///     Saturation stays low everywhere EXCEPT the warm urgency signals,
    ///     which keep their vividness so they pop off the green/cyan field.
    pub const fn phosphor() -> Self {
        Theme {
            // GREEN — the agent's prose. Focal point; brightest content color.
            agent: Color::Rgb {
                r: 138,
                g: 232,
                b: 156,
            },
            // CYAN — your messages. Cool complement to green; bright enough
            // to scan your own turns, clearly distinct from the agent.
            user: Color::Rgb {
                r: 125,
                g: 205,
                b: 210,
            },
            // Muted green-grey — system / info notes ("context loaded",
            // compactions). Supporting; recedes below the conversation.
            system: Color::Rgb {
                r: 106,
                g: 140,
                b: 120,
            },
            // TEAL — tool headers ("what's running"). In the agent's green
            // family (a tool is the agent acting) but cooler so it reads as
            // activity, not answer; brighter than its own output below.
            tool: Color::Rgb {
                r: 108,
                g: 188,
                b: 150,
            },
            // AMBER — permission prompts. Needs YOU: warm + bright so it
            // jumps off the green field and demands a glance.
            perm: Color::Rgb {
                r: 255,
                g: 185,
                b: 85,
            },
            // Dim green — tool OUTPUT body. Readable, but well below the
            // header: the result is detail, the header is the headline.
            result: Color::Rgb {
                r: 118,
                g: 158,
                b: 132,
            },
            // LAVENDER — the critic's review voice. Off the green/cyan axis
            // so it instantly reads as "a different speaker"; mid brightness.
            critic: Color::Rgb {
                r: 186,
                g: 166,
                b: 216,
            },
            // Soft green-grey — the thinking register. Quiet background that
            // never competes with the answer.
            thinking: Color::Rgb {
                r: 128,
                g: 150,
                b: 140,
            },
            // RED — errors. The loudest thing on screen; the eye must snap
            // to it. The one place we keep high saturation AND brightness.
            error: Color::Rgb {
                r: 255,
                g: 95,
                b: 90,
            },
            // Muted amber — warnings. Same warm "attention" hue as perms,
            // dimmer: notable, not act-now.
            warn: Color::Rgb {
                r: 212,
                g: 168,
                b: 96,
            },
            // Light green — accents / focused picker rows / strings in code.
            // Distinct from `header` so highlighted strings ≠ types.
            accent: Color::Rgb {
                r: 158,
                g: 238,
                b: 172,
            },
            // Dark green-grey — low-noise auxiliary text + comments; recedes hard.
            dim: Color::Rgb {
                r: 86,
                g: 116,
                b: 96,
            },
            // Vivid green — panel headers + code types; a scan target.
            header: Color::Rgb {
                r: 96,
                g: 220,
                b: 140,
            },
            // Dimmest green — separators; barely registers.
            divider: Color::Rgb {
                r: 72,
                g: 98,
                b: 82,
            },
            banner_primary: Color::Rgb {
                r: 138,
                g: 232,
                b: 156,
            },
            banner_secondary: Color::Rgb {
                r: 86,
                g: 116,
                b: 96,
            },
            // Near-black charcoal (#222) instead of pure terminal black — gives
            // the phosphor green a touch of CRT-bezel depth without washing out.
            background: Color::Rgb {
                r: 0x22,
                g: 0x22,
                b: 0x22,
            },
            label: "PHOSPHOR",
        }
    }

    /// Pre-theme look. Use this when the green doesn't suit your
    /// terminal background or you just want the boring default.
    pub const fn plain() -> Self {
        Theme {
            agent: Color::White,
            user: Color::Green,
            system: Color::DarkGrey,
            tool: Color::Yellow,
            perm: Color::Magenta,
            result: Color::DarkGrey,
            // Blue — distinct from plain's Magenta(perm)/Green(user)/Cyan(accent).
            critic: Color::Blue,
            // Soft grey-blue: recessive, distinct from the dim-grey `dim`.
            thinking: Color::Rgb {
                r: 140,
                g: 140,
                b: 155,
            },
            error: Color::Red,
            warn: Color::Yellow,
            accent: Color::Cyan,
            dim: Color::DarkGrey,
            header: Color::Cyan,
            divider: Color::DarkGrey,
            banner_primary: Color::Cyan,
            banner_secondary: Color::DarkGrey,
            // Keep the terminal's own background — `plain` shouldn't override it.
            background: Color::Reset,
            label: "PLAIN",
        }
    }
}

/// JSON shape for `<name>.theme.json` overrides. Every field is
/// optional; absent fields inherit from the base preset
/// (phosphor). Color values accept named colors, hex strings, or
/// 256-color palette indices — see `parse_color_value`.
#[derive(Deserialize, Default, Debug)]
#[serde(default, deny_unknown_fields)]
struct ThemeJson {
    agent: Option<ColorValue>,
    user: Option<ColorValue>,
    system: Option<ColorValue>,
    tool: Option<ColorValue>,
    perm: Option<ColorValue>,
    result: Option<ColorValue>,
    critic: Option<ColorValue>,
    thinking: Option<ColorValue>,
    error: Option<ColorValue>,
    warn: Option<ColorValue>,
    accent: Option<ColorValue>,
    dim: Option<ColorValue>,
    header: Option<ColorValue>,
    divider: Option<ColorValue>,
    banner_primary: Option<ColorValue>,
    banner_secondary: Option<ColorValue>,
    background: Option<ColorValue>,
    label: Option<String>,
}

/// Polymorphic color value: name string, hex `"#rrggbb"`, or
/// 256-color palette index `0..=255`. Custom deserializer below.
#[derive(Debug)]
struct ColorValue(Color);

impl<'de> Deserialize<'de> for ColorValue {
    fn deserialize<D: serde::Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
        use serde::de::Error;
        let v = serde_json::Value::deserialize(d)?;
        match v {
            serde_json::Value::String(s) => parse_color_value(&s)
                .map(ColorValue)
                .map_err(D::Error::custom),
            serde_json::Value::Number(n) => {
                let n = n.as_u64().ok_or_else(|| {
                    D::Error::custom("color index must be a non-negative integer 0..=255")
                })?;
                if n > 255 {
                    return Err(D::Error::custom("color index out of range 0..=255"));
                }
                Ok(ColorValue(Color::AnsiValue(n as u8)))
            }
            other => Err(D::Error::custom(format!(
                "color must be a name string, hex string, or 0..=255 integer; got {other:?}"
            ))),
        }
    }
}

/// Parse a color name or hex string. Names match crossterm's
/// `Color::<Name>` variants case-insensitively; `_` and `-`
/// separators are both accepted (`"dark_red"` == `"dark-red"` ==
/// `"darkred"`). Hex form is `"#rrggbb"`.
fn parse_color_value(raw: &str) -> Result<Color, String> {
    let s = raw.trim();
    if let Some(hex) = s.strip_prefix('#') {
        if hex.len() != 6 {
            return Err(format!(
                "hex color must be `#rrggbb` (6 hex digits); got `{}`",
                raw
            ));
        }
        let r = u8::from_str_radix(&hex[0..2], 16).map_err(|e| format!("bad red byte: {e}"))?;
        let g = u8::from_str_radix(&hex[2..4], 16).map_err(|e| format!("bad green byte: {e}"))?;
        let b = u8::from_str_radix(&hex[4..6], 16).map_err(|e| format!("bad blue byte: {e}"))?;
        return Ok(Color::Rgb { r, g, b });
    }
    // Normalize: lowercase, strip `_` and `-` so "dark_red", "dark-red"
    // and "darkred" all match.
    let key: String = s
        .chars()
        .filter(|c| *c != '_' && *c != '-')
        .map(|c| c.to_ascii_lowercase())
        .collect();
    Ok(match key.as_str() {
        "black" => Color::Black,
        "darkgrey" | "darkgray" => Color::DarkGrey,
        "red" => Color::Red,
        "darkred" => Color::DarkRed,
        "green" => Color::Green,
        "darkgreen" => Color::DarkGreen,
        "yellow" => Color::Yellow,
        "darkyellow" => Color::DarkYellow,
        "blue" => Color::Blue,
        "darkblue" => Color::DarkBlue,
        "magenta" => Color::Magenta,
        "darkmagenta" => Color::DarkMagenta,
        "cyan" => Color::Cyan,
        "darkcyan" => Color::DarkCyan,
        "white" => Color::White,
        "grey" | "gray" => Color::Grey,
        "reset" => Color::Reset,
        _ => return Err(format!("unknown color name: {raw}")),
    })
}

impl ThemeJson {
    /// Apply override fields onto `base`. Each `Some` field replaces
    /// the corresponding base color; `None` keeps the base value.
    /// `label` comes from the caller (filename-derived or
    /// JSON-supplied) — already-leaked `&'static str` so the
    /// resulting Theme stays Copy.
    fn merge_into(self, base: Theme, label: &'static str) -> Result<Theme, String> {
        let pick = |o: Option<ColorValue>, b: Color| match o {
            Some(c) => c.0,
            None => b,
        };
        Ok(Theme {
            agent: pick(self.agent, base.agent),
            user: pick(self.user, base.user),
            system: pick(self.system, base.system),
            tool: pick(self.tool, base.tool),
            perm: pick(self.perm, base.perm),
            result: pick(self.result, base.result),
            critic: pick(self.critic, base.critic),
            thinking: pick(self.thinking, base.thinking),
            error: pick(self.error, base.error),
            warn: pick(self.warn, base.warn),
            accent: pick(self.accent, base.accent),
            dim: pick(self.dim, base.dim),
            header: pick(self.header, base.header),
            divider: pick(self.divider, base.divider),
            banner_primary: pick(self.banner_primary, base.banner_primary),
            banner_secondary: pick(self.banner_secondary, base.banner_secondary),
            background: pick(self.background, base.background),
            label,
        })
    }
}

/// Global theme set once at startup. Defaults to `phosphor` if `init`
/// is never called (handy for tests + the `--no-tools` no-UI mode).
static THEME: OnceLock<Theme> = OnceLock::new();

/// Initialize the global theme from a name. Resolution order:
/// 1. Built-in: `phosphor` (default), `plain`.
/// 2. Custom JSON: `~/.config/dirge/<name>.theme.json`. Fields not
///    present in the file inherit from phosphor — minimal overrides
///    are encouraged (e.g. `{"accent": "magenta"}`).
/// 3. Fallback: phosphor with a stderr warning if neither matched.
///
/// Safe to call once; subsequent calls are ignored (`OnceLock`).
pub fn init(name: &str) {
    let theme = match name.to_ascii_lowercase().as_str() {
        "phosphor" | "" => Theme::phosphor(),
        "plain" => Theme::plain(),
        other => load_custom_theme(other).unwrap_or_else(|err| {
            eprintln!(
                "warning: theme '{}' could not be loaded ({}); using phosphor.\n\
                 Custom themes live at ~/.config/dirge/<name>.theme.json.",
                other, err,
            );
            Theme::phosphor()
        }),
    };
    let _ = THEME.set(theme);
}

/// Try to load `~/.config/dirge/<name>.theme.json` and merge its
/// fields over the phosphor preset. Returns Err with a
/// human-readable message when:
/// - The file doesn't exist.
/// - The JSON fails to parse.
/// - A color value is unrecognized.
fn load_custom_theme(name: &str) -> Result<Theme, String> {
    let path = crate::session::storage::config_path().join(format!("{name}.theme.json"));
    if !path.exists() {
        return Err(format!("no such file: {}", path.display()));
    }
    let raw =
        std::fs::read_to_string(&path).map_err(|e| format!("read {}: {e}", path.display()))?;
    let overrides: ThemeJson =
        serde_json::from_str(&raw).map_err(|e| format!("parse {}: {e}", path.display()))?;
    // Label defaults to the filename's stem in uppercase if the JSON
    // doesn't specify one. Leak the string so the global Theme
    // stays `&'static str` and `Copy`-able — one leak per process
    // is negligible (a few dozen bytes once at startup).
    let label_str = overrides
        .label
        .clone()
        .unwrap_or_else(|| name.to_ascii_uppercase());
    let label: &'static str = Box::leak(label_str.into_boxed_str());
    overrides.merge_into(Theme::phosphor(), label)
}

/// Read the active theme. Lazy-initializes to `phosphor` if no `init`
/// call has happened (the happy path during `cargo test`).
pub fn current() -> &'static Theme {
    THEME.get_or_init(Theme::phosphor)
}

/// Global `--no-color` flag (https://no-color.org). Set once at startup next
/// to [`init`]; when on, every accessor below collapses to `Color::Reset` so
/// the *entire* TUI — scene, panels, chat, banner, tool output — paints in the
/// terminal's default foreground, not just the two legacy write_line sites that
/// used to honor it [dirge-zrda].
static NO_COLOR: OnceLock<bool> = OnceLock::new();

/// Initialize the no-color flag (set-once, like [`init`]). Call from `main`
/// right after `theme::init`.
pub fn init_no_color(enabled: bool) {
    let _ = NO_COLOR.set(enabled);
}

/// Whether `--no-color` is active. Defaults to `false` when never set (tests,
/// library use).
#[inline]
pub fn no_color() -> bool {
    NO_COLOR.get().copied().unwrap_or(false)
}

/// Pure no-color collapse — split from [`themed`] so it's testable without the
/// set-once global. `Color::Reset` is the terminal's default foreground.
#[inline]
fn apply_no_color(c: Color, no_color: bool) -> Color {
    if no_color { Color::Reset } else { c }
}

/// Collapse a themed color to the terminal default when `--no-color` is on.
/// Standard NO_COLOR semantics suppress *all* color; error/warning text stays
/// legible via its own prefix/glyph, so they don't need to stay loud.
#[inline]
fn themed(c: Color) -> Color {
    apply_no_color(c, no_color())
}

// Convenience accessors. Call sites use these instead of touching the
// struct so renaming/restructuring fields in `Theme` doesn't ripple
// across the codebase. Each routes through `themed()` so `--no-color`
// is honored at this single chokepoint.

pub fn agent() -> Color {
    themed(current().agent)
}
pub fn user() -> Color {
    themed(current().user)
}
pub fn system() -> Color {
    themed(current().system)
}
pub fn tool() -> Color {
    themed(current().tool)
}
pub fn perm() -> Color {
    themed(current().perm)
}
pub fn result() -> Color {
    themed(current().result)
}
pub fn critic() -> Color {
    themed(current().critic)
}
pub fn thinking() -> Color {
    themed(current().thinking)
}
pub fn error() -> Color {
    themed(current().error)
}
pub fn warn() -> Color {
    themed(current().warn)
}
pub fn accent() -> Color {
    themed(current().accent)
}
pub fn dim() -> Color {
    themed(current().dim)
}
pub fn header() -> Color {
    themed(current().header)
}
pub fn divider() -> Color {
    themed(current().divider)
}
pub fn banner_primary() -> Color {
    themed(current().banner_primary)
}
pub fn banner_secondary() -> Color {
    themed(current().banner_secondary)
}
pub fn background() -> Color {
    themed(current().background)
}

/// Whether the given color should render with the Bold attribute to
/// fake the CRT phosphor "bloom" effect. Bright phosphor tones glow;
/// dim secondary tones stay un-bloomed so the two-tone depth in the
/// reference screenshots is preserved.
///
/// Custom themes (PR #102) can use `Color::Rgb { r, g, b }` and
/// `Color::AnsiValue(u8)`. Without per-color brightness detection
/// those rendered as dim because the original `matches!` only
/// covered the 16-color named palette — a user theme with
/// `#ff00ff` (vibrant magenta) was treated as dim and lost its
/// bold attribute.
#[allow(dead_code)]
pub fn is_bright(c: Color) -> bool {
    match c {
        Color::Green
        | Color::Red
        | Color::Yellow
        | Color::Cyan
        | Color::Magenta
        | Color::Blue
        | Color::White => true,
        // Use max-channel rather than luminance: terminal "bright"
        // means visually-saturated, and a vibrant magenta
        // (#ff00ff, lum ≈ 105) is intuitively bright even though
        // BT.601 luminance puts it below the halfway mark. Max-
        // channel correctly catches pure red / blue / magenta in
        // addition to white / yellow.
        Color::Rgb { r, g, b } => r.max(g).max(b) > 128,
        // 256-color palette: 0..=7 dim, 8..=15 bright, 16..=231 6×6×6
        // RGB cube where the higher half is bright, 232..=255 grayscale
        // ramp where the top half is bright. This is a coarse but
        // reasonable mapping — perfect accuracy would require looking
        // up the exact xterm palette.
        Color::AnsiValue(v) => match v {
            0..=7 => false,
            8..=15 => true,
            16..=231 => {
                // 6×6×6 RGB cube starts at 16. Compute approximate
                // average of the three channels in [0..=5].
                let n = v - 16;
                let r = n / 36;
                let g = (n / 6) % 6;
                let b = n % 6;
                (r + g + b) as u32 > 7 // > half of max 15
            }
            232..=255 => v >= 244, // grayscale: top half = bright
        },
        _ => false,
    }
}

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

    /// dirge-zrda: `--no-color` collapses every themed color to the terminal
    /// default; without it, colors pass through untouched. This is the single
    /// chokepoint every theme accessor routes through.
    #[test]
    fn apply_no_color_collapses_only_when_enabled() {
        assert_eq!(apply_no_color(Color::Green, true), Color::Reset);
        assert_eq!(
            apply_no_color(Color::Rgb { r: 1, g: 2, b: 3 }, true),
            Color::Reset
        );
        assert_eq!(apply_no_color(Color::Green, false), Color::Green);
        assert_eq!(
            apply_no_color(Color::Rgb { r: 1, g: 2, b: 3 }, false),
            Color::Rgb { r: 1, g: 2, b: 3 }
        );
    }

    /// `phosphor` and `plain` differ in their agent color — quick
    /// sanity check that the presets aren't accidentally identical.
    /// Regression: `is_bright` must handle `Color::Rgb` and
    /// `Color::AnsiValue` introduced by PR #102's custom theme
    /// JSON. Without this, vibrant RGB colors in a user theme
    /// rendered dim because the original `matches!` only covered
    /// the named 16-color palette.
    #[test]
    fn is_bright_handles_rgb_and_ansivalue() {
        // RGB: bright magenta should glow.
        assert!(is_bright(Color::Rgb {
            r: 255,
            g: 0,
            b: 255,
        }));
        // RGB: deep navy should not.
        assert!(!is_bright(Color::Rgb { r: 0, g: 0, b: 32 }));
        // AnsiValue: low (0..=7) = dim; high (8..=15) = bright.
        assert!(!is_bright(Color::AnsiValue(0)));
        assert!(is_bright(Color::AnsiValue(15)));
        // 6x6x6 cube — saturated yellow ~226 is bright.
        assert!(is_bright(Color::AnsiValue(226)));
        // Grayscale ramp — 232 darkest, 255 lightest.
        assert!(!is_bright(Color::AnsiValue(232)));
        assert!(is_bright(Color::AnsiValue(255)));
    }

    #[test]
    fn presets_are_distinct() {
        assert_ne!(Theme::phosphor().agent, Theme::plain().agent);
        assert_ne!(Theme::phosphor().accent, Theme::plain().accent);
    }

    /// Errors and warnings must stay in the red/yellow family across
    /// every preset — that's the load-bearing semantic contract.
    #[test]
    fn error_and_warn_stay_loud() {
        // The contract is semantic, not a specific palette entry: errors
        // must read red-family and warnings amber/warm, however the theme
        // expresses it (named ANSI or a custom RGB tone).
        fn is_reddish(c: Color) -> bool {
            match c {
                Color::Red | Color::DarkRed => true,
                Color::Rgb { r, g, b } => r > 180 && r >= g + 40 && r >= b + 40,
                _ => false,
            }
        }
        fn is_amber(c: Color) -> bool {
            match c {
                Color::Yellow | Color::DarkYellow => true,
                // Warm: red + green high, blue low (amber/gold).
                Color::Rgb { r, g, b } => r >= 160 && g >= 120 && r >= g && b + 40 <= g,
                _ => false,
            }
        }
        for t in [Theme::phosphor(), Theme::plain()] {
            assert!(
                is_reddish(t.error),
                "theme {} broke error contract",
                t.label
            );
            assert!(is_amber(t.warn), "theme {} broke warn contract", t.label);
        }
    }

    /// `init` with an unknown name does not panic and the theme still
    /// resolves (falls back to phosphor).
    #[test]
    fn init_with_unknown_name_falls_back() {
        // Can't actually call init() — it's OnceLock-backed and a
        // prior test may have already set the global. Instead verify
        // `current()` resolves without panicking and has a label.
        let t = current();
        assert!(!t.label.is_empty());
    }

    // ---- Custom theme file loading (`<name>.theme.json`) ----

    #[test]
    fn parse_color_value_named() {
        assert!(matches!(parse_color_value("green"), Ok(Color::Green)));
        assert!(matches!(parse_color_value("GREEN"), Ok(Color::Green)));
        assert!(matches!(parse_color_value("DarkRed"), Ok(Color::DarkRed)));
        // `_` and `-` separators normalize away.
        assert!(matches!(parse_color_value("dark_red"), Ok(Color::DarkRed)));
        assert!(matches!(parse_color_value("dark-red"), Ok(Color::DarkRed)));
        // Both Grey spellings.
        assert!(matches!(parse_color_value("gray"), Ok(Color::Grey)));
        assert!(matches!(parse_color_value("grey"), Ok(Color::Grey)));
    }

    #[test]
    fn parse_color_value_hex_rgb() {
        let c = parse_color_value("#1a2b3c").unwrap();
        assert!(matches!(
            c,
            Color::Rgb {
                r: 0x1a,
                g: 0x2b,
                b: 0x3c,
            }
        ));
        // Uppercase hex digits work too.
        assert!(parse_color_value("#FFFFFF").is_ok());
    }

    #[test]
    fn parse_color_value_hex_must_be_6_digits() {
        assert!(parse_color_value("#abc").is_err());
        assert!(parse_color_value("#1234567").is_err());
        assert!(parse_color_value("#xx1234").is_err());
    }

    #[test]
    fn parse_color_value_rejects_unknown_name() {
        assert!(parse_color_value("eggplant").is_err());
        assert!(parse_color_value("").is_err());
    }

    /// Theme JSON with partial fields merges over phosphor base.
    /// The file `{"agent": "blue"}` only changes `agent`; everything
    /// else stays phosphor.
    #[test]
    fn theme_json_partial_override_inherits_base() {
        let json = r#"{"agent": "blue"}"#;
        let overrides: ThemeJson = serde_json::from_str(json).unwrap();
        let base = Theme::phosphor();
        let theme = overrides.merge_into(base, "TEST").unwrap();
        assert!(matches!(theme.agent, Color::Blue), "agent overridden");
        // Everything else stays exactly the base preset's value (compare to
        // the preset, not a hardcoded color, so the test survives palette
        // tuning).
        assert_eq!(theme.error, base.error, "error unchanged");
        assert_eq!(theme.warn, base.warn, "warn unchanged");
        assert_eq!(theme.user, base.user, "user unchanged");
    }

    /// All-fields override produces a fully custom theme.
    #[test]
    fn theme_json_full_override_replaces_all_fields() {
        let json = r#"{
            "agent": "red",
            "user": "green",
            "system": "yellow",
            "tool": "blue",
            "perm": "magenta",
            "result": "cyan",
            "critic": "blue",
            "thinking": "darkgrey",
            "error": "darkred",
            "warn": "darkyellow",
            "accent": "white",
            "dim": "darkgrey",
            "header": "darkcyan",
            "divider": "darkgreen",
            "banner_primary": "darkblue",
            "banner_secondary": "darkmagenta",
            "label": "MIDNIGHT"
        }"#;
        let overrides: ThemeJson = serde_json::from_str(json).unwrap();
        let theme = overrides.merge_into(Theme::phosphor(), "MIDNIGHT").unwrap();
        assert!(matches!(theme.agent, Color::Red));
        assert!(matches!(theme.error, Color::DarkRed));
        assert!(matches!(theme.banner_primary, Color::DarkBlue));
        // The newer roles (critic, thinking) are config-themeable too.
        assert!(matches!(theme.critic, Color::Blue));
        assert!(matches!(theme.thinking, Color::DarkGrey));
        assert_eq!(theme.label, "MIDNIGHT");
    }

    /// Hex-color overrides flow through the parser.
    #[test]
    fn theme_json_accepts_hex_colors() {
        let json = r##"{"accent": "#ff8800"}"##;
        let overrides: ThemeJson = serde_json::from_str(json).unwrap();
        let theme = overrides.merge_into(Theme::phosphor(), "T").unwrap();
        assert!(matches!(
            theme.accent,
            Color::Rgb {
                r: 0xff,
                g: 0x88,
                b: 0x00,
            }
        ));
    }

    /// AnsiValue indices (256-color palette) parse.
    #[test]
    fn theme_json_accepts_ansi_value() {
        let json = r#"{"accent": 42}"#;
        let overrides: ThemeJson = serde_json::from_str(json).unwrap();
        let theme = overrides.merge_into(Theme::phosphor(), "T").unwrap();
        assert!(matches!(theme.accent, Color::AnsiValue(42)));
    }

    /// Unknown color name surfaces a parse error.
    #[test]
    fn theme_json_unknown_color_name_errors() {
        let json = r#"{"agent": "eggplant"}"#;
        let r: Result<ThemeJson, _> = serde_json::from_str(json);
        assert!(r.is_err(), "expected parse error for unknown color");
    }

    /// Unknown fields error out rather than silently being ignored —
    /// catches typos like `"acccent"` instead of `"accent"`.
    #[test]
    fn theme_json_unknown_field_errors() {
        let json = r#"{"acccent": "blue"}"#;
        let r: Result<ThemeJson, _> = serde_json::from_str(json);
        assert!(r.is_err(), "expected error for misspelled field");
    }

    /// `load_custom_theme` returns an Err with the file path when the
    /// file is missing — the path appears in the warning emitted by
    /// `init`, helping users find what dirge is looking for.
    #[test]
    fn load_custom_theme_missing_file_includes_path() {
        // Use a definitely-nonexistent theme name. The function
        // looks up `config_path()/<name>.theme.json` — even if
        // somebody has dirge configured, this name won't collide.
        let err = load_custom_theme("__definitely_not_a_real_theme_xyz")
            .expect_err("missing file must error");
        assert!(
            err.contains("__definitely_not_a_real_theme_xyz") || err.contains("no such file"),
            "error should reference the path or 'no such file': {err}",
        );
    }
}