//! Render-side helpers for the input panel
//! (ADR-0022 stage 2 — token-class colouring of the live
//! input field with cursor injection).
//!
//! The functions here are pure: given an input string, a
//! cursor byte position, and a theme, they return a sequence
//! of `StyledRun`s describing each contiguous span with its
//! ratatui style. `ui::render_input_panel` converts these to
//! `Span<'_>`s at render time.
//!
//! Cursor handling:
//!   - Cursor inside a token splits that token's run into
//!     before/under/after, with `under` carrying the token's
//!     colour plus `Modifier::REVERSED`.
//!   - Cursor on a whitespace gap between tokens splits the
//!     gap the same way.
//!   - Cursor at end-of-input is represented as a trailing
//!     run with empty byte range; the renderer treats that as
//!     "inverted space".
//!
//! Per ADR-0022 §2/§3, this is the silent always-on layer.
//! The error overlay (stage 4) and hint panel (stage 5)
//! compose with these runs without fighting them.

use ratatui::style::{Modifier, Style};

use crate::dsl::lexer::lex;
use crate::dsl::{ParseError, parse_command};
use crate::theme::Theme;

/// A run of text with its byte range in the source and the
/// ratatui style it should render with. The text itself is
/// not stored — callers slice `source[byte_range.0..byte_range.1]`.
///
/// An empty byte range (`(n, n)`) represents the end-of-input
/// cursor and is rendered as an inverted space.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct StyledRun {
    pub byte_range: (usize, usize),
    pub style: Style,
}

impl StyledRun {
    /// The text this run covers in `source`. Empty for the
    /// end-of-input cursor sentinel.
    #[must_use]
    pub fn text<'a>(&self, source: &'a str) -> &'a str {
        &source[self.byte_range.0..self.byte_range.1]
    }
}

/// Build the run sequence for the input panel.
///
/// Lexes `input`, assigns each token its `theme.token_color`,
/// applies the parse-error overlay if the input is in the
/// definite-error state (ADR-0022 §1, §4), applies the
/// invalid-identifier overlay if the cursor is in a known-set
/// slot with no schema match (stage 8e), preserves whitespace
/// gaps as `theme.fg` runs, then injects the cursor at
/// `cursor_byte` (clamped to `input.len()`).
#[must_use]
pub fn render_input_runs(
    input: &str,
    cursor_byte: usize,
    theme: &Theme,
    cache: &crate::completion::SchemaCache,
) -> Vec<StyledRun> {
    let mut runs = lex_to_runs(input, theme);
    if let InputState::DefiniteErrorAt(pos) = classify_input(input) {
        overlay_error(&mut runs, pos, theme);
    }
    if let Some(inv) = crate::completion::invalid_ident_at_cursor(input, cursor_byte, cache) {
        overlay_error(&mut runs, inv.range.0, theme);
    }
    inject_cursor(&mut runs, input, cursor_byte, theme);
    runs
}

/// One of three mid-typing classifications (ADR-0022 §1).
///
/// Distinguishes "the user isn't done yet" from "this token
/// can never fit". Drives error overlay (this stage) and the
/// hint panel ambient mode (stage 5).
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum InputState {
    /// No tokens at all (empty / whitespace-only input).
    Empty,
    /// Parses to a complete `Command`. The user can submit.
    Valid,
    /// Parse failed because more input was expected — every
    /// consumed token fits a known command, just not all of
    /// it is here yet.
    IncompleteAtEof,
    /// Parse failed at a token strictly inside the input —
    /// no continuation can recover. The byte offset is the
    /// failing token's start.
    DefiniteErrorAt(usize),
}

/// Classify `input` into one of the three mid-typing states.
/// Cheap (lex + parse) per ADR-0022 §13.
#[must_use]
pub fn classify_input(input: &str) -> InputState {
    if input.trim().is_empty() {
        return InputState::Empty;
    }
    match parse_command(input) {
        Ok(_) => InputState::Valid,
        Err(ParseError::Empty) => InputState::Empty,
        Err(err @ ParseError::Invalid { position, .. }) => {
            // `at_eof` is the parser's own classification: true
            // when more input would (potentially) help, false
            // when a specific token is in the wrong place.
            // Custom-error inputs (try_map failures) currently
            // map to `at_eof = true` — see the field docstring
            // on `ParseError::Invalid::at_eof`.
            if err.at_eof() {
                InputState::IncompleteAtEof
            } else {
                InputState::DefiniteErrorAt(position)
            }
        }
    }
}

/// Ambient hint-panel content for the user's current input
/// (ADR-0022 §6, stage 8b). The renderer dispatches on the
/// returned variant.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum AmbientHint {
    /// Single-line prose hint — used for "submit with Enter",
    /// IncompleteAtEof with no keyword candidates (i.e. an
    /// identifier or punctuation slot), and definite-error
    /// states with optional usage template.
    Prose(String),
    /// Multi-candidate (or single-candidate keyword)
    /// completion at the cursor. Stage 8b renders these as
    /// styled spans with the selected item highlighted (if
    /// any) and `<` / `>` scroll markers when items overflow
    /// the panel width.
    Candidates {
        items: Vec<String>,
        /// Index into `items` of the currently-inserted Tab
        /// candidate (per the live `LastCompletion` memo), or
        /// `None` if the user hasn't pressed Tab yet.
        selected: Option<usize>,
    },
}

/// Compute the ambient hint for the input panel
/// (ADR-0022 §6).
///
/// Returns `None` for empty input — caller falls back to
/// `panel.hint_empty`.
#[must_use]
pub fn ambient_hint(
    input: &str,
    cursor: usize,
    memo: Option<&crate::completion::LastCompletion>,
    cache: &crate::completion::SchemaCache,
) -> Option<AmbientHint> {
    if input.trim().is_empty() {
        return None;
    }
    // First check for candidates at the cursor (keywords +
    // schema identifiers). When any exist the user can Tab to
    // insert one, and the panel surfaces them directly — this
    // wins over the prose IncompleteAtEof framing because the
    // candidate list is more actionable.
    if let Some(comp) = crate::completion::candidates_at_cursor(input, cursor, cache) {
        let selected = memo.map(|m| m.selection_idx);
        return Some(AmbientHint::Candidates {
            items: comp.candidates,
            selected,
        });
    }
    // Invalid identifier: cursor sits in a known-set slot but
    // the typed prefix matches nothing in the schema. (Stage
    // 8e / the user's #5.)
    if let Some(inv) = crate::completion::invalid_ident_at_cursor(input, cursor, cache) {
        let kind = match inv.slot {
            crate::dsl::ident_slot::IdentSlot::TableName => "table",
            crate::dsl::ident_slot::IdentSlot::Column => "column",
            crate::dsl::ident_slot::IdentSlot::RelationshipName => "relationship",
            // `NewName` is filtered out by `invalid_ident_at_cursor`
            // (it only fires for known-set slots), so this arm
            // is unreachable in practice; render a neutral
            // fallback rather than panic.
            crate::dsl::ident_slot::IdentSlot::NewName => "identifier",
        };
        return Some(AmbientHint::Prose(crate::t!(
            "hint.ambient_invalid_ident",
            kind = kind,
            found = inv.found,
        )));
    }
    // Otherwise fall back to the prose framings from stage 5.
    match parse_command(input) {
        Ok(_) => Some(AmbientHint::Prose(crate::t!("hint.ambient_complete"))),
        Err(ParseError::Empty) => None,
        Err(ParseError::Invalid {
            message,
            position,
            at_eof,
            expected,
        }) => {
            if at_eof {
                if expected.is_empty() {
                    Some(AmbientHint::Prose(message))
                } else {
                    let joined = oxford_or(&expected);
                    Some(AmbientHint::Prose(crate::t!(
                        "hint.ambient_expected",
                        expected = joined
                    )))
                }
            } else {
                let tokens = lex(input);
                let usage = crate::dsl::usage::matched_entry(&tokens, position)
                    .and_then(|(_, keys)| keys.first().copied())
                    .map(|key| crate::friendly::translate(key, &[]));
                Some(AmbientHint::Prose(match usage {
                    Some(u) => crate::t!(
                        "hint.ambient_error_with_usage",
                        message = message,
                        usage = u,
                    ),
                    None => message,
                }))
            }
        }
    }
}

/// "A, B, or C" / "A or B" / "A". Local copy because the
/// parser's identical helper is private.
fn oxford_or(items: &[String]) -> String {
    match items {
        [] => String::new(),
        [a] => a.clone(),
        [a, b] => format!("{a} or {b}"),
        rest => {
            let (last, head) = rest.split_last().expect("len >= 3");
            format!("{}, or {last}", head.join(", "))
        }
    }
}

fn overlay_error(runs: &mut [StyledRun], error_byte: usize, theme: &Theme) {
    // Failing tokens have their byte_range starting exactly at
    // `error_byte`. Override the fg colour while preserving any
    // other style bits the base run carried.
    if let Some(run) = runs.iter_mut().find(|r| r.byte_range.0 == error_byte) {
        run.style = run.style.fg(theme.tok_error);
    }
    // If no run starts at error_byte, the failure is past the
    // last token (an EOF failure misclassified as definite —
    // shouldn't happen given classify_input's contract). No-op.
}

/// Cursor-less variant: tokenises `input` into styled runs
/// covering the full byte range, with no inverted cursor.
/// Used by the echo-line renderer (ADR-0022 §5) where there's
/// no cursor to show.
#[must_use]
pub fn lex_to_runs(input: &str, theme: &Theme) -> Vec<StyledRun> {
    base_runs(input, theme)
}

fn base_runs(input: &str, theme: &Theme) -> Vec<StyledRun> {
    let tokens = lex(input);
    let mut runs = Vec::with_capacity(tokens.len() * 2);
    let mut pos = 0;
    for tok in tokens {
        let (start, end) = tok.span;
        if pos < start {
            // Whitespace gap before this token.
            runs.push(StyledRun {
                byte_range: (pos, start),
                style: Style::default().fg(theme.fg),
            });
        }
        runs.push(StyledRun {
            byte_range: (start, end),
            style: Style::default().fg(theme.token_color(&tok.kind)),
        });
        pos = end;
    }
    if pos < input.len() {
        runs.push(StyledRun {
            byte_range: (pos, input.len()),
            style: Style::default().fg(theme.fg),
        });
    }
    runs
}

fn inject_cursor(
    runs: &mut Vec<StyledRun>,
    input: &str,
    cursor_byte: usize,
    theme: &Theme,
) {
    let cursor_byte = cursor_byte.min(input.len());

    // End-of-input cursor: append the empty-range sentinel.
    if cursor_byte == input.len() {
        runs.push(StyledRun {
            byte_range: (input.len(), input.len()),
            style: Style::default()
                .fg(theme.fg)
                .add_modifier(Modifier::REVERSED),
        });
        return;
    }

    let idx = runs
        .iter()
        .position(|r| r.byte_range.0 <= cursor_byte && cursor_byte < r.byte_range.1)
        .expect("cursor_byte < input.len() ⇒ some run contains it");
    let target = runs[idx].clone();
    let (start, end) = target.byte_range;

    // Walk to the next char boundary so a multi-byte UTF-8
    // codepoint is treated as a single visual unit at the
    // cursor.
    let mut char_end = cursor_byte + 1;
    while char_end < input.len() && !input.is_char_boundary(char_end) {
        char_end += 1;
    }

    let mut replacement: Vec<StyledRun> = Vec::with_capacity(3);
    if start < cursor_byte {
        replacement.push(StyledRun {
            byte_range: (start, cursor_byte),
            style: target.style,
        });
    }
    replacement.push(StyledRun {
        byte_range: (cursor_byte, char_end),
        style: target.style.add_modifier(Modifier::REVERSED),
    });
    if char_end < end {
        replacement.push(StyledRun {
            byte_range: (char_end, end),
            style: target.style,
        });
    }

    runs.splice(idx..=idx, replacement);
}

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

    fn dark() -> Theme {
        Theme::dark()
    }

    fn reversed(r: &StyledRun) -> bool {
        r.style.add_modifier.contains(Modifier::REVERSED)
    }

    #[test]
    fn empty_input_renders_only_the_end_of_input_cursor() {
        let runs = render_input_runs("", 0, &dark(), &empty_cache());
        assert_eq!(runs.len(), 1);
        assert_eq!(runs[0].byte_range, (0, 0));
        assert!(reversed(&runs[0]));
    }

    #[test]
    fn keyword_token_takes_keyword_colour() {
        let theme = dark();
        let runs = render_input_runs("create", 6, &theme, &empty_cache());
        // Token + end-of-input cursor.
        assert_eq!(runs.len(), 2);
        assert_eq!(runs[0].byte_range, (0, 6));
        assert_eq!(runs[0].style.fg, Some(theme.tok_keyword));
        assert!(!reversed(&runs[0]));
        assert!(reversed(&runs[1]));
    }

    #[test]
    fn cursor_inside_token_splits_into_three_runs_keeping_colour() {
        let theme = dark();
        let runs = render_input_runs("create", 3, &theme, &empty_cache());
        assert_eq!(runs.len(), 3);
        assert_eq!(runs[0].byte_range, (0, 3));
        assert_eq!(runs[1].byte_range, (3, 4));
        assert_eq!(runs[2].byte_range, (4, 6));
        // All three keep the keyword colour.
        for r in &runs {
            assert_eq!(r.style.fg, Some(theme.tok_keyword));
        }
        assert!(!reversed(&runs[0]));
        assert!(reversed(&runs[1]));
        assert!(!reversed(&runs[2]));
    }

    #[test]
    fn cursor_on_whitespace_inverts_a_single_space() {
        let theme = dark();
        // "create table" has whitespace at byte 6.
        let runs = render_input_runs("create table", 6, &theme, &empty_cache());
        // base: keyword, ws(6,7), keyword. After cursor injection
        // at the start of ws: under=(6,7) REVERSED. The
        // before/after slices are empty so we get 3 runs total.
        assert_eq!(runs.len(), 3);
        let r_under: Vec<_> = runs.iter().filter(|r| reversed(r)).collect();
        assert_eq!(r_under.len(), 1);
        assert_eq!(r_under[0].byte_range, (6, 7));
        assert_eq!(r_under[0].style.fg, Some(theme.fg));
    }

    #[test]
    fn lex_error_token_renders_in_error_colour() {
        let theme = dark();
        let runs = render_input_runs("$", 1, &theme, &empty_cache());
        // Error token (0,1), then end-of-input cursor (1,1).
        assert_eq!(runs.len(), 2);
        assert_eq!(runs[0].style.fg, Some(theme.tok_error));
    }

    #[test]
    fn whitespace_between_tokens_takes_default_fg() {
        let theme = dark();
        let runs = render_input_runs("create table", 12, &theme, &empty_cache());
        // base: keyword(0,6), ws(6,7), keyword(7,12). Plus
        // end-of-input cursor (12,12) = 4 runs.
        assert_eq!(runs.len(), 4);
        assert_eq!(runs[1].byte_range, (6, 7));
        assert_eq!(runs[1].style.fg, Some(theme.fg));
        assert_eq!(runs[3].byte_range, (12, 12));
        assert!(reversed(&runs[3]));
    }

    #[test]
    fn cursor_inside_multi_byte_string_literal_advances_to_char_boundary() {
        let theme = dark();
        // 'café' = ['(0)', c(1), a(2), f(3), é(4-5), '(6)] — é is 2 bytes.
        // Cursor at byte 4: inside é. char_end advances to 6.
        let runs = render_input_runs("'café'", 4, &theme, &empty_cache());
        let r_under: Vec<_> = runs.iter().filter(|r| reversed(r)).collect();
        assert_eq!(r_under.len(), 1);
        assert_eq!(r_under[0].byte_range, (4, 6));
    }

    #[test]
    fn end_of_input_cursor_is_an_empty_range() {
        let runs = render_input_runs("create", 6, &dark(), &empty_cache());
        let last = runs.last().expect("non-empty");
        assert_eq!(last.byte_range, (6, 6));
        assert!(reversed(last));
    }

    // ---- ambient_hint (stage 5 + stage 8b) ----

    fn empty_cache() -> crate::completion::SchemaCache {
        crate::completion::SchemaCache::default()
    }

    fn prose(input: &str, cursor: usize) -> Option<String> {
        match ambient_hint(input, cursor, None, &empty_cache()) {
            Some(AmbientHint::Prose(s)) => Some(s),
            _ => None,
        }
    }

    fn cands_hint(input: &str, cursor: usize) -> Option<Vec<String>> {
        match ambient_hint(input, cursor, None, &empty_cache()) {
            Some(AmbientHint::Candidates { items, .. }) => Some(items),
            _ => None,
        }
    }

    #[test]
    fn ambient_hint_is_none_for_empty_input() {
        assert!(ambient_hint("", 0, None, &empty_cache()).is_none());
        assert!(ambient_hint("   ", 3, None, &empty_cache()).is_none());
    }

    #[test]
    fn ambient_hint_for_valid_input_invites_submit() {
        let h = prose("create table T with pk", 22).expect("prose hint");
        assert!(h.contains("Enter"), "got {h:?}");
    }

    #[test]
    fn ambient_hint_at_partial_keyword_position_returns_candidates() {
        // `show` mid-keyword: candidates_at_cursor returns
        // {data, table} filtered by prefix "show" — but
        // "show" doesn't match any keyword's prefix. The
        // partial prefix walk finds `show`; expected set at
        // start-of-input is the entry keywords; none start
        // with "show" except `show` itself. Hmm — let me
        // check the actual semantics: at "show" cursor 4,
        // start = 0, partial = "show", expected = entry
        // keywords. Filter by "show" → just `show`. Single
        // candidate.
        let cs = cands_hint("show", 4).expect("candidate hint");
        assert_eq!(cs, vec!["show".to_string()]);
    }

    #[test]
    fn ambient_hint_at_word_boundary_after_show_returns_data_table() {
        let cs = cands_hint("show ", 5).expect("candidate hint");
        assert_eq!(cs, vec!["data".to_string(), "table".to_string()]);
    }

    #[test]
    fn ambient_hint_for_definite_error_includes_usage_template() {
        let h = prose("insert into T extra", 19).expect("prose hint");
        assert!(
            h.contains("usage:"),
            "definite-error hint should include usage template, got {h:?}",
        );
        assert!(
            h.contains("insert into <Table>"),
            "should reference the insert usage template, got {h:?}",
        );
    }

    #[test]
    fn ambient_hint_for_unknown_command_falls_back_to_message() {
        // `frobulate widgets` cursor at start: candidates are
        // computed first; "frobulate" doesn't match any
        // keyword, so candidates = empty → falls back to
        // prose error message.
        let h = prose("frobulate widgets", 17).expect("prose hint");
        assert!(
            !h.contains("usage:"),
            "no entry keyword consumed → no usage template; got {h:?}",
        );
        assert!(
            h.contains("frobulate"),
            "message should mention the unknown word; got {h:?}",
        );
    }

    #[test]
    fn ambient_hint_for_invalid_identifier_says_no_such() {
        use crate::completion::SchemaCache;
        // Schema knows "Customers"; user typed "Custp" — no match.
        let cache = SchemaCache {
            tables: vec!["Customers".to_string()],
            ..SchemaCache::default()
        };
        match ambient_hint("show data Custp", 15, None, &cache) {
            Some(AmbientHint::Prose(p)) => {
                assert!(
                    p.contains("no such table"),
                    "expected 'no such table' wording, got {p:?}",
                );
                assert!(p.contains("Custp"), "should name the bad ident, got {p:?}");
            }
            other => panic!("expected Prose for invalid-ident, got {other:?}"),
        }
    }

    #[test]
    fn ambient_hint_with_memo_carries_selected_index() {
        use crate::completion::LastCompletion;
        // Simulate the post-Tab state at "show " — but with
        // the original word still pending (cursor placed
        // after `show ` to expose the multi-candidate slot).
        // The memo's selection_idx is what the renderer uses
        // to highlight one of the items.
        let memo = LastCompletion {
            inserted_range: (5, 5),
            original_text: String::new(),
            candidates: vec!["data".to_string(), "table".to_string()],
            selection_idx: 1,
        };
        match ambient_hint("show ", 5, Some(&memo), &empty_cache()) {
            Some(AmbientHint::Candidates { items, selected }) => {
                assert_eq!(items, vec!["data".to_string(), "table".to_string()]);
                assert_eq!(selected, Some(1));
            }
            other => panic!("expected Candidates, got {other:?}"),
        }
    }

    // ---- classify_input + error overlay (stage 4) ----

    #[test]
    fn classify_empty_input() {
        assert_eq!(classify_input(""), InputState::Empty);
        assert_eq!(classify_input("   "), InputState::Empty);
    }

    #[test]
    fn classify_complete_command_is_valid() {
        assert_eq!(
            classify_input("create table Customers with pk"),
            InputState::Valid,
        );
    }

    #[test]
    fn classify_partial_keyword_only_is_incomplete() {
        // `create` alone — parser fails at EOF expecting `table`.
        assert_eq!(classify_input("create"), InputState::IncompleteAtEof);
    }

    #[test]
    fn classify_partial_command_mid_clause_is_incomplete() {
        assert_eq!(
            classify_input("create table Customers"),
            InputState::IncompleteAtEof,
        );
    }

    #[test]
    fn classify_unknown_command_is_definite_error_at_zero() {
        assert_eq!(
            classify_input("frobulate widgets"),
            InputState::DefiniteErrorAt(0),
        );
    }

    #[test]
    fn classify_wrong_token_mid_command_is_definite_error_at_token_position() {
        // `create table` consumed (12 bytes inc. trailing space
        // skipped by lexer); `1Bad` lexes as Number(13)+Identifier(14).
        // Parser expects ident at position 13, finds Number — fails.
        let state = classify_input("create table 1Bad");
        match state {
            InputState::DefiniteErrorAt(pos) => assert_eq!(pos, 13),
            other => panic!("expected DefiniteErrorAt(13), got {other:?}"),
        }
    }

    #[test]
    fn classify_trailing_whitespace_does_not_create_definite_error() {
        // Trailing whitespace alone shouldn't promote an
        // incomplete-at-EOF state into a definite error.
        assert_eq!(
            classify_input("create   "),
            InputState::IncompleteAtEof,
        );
    }

    #[test]
    fn render_input_runs_overlays_error_on_failing_token() {
        let theme = dark();
        let runs = render_input_runs("frobulate widgets", 17, &theme, &empty_cache());
        // First run is `frobulate` at (0,9). Should be tok_error
        // colour (definite error overlay).
        assert_eq!(runs[0].byte_range, (0, 9));
        assert_eq!(runs[0].style.fg, Some(theme.tok_error));
        // Second run is whitespace, third is `widgets` — these
        // don't get the overlay (only the failing token).
        let widgets = runs.iter().find(|r| r.byte_range == (10, 17));
        assert!(widgets.is_some());
        assert_eq!(
            widgets.unwrap().style.fg,
            Some(theme.tok_identifier),
            "tokens after the error stay in their lex-class colour",
        );
    }

    #[test]
    fn render_input_runs_does_not_overlay_for_incomplete_input() {
        let theme = dark();
        let runs = render_input_runs("create", 6, &theme, &empty_cache());
        // No error overlay — `create` keeps tok_keyword.
        assert_eq!(runs[0].byte_range, (0, 6));
        assert_eq!(runs[0].style.fg, Some(theme.tok_keyword));
    }

    #[test]
    fn render_input_runs_does_not_overlay_for_valid_input() {
        let theme = dark();
        let runs = render_input_runs("create table T with pk", 22, &theme, &empty_cache());
        // None of the tokens should be tok_error.
        for r in &runs {
            assert_ne!(
                r.style.fg,
                Some(theme.tok_error),
                "no error overlay for valid input: {r:?}",
            );
        }
    }

    #[test]
    fn full_valid_command_lexes_to_each_token_class() {
        // Use a valid command — `update ... --all-rows` —
        // so the error overlay (stage 4) doesn't replace any
        // class colours with tok_error. Tokens: keyword(s),
        // identifier(s), string literal, punct (=), flag.
        let theme = dark();
        let input = "update T set Name='hi' --all-rows";
        let runs = render_input_runs(input, input.len(), &theme, &empty_cache());
        let fgs: Vec<_> = runs.iter().filter_map(|r| r.style.fg).collect();
        assert!(fgs.contains(&theme.tok_keyword)); // update / set
        assert!(fgs.contains(&theme.tok_identifier)); // T / Name
        assert!(fgs.contains(&theme.tok_string)); // 'hi'
        assert!(fgs.contains(&theme.tok_punct)); // =
        assert!(fgs.contains(&theme.tok_flag)); // --all-rows
        // The valid command must not have any error overlay.
        for r in &runs {
            assert_ne!(r.style.fg, Some(theme.tok_error));
        }
    }
}