mtui 0.9.4

use crate::config::Keybinds;
use crate::constants::SEARCH_POPUP_ROWS;
use crate::register::RegisterCell;
use crate::state::SearchParams;
use crate::tui::hints::{self, Hint};
use crate::tui::theme::Theme;
use ratatui::layout::Rect;
use ratatui::style::Style;
use ratatui::text::{Line, Span};
use ratatui::Frame;

const LABEL_W: usize = 24;

pub(super) fn draw(
    frame: &mut Frame,
    area: Rect,
    theme: &Theme,
    kb: &Keybinds,
    search: &SearchParams,
) {
    let len = search.matches.len();
    let (top, end) = super::window(search.top as usize, SEARCH_POPUP_ROWS as usize, len);

    let mut lines = vec![
        super::query_line(theme, &search.query, len),
        Line::default(),
    ];

    if search.matches.is_empty() {
        lines.push(Line::from(Span::styled(
            " Type an address or a label.",
            theme.dim_style(),
        )));
        lines.push(Line::from(Span::styled(
            " Prefix with h/i/c/d to pick the register type.",
            theme.dim_style(),
        )));
    } else {
        for i in top..end {
            let (cell, text) = &search.matches[i];
            lines.push(row(
                theme,
                *cell,
                text,
                &search.query,
                i as u16 == search.selected,
            ));
        }
    }

    let footer = [
        Hint::pair(kb.move_up, kb.move_down, "Select"),
        Hint::key(kb.action, "Go"),
        Hint::key(kb.exit, "Close"),
    ];
    lines.push(hints::more(theme, top, len.saturating_sub(end)));
    let width = hints::min_width(44, &footer);
    lines.push(Line::default());
    lines.push(hints::footer(theme, footer));

    super::render(frame, area, theme, "Go to", width, lines);
}

fn row(
    theme: &Theme,
    cell: RegisterCell,
    text: &str,
    query: &str,
    selected: bool,
) -> Line<'static> {
    let style = |s: Style| if selected { theme.selected_style() } else { s };
    let (kind, address) = cell;

    let mut spans = vec![
        Span::styled(format!(" {address:>5}  "), style(theme.accent_style())),
        Span::styled(
            format!("{:<10}", format!("{kind:?}")),
            style(theme.dim_style()),
        ),
    ];

    let chars: Vec<char> = text.chars().collect();
    let truncated = chars.len() > LABEL_W;
    let shown = if truncated {
        &chars[..LABEL_W - 1]
    } else {
        &chars[..]
    };

    // Split the label into runs of matched/unmatched characters so the part
    // that matched the query lights up.
    let hits = match_positions(query, text);
    let mut run = String::new();
    let mut run_hit = false;
    for (i, &ch) in shown.iter().enumerate() {
        let hit = hits.contains(&i);
        if hit != run_hit && !run.is_empty() {
            spans.push(label_span(
                theme,
                std::mem::take(&mut run),
                run_hit,
                selected,
            ));
        }
        run_hit = hit;
        run.push(ch);
    }
    if !run.is_empty() {
        spans.push(label_span(theme, run, run_hit, selected));
    }
    if truncated {
        spans.push(Span::styled("\u{2026}", style(theme.dim_style())));
    }

    Line::from(spans)
}

fn label_span(theme: &Theme, text: String, hit: bool, selected: bool) -> Span<'static> {
    let style = if selected {
        theme.selected_style()
    } else if hit {
        theme.accent_style()
    } else {
        theme.base()
    };
    Span::styled(text, style)
}

fn match_positions(query: &str, text: &str) -> Vec<usize> {
    if query.is_empty() {
        return Vec::new();
    }
    let query = query.to_ascii_lowercase();
    let text = text.to_ascii_lowercase();

    if let Some(byte_pos) = text.find(&query) {
        let start = text[..byte_pos].chars().count();
        return (start..start + query.chars().count()).collect();
    }

    let mut positions = Vec::new();
    let mut want = query.chars().peekable();
    for (i, ch) in text.chars().enumerate() {
        if want.peek() == Some(&ch) {
            positions.push(i);
            want.next();
        }
    }
    if want.peek().is_some() {
        Vec::new()
    } else {
        positions
    }
}