kimun-notes 0.7.0

use std::sync::Arc;

use kimun_core::nfs::VaultPath;
use kimun_core::NoteVault;
use ratatui::crossterm::event::{KeyCode, KeyEvent};
use ratatui::layout::{Constraint, Direction, Layout, Rect};
use ratatui::style::{Modifier, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::{Block, Borders, List, ListItem, ListState, Paragraph};
use ratatui::Frame;

use crate::components::event_state::EventState;
use crate::components::events::{AppEvent, AppTx};
use crate::components::file_list::{SortField, SortOrder};
use crate::keys::action_shortcuts::ActionShortcuts;
use crate::keys::{key_event_to_combo, KeyBindings};
use crate::settings::themes::Theme;

// ---------------------------------------------------------------------------
// BacklinkEntry
// ---------------------------------------------------------------------------

/// A single backlink entry with preloaded context.
#[derive(Debug, Clone)]
pub struct BacklinkEntry {
    pub path: VaultPath,
    pub title: String,
    pub filename: String,
    /// The paragraph in this note that contains the link to the current note.
    pub context: String,
    /// Full note text, loaded when backlinks are fetched.
    pub full_text: Option<String>,
}

// ---------------------------------------------------------------------------
// ExpandState (private)
// ---------------------------------------------------------------------------

#[derive(Clone, Copy, PartialEq)]
enum ExpandState {
    Collapsed,
    Context,
    Full,
}

// ---------------------------------------------------------------------------
// BacklinksPanel
// ---------------------------------------------------------------------------

pub struct BacklinksPanel {
    entries: Vec<BacklinkEntry>,
    expand_states: Vec<ExpandState>,
    list_state: ListState,
    loading: bool,
    current_note: VaultPath,
    sort_field: SortField,
    sort_order: SortOrder,
    vault: Arc<NoteVault>,
    key_bindings: KeyBindings,
    /// Scroll offset for full-expanded content view.
    content_scroll: usize,
    /// Maximum scroll offset (computed during render).
    content_scroll_max: usize,
}

impl BacklinksPanel {
    pub fn new(vault: Arc<NoteVault>, key_bindings: KeyBindings) -> Self {
        Self {
            entries: Vec::new(),
            expand_states: Vec::new(),
            list_state: ListState::default(),
            loading: false,
            current_note: VaultPath::empty(),
            sort_field: SortField::Name,
            sort_order: SortOrder::Ascending,
            vault,
            key_bindings,
            content_scroll: 0,
            content_scroll_max: 0,
        }
    }

    // ── Helpers ─────────────────────────────────────────────────────────

    /// Returns true if the selected entry is in full-expand mode (content takes
    /// the whole panel, up/down scrolls content).
    fn is_full_expanded(&self) -> bool {
        self.list_state
            .selected()
            .and_then(|i| self.expand_states.get(i))
            .is_some_and(|s| *s == ExpandState::Full)
    }

    pub fn is_empty(&self) -> bool {
        self.entries.is_empty()
    }

    pub fn selected_path(&self) -> Option<&VaultPath> {
        self.list_state
            .selected()
            .and_then(|i| self.entries.get(i))
            .map(|e| &e.path)
    }

    // ── Loading ─────────────────────────────────────────────────────────

    /// Begin loading backlinks for `note_path`. Clears existing state, sets
    /// `loading = true`, and spawns a background task that sends
    /// `AppEvent::BacklinksLoaded` when finished.
    pub fn load(&mut self, note_path: VaultPath, tx: AppTx) {
        self.entries.clear();
        self.expand_states.clear();
        self.list_state.select(None);
        self.loading = true;
        self.current_note = note_path.clone();
        self.content_scroll = 0;
        self.content_scroll_max = 0;

        let vault = Arc::clone(&self.vault);
        tokio::spawn(async move {
            let entries = load_backlinks(&vault, &note_path).await;
            let _ = tx.send(AppEvent::BacklinksLoaded(entries));
        });
    }

    /// Called when the background task completes. Stores the entries, applies
    /// the current sort, and initialises expand states.
    pub fn on_loaded(&mut self, entries: Vec<BacklinkEntry>) {
        self.entries = entries;
        self.apply_sort();
        self.expand_states = vec![ExpandState::Collapsed; self.entries.len()];
        self.loading = false;
        if !self.entries.is_empty() {
            self.list_state.select(Some(0));
        }
    }

    /// Sort `entries` (and their parallel `expand_states`) by the active
    /// sort field and order.
    pub fn apply_sort(&mut self) {
        let field = self.sort_field;
        let order = self.sort_order;

        // Build index permutation so we can reorder expand_states in sync.
        let mut indices: Vec<usize> = (0..self.entries.len()).collect();
        indices.sort_by(|&a, &b| {
            let cmp = match field {
                SortField::Name => self.entries[a]
                    .filename
                    .to_lowercase()
                    .cmp(&self.entries[b].filename.to_lowercase()),
                SortField::Title => self.entries[a]
                    .title
                    .to_lowercase()
                    .cmp(&self.entries[b].title.to_lowercase()),
            };
            match order {
                SortOrder::Ascending => cmp,
                SortOrder::Descending => cmp.reverse(),
            }
        });

        let sorted_entries: Vec<BacklinkEntry> =
            indices.iter().map(|&i| self.entries[i].clone()).collect();
        let sorted_states: Vec<ExpandState> = if self.expand_states.len() == self.entries.len() {
            indices.iter().map(|&i| self.expand_states[i]).collect()
        } else {
            vec![ExpandState::Collapsed; sorted_entries.len()]
        };

        self.entries = sorted_entries;
        self.expand_states = sorted_states;
    }

    // ── Input handling ──────────────────────────────────────────────────

    pub fn handle_key(&mut self, key: &KeyEvent, tx: &AppTx) -> EventState {
        // Check for action shortcuts first.
        if let Some(combo) = key_event_to_combo(key) {
            match self.key_bindings.get_action(&combo) {
                Some(ActionShortcuts::CycleSortField) => {
                    self.sort_field = self.sort_field.cycle();
                    self.apply_sort();
                    self.expand_states = vec![ExpandState::Collapsed; self.entries.len()];
                    return EventState::Consumed;
                }
                Some(ActionShortcuts::SortReverseOrder) => {
                    self.sort_order = self.sort_order.toggle();
                    self.apply_sort();
                    self.expand_states = vec![ExpandState::Collapsed; self.entries.len()];
                    return EventState::Consumed;
                }
                // FocusSidebar / FocusEditor are intercepted at the
                // EditorScreen level for directional navigation.
                Some(ActionShortcuts::FollowLink) => {
                    if let Some(path) = self.selected_path().cloned() {
                        tx.send(AppEvent::OpenPath(path)).ok();
                    }
                    return EventState::Consumed;
                }
                _ => {}
            }
        }

        match key.code {
            KeyCode::Up => {
                if self.is_full_expanded() {
                    self.content_scroll = self.content_scroll.saturating_sub(1);
                } else {
                    self.move_selection(-1);
                }
                EventState::Consumed
            }
            KeyCode::Down => {
                if self.is_full_expanded() {
                    // Increment freely; render() clamps to content_scroll_max.
                    self.content_scroll += 1;
                } else {
                    self.move_selection(1);
                }
                EventState::Consumed
            }
            KeyCode::Enter => {
                self.toggle_expand();
                EventState::Consumed
            }
            KeyCode::Esc => EventState::NotConsumed,
            _ => EventState::NotConsumed,
        }
    }

    fn move_selection(&mut self, delta: i32) {
        if self.entries.is_empty() {
            return;
        }
        let current = self.list_state.selected().unwrap_or(0) as i32;
        let next = (current + delta).clamp(0, self.entries.len() as i32 - 1) as usize;
        self.list_state.select(Some(next));
    }

    fn toggle_expand(&mut self) {
        let Some(idx) = self.list_state.selected() else {
            return;
        };
        if idx >= self.expand_states.len() {
            return;
        }

        match self.expand_states[idx] {
            ExpandState::Collapsed => {
                self.expand_states[idx] = ExpandState::Context;
            }
            ExpandState::Context => {
                self.content_scroll = 0;
                self.expand_states[idx] = ExpandState::Full;
            }
            ExpandState::Full => {
                self.content_scroll = 0;
                self.expand_states[idx] = ExpandState::Collapsed;
            }
        }
    }

    pub fn hint_shortcuts(&self) -> Vec<(String, String)> {
        [
            (ActionShortcuts::FocusSidebar, "\u{2190} editor"),
            (ActionShortcuts::FollowLink, "open note"),
            (ActionShortcuts::CycleSortField, "sort"),
        ]
        .iter()
        .filter_map(|(action, label)| {
            self.key_bindings
                .first_combo_for(action)
                .map(|k| (k, label.to_string()))
        })
        .collect()
    }

    // ── Rendering ──────────────────────────────────────────────────────

    pub fn render(&mut self, f: &mut Frame, rect: Rect, theme: &Theme, focused: bool) {
        let border_style = theme.border_style(focused);
        let fg = theme.fg.to_ratatui();
        let fg_muted = theme.fg_muted.to_ratatui();
        let bg = theme.bg_panel.to_ratatui();

        let sort_indicator = format!("{}{}", self.sort_field.label(), self.sort_order.label());
        let title = format!("Backlinks ({}) {}", self.entries.len(), sort_indicator);

        let outer = Block::default()
            .title(title)
            .borders(Borders::ALL)
            .border_style(border_style)
            .style(theme.panel_style());
        let inner = outer.inner(rect);
        f.render_widget(outer, rect);

        if self.loading {
            f.render_widget(
                Paragraph::new("  Loading...")
                    .style(Style::default().fg(fg_muted).bg(bg)),
                inner,
            );
            return;
        }

        if self.entries.is_empty() {
            f.render_widget(
                Paragraph::new("  No backlinks")
                    .style(Style::default().fg(fg_muted).bg(bg)),
                inner,
            );
            return;
        }

        let selected = self.list_state.selected();
        let selected_state = selected
            .and_then(|i| self.expand_states.get(i).copied())
            .unwrap_or(ExpandState::Collapsed);

        // Full mode: content takes the entire panel, no list visible.
        if selected_state == ExpandState::Full {
            if let Some(idx) = selected
                && let Some(entry) = self.entries.get(idx)
            {
                let text = entry
                    .full_text
                    .as_deref()
                    .unwrap_or(&entry.context);

                // Split into fixed header (title + divider) and scrollable content.
                let title_display = if entry.title.is_empty() {
                    &entry.filename
                } else {
                    &entry.title
                };

                let parts = Layout::default()
                    .direction(Direction::Vertical)
                    .constraints([
                        Constraint::Length(1), // title
                        Constraint::Length(1), // divider
                        Constraint::Min(0),    // content
                    ])
                    .split(inner);

                // Fixed title header.
                f.render_widget(
                    Paragraph::new(Line::from(vec![
                        Span::styled(
                            format!("\u{25BC} {} ", title_display),
                            Style::default()
                                .fg(theme.fg_selected.to_ratatui())
                                .bg(bg)
                                .add_modifier(Modifier::BOLD),
                        ),
                        Span::styled(
                            format!(" {}", entry.filename),
                            Style::default().fg(fg_muted).bg(bg),
                        ),
                    ]))
                    .style(Style::default().bg(bg)),
                    parts[0],
                );

                // Fixed divider.
                f.render_widget(
                    Paragraph::new("\u{2500}".repeat(parts[1].width as usize))
                        .style(Style::default().fg(fg_muted).bg(bg)),
                    parts[1],
                );

                // Scrollable content.
                let indent = 2usize;
                let wrap_width = parts[2].width.saturating_sub(indent as u16 + 1) as usize;
                let target = self.current_note.get_clean_name().to_lowercase();

                let mut lines = Vec::new();
                for line in text.lines() {
                    let wrapped = wrap_line(line, wrap_width);
                    for wline in wrapped {
                        let spans = highlight_link(&wline, &target, fg_muted, bg, theme);
                        let mut indented = vec![Span::styled(
                            " ".repeat(indent),
                            Style::default().bg(bg),
                        )];
                        indented.extend(spans);
                        lines.push(Line::from(indented));
                    }
                }

                let total_lines = lines.len();
                let viewport = parts[2].height as usize;
                self.content_scroll_max = total_lines.saturating_sub(viewport);
                self.content_scroll = self.content_scroll.min(self.content_scroll_max);

                f.render_widget(
                    Paragraph::new(lines)
                        .scroll((self.content_scroll as u16, 0))
                        .style(Style::default().bg(bg)),
                    parts[2],
                );
            }
            return;
        }

        // Context or Collapsed: show the list, optionally with preview below.
        let has_context = selected_state == ExpandState::Context;

        let (list_area, divider_area, content_area) = if has_context {
            let max_list = inner.height / 2;
            let list_height = (self.entries.len() as u16).min(max_list).max(1);
            let areas = Layout::default()
                .direction(Direction::Vertical)
                .constraints([
                    Constraint::Length(list_height),
                    Constraint::Length(1),
                    Constraint::Min(0),
                ])
                .split(inner);
            (areas[0], Some(areas[1]), Some(areas[2]))
        } else {
            (inner, None, None)
        };

        // Build list items (1 line per entry).
        let items: Vec<ListItem> = self
            .entries
            .iter()
            .enumerate()
            .map(|(i, entry)| {
                let is_selected = selected == Some(i);
                let title_style = if is_selected {
                    Style::default()
                        .fg(theme.fg_selected.to_ratatui())
                        .bg(theme.bg_selected.to_ratatui())
                        .add_modifier(Modifier::BOLD)
                } else {
                    Style::default().fg(fg).bg(bg)
                };
                let title_display = if entry.title.is_empty() {
                    &entry.filename
                } else {
                    &entry.title
                };
                let expand_marker = match self.expand_states.get(i) {
                    Some(ExpandState::Context) => "\u{25BC}",
                    _ => " ",
                };
                ListItem::new(Line::from(vec![
                    Span::styled(format!("{} {} ", expand_marker, title_display), title_style),
                    Span::styled(
                        format!(" {}", entry.filename),
                        Style::default().fg(fg_muted).bg(if is_selected {
                            theme.bg_selected.to_ratatui()
                        } else {
                            bg
                        }),
                    ),
                ]))
            })
            .collect();

        let list = List::new(items)
            .style(Style::default().bg(bg))
            .highlight_style(Style::default().bg(theme.bg_selected.to_ratatui()));

        f.render_stateful_widget(list, list_area, &mut self.list_state);

        // Divider between list and content.
        if let Some(div) = divider_area {
            f.render_widget(
                Paragraph::new("\u{2500}".repeat(div.width as usize))
                    .style(Style::default().fg(fg_muted).bg(bg)),
                div,
            );
        }

        // Render context preview below the list: show the full note text
        // scrolled so the first link occurrence is visible with context above.
        if let Some(area) = content_area
            && let Some(idx) = selected
            && let Some(entry) = self.entries.get(idx)
            && selected_state == ExpandState::Context
        {
            let text = entry.full_text.as_deref().unwrap_or(&entry.context);
            let indent = 2usize;
            let wrap_width = area.width.saturating_sub(indent as u16 + 1) as usize;
            let target = self.current_note.get_clean_name().to_lowercase();

            let mut lines = Vec::new();

            // Track which rendered line contains the first link match.
            let mut link_line: Option<usize> = None;

            for line in text.lines() {
                let wrapped = wrap_line(line, wrap_width);
                for wline in wrapped {
                    if link_line.is_none()
                        && (find_case_insensitive(&wline, &format!("[[{}", target)).is_some()
                            || find_case_insensitive(&wline, &format!("({})", target)).is_some())
                    {
                        link_line = Some(lines.len());
                    }
                    let spans = highlight_link(&wline, &target, fg_muted, bg, theme);
                    let mut indented = vec![Span::styled(
                        " ".repeat(indent),
                        Style::default().bg(bg),
                    )];
                    indented.extend(spans);
                    lines.push(Line::from(indented));
                }
            }

            // Scroll to show the link with context above. If the content from
            // the link to the end fits within the viewport, scroll back further
            // to fill the available space.
            let viewport = area.height as usize;
            let total = lines.len();
            let link_pos = link_line.unwrap_or(0);
            let lines_after_link = total.saturating_sub(link_pos);
            let scroll_to = if lines_after_link <= viewport {
                // Content from link to end fits — scroll back to fill the viewport.
                total.saturating_sub(viewport)
            } else {
                // More content below the link — show 2 lines of context above.
                link_pos.saturating_sub(2)
            } as u16;

            f.render_widget(
                Paragraph::new(lines)
                    .scroll((scroll_to, 0))
                    .style(Style::default().bg(bg)),
                area,
            );
        }
    }
}

// ---------------------------------------------------------------------------
// Standalone async helpers
// ---------------------------------------------------------------------------

/// Load all backlinks for `note_path` from the vault, fetching note text and
/// extracting context for each one.
async fn load_backlinks(vault: &NoteVault, note_path: &VaultPath) -> Vec<BacklinkEntry> {
    let backlinks = match vault.get_backlinks(note_path).await {
        Ok(bl) => bl,
        Err(_) => return Vec::new(),
    };

    let target_name = note_path.get_clean_name();

    let mut entries = Vec::with_capacity(backlinks.len());
    for (entry_data, content_data) in backlinks {
        let text = vault
            .get_note_text(&entry_data.path)
            .await
            .unwrap_or_default();
        let context = extract_context(&text, &target_name);
        let (_parent, filename) = entry_data.path.get_parent_path();

        entries.push(BacklinkEntry {
            path: entry_data.path,
            title: content_data.title,
            filename,
            context,
            full_text: Some(text),
        });
    }

    entries
}

/// Find the paragraph in `text` that contains a link to `target_name`.
///
/// A "paragraph" is a run of consecutive non-blank lines. The function
/// searches for several link patterns (case-insensitive):
/// - `[[target_name]]`        — full wikilink
/// - `[[target_name`          — partial wikilink (e.g. with alias)
/// - `(target_name)`          — markdown link
/// - `(target_name.md)`       — markdown link with extension
///
/// If no match is found, returns the first non-blank line as a fallback.
fn extract_context(text: &str, target_name: &str) -> String {
    let target_lower = target_name.to_lowercase();

    // Build the name with extension via VaultPath (avoids hardcoding `.md`).
    let with_ext = VaultPath::note_path_from(&target_lower)
        .to_string_with_ext()
        .to_lowercase();
    // Extract just the filename portion (after the last `/`).
    let filename_ext = with_ext
        .rsplit('/')
        .next()
        .unwrap_or(&with_ext);

    // Build search needles (lowercase).
    let wikilink_full = format!("[[{}]]", target_lower);
    let wikilink_partial = format!("[[{}", target_lower);
    let md_link = format!("({})", target_lower);
    let md_link_ext = format!("({})", filename_ext);

    // Split text into paragraphs (groups of consecutive non-blank lines).
    let paragraphs = split_paragraphs(text);

    for para in &paragraphs {
        let lower = para.to_lowercase();
        if lower.contains(&wikilink_full)
            || lower.contains(&wikilink_partial)
            || lower.contains(&md_link)
            || lower.contains(&md_link_ext)
        {
            return para.clone();
        }
    }

    // Fallback: first non-blank line.
    text.lines()
        .find(|l| !l.trim().is_empty())
        .unwrap_or("")
        .to_string()
}

/// Split text into paragraphs. A paragraph is one or more consecutive
/// non-blank lines. Blank lines act as separators.
fn split_paragraphs(text: &str) -> Vec<String> {
    let mut paragraphs = Vec::new();
    let mut current: Vec<&str> = Vec::new();

    for line in text.lines() {
        if line.trim().is_empty() {
            if !current.is_empty() {
                paragraphs.push(current.join("\n"));
                current.clear();
            }
        } else {
            current.push(line);
        }
    }
    if !current.is_empty() {
        paragraphs.push(current.join("\n"));
    }

    paragraphs
}

// ---------------------------------------------------------------------------
// Rendering helpers
// ---------------------------------------------------------------------------

/// Wrap a single line into multiple lines that fit within `max_width` characters.
/// Uses character count (not byte length) for width. Wraps at word boundaries
/// when possible, hard-breaks otherwise.
fn wrap_line(line: &str, max_width: usize) -> Vec<String> {
    if max_width == 0 || line.chars().count() <= max_width {
        return vec![line.to_string()];
    }

    let mut result = Vec::new();
    let mut remaining = line;

    while remaining.chars().count() > max_width {
        // Find the byte index of the max_width-th character.
        let byte_limit = remaining
            .char_indices()
            .nth(max_width)
            .map(|(i, _)| i)
            .unwrap_or(remaining.len());

        // Try to find a space to break at (within the allowed character range).
        let break_at = remaining[..byte_limit]
            .rfind(' ')
            .map(|i| i + 1) // include the space on the current line
            .unwrap_or(byte_limit); // hard break if no space
        result.push(remaining[..break_at].trim_end().to_string());
        remaining = &remaining[break_at..];
    }
    if !remaining.is_empty() {
        result.push(remaining.to_string());
    }
    result
}

/// Case-insensitive search for `needle` in `haystack`, returning the byte
/// range `(start, end)` in `haystack` where the match occurs. Compares
/// char-by-char via `to_lowercase()` so byte lengths are always derived from
/// the original string, avoiding the case-folding byte-mismatch problem.
fn find_case_insensitive(haystack: &str, needle: &str) -> Option<(usize, usize)> {
    let needle_chars: Vec<char> = needle.chars().collect();
    if needle_chars.is_empty() {
        return None;
    }
    let hay_indices: Vec<(usize, char)> = haystack.char_indices().collect();
    'outer: for start_idx in 0..hay_indices.len() {
        if start_idx + needle_chars.len() > hay_indices.len() {
            break;
        }
        for (j, &nc) in needle_chars.iter().enumerate() {
            let hc = hay_indices[start_idx + j].1;
            // Compare lowercased chars.
            let mut h_lower = hc.to_lowercase();
            let mut n_lower = nc.to_lowercase();
            if h_lower.next() != n_lower.next() {
                continue 'outer;
            }
        }
        // Match found — compute byte range from haystack char indices.
        let byte_start = hay_indices[start_idx].0;
        let byte_end = if start_idx + needle_chars.len() < hay_indices.len() {
            hay_indices[start_idx + needle_chars.len()].0
        } else {
            haystack.len()
        };
        return Some((byte_start, byte_end));
    }
    None
}

/// Render a line with link references to `target` in bold.
/// Splits the line into owned spans: normal text in `fg_muted`, link matches in bold accent.
/// Uses case-insensitive char-by-char matching to avoid byte-index mismatches.
fn highlight_link(
    line: &str,
    target: &str,
    fg_muted: ratatui::style::Color,
    bg: ratatui::style::Color,
    theme: &Theme,
) -> Vec<Span<'static>> {
    let normal_style = Style::default().fg(fg_muted).bg(bg);
    let bold_style = Style::default()
        .fg(theme.accent.to_ratatui())
        .bg(bg)
        .add_modifier(Modifier::BOLD);

    // Build the with-extension form for markdown links.
    let with_ext = VaultPath::note_path_from(target)
        .to_string_with_ext()
        .to_lowercase();
    let filename_ext = with_ext
        .rsplit('/')
        .next()
        .unwrap_or(&with_ext)
        .to_string();

    // Build all needles to search for.
    let needles = [
        format!("[[{}]]", target),
        format!("[[{}", target),
        format!("({})", target),
        format!("({})", filename_ext),
    ];

    // Find the earliest matching needle by byte position.
    let mut best_match: Option<(usize, usize)> = None; // (byte_start, byte_end)
    for needle in &needles {
        if let Some((start, end)) = find_case_insensitive(line, needle)
            && (best_match.is_none() || start < best_match.unwrap().0)
        {
            best_match = Some((start, end));
        }
    }

    let Some((start, end)) = best_match else {
        return vec![Span::styled(line.to_string(), normal_style)];
    };

    let mut spans = Vec::new();
    if start > 0 {
        spans.push(Span::styled(line[..start].to_string(), normal_style));
    }
    spans.push(Span::styled(line[start..end].to_string(), bold_style));
    if end < line.len() {
        spans.push(Span::styled(line[end..].to_string(), normal_style));
    }
    spans
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

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

    #[test]
    fn extract_context_finds_wikilink_paragraph() {
        let text = "\
# Heading

This is an intro paragraph.

Here I reference [[my-note]] in some context
that spans two lines.

Another paragraph without links.";

        let result = extract_context(text, "my-note");
        assert!(result.contains("[[my-note]]"));
        assert!(result.contains("that spans two lines"));
    }

    #[test]
    fn extract_context_fallback_to_first_line() {
        let text = "\
# No links here

Just a normal paragraph.";

        let result = extract_context(text, "other-note");
        assert_eq!(result, "# No links here");
    }

    #[test]
    fn extract_context_finds_markdown_link() {
        let text = "\
# Title

See [related](my-note.md) for details.

Unrelated content.";

        let result = extract_context(text, "my-note");
        assert!(result.contains("(my-note.md)"));
    }

    #[test]
    fn wrap_line_fits_within_width() {
        let result = wrap_line("short", 20);
        assert_eq!(result, vec!["short"]);
    }

    #[test]
    fn wrap_line_breaks_at_word_boundary() {
        let result = wrap_line("hello world foo bar", 12);
        assert_eq!(result, vec!["hello world", "foo bar"]);
    }

    #[test]
    fn wrap_line_hard_breaks_long_word() {
        let result = wrap_line("abcdefghij", 5);
        assert_eq!(result, vec!["abcde", "fghij"]);
    }

    #[test]
    fn wrap_line_handles_multibyte_chars() {
        // 5 CJK characters — each is 1 char, should wrap at char boundary
        let result = wrap_line("日本語テスト", 3);
        assert_eq!(result, vec!["日本語", "テスト"]);
    }

    #[test]
    fn wrap_line_empty_string() {
        let result = wrap_line("", 10);
        assert_eq!(result, vec![""]);
    }

    #[test]
    fn highlight_link_bolds_wikilink() {
        let spans = highlight_link(
            "see [[my-note]] here",
            "my-note",
            ratatui::style::Color::Gray,
            ratatui::style::Color::Black,
            &crate::settings::themes::Theme::default(),
        );
        assert_eq!(spans.len(), 3);
        assert_eq!(spans[0].content, "see ");
        assert_eq!(spans[1].content, "[[my-note]]");
        assert!(spans[1].style.add_modifier.contains(Modifier::BOLD));
        assert_eq!(spans[2].content, " here");
    }

    #[test]
    fn highlight_link_case_insensitive() {
        let spans = highlight_link(
            "See [[My-Note]] here",
            "my-note",
            ratatui::style::Color::Gray,
            ratatui::style::Color::Black,
            &crate::settings::themes::Theme::default(),
        );
        assert_eq!(spans.len(), 3);
        assert_eq!(spans[1].content, "[[My-Note]]");
        assert!(spans[1].style.add_modifier.contains(Modifier::BOLD));
    }

    #[test]
    fn highlight_link_markdown_with_extension() {
        let spans = highlight_link(
            "see [link](my-note.md) here",
            "my-note",
            ratatui::style::Color::Gray,
            ratatui::style::Color::Black,
            &crate::settings::themes::Theme::default(),
        );
        assert_eq!(spans.len(), 3);
        assert!(spans[1].content.contains("my-note.md"));
        assert!(spans[1].style.add_modifier.contains(Modifier::BOLD));
    }

    #[test]
    fn highlight_link_no_match_returns_single_span() {
        let spans = highlight_link(
            "nothing here",
            "other",
            ratatui::style::Color::Gray,
            ratatui::style::Color::Black,
            &crate::settings::themes::Theme::default(),
        );
        assert_eq!(spans.len(), 1);
    }
}