use crate::core::app::AppContext;
use crate::core::keymap::{nav_bindings, ActionHelp, Keymap, NavAction};
use crate::core::pane::{Pane, PaneEvent, PaneShared};
use crate::core::syntax::SyntaxHighlighter;
use crate::core::theme;
use crate::files::domain::fs::{self, DirEntry, Preview};
use crate::files::panes::entry_line;
use crossterm::event::KeyCode;
use ratatui::style::{Color, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::Paragraph;
use ratatui::{layout::Rect, Frame};
#[derive(Debug, Clone)]
pub enum PreviewAction {
Nav(NavAction),
Back,
Esc,
}
crate::impl_pane_action_from_str!(PreviewAction, nav: Nav, Back, Esc);
impl ActionHelp for PreviewAction {
fn label(&self) -> Option<&'static str> {
match self {
PreviewAction::Nav(NavAction::MoveDown) => Some("Scroll down"),
PreviewAction::Nav(NavAction::MoveUp) => Some("Scroll up"),
PreviewAction::Nav(nav) => nav.label(),
PreviewAction::Back => Some("Back to file list"),
PreviewAction::Esc => Some("Back to file list"),
}
}
}
pub fn default_keymap() -> Keymap<PreviewAction> {
Keymap::new()
.bindings(nav_bindings(PreviewAction::Nav))
.key(KeyCode::Char('h'), PreviewAction::Back)
.key(KeyCode::Left, PreviewAction::Back)
.key(KeyCode::Esc, PreviewAction::Esc)
}
pub struct PreviewPane {
pane_id: usize,
list_pane_id: usize,
keymap: Keymap<PreviewAction>,
highlighter: SyntaxHighlighter,
entry: Option<DirEntry>,
content: Preview,
colors: Option<Vec<Vec<Color>>>,
scroll: usize,
view_height: u16,
icons: bool,
}
impl PreviewPane {
pub fn new(pane_id: usize, list_pane_id: usize, theme: &str, icons: bool) -> Self {
Self {
icons,
pane_id,
list_pane_id,
keymap: default_keymap(),
highlighter: SyntaxHighlighter::with_theme(theme).unwrap_or_default(),
entry: None,
content: Preview::Empty,
colors: None,
scroll: 0,
view_height: 20,
}
}
pub fn set_keymap(&mut self, km: Keymap<PreviewAction>) {
self.keymap = km;
}
pub fn keymap(&self) -> &Keymap<PreviewAction> {
&self.keymap
}
pub fn load(&mut self, entry: Option<&DirEntry>) {
self.scroll = 0;
self.entry = entry.cloned();
self.colors = None;
self.content = match entry {
Some(e) => fs::preview(e),
None => Preview::Empty,
};
if let (Some(e), Preview::Text { lines, .. }) = (entry, &self.content) {
self.colors = self
.highlighter
.highlight_lines(&e.path.to_string_lossy(), lines);
}
}
fn line_count(&self) -> usize {
match &self.content {
Preview::Text { lines, .. } => lines.len(),
Preview::Dir(entries) => entries.len(),
_ => 0,
}
}
fn execute(&mut self, _shared: &PaneShared, action: PreviewAction) -> Vec<PaneEvent> {
match action {
PreviewAction::Nav(nav) => {
let max = self.line_count().saturating_sub(self.view_height as usize);
let half = crate::core::keymap::half_page_step(self.view_height) as usize;
self.scroll = match nav {
NavAction::MoveDown => self.scroll + 1,
NavAction::MoveUp => self.scroll.saturating_sub(1),
NavAction::HalfPageDown => self.scroll + half,
NavAction::HalfPageUp => self.scroll.saturating_sub(half),
NavAction::JumpTop => 0,
NavAction::JumpBottom => max,
}
.min(max);
vec![]
}
PreviewAction::Back | PreviewAction::Esc => {
vec![PaneEvent::SetFocus(self.list_pane_id)]
}
}
}
fn text_line(&self, row: usize, text: &str, gutter: usize) -> Line<'static> {
let mut spans = vec![Span::styled(
format!("{:>gutter$} ", row + 1),
Style::default().fg(Color::DarkGray),
)];
match self.colors.as_ref().and_then(|c| c.get(row)) {
Some(colors) if !colors.is_empty() => {
let mut run = String::new();
let mut run_color: Option<Color> = None;
for (i, ch) in text.chars().enumerate() {
let color = colors.get(i).copied();
if color != run_color && !run.is_empty() {
spans.push(colored(std::mem::take(&mut run), run_color));
}
run_color = color;
run.push(ch);
}
if !run.is_empty() {
spans.push(colored(run, run_color));
}
}
_ => spans.push(Span::raw(text.to_string())),
}
Line::from(spans)
}
}
fn colored(text: String, color: Option<Color>) -> Span<'static> {
match color {
Some(c) => Span::styled(text, Style::default().fg(c)),
None => Span::raw(text),
}
}
impl Pane<PaneEvent> for PreviewPane {
crate::impl_handle_key!(keymap);
fn render(&mut self, f: &mut Frame, _ctx: &AppContext, shared: &PaneShared, area: Rect) {
self.view_height = area.height.saturating_sub(2);
self.scroll = self
.scroll
.min(self.line_count().saturating_sub(self.view_height as usize));
let title = self
.entry
.as_ref()
.map(|e| e.display_name())
.unwrap_or_else(|| "Preview".to_string());
let block = theme::pane_block(&title, shared.focused_pane == self.pane_id);
let height = self.view_height as usize;
let width = area.width.saturating_sub(2) as usize;
let dim = Style::default().fg(Color::DarkGray);
let lines: Vec<Line> = match &self.content {
Preview::Text { lines, truncated } => {
let gutter = lines.len().to_string().len();
let mut out: Vec<Line> = lines
.iter()
.enumerate()
.skip(self.scroll)
.take(height)
.map(|(row, text)| self.text_line(row, text, gutter))
.collect();
if *truncated && self.scroll + height >= lines.len() {
out.push(Line::from(Span::styled(" … (truncated)", dim)));
}
out
}
Preview::Dir(entries) if entries.is_empty() => {
vec![Line::from(Span::styled(" (empty directory)", dim))]
}
Preview::Dir(entries) => entries
.iter()
.skip(self.scroll)
.take(height)
.map(|e| entry_line(e, width, self.icons))
.collect(),
Preview::Binary => vec![Line::from(Span::styled(" (binary file)", dim))],
Preview::Empty => vec![Line::from(Span::styled(
if self.entry.is_some() {
" (empty file)"
} else {
" Select a file to preview"
},
dim,
))],
Preview::Error(e) => vec![Line::from(Span::styled(
format!(" {e}"),
Style::default().fg(Color::Red),
))],
};
f.render_widget(Paragraph::new(lines).block(block), area);
}
}