use crate::git::{self, Commit};
use crate::ui::truncate;
use anyhow::Result;
use crossterm::{
cursor,
event::{self, Event, KeyCode, KeyEvent, KeyEventKind, KeyModifiers},
execute, queue,
style::{Attribute, Color, Print, ResetColor, SetAttribute, SetForegroundColor},
terminal::{self, ClearType, EnterAlternateScreen, LeaveAlternateScreen},
};
use std::fs;
use std::io::{Write, stdout};
const PAGE: usize = 500;
const MIN_SPLIT_WIDTH: usize = 80;
struct TerminalGuard;
impl TerminalGuard {
fn new() -> Result<Self> {
terminal::enable_raw_mode()?;
execute!(stdout(), EnterAlternateScreen, cursor::Hide)?;
Ok(TerminalGuard)
}
}
impl Drop for TerminalGuard {
fn drop(&mut self) {
let _ = execute!(stdout(), cursor::Show, LeaveAlternateScreen);
let _ = terminal::disable_raw_mode();
}
}
fn suspended<T>(f: impl FnOnce() -> T) -> Result<T> {
execute!(stdout(), cursor::Show, LeaveAlternateScreen)?;
terminal::disable_raw_mode()?;
let result = f();
terminal::enable_raw_mode()?;
execute!(
stdout(),
EnterAlternateScreen,
cursor::Hide,
terminal::Clear(ClearType::All)
)?;
Ok(result)
}
struct Preview {
hash: String,
width: usize,
lines: Vec<String>,
}
struct State {
commits: Vec<Commit>,
limit: usize,
selected: usize,
offset: usize,
message: Option<(bool, String)>,
confirm_hard_reset: Option<usize>,
preview: Option<Preview>,
}
impl State {
fn reload(&mut self) -> Result<()> {
self.commits = git::commits(self.limit)?;
self.selected = self.selected.min(self.commits.len().saturating_sub(1));
Ok(())
}
fn select(&mut self, index: usize) -> Result<()> {
if index + 1 >= self.commits.len() && self.commits.len() == self.limit {
self.limit += PAGE;
self.reload()?;
}
self.selected = index.min(self.commits.len().saturating_sub(1));
Ok(())
}
fn current(&self) -> Option<&Commit> {
self.commits.get(self.selected)
}
}
pub fn run() -> Result<i32> {
let commits = match git::commits(PAGE) {
Ok(c) if !c.is_empty() => c,
_ => {
eprintln!("No commits.");
return Ok(1);
}
};
let mut state = State {
commits,
limit: PAGE,
selected: 0,
offset: 0,
message: None,
confirm_hard_reset: None,
preview: None,
};
let _guard = TerminalGuard::new()?;
event_loop(&mut state)?;
Ok(0)
}
fn event_loop(state: &mut State) -> Result<()> {
loop {
draw(state)?;
let (code, modifiers) = match event::read()? {
Event::Key(KeyEvent {
code,
modifiers,
kind: KeyEventKind::Press,
..
}) => (code, modifiers),
Event::Resize(..) => {
execute!(stdout(), terminal::Clear(ClearType::All))?;
continue;
}
_ => continue,
};
if code == KeyCode::Char('c') && modifiers.contains(KeyModifiers::CONTROL) {
return Ok(());
}
if let Some(index) = state.confirm_hard_reset.take() {
if matches!(code, KeyCode::Char('y' | 'Y')) {
reset(state, index, true)?;
} else {
state.message = Some((false, "Hard reset cancelled.".to_string()));
}
continue;
}
let page = page_size();
match code {
KeyCode::Char('q') | KeyCode::Esc => return Ok(()),
KeyCode::Up | KeyCode::Char('k') => state.select(state.selected.saturating_sub(1))?,
KeyCode::Down | KeyCode::Char('j') => state.select(state.selected + 1)?,
KeyCode::PageUp => state.select(state.selected.saturating_sub(page))?,
KeyCode::PageDown => state.select(state.selected + page)?,
KeyCode::Home | KeyCode::Char('g') => state.select(0)?,
KeyCode::End | KeyCode::Char('G') => state.select(state.commits.len() - 1)?,
KeyCode::Enter => {
if let Some(c) = state.current() {
let hash = c.hash.clone();
suspended(|| git::show(&hash))??;
}
}
KeyCode::Char('e') => edit_message(state)?,
KeyCode::Char('r') => reset(state, state.selected, false)?,
KeyCode::Char('R') => {
if let Some(c) = state.current() {
state.message = Some((
false,
format!(
"Hard reset to {}? Uncommitted changes will be lost. [y/N]",
c.short
),
));
state.confirm_hard_reset = Some(state.selected);
}
}
_ => {}
}
}
}
fn page_size() -> usize {
terminal::size().map_or(10, |(_, h)| (h as usize).saturating_sub(3).max(1))
}
fn reset(state: &mut State, index: usize, hard: bool) -> Result<()> {
let Some(c) = state.commits.get(index) else {
return Ok(());
};
let short = c.short.clone();
let (ok, output) = git::reset(&c.hash, hard)?;
let kind = if hard { "Hard" } else { "Soft" };
state.message = Some(if ok {
let details = output.lines().next().unwrap_or("");
let summary = format!("{kind} reset to {short}.");
(true, if details.is_empty() { summary } else { format!("{summary} {details}") })
} else {
(false, output)
});
if ok {
state.selected = 0;
state.offset = 0;
}
state.reload()
}
fn edit_message(state: &mut State) -> Result<()> {
let Some(c) = state.current() else {
return Ok(());
};
let (hash, short) = (c.hash.clone(), c.short.clone());
let original = git::message(&hash)?;
let comment = git::comment_char();
let path = git::git_path("GUD_EDITMSG")?;
fs::write(
&path,
format!(
"{}\n\n{comment} Editing the message of {short}.\n\
{comment} Lines starting with '{comment}' will be ignored, \
and an empty message aborts.\n",
original.trim_end()
),
)?;
let edited = suspended(|| git::edit_file(&path))?;
let text = fs::read_to_string(&path);
let _ = fs::remove_file(&path);
if !edited? {
state.message = Some((false, "Editor failed; message unchanged.".to_string()));
return Ok(());
}
let new = git::stripspace(&text?)?;
state.message = Some(if new.trim().is_empty() {
(false, "Empty message; aborted.".to_string())
} else if new == git::stripspace(&original)? {
(true, "Message unchanged.".to_string())
} else {
match git::reword(&hash, &new) {
Ok((new_hash, count)) => {
let mut msg = format!("Reworded {short} → {}.", &new_hash[..short.len()]);
if count > 1 {
msg.push_str(&format!(" Rewrote {count} commits."));
}
(true, msg)
}
Err(e) => (false, format!("Reword failed: {e}")),
}
});
state.reload()
}
fn draw(state: &mut State) -> Result<()> {
let (width, height) = match terminal::size()? {
(0, _) | (_, 0) => (80, 24),
(w, h) => (w as usize, h as usize),
};
let footer_lines = if state.message.is_some() { 2 } else { 1 };
let body_height = height.saturating_sub(footer_lines).max(1);
let list_height = state.commits.len().min(body_height);
if state.selected < state.offset {
state.offset = state.selected;
} else if state.selected >= state.offset + list_height {
state.offset = state.selected + 1 - list_height;
}
let (list_width, preview_width) = if width >= MIN_SPLIT_WIDTH {
let list = width / 2;
(list, width - list - 2)
} else {
(width, 0)
};
if preview_width > 0 {
update_preview(state, preview_width);
}
let mut out = stdout();
for row in 0..body_height {
queue!(out, cursor::MoveTo(0, row as u16))?;
let index = state.offset + row;
if let Some(c) = state.commits.get(index) {
draw_commit(&mut out, c, index == state.selected, list_width)?;
} else {
queue!(out, Print(" ".repeat(list_width)))?;
}
if preview_width > 0 {
queue!(out, SetForegroundColor(Color::DarkGrey), Print("│ "), ResetColor)?;
let line = state
.preview
.as_ref()
.and_then(|p| p.lines.get(row))
.map_or("", String::as_str);
let color = if row == 0 { Some(Color::Yellow) } else { None };
print_span(&mut out, color, line, preview_width)?;
}
queue!(out, terminal::Clear(ClearType::UntilNewLine))?;
}
let mut row = body_height;
if let Some((ok, msg)) = &state.message {
let color = if state.confirm_hard_reset.is_some() {
Color::Yellow
} else if *ok {
Color::Green
} else {
Color::Red
};
let msg = msg.lines().next().unwrap_or("");
queue!(out, cursor::MoveTo(0, row as u16))?;
print_span(&mut out, Some(color), msg, width)?;
queue!(out, terminal::Clear(ClearType::UntilNewLine))?;
row += 1;
}
queue!(out, cursor::MoveTo(0, row as u16))?;
print_span(
&mut out,
Some(Color::DarkGrey),
"↑/k ↓/j move · enter show · e edit message · r soft reset · R hard reset · q quit",
width,
)?;
queue!(out, terminal::Clear(ClearType::UntilNewLine))?;
out.flush()?;
Ok(())
}
fn update_preview(state: &mut State, width: usize) {
let Some(c) = state.current() else {
state.preview = None;
return;
};
if state
.preview
.as_ref()
.is_some_and(|p| p.hash == c.hash && p.width == width)
{
return;
}
let text = git::preview(&c.hash, width).unwrap_or_else(|e| e.to_string());
state.preview = Some(Preview {
hash: c.hash.clone(),
width,
lines: text
.lines()
.map(|l| l.replace('\t', " ").replace('\r', ""))
.collect(),
});
}
fn draw_commit(out: &mut impl Write, c: &Commit, selected: bool, width: usize) -> Result<()> {
let refs = if c.refs.is_empty() {
String::new()
} else {
format!("({}) ", c.refs)
};
if selected {
let line = format!("> {} {refs}{}", c.short, c.subject);
queue!(
out,
SetForegroundColor(Color::Cyan),
SetAttribute(Attribute::Reverse),
)?;
print_span(out, None, &line, width)?;
queue!(out, SetAttribute(Attribute::Reset), ResetColor)?;
return Ok(());
}
let spans = [
(None, " "),
(Some(Color::Yellow), c.short.as_str()),
(None, " "),
(Some(Color::Green), refs.as_str()),
(None, c.subject.as_str()),
];
let mut left = width;
for (color, text) in spans {
let text = truncate(text, left);
left -= text.chars().count();
if let Some(color) = color {
queue!(out, SetForegroundColor(color), Print(text), ResetColor)?;
} else {
queue!(out, Print(text))?;
}
}
queue!(out, Print(" ".repeat(left)))?;
Ok(())
}
fn print_span(out: &mut impl Write, color: Option<Color>, text: &str, width: usize) -> Result<()> {
let text = truncate(text, width);
let pad = width - text.chars().count();
if let Some(color) = color {
queue!(out, SetForegroundColor(color), Print(text), ResetColor)?;
} else {
queue!(out, Print(text))?;
}
queue!(out, Print(" ".repeat(pad)))?;
Ok(())
}