custom history list (#524)

* use custom list impl

* fmt

* segment

* clean up

* fix offsets

* fix scroll back space

* small touch ups

5 files changed, 232 insertions, 140 deletions

diff --git a/src/command/client/search.rs b/src/command/client/search.rs
index 915589a5..eda20ac5 100644
--- a/src/command/client/search.rs
+++ b/src/command/client/search.rs
@@ -11,6 +11,7 @@ use super::history::ListMode;
 mod cursor;
 mod duration;
 mod event;
+mod history_list;
 mod interactive;
 pub use duration::format_duration;
 
diff --git a/src/command/client/search/cursor.rs b/src/command/client/search/cursor.rs
index 1d0e6b8e..da2be45e 100644
--- a/src/command/client/search/cursor.rs
+++ b/src/command/client/search/cursor.rs
@@ -14,6 +14,10 @@ impl Cursor {
         self.source.as_str()
     }
 
+    pub fn into_inner(self) -> String {
+        self.source
+    }
+
     /// Returns the string before the cursor
     pub fn substring(&self) -> &str {
         &self.source[..self.index]
diff --git a/src/command/client/search/history_list.rs b/src/command/client/search/history_list.rs
new file mode 100644
index 00000000..e4d8ee6b
--- /dev/null
+++ b/src/command/client/search/history_list.rs
@@ -0,0 +1,175 @@
+use std::time::Duration;
+
+use atuin_client::history::History;
+use tui::{
+    buffer::Buffer,
+    layout::Rect,
+    style::{Color, Modifier, Style},
+    widgets::{Block, StatefulWidget, Widget},
+};
+
+use super::format_duration;
+
+pub struct HistoryList<'a> {
+    history: &'a [History],
+    block: Option<Block<'a>>,
+}
+
+#[derive(Default)]
+pub struct ListState {
+    offset: usize,
+    selected: usize,
+}
+
+impl ListState {
+    pub fn selected(&self) -> usize {
+        self.selected
+    }
+
+    pub fn select(&mut self, index: usize) {
+        self.selected = index;
+    }
+}
+
+impl<'a> StatefulWidget for HistoryList<'a> {
+    type State = ListState;
+
+    fn render(mut self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
+        let list_area = match self.block.take() {
+            Some(b) => {
+                let inner_area = b.inner(area);
+                b.render(area, buf);
+                inner_area
+            }
+            None => area,
+        };
+
+        if list_area.width < 1 || list_area.height < 1 || self.history.is_empty() {
+            return;
+        }
+        let list_height = list_area.height as usize;
+
+        let (start, end) = self.get_items_bounds(state.selected, state.offset, list_height);
+        state.offset = start;
+
+        let mut s = DrawState {
+            buf,
+            list_area,
+            x: 0,
+            y: 0,
+            state,
+        };
+
+        for item in self.history.iter().skip(state.offset).take(end - start) {
+            s.index();
+            s.duration(item);
+            s.time(item);
+            s.command(item);
+
+            // reset line
+            s.y += 1;
+            s.x = 0;
+        }
+    }
+}
+
+impl<'a> HistoryList<'a> {
+    pub fn new(history: &'a [History]) -> Self {
+        Self {
+            history,
+            block: None,
+        }
+    }
+
+    pub fn block(mut self, block: Block<'a>) -> Self {
+        self.block = Some(block);
+        self
+    }
+
+    fn get_items_bounds(&self, selected: usize, offset: usize, height: usize) -> (usize, usize) {
+        let offset = offset.min(self.history.len().saturating_sub(1));
+
+        let max_scroll_space = height.min(10);
+        if offset + height < selected + max_scroll_space {
+            let end = selected + max_scroll_space;
+            (end - height, end)
+        } else if selected < offset {
+            (selected, selected + height)
+        } else {
+            (offset, offset + height)
+        }
+    }
+}
+
+struct DrawState<'a> {
+    buf: &'a mut Buffer,
+    list_area: Rect,
+    x: u16,
+    y: u16,
+    state: &'a ListState,
+}
+
+// longest line prefix I could come up with
+#[allow(clippy::cast_possible_truncation)] // we know that this is <65536 length
+pub const PREFIX_LENGTH: u16 = " > 123ms 59s ago".len() as u16;
+
+impl DrawState<'_> {
+    fn index(&mut self) {
+        // these encode the slices of `" > "`, `" {n} "`, or `"   "` in a compact form.
+        // Yes, this is a hack, but it makes me feel happy
+        static SLICES: &str = " > 1 2 3 4 5 6 7 8 9   ";
+
+        let i = self.y as usize + self.state.offset;
+        let i = i.checked_sub(self.state.selected);
+        let i = i.unwrap_or(10).min(10) * 2;
+        self.draw(&SLICES[i..i + 3], Style::default());
+    }
+
+    fn duration(&mut self, h: &History) {
+        let status = Style::default().fg(if h.success() {
+            Color::Green
+        } else {
+            Color::Red
+        });
+        let duration = Duration::from_nanos(u64::try_from(h.duration).unwrap_or(0));
+        self.draw(&format_duration(duration), status);
+    }
+
+    #[allow(clippy::cast_possible_truncation)] // we know that time.len() will be <6
+    fn time(&mut self, h: &History) {
+        let style = Style::default().fg(Color::Blue);
+
+        // Account for the chance that h.timestamp is "in the future"
+        // This would mean that "since" is negative, and the unwrap here
+        // would fail.
+        // If the timestamp would otherwise be in the future, display
+        // the time since as 0.
+        let since = chrono::Utc::now() - h.timestamp;
+        let time = format_duration(since.to_std().unwrap_or_default());
+
+        // pad the time a little bit before we write. this aligns things nicely
+        self.x = PREFIX_LENGTH - 4 - time.len() as u16;
+
+        self.draw(&time, style);
+        self.draw(" ago", style);
+    }
+
+    fn command(&mut self, h: &History) {
+        let mut style = Style::default();
+        if self.y as usize + self.state.offset == self.state.selected {
+            style = style.fg(Color::Red).add_modifier(Modifier::BOLD);
+        }
+
+        for section in h.command.split_ascii_whitespace() {
+            self.x += 1;
+            self.draw(section, style);
+        }
+    }
+
+    fn draw(&mut self, s: &str, style: Style) {
+        let cx = self.list_area.left() + self.x;
+        let cy = self.list_area.bottom() - self.y - 1;
+        let w = (self.list_area.width - self.x) as usize;
+        self.x += self.buf.set_stringn(cx, cy, s, w, style).0 - cx;
+    }
+}
diff --git a/src/command/client/search/interactive.rs b/src/command/client/search/interactive.rs
index 10a440a3..069b7f3c 100644
--- a/src/command/client/search/interactive.rs
+++ b/src/command/client/search/interactive.rs
@@ -1,4 +1,4 @@
-use std::{io::stdout, ops::Sub, time::Duration};
+use std::io::stdout;
 
 use eyre::Result;
 use termion::{
@@ -7,10 +7,10 @@ use termion::{
 };
 use tui::{
     backend::{Backend, TermionBackend},
-    layout::{Alignment, Constraint, Corner, Direction, Layout},
+    layout::{Alignment, Constraint, Direction, Layout},
     style::{Color, Modifier, Style},
     text::{Span, Spans, Text},
-    widgets::{Block, BorderType, Borders, List, ListItem, ListState, Paragraph},
+    widgets::{Block, BorderType, Borders, Paragraph},
     Frame, Terminal,
 };
 use unicode_width::UnicodeWidthStr;
@@ -26,98 +26,24 @@ use atuin_client::{
 use super::{
     cursor::Cursor,
     event::{Event, Events},
-    format_duration,
+    history_list::{HistoryList, ListState, PREFIX_LENGTH},
 };
 use crate::VERSION;
 
 struct State {
+    history_count: i64,
     input: Cursor,
-
     filter_mode: FilterMode,
-
-    results: Vec<History>,
-
     results_state: ListState,
-
     context: Context,
 }
 
-fn duration(h: &History) -> String {
-    let duration = Duration::from_nanos(u64::try_from(h.duration).unwrap_or(0));
-    format_duration(duration)
-}
-
-fn ago(h: &History) -> String {
-    let ago = chrono::Utc::now().sub(h.timestamp);
-
-    // Account for the chance that h.timestamp is "in the future"
-    // This would mean that "ago" is negative, and the unwrap here
-    // would fail.
-    // If the timestamp would otherwise be in the future, display
-    // the time ago as 0.
-    let ago = ago.to_std().unwrap_or_default();
-    format_duration(ago) + " ago"
-}
-
-impl State {
-    fn render_results<T: tui::backend::Backend>(
-        &mut self,
-        f: &mut tui::Frame<T>,
-        r: tui::layout::Rect,
-        b: tui::widgets::Block,
-    ) {
-        let max_length = 12; // '123ms' + '59s ago'
-
-        let results: Vec<ListItem> = self
-            .results
-            .iter()
-            .enumerate()
-            .map(|(i, m)| {
-                // these encode the slices of `" > "`, `" {n} "`, or `"   "` in a compact form.
-                // Yes, this is a hack, but it makes me feel happy
-                let slices = " > 1 2 3 4 5 6 7 8 9   ";
-                let index = self.results_state.selected().and_then(|s| i.checked_sub(s));
-                let slice_index = index.unwrap_or(10).min(10) * 2;
-
-                let status_colour = if m.success() {
-                    Color::Green
-                } else {
-                    Color::Red
-                };
-                let ago = ago(m);
-                let duration = format!("{:width$}", duration(m), width = max_length - ago.len());
-
-                let command = m.command.replace(['\n', '\t'], " ");
-                let mut command = Span::raw(command);
-                if slice_index == 0 {
-                    command.style = Style::default().fg(Color::Red).add_modifier(Modifier::BOLD);
-                }
-
-                let spans = Spans::from(vec![
-                    Span::raw(&slices[slice_index..slice_index + 3]),
-                    Span::styled(duration, Style::default().fg(status_colour)),
-                    Span::raw(" "),
-                    Span::styled(ago, Style::default().fg(Color::Blue)),
-                    Span::raw(" "),
-                    command,
-                ]);
-
-                ListItem::new(spans)
-            })
-            .collect();
-
-        let results = List::new(results).block(b).start_corner(Corner::BottomLeft);
-
-        f.render_stateful_widget(results, r, &mut self.results_state);
-    }
-}
-
 impl State {
     async fn query_results(
         &mut self,
         search_mode: SearchMode,
         db: &mut impl Database,
-    ) -> Result<()> {
+    ) -> Result<Vec<History>> {
         let i = self.input.as_str();
         let results = if i.is_empty() {
             db.list(self.filter_mode, &self.context, Some(200), true)
@@ -127,38 +53,19 @@ impl State {
                 .await?
         };
 
-        self.results = results;
-
-        if self.results.is_empty() {
-            self.results_state.select(None);
-        } else {
-            self.results_state.select(Some(0));
-        }
-
-        Ok(())
+        self.results_state.select(0);
+        Ok(results)
     }
 
-    fn handle_input(&mut self, input: &TermEvent) -> Option<&str> {
+    fn handle_input(&mut self, input: &TermEvent, len: usize) -> Option<usize> {
         match input {
-            TermEvent::Key(Key::Esc | Key::Ctrl('c' | 'd' | 'g')) => return Some(""),
+            TermEvent::Key(Key::Esc | Key::Ctrl('c' | 'd' | 'g')) => return Some(usize::MAX),
             TermEvent::Key(Key::Char('\n')) => {
-                let i = self.results_state.selected().unwrap_or(0);
-
-                return Some(
-                    self.results
-                        .get(i)
-                        .map_or(self.input.as_str(), |h| h.command.as_str()),
-                );
+                return Some(self.results_state.selected());
             }
             TermEvent::Key(Key::Alt(c @ '1'..='9')) => {
                 let c = c.to_digit(10)? as usize;
-                let i = self.results_state.selected()? + c;
-
-                return Some(
-                    self.results
-                        .get(i)
-                        .map_or(self.input.as_str(), |h| h.command.as_str()),
-                );
+                return Some(self.results_state.selected() + c);
             }
             TermEvent::Key(Key::Left | Key::Ctrl('h')) => {
                 self.input.left();
@@ -195,20 +102,13 @@ impl State {
             }
             TermEvent::Key(Key::Down | Key::Ctrl('n' | 'j'))
             | TermEvent::Mouse(MouseEvent::Press(MouseButton::WheelDown, _, _)) => {
-                let i = self
-                    .results_state
-                    .selected() // try get current selection
-                    .map_or(0, |i| i.saturating_sub(1)); // subtract 1 if possible
-                self.results_state.select(Some(i));
+                let i = self.results_state.selected().saturating_sub(1);
+                self.results_state.select(i);
             }
             TermEvent::Key(Key::Up | Key::Ctrl('p' | 'k'))
             | TermEvent::Mouse(MouseEvent::Press(MouseButton::WheelUp, _, _)) => {
-                let i = self
-                    .results_state
-                    .selected()
-                    .map_or(0, |i| i + 1) // increment the selected index
-                    .min(self.results.len() - 1); // clamp it to the last entry
-                self.results_state.select(Some(i));
+                let i = self.results_state.selected() + 1;
+                self.results_state.select(i.min(len - 1));
             }
             _ => {}
         };
@@ -217,7 +117,7 @@ impl State {
     }
 
     #[allow(clippy::cast_possible_truncation)]
-    fn draw<T: Backend>(&mut self, f: &mut Frame<'_, T>, history_count: i64) {
+    fn draw<T: Backend>(&mut self, f: &mut Frame<'_, T>, results: &[History]) {
         let chunks = Layout::default()
             .direction(Direction::Vertical)
             .margin(0)
@@ -256,21 +156,22 @@ impl State {
 
         let help = Paragraph::new(Text::from(Spans::from(help)));
         let stats = Paragraph::new(Text::from(Span::raw(format!(
-            "history count: {history_count} ",
+            "history count: {} ",
+            self.history_count
         ))));
 
         f.render_widget(title, top_left_chunks[1]);
         f.render_widget(help, top_left_chunks[2]);
         f.render_widget(stats.alignment(Alignment::Right), top_right_chunks[1]);
 
-        self.render_results(
-            f,
-            chunks[1],
+        let results = HistoryList::new(results).block(
             Block::default()
                 .borders(Borders::TOP | Borders::LEFT | Borders::RIGHT)
-                .border_type(BorderType::Rounded), // .title("History"),
+                .border_type(BorderType::Rounded),
         );
 
+        f.render_stateful_widget(results, chunks[1], &mut self.results_state);
+
         let input = format!(
             "[{:^14}] {}",
             self.filter_mode.as_str(),
@@ -291,14 +192,14 @@ impl State {
         let width = UnicodeWidthStr::width(self.input.substring());
         f.set_cursor(
             // Put cursor past the end of the input text
-            chunks[2].x + width as u16 + 18,
+            chunks[2].x + width as u16 + PREFIX_LENGTH + 2,
             // Move one line down, from the border to the input line
             chunks[2].y + 1,
         );
     }
 
     #[allow(clippy::cast_possible_truncation)]
-    fn draw_compact<T: Backend>(&mut self, f: &mut Frame<'_, T>, history_count: i64) {
+    fn draw_compact<T: Backend>(&mut self, f: &mut Frame<'_, T>, results: &[History]) {
         let chunks = Layout::default()
             .direction(Direction::Vertical)
             .margin(0)
@@ -339,7 +240,7 @@ impl State {
 
         let stats = Paragraph::new(Text::from(Span::raw(format!(
             "history count: {}",
-            history_count,
+            self.history_count,
         ))))
         .style(Style::default().fg(Color::DarkGray))
         .alignment(Alignment::Right);
@@ -348,21 +249,22 @@ impl State {
         f.render_widget(help, header_chunks[1]);
         f.render_widget(stats, header_chunks[2]);
 
-        self.render_results(f, chunks[1], Block::default());
+        let results = HistoryList::new(results);
+        f.render_stateful_widget(results, chunks[1], &mut self.results_state);
 
         let input = format!(
             "[{:^14}] {}",
             self.filter_mode.as_str(),
             self.input.as_str(),
         );
-        let input = Paragraph::new(input).block(Block::default());
+        let input = Paragraph::new(input);
         f.render_widget(input, chunks[2]);
 
         let extra_width = UnicodeWidthStr::width(self.input.substring());
 
         f.set_cursor(
             // Put cursor past the end of the input text
-            chunks[2].x + extra_width as u16 + 17,
+            chunks[2].x + extra_width as u16 + PREFIX_LENGTH + 1,
             // Move one line down, from the border to the input line
             chunks[2].y + 1,
         );
@@ -393,36 +295,35 @@ pub async fn history(
     // Put the cursor at the end of the query by default
     input.end();
     let mut app = State {
+        history_count: db.history_count().await?,
         input,
-        results: Vec::new(),
         results_state: ListState::default(),
         context: current_context(),
         filter_mode,
     };
 
-    app.query_results(search_mode, db).await?;
+    let mut results = app.query_results(search_mode, db).await?;
 
-    loop {
-        let history_count = db.history_count().await?;
+    let index = 'render: loop {
         let initial_input = app.input.as_str().to_owned();
         let initial_filter_mode = app.filter_mode;
 
         // Handle input
         if let Event::Input(input) = events.next()? {
-            if let Some(output) = app.handle_input(&input) {
-                return Ok(output.to_owned());
+            if let Some(i) = app.handle_input(&input, results.len()) {
+                break 'render i;
             }
         }
 
         // After we receive input process the whole event channel before query/render.
         while let Ok(Event::Input(input)) = events.try_next() {
-            if let Some(output) = app.handle_input(&input) {
-                return Ok(output.to_owned());
+            if let Some(i) = app.handle_input(&input, results.len()) {
+                break 'render i;
             }
         }
 
         if initial_input != app.input.as_str() || initial_filter_mode != app.filter_mode {
-            app.query_results(search_mode, db).await?;
+            results = app.query_results(search_mode, db).await?;
         }
 
         let compact = match style {
@@ -433,9 +334,20 @@ pub async fn history(
             atuin_client::settings::Style::Full => false,
         };
         if compact {
-            terminal.draw(|f| app.draw_compact(f, history_count))?;
+            terminal.draw(|f| app.draw_compact(f, &results))?;
         } else {
-            terminal.draw(|f| app.draw(f, history_count))?;
+            terminal.draw(|f| app.draw(f, &results))?;
         }
+    };
+
+    if index < results.len() {
+        // index is in bounds so we return that entry
+        Ok(results.swap_remove(index).command)
+    } else if index == usize::MAX {
+        // index is max which implies an early exit
+        Ok(String::new())
+    } else {
+        // out of bounds usually implies no selected entry so we return the input
+        Ok(app.input.into_inner())
     }
 }
diff --git a/src/main.rs b/src/main.rs
index 5d43cc72..bffb7249 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,5 @@
 #![warn(clippy::pedantic, clippy::nursery)]
-#![allow(clippy::use_self)] // not 100% reliable
+#![allow(clippy::use_self, clippy::missing_const_for_fn)] // not 100% reliable
 
 use clap::{AppSettings, Parser};
 use eyre::Result;