feat: add common default keybindings (#719)

* feat: add common default keybindings

* feat: add `WORD_SEPARATORS` to config as `word_chars`, as this is what *Zsh* calls it

* feat: add option for *Emacs* word jumping

* feat: scroll with `PageUp` and `PageDown`, cf #374

5 files changed, 226 insertions, 0 deletions

diff --git a/atuin-client/config.toml b/atuin-client/config.toml
index 0c9b4ede..a3c255b6 100644
--- a/atuin-client/config.toml
+++ b/atuin-client/config.toml
@@ -38,6 +38,15 @@
 ## possible values: return-original, return-query
 # exit_mode = "return-original"
 
+## possible values: emacs, subl
+# word_jump_mode = "emacs"
+
+## characters that count as a part of a word
+# word_chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+
+## number of context lines to show when scrolling by pages
+# scroll_context_lines = 1
+
 ## prevent commands matching any of these regexes from being written to history.
 ## Note that these regular expressions are unanchored, i.e. if they don't start
 ## with ^ or end with $, they'll match anywhere in the command.
diff --git a/atuin-client/src/settings.rs b/atuin-client/src/settings.rs
index 6b642b78..bd47d5aa 100644
--- a/atuin-client/src/settings.rs
+++ b/atuin-client/src/settings.rs
@@ -97,6 +97,15 @@ pub enum Style {
     Compact,
 }
 
+#[derive(Clone, Debug, Deserialize, Copy)]
+pub enum WordJumpMode {
+    #[serde(rename = "emacs")]
+    Emacs,
+
+    #[serde(rename = "subl")]
+    Subl,
+}
+
 #[derive(Clone, Debug, Deserialize)]
 pub struct Settings {
     pub dialect: Dialect,
@@ -114,6 +123,9 @@ pub struct Settings {
     pub shell_up_key_binding: bool,
     pub show_preview: bool,
     pub exit_mode: ExitMode,
+    pub word_jump_mode: WordJumpMode,
+    pub word_chars: String,
+    pub scroll_context_lines: usize,
     #[serde(with = "serde_regex", default = "RegexSet::empty")]
     pub history_filter: RegexSet,
 
@@ -300,6 +312,12 @@ impl Settings {
             .set_default("exit_mode", "return-original")?
             .set_default("session_token", "")?
             .set_default("style", "auto")?
+            .set_default("word_jump_mode", "emacs")?
+            .set_default(
+                "word_chars",
+                "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
+            )?
+            .set_default("scroll_context_lines", 1)?
             .add_source(
                 Environment::with_prefix("atuin")
                     .prefix_separator("_")
diff --git a/src/command/client/search/cursor.rs b/src/command/client/search/cursor.rs
index 827242c8..2bce4f37 100644
--- a/src/command/client/search/cursor.rs
+++ b/src/command/client/search/cursor.rs
@@ -1,3 +1,5 @@
+use atuin_client::settings::WordJumpMode;
+
 pub struct Cursor {
     source: String,
     index: usize,
@@ -9,6 +11,87 @@ impl From<String> for Cursor {
     }
 }
 
+pub struct WordJumper<'a> {
+    word_chars: &'a str,
+    word_jump_mode: WordJumpMode,
+}
+
+impl WordJumper<'_> {
+    fn is_word_boundary(&self, c: char, next_c: char) -> bool {
+        (c.is_whitespace() && !next_c.is_whitespace())
+            || (!c.is_whitespace() && next_c.is_whitespace())
+            || (self.word_chars.contains(c) && !self.word_chars.contains(next_c))
+            || (!self.word_chars.contains(c) && self.word_chars.contains(next_c))
+    }
+
+    fn emacs_get_next_word_pos(&self, source: &str, index: usize) -> usize {
+        let index = (index + 1..source.len().saturating_sub(1))
+            .find(|&i| self.word_chars.contains(source.chars().nth(i).unwrap()))
+            .unwrap_or(source.len());
+        (index + 1..source.len().saturating_sub(1))
+            .find(|&i| !self.word_chars.contains(source.chars().nth(i).unwrap()))
+            .unwrap_or(source.len())
+    }
+
+    fn emacs_get_prev_word_pos(&self, source: &str, index: usize) -> usize {
+        let index = (1..index)
+            .rev()
+            .find(|&i| self.word_chars.contains(source.chars().nth(i).unwrap()))
+            .unwrap_or(0);
+        (1..index)
+            .rev()
+            .find(|&i| !self.word_chars.contains(source.chars().nth(i).unwrap()))
+            .map_or(0, |i| i + 1)
+    }
+
+    fn subl_get_next_word_pos(&self, source: &str, index: usize) -> usize {
+        let index = (index..source.len().saturating_sub(1)).find(|&i| {
+            self.is_word_boundary(
+                source.chars().nth(i).unwrap(),
+                source.chars().nth(i + 1).unwrap(),
+            )
+        });
+        if index.is_none() {
+            return source.len();
+        }
+        (index.unwrap() + 1..source.len())
+            .find(|&i| !source.chars().nth(i).unwrap().is_whitespace())
+            .unwrap_or(source.len())
+    }
+
+    fn subl_get_prev_word_pos(&self, source: &str, index: usize) -> usize {
+        let index = (1..index)
+            .rev()
+            .find(|&i| !source.chars().nth(i).unwrap().is_whitespace());
+        if index.is_none() {
+            return 0;
+        }
+        (1..index.unwrap())
+            .rev()
+            .find(|&i| {
+                self.is_word_boundary(
+                    source.chars().nth(i - 1).unwrap(),
+                    source.chars().nth(i).unwrap(),
+                )
+            })
+            .unwrap_or(0)
+    }
+
+    fn get_next_word_pos(&self, source: &str, index: usize) -> usize {
+        match self.word_jump_mode {
+            WordJumpMode::Emacs => self.emacs_get_next_word_pos(source, index),
+            WordJumpMode::Subl => self.subl_get_next_word_pos(source, index),
+        }
+    }
+
+    fn get_prev_word_pos(&self, source: &str, index: usize) -> usize {
+        match self.word_jump_mode {
+            WordJumpMode::Emacs => self.emacs_get_prev_word_pos(source, index),
+            WordJumpMode::Subl => self.subl_get_prev_word_pos(source, index),
+        }
+    }
+}
+
 impl Cursor {
     pub fn as_str(&self) -> &str {
         self.source.as_str()
@@ -52,6 +135,22 @@ impl Cursor {
         }
     }
 
+    pub fn next_word(&mut self, word_chars: &str, word_jump_mode: WordJumpMode) {
+        let word_jumper = WordJumper {
+            word_chars,
+            word_jump_mode,
+        };
+        self.index = word_jumper.get_next_word_pos(&self.source, self.index);
+    }
+
+    pub fn prev_word(&mut self, word_chars: &str, word_jump_mode: WordJumpMode) {
+        let word_jumper = WordJumper {
+            word_chars,
+            word_jump_mode,
+        };
+        self.index = word_jumper.get_prev_word_pos(&self.source, self.index);
+    }
+
     pub fn insert(&mut self, c: char) {
         self.source.insert(self.index, c);
         self.index += c.len_utf8();
@@ -65,6 +164,25 @@ impl Cursor {
         }
     }
 
+    pub fn remove_next_word(&mut self, word_chars: &str, word_jump_mode: WordJumpMode) {
+        let word_jumper = WordJumper {
+            word_chars,
+            word_jump_mode,
+        };
+        let next_index = word_jumper.get_next_word_pos(&self.source, self.index);
+        self.source.replace_range(self.index..next_index, "");
+    }
+
+    pub fn remove_prev_word(&mut self, word_chars: &str, word_jump_mode: WordJumpMode) {
+        let word_jumper = WordJumper {
+            word_chars,
+            word_jump_mode,
+        };
+        let next_index = word_jumper.get_prev_word_pos(&self.source, self.index);
+        self.source.replace_range(next_index..self.index, "");
+        self.index = next_index;
+    }
+
     pub fn back(&mut self) -> Option<char> {
         if self.left() {
             self.remove()
@@ -90,6 +208,17 @@ impl Cursor {
 #[cfg(test)]
 mod cursor_tests {
     use super::Cursor;
+    use super::*;
+
+    static EMACS_WORD_JUMPER: WordJumper = WordJumper {
+        word_chars: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
+        word_jump_mode: WordJumpMode::Emacs,
+    };
+
+    static SUBL_WORD_JUMPER: WordJumper = WordJumper {
+        word_chars: "./\\()\"'-:,.;<>~!@#$%^&*|+=[]{}`~?",
+        word_jump_mode: WordJumpMode::Subl,
+    };
 
     #[test]
     fn right() {
@@ -115,6 +244,46 @@ mod cursor_tests {
     }
 
     #[test]
+    fn test_emacs_get_next_word_pos() {
+        let s = String::from("   aaa   ((()))bbb   ((()))   ");
+        let indices = [(0, 6), (3, 6), (7, 18), (19, 30)];
+        for (i_src, i_dest) in indices {
+            assert_eq!(EMACS_WORD_JUMPER.get_next_word_pos(&s, i_src), i_dest);
+        }
+        assert_eq!(EMACS_WORD_JUMPER.get_next_word_pos("", 0), 0);
+    }
+
+    #[test]
+    fn test_emacs_get_prev_word_pos() {
+        let s = String::from("   aaa   ((()))bbb   ((()))   ");
+        let indices = [(30, 15), (29, 15), (15, 3), (3, 0)];
+        for (i_src, i_dest) in indices {
+            assert_eq!(EMACS_WORD_JUMPER.get_prev_word_pos(&s, i_src), i_dest);
+        }
+        assert_eq!(EMACS_WORD_JUMPER.get_prev_word_pos("", 0), 0);
+    }
+
+    #[test]
+    fn test_subl_get_next_word_pos() {
+        let s = String::from("   aaa   ((()))bbb   ((()))   ");
+        let indices = [(0, 3), (1, 3), (3, 9), (9, 15), (15, 21), (21, 30)];
+        for (i_src, i_dest) in indices {
+            assert_eq!(SUBL_WORD_JUMPER.get_next_word_pos(&s, i_src), i_dest);
+        }
+        assert_eq!(SUBL_WORD_JUMPER.get_next_word_pos("", 0), 0);
+    }
+
+    #[test]
+    fn test_subl_get_prev_word_pos() {
+        let s = String::from("   aaa   ((()))bbb   ((()))   ");
+        let indices = [(30, 21), (21, 15), (15, 9), (9, 3), (3, 0)];
+        for (i_src, i_dest) in indices {
+            assert_eq!(SUBL_WORD_JUMPER.get_prev_word_pos(&s, i_src), i_dest);
+        }
+        assert_eq!(SUBL_WORD_JUMPER.get_prev_word_pos("", 0), 0);
+    }
+
+    #[test]
     fn pop() {
         let mut s = String::from("öaöböcödöeöfö");
         let mut c = Cursor::from(s.clone());
diff --git a/src/command/client/search/history_list.rs b/src/command/client/search/history_list.rs
index f4725b02..9e266fe9 100644
--- a/src/command/client/search/history_list.rs
+++ b/src/command/client/search/history_list.rs
@@ -19,6 +19,7 @@ pub struct HistoryList<'a> {
 pub struct ListState {
     offset: usize,
     selected: usize,
+    max_entries: usize,
 }
 
 impl ListState {
@@ -26,6 +27,10 @@ impl ListState {
         self.selected
     }
 
+    pub fn max_entries(&self) -> usize {
+        self.max_entries
+    }
+
     pub fn select(&mut self, index: usize) {
         self.selected = index;
     }
@@ -48,6 +53,7 @@ impl<'a> StatefulWidget for HistoryList<'a> {
 
         let (start, end) = self.get_items_bounds(state.selected, state.offset, list_height);
         state.offset = start;
+        state.max_entries = end - start;
 
         let mut s = DrawState {
             buf,
diff --git a/src/command/client/search/interactive.rs b/src/command/client/search/interactive.rs
index 01175b52..c5c983ac 100644
--- a/src/command/client/search/interactive.rs
+++ b/src/command/client/search/interactive.rs
@@ -111,19 +111,33 @@ impl State {
                 let c = c.to_digit(10)? as usize;
                 return Some(self.results_state.selected() + c);
             }
+            KeyCode::Left if ctrl => self
+                .input
+                .prev_word(&settings.word_chars, settings.word_jump_mode),
             KeyCode::Left => {
                 self.input.left();
             }
             KeyCode::Char('h') if ctrl => {
                 self.input.left();
             }
+            KeyCode::Right if ctrl => self
+                .input
+                .next_word(&settings.word_chars, settings.word_jump_mode),
             KeyCode::Right => self.input.right(),
             KeyCode::Char('l') if ctrl => self.input.right(),
             KeyCode::Char('a') if ctrl => self.input.start(),
+            KeyCode::Home => self.input.start(),
             KeyCode::Char('e') if ctrl => self.input.end(),
+            KeyCode::End => self.input.end(),
+            KeyCode::Backspace if ctrl => self
+                .input
+                .remove_prev_word(&settings.word_chars, settings.word_jump_mode),
             KeyCode::Backspace => {
                 self.input.back();
             }
+            KeyCode::Delete if ctrl => self
+                .input
+                .remove_next_word(&settings.word_chars, settings.word_jump_mode),
             KeyCode::Delete => {
                 self.input.remove();
             }
@@ -168,6 +182,16 @@ impl State {
                 self.results_state.select(i.min(len - 1));
             }
             KeyCode::Char(c) => self.input.insert(c),
+            KeyCode::PageDown => {
+                let scroll_len = self.results_state.max_entries() - settings.scroll_context_lines;
+                let i = self.results_state.selected().saturating_sub(scroll_len);
+                self.results_state.select(i);
+            }
+            KeyCode::PageUp => {
+                let scroll_len = self.results_state.max_entries() - settings.scroll_context_lines;
+                let i = self.results_state.selected() + scroll_len;
+                self.results_state.select(i.min(len - 1));
+            }
             _ => {}
         };