Suggestion feature

crates/shrs_core/src/history.rs

@@ -11,6 +11,7 @@ use thiserror::Error;
 
 /// Trait to implement for shell history
 pub trait History {
+    fn iter(&self) -> Box<dyn Iterator<Item = &String> + '_>;
     /// Insert item into shell history
     fn add(&mut self, cmd: String);
     /// Remove all history entries
@@ -62,6 +63,10 @@ impl History for DefaultHistory {
     fn get(&self, i: usize) -> Option<&String> {
         self.hist.get(i)
     }
+
+    fn iter(&self) -> Box<dyn Iterator<Item = &String> + '_> {
+        Box::new(self.hist.iter())
+    }
 }
 
 /// Store the history persistently in a file on disk
@@ -148,6 +153,10 @@ impl History for FileBackedHistory {
     fn get(&self, i: usize) -> Option<&String> {
         self.hist.get(i)
     }
+
+    fn iter(&self) -> Box<dyn Iterator<Item = &String> + '_> {
+        Box::new(self.hist.iter())
+    }
 }
 
 fn parse_history_file(hist_file: PathBuf) -> Result<Vec<String>, FileBackedHistoryError> {

crates/shrs_core/src/readline/line.rs

@@ -14,6 +14,7 @@ use ::crossterm::{
     style::{Color, ContentStyle},
     terminal::{disable_raw_mode, enable_raw_mode},
 };
+use clap::builder;
 use shrs_utils::{
     cursor_buffer::{CursorBuffer, Location},
     styled_buf::StyledBuf,
@@ -112,7 +113,7 @@ impl LineState {
     }
 
     /// Get the contents of the prompt
-    fn get_full_command(&self) -> String {
+    pub fn get_full_command(&self) -> String {
         let mut res: String = self.lines.clone();
         let cur_line: String = self.cb.as_str().into();
         res += cur_line.as_str();
@@ -173,6 +174,9 @@ pub struct Line {
     #[builder(default = "String::new()")]
     #[builder(setter(skip))]
     normal_keys: String,
+
+    #[builder(default = "Box::new(DefaultSuggester)")]
+    suggester: Box<dyn Suggester>,
 }
 
 impl Default for Line {
@@ -255,6 +259,12 @@ impl Line {
                         },
                     );
                 }
+            } else {
+                // get search results from history and suggest the first result
+                if let Some(suggestion) = self.suggester.suggest(state) {
+                    let trimmed_selection = suggestion[res.len()..].to_string();
+                    styled_buf.push(trimmed_selection.as_str(), state.sh.theme.suggestion_style);
+                }
             }
 
             self.painter.paint(
@@ -387,6 +397,20 @@ impl Line {
 
                 return Ok(true);
             },
+            // Insert suggestion when right arrow
+            Event::Key(KeyEvent {
+                code: KeyCode::Right,
+                modifiers: KeyModifiers::NONE,
+                ..
+            }) => {
+                if let Some(suggestion) = self.suggester.suggest(state) {
+                    state.line.cb.clear();
+                    state
+                        .line
+                        .cb
+                        .insert(Location::Cursor(), suggestion.as_str())?;
+                }
+            },
 
             Event::Key(KeyEvent {
                 code: KeyCode::Enter,

crates/shrs_core/src/readline/mod.rs

@@ -22,6 +22,7 @@ pub mod line;
 pub mod menu;
 pub mod painter;
 pub mod prompt;
+pub mod suggester;
 pub mod vi;
 
 pub use buffer_history::{BufferHistory, DefaultBufferHistory};
@@ -31,4 +32,5 @@ pub use hooks::*;
 pub use line::{Line, LineBuilder, LineBuilderError, LineMode, LineStateBundle, Readline};
 pub use menu::{DefaultMenu, Menu};
 pub use prompt::{DefaultPrompt, Prompt, *};
+pub use suggester::{DefaultSuggester, Suggester};
 pub use vi::*;

crates/shrs_core/src/readline/suggester.rs

@@ -0,0 +1,22 @@
+use super::line::LineStateBundle;
+
+pub trait Suggester {
+    fn suggest(&self, line_ctx: &LineStateBundle) -> Option<String>;
+}
+pub struct DefaultSuggester;
+impl Suggester for DefaultSuggester {
+    fn suggest(&self, line_ctx: &LineStateBundle) -> Option<String> {
+        let h = &line_ctx.ctx.history;
+        let res = line_ctx.line.get_full_command();
+        if res.is_empty() {
+            return None;
+        }
+
+        for s in h.iter() {
+            if s.starts_with(&res) {
+                return Some(s.to_owned());
+            }
+        }
+        None
+    }
+}

crates/shrs_core/src/theme.rs

@@ -7,6 +7,7 @@ pub struct Theme {
     pub err_style: ContentStyle,
     pub selection_style: ContentStyle,
     pub completion_style: ContentStyle,
+    pub suggestion_style: ContentStyle,
 }
 
 impl Default for Theme {
@@ -16,6 +17,7 @@ impl Default for Theme {
             err_style: ContentStyle::new().red(),
             selection_style: ContentStyle::new().white(),
             completion_style: ContentStyle::new().red(),
+            suggestion_style: ContentStyle::new().dark_grey(),
         }
     }
 }