1 files changed, 126 insertions, 0 deletions
diff --git a/helix-term/src/prompt.rs b/helix-term/src/prompt.rs
new file mode 100644
index 00000000..4a39f2ec
--- /dev/null
+++ b/helix-term/src/prompt.rs
@@ -0,0 +1,126 @@
+use crate::Editor;
+use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
+use std::string::String;
+
+pub struct Prompt {
+    pub prompt: String,
+    pub line: String,
+    pub cursor: usize,
+    pub completion: Vec<String>,
+    pub should_close: bool,
+    pub completion_selection_index: Option<usize>,
+    completion_fn: Box<dyn FnMut(&str) -> Vec<String>>,
+    callback_fn: Box<dyn FnMut(&mut Editor, &str)>,
+}
+
+impl Prompt {
+    pub fn new(
+        prompt: String,
+        mut completion_fn: impl FnMut(&str) -> Vec<String> + 'static,
+        callback_fn: impl FnMut(&mut Editor, &str) + 'static,
+    ) -> Prompt {
+        Prompt {
+            prompt,
+            line: String::new(),
+            cursor: 0,
+            completion: completion_fn(""),
+            should_close: false,
+            completion_selection_index: None,
+            completion_fn: Box::new(completion_fn),
+            callback_fn: Box::new(callback_fn),
+        }
+    }
+
+    pub fn insert_char(&mut self, c: char) {
+        self.line.insert(self.cursor, c);
+        self.cursor += 1;
+        self.completion = (self.completion_fn)(&self.line);
+        self.exit_selection();
+    }
+
+    pub fn move_char_left(&mut self) {
+        if self.cursor > 0 {
+            self.cursor -= 1;
+        }
+    }
+
+    pub fn move_char_right(&mut self) {
+        if self.cursor < self.line.len() {
+            self.cursor += 1;
+        }
+    }
+
+    pub fn move_start(&mut self) {
+        self.cursor = 0;
+    }
+
+    pub fn move_end(&mut self) {
+        self.cursor = self.line.len();
+    }
+
+    pub fn delete_char_backwards(&mut self) {
+        if self.cursor > 0 {
+            self.line.remove(self.cursor - 1);
+            self.cursor -= 1;
+            self.completion = (self.completion_fn)(&self.line);
+        }
+        self.exit_selection();
+    }
+
+    pub fn change_completion_selection(&mut self) {
+        if self.completion.is_empty() {
+            return;
+        }
+        let index =
+            self.completion_selection_index.map(|i| i + 1).unwrap_or(0) % self.completion.len();
+        self.completion_selection_index = Some(index);
+        self.line = self.completion[index].clone();
+    }
+    pub fn exit_selection(&mut self) {
+        self.completion_selection_index = None;
+    }
+
+    pub fn handle_event(&mut self, key_event: KeyEvent, editor: &mut Editor) {
+        match key_event {
+            KeyEvent {
+                code: KeyCode::Char(c),
+                modifiers: KeyModifiers::NONE,
+            } => self.insert_char(c),
+            KeyEvent {
+                code: KeyCode::Esc, ..
+            } => self.should_close = true,
+            KeyEvent {
+                code: KeyCode::Right,
+                ..
+            } => self.move_char_right(),
+            KeyEvent {
+                code: KeyCode::Left,
+                ..
+            } => self.move_char_left(),
+            KeyEvent {
+                code: KeyCode::Char('e'),
+                modifiers: KeyModifiers::CONTROL,
+            } => self.move_end(),
+            KeyEvent {
+                code: KeyCode::Char('a'),
+                modifiers: KeyModifiers::CONTROL,
+            } => self.move_start(),
+            KeyEvent {
+                code: KeyCode::Backspace,
+                modifiers: KeyModifiers::NONE,
+            } => self.delete_char_backwards(),
+            KeyEvent {
+                code: KeyCode::Enter,
+                ..
+            } => (self.callback_fn)(editor, &self.line),
+            KeyEvent {
+                code: KeyCode::Tab, ..
+            } => self.change_completion_selection(),
+            KeyEvent {
+                code: KeyCode::Char('q'),
+                modifiers: KeyModifiers::CONTROL,
+            } => self.exit_selection(),
+            _ => (),
+        }
+    }
+}