Add initial vim mode mode switching

Co-authored-by: Nathan Sobo <nathan@zed.dev>

crates/vim/src/normal.rs

@@ -0,0 +1,58 @@
+use editor::{movement, Bias};
+use gpui::{action, keymap::Binding, MutableAppContext, ViewContext};
+use language::SelectionGoal;
+use workspace::Workspace;
+
+use crate::{editor_utils::VimEditorExt, Mode, SwitchMode, VimState};
+
+action!(InsertBefore);
+action!(MoveLeft);
+action!(MoveDown);
+action!(MoveUp);
+action!(MoveRight);
+
+pub fn init(cx: &mut MutableAppContext) {
+    let context = Some("Editor && vim_mode == normal");
+    cx.add_bindings(vec![
+        Binding::new("i", SwitchMode(Mode::Insert), context),
+        Binding::new("h", MoveLeft, context),
+        Binding::new("j", MoveDown, context),
+        Binding::new("k", MoveUp, context),
+        Binding::new("l", MoveRight, context),
+    ]);
+
+    cx.add_action(move_left);
+    cx.add_action(move_down);
+    cx.add_action(move_up);
+    cx.add_action(move_right);
+}
+
+fn move_left(_: &mut Workspace, _: &MoveLeft, cx: &mut ViewContext<Workspace>) {
+    VimState::update_active_editor(cx, |editor, cx| {
+        editor.adjusted_move_cursors(cx, |map, mut cursor, _| {
+            *cursor.column_mut() = cursor.column().saturating_sub(1);
+            (map.clip_point(cursor, Bias::Left), SelectionGoal::None)
+        });
+    });
+}
+
+fn move_down(_: &mut Workspace, _: &MoveDown, cx: &mut ViewContext<Workspace>) {
+    VimState::update_active_editor(cx, |editor, cx| {
+        editor.adjusted_move_cursors(cx, movement::down);
+    });
+}
+
+fn move_up(_: &mut Workspace, _: &MoveUp, cx: &mut ViewContext<Workspace>) {
+    VimState::update_active_editor(cx, |editor, cx| {
+        editor.adjusted_move_cursors(cx, movement::up);
+    });
+}
+
+fn move_right(_: &mut Workspace, _: &MoveRight, cx: &mut ViewContext<Workspace>) {
+    VimState::update_active_editor(cx, |editor, cx| {
+        editor.adjusted_move_cursors(cx, |map, mut cursor, _| {
+            *cursor.column_mut() += 1;
+            (map.clip_point(cursor, Bias::Right), SelectionGoal::None)
+        });
+    });
+}