Fix offseting carets after edit without killing selection, add dedent

src/text_editor/buffer_history.cpp

@@ -132,11 +132,16 @@ void AfterEdit(Buffer *buffer, Array<Edit> *edits, Array<Caret> *carets, bool ki
         for (Int i = 0; i < carets->len; i += 1) {
             Caret &old_cursor = carets->data[i];
             Caret &new_cursor = new_carets.data[i];
+
             if (old_cursor.range.min == edit.range.min) {
                 new_cursor.range.min += insert_size;
-                new_cursor.range.max += insert_size;
             } else if (old_cursor.range.min > edit.range.min) {
                 new_cursor.range.min += offset;
+            }
+
+            if (old_cursor.range.max == edit.range.max) {
+                new_cursor.range.max += insert_size;
+            } else if (old_cursor.range.max > edit.range.max) {
                 new_cursor.range.max += offset;
             }
         }

src/text_editor/commands_window.cpp

@@ -31,7 +31,7 @@ void Command_DuplicateLine(View *view, int direction) {
     For(view->carets) it = MakeCaret(MovePos(*buffer, it.range.min, direction, false));
 }
 
-void Command_IndentSelectedLines(View *view) {
+void Command_IndentSelectedLines(View *view, bool shift = false) {
     Scratch scratch;
     Buffer *buffer = GetBuffer(view->active_buffer);
 
@@ -65,7 +65,18 @@ void Command_IndentSelectedLines(View *view) {
     For(line_ranges_to_indent) {
         for (Int i = it.min; i <= it.max; i += 1) {
             Range pos_range_of_line = GetLineRange(*buffer, i);
+
+            if (!shift) {
                 AddEdit(&edits, {pos_range_of_line.min, pos_range_of_line.min}, L"    ");
+            } else {
+                String16 string         = GetString(*buffer, pos_range_of_line);
+                Int      whitespace_len = 0;
+                for (Int i = 0; i < 4 && i < string.len && string.data[i] == ' '; i += 1) {
+                    whitespace_len += 1;
+                }
+
+                AddEdit(&edits, {pos_range_of_line.min, pos_range_of_line.min + whitespace_len}, L"");
+            }
         }
     }
 
@@ -401,8 +412,10 @@ void WindowCommand(Event event, Window *window, View *view) {
     }
 
     bool search = false;
-    if (Press(SDLK_TAB)) {
+    if (Shift(SDLK_TAB)) {
-        // Command_Replace(view, L"    ");
+        Command_IndentSelectedLines(view, SHIFT_PRESSED);
+        search = true;
+    } else if (Press(SDLK_TAB)) {
         Command_IndentSelectedLines(view);
         search = true;
     }

src/text_editor/todo.txt

@@ -6,6 +6,7 @@
 
 - underline the word which can be loaded / executed
 - search as a command to execute which is going to be in the title bar
+- I think the way sublime text and we display line highlights is confusing with multiple cursors (line highlight can be confused with selection)
 
 - commands:
     - indent selected lines