textUnwrapSelection function

Implementation

TextCommandResult textUnwrapSelection({
  required TextDocument document,
  required TextOffsetStateSnapshot state,
  required Map<String, String> surroundPairs,
}) {
  final selection = normalizedSelectionRange(
    state.selectionBaseOffset,
    state.selectionExtentOffset,
  );
  if (selection == null || selection.start == selection.end) {
    return _unchangedDocumentCommandResult(document, state);
  }

  if (selection.start < 1 || selection.end >= document.length) {
    return _unchangedDocumentCommandResult(document, state);
  }

  final leading = document.graphemeAt(selection.start - 1);
  final trailing = document.graphemeAt(selection.end);
  if (surroundPairs[leading] != trailing) {
    return _unchangedDocumentCommandResult(document, state);
  }

  final selected = document.textInRange(
    startOffset: selection.start,
    endOffset: selection.end,
  );
  final working = document.copy();
  final result = edit_ops.replaceDocumentTextRange(
    working,
    start: selection.start - 1,
    end: selection.end + 1,
    replacement: selected,
  );
  final nextSelectionStart = selection.start - 1;
  final nextSelectionEnd = nextSelectionStart + selected.characters.length;

  return _documentCommandResult(
    working,
    cursorOffset: nextSelectionEnd,
    selectionBaseOffset: nextSelectionStart,
    selectionExtentOffset: nextSelectionEnd,
    documentChange: result.change,
    changed: result.changed,
  );
}