findCommonParent function

Implementation

Module? findCommonParent(Module firstChild, Module secondChild) {
  final firstPath = List<Module>.from(firstChild.hierarchy(), growable: false);
  final secondPath =
      List<Module>.from(secondChild.hierarchy(), growable: false);

  if (firstChild.parent == secondChild.parent && firstChild.parent != null) {
    return firstChild.parent;
  }

  if (firstPath[0] != secondPath[0]) {
    // base top parent is not the same, no common parent
    return null;
  }

  if (firstChild == secondChild) {
    // if the two modules are the same, return that module as the common parent
    return firstChild;
  }

  if (secondPath.contains(firstChild) && !firstPath.contains(secondChild)) {
    // firstChild is in the parent hierarchy of second
    return firstChild;
  } else if (!secondPath.contains(firstChild) &&
      firstPath.contains(secondChild)) {
    // secondChild is in the parent hierarchy of first
    return secondChild;
  }

  for (var i = 0; i < firstPath.length; i++) {
    if (firstPath[i] != secondPath[i]) {
      // Assumption there has to be one common parent at the top
      return firstPath[i - 1];
    }
  }

  return null;
}