// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

part of $LIBRARYNAME;

/**
 * Lazy implementation of the child nodes of an element that does not request
 * the actual child nodes of an element until strictly necessary greatly
 * improving performance for the typical cases where it is not required.
 */
class _ChildNodeListLazy extends ListBase<Node> implements NodeListWrapper {
  final Node _this;

  _ChildNodeListLazy(this._this);


  Node get first {
    Node$NULLABLE result = JS('Node|Null', '#.firstChild', _this);
    if (result == null) throw new StateError("No elements");
    return result;
  }
  Node get last {
    Node$NULLABLE result = JS('Node|Null', '#.lastChild', _this);
    if (result == null) throw new StateError("No elements");
    return result;
  }
  Node get single {
    int l = this.length;
    if (l == 0) throw new StateError("No elements");
    if (l > 1) throw new StateError("More than one element");
    return JS('Node|Null', '#.firstChild', _this)$NULLASSERT;
  }

  void add(Node value) {
    _this.append(value);
  }

  void addAll(Iterable<Node> iterable) {
    if (iterable is _ChildNodeListLazy) {
      _ChildNodeListLazy otherList = iterable;
      if (!identical(otherList._this, _this)) {
        // Optimized route for copying between nodes.
        for (var i = 0, len = otherList.length; i < len; ++i) {
          _this.append(otherList._this.firstChild$NULLASSERT);
        }
      }
      return;
    }
    for (Node node in iterable) {
      _this.append(node);
    }
  }

  void insert(int index, Node node) {
    if (index < 0 || index > length) {
      throw new RangeError.range(index, 0, length);
    }
    if (index == length) {
      _this.append(node);
    } else {
      _this.insertBefore(node, this[index]);
    }
  }

  void insertAll(int index, Iterable<Node> iterable) {
    if (index == length) {
      addAll(iterable);
    } else {
      var item = this[index];
      _this.insertAllBefore(iterable, item);
    }
  }

  void setAll(int index, Iterable<Node> iterable) {
    throw new UnsupportedError("Cannot setAll on Node list");
  }

  Node removeLast() {
    final result = last;
    if (result != null) {
      _this._removeChild(result);
    }
    return result;
  }

  Node removeAt(int index) {
    var result = this[index];
    if (result != null) {
      _this._removeChild(result);
    }
    return result;
  }

  bool remove(Object$NULLABLE object) {
    if (object is! Node) return false;
    Node node = object;
    if (!identical(_this, node.parentNode)) return false;
    _this._removeChild(node);
    return true;
  }

  void _filter(bool test(Node node), bool removeMatching) {
    // This implementation of removeWhere/retainWhere is more efficient
    // than the default in ListBase. Child nodes can be removed in constant
    // time.
    Node$NULLABLE child = _this.firstChild;
    while (child != null) {
      Node$NULLABLE nextChild = child.nextNode;
      if (test(child) == removeMatching) {
        _this._removeChild(child);
      }
      child = nextChild;
    }
  }

  void removeWhere(bool test(Node node)) {
    _filter(test, true);
  }

  void retainWhere(bool test(Node node)) {
    _filter(test, false);
  }

  void clear() {
    _this._clearChildren();
  }

  void operator []=(int index, Node value) {
    _this._replaceChild(value, this[index]);
  }

  Iterator<Node> get iterator => _this.childNodes.iterator;

  // From List<Node>:

  // TODO(jacobr): this could be implemented for child node lists.
  // The exception we throw here is misleading.
  void sort([Comparator<Node>$NULLABLE compare]) {
    throw new UnsupportedError("Cannot sort Node list");
  }

  void shuffle([Random$NULLABLE random]) {
    throw new UnsupportedError("Cannot shuffle Node list");
  }

  // FIXME: implement these.
  void setRange(int start, int end, Iterable<Node> iterable,
                [int skipCount = 0]) {
    throw new UnsupportedError("Cannot setRange on Node list");
  }

  void fillRange(int start, int end, [Node$NULLABLE fill]) {
    throw new UnsupportedError("Cannot fillRange on Node list");
  }

  void removeRange(int start, int end) {
    throw new UnsupportedError("Cannot removeRange on Node list");
  }
  // -- end List<Node> mixins.

  // TODO(jacobr): benchmark whether this is more efficient or whether caching
  // a local copy of childNodes is more efficient.
  int get length => _this.childNodes.length;

  set length(int value) {
    throw new UnsupportedError(
        "Cannot set length on immutable List.");
  }

  Node operator[](int index) => _this.childNodes[index];

  List<Node> get rawList => _this.childNodes;
}


$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {

  // Custom element created callback.
  Node._created() : super._created();

  /**
   * A modifiable list of this node's children.
   */
  List<Node> get nodes {
    return new _ChildNodeListLazy(this);
  }

  set nodes(Iterable<Node> value) {
    // Copy list first since we don't want liveness during iteration.
    // TODO(jacobr): there is a better way to do this.
    var copy = value.toList();
    text = '';
    for (Node node in copy) {
      append(node);
    }
  }

  /**
   * Removes this node from the DOM.
   */
  void remove() {
    // TODO(jacobr): should we throw an exception if parent is already null?
    // TODO(vsm): Use the native remove when available.
    if (this.parentNode != null) {
      final Node parent = this.parentNode$NULLASSERT;
      parent._removeChild(this);
    }
  }

  /**
   * Replaces this node with another node.
   */
  Node replaceWith(Node otherNode) {
    try {
      final Node parent = this.parentNode$NULLASSERT;
      parent._replaceChild(otherNode, this);
    } catch (e) {}
    return this;
  }

  /**
   * Inserts all of the nodes into this node directly before refChild.
   *
   * See also:
   *
   * * [insertBefore]
   */
  void insertAllBefore(Iterable<Node> newNodes, Node refChild) {
    if (newNodes is _ChildNodeListLazy) {
      _ChildNodeListLazy otherList = newNodes;
      if (identical(otherList._this, this)) {
        throw new ArgumentError(newNodes);
      }

      // Optimized route for copying between nodes.
      for (var i = 0, len = otherList.length; i < len; ++i) {
        this.insertBefore(otherList._this.firstChild$NULLASSERT, refChild);
      }
    } else {
      for (var node in newNodes) {
        this.insertBefore(node, refChild);
      }
    }
  }

  void _clearChildren() {
    while (firstChild != null) {
      _removeChild(firstChild$NULLASSERT);
    }
  }

  /**
   * Print out a String representation of this Node.
   */
  String toString() {
    String$NULLABLE value = nodeValue;  // Fetch DOM Node property once.
    return value == null ? super.toString() : value;
  }

  /**
   * A list of this node's children.
   *
   * ## Other resources
   *
   * * [Node.childNodes](https://developer.mozilla.org/en-US/docs/Web/API/Node.childNodes)
   *   from MDN.
   */
  @Returns('NodeList')
  @Creates('NodeList')
  List<Node> get childNodes native;

$!MEMBERS
}