// 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 html;

/**
 * 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 implements List {
  final Node _this;

  _ChildNodeListLazy(this._this);


$if DART2JS
  Node get first => JS('Node', '#.firstChild', _this);
  Node get last => JS('Node', '#.lastChild', _this);
$else
  Node get first => _this.$dom_firstChild;
  Node get last => _this.$dom_lastChild;
$endif

  void add(Node value) {
    _this.$dom_appendChild(value);
  }

  void addLast(Node value) {
    _this.$dom_appendChild(value);
  }


  void addAll(Collection<Node> collection) {
    for (Node node in collection) {
      _this.$dom_appendChild(node);
    }
  }

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

  void clear() {
    _this.text = '';
  }

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

  Iterator<Node> iterator() => _this.$dom_childNodes.iterator();

  // TODO(jacobr): We can implement these methods much more efficiently by
  // looking up the nodeList only once instead of once per iteration.
  bool contains(Node element) => _Collections.contains(this, element);

  void forEach(void f(Node element)) => _Collections.forEach(this, f);

  Collection map(f(Node element)) => _Collections.map(this, [], f);

  Collection<Node> filter(bool f(Node element)) =>
     new _NodeListWrapper(_Collections.filter(this, <Node>[], f));

  bool every(bool f(Node element)) => _Collections.every(this, f);

  bool some(bool f(Node element)) => _Collections.some(this, f);

  bool get isEmpty => this.length == 0;

  // From List<Node>:

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

  int indexOf(Node element, [int start = 0]) =>
      _Lists.indexOf(this, element, start, this.length);

  int lastIndexOf(Node element, [int start = 0]) =>
      _Lists.lastIndexOf(this, element, start);

  // FIXME: implement these.
  void setRange(int start, int rangeLength, List<Node> from, [int startFrom]) {
    throw new UnsupportedError(
        "Cannot setRange on immutable List.");
  }
  void removeRange(int start, int rangeLength) {
    throw new UnsupportedError(
        "Cannot removeRange on immutable List.");
  }
  void insertRange(int start, int rangeLength, [Node initialValue]) {
    throw new UnsupportedError(
        "Cannot insertRange on immutable List.");
  }
  List<Node> getRange(int start, int rangeLength) =>
    new _NodeListWrapper(_Lists.getRange(this, start, rangeLength, <Node>[]));

  // -- end List<Node> mixins.

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

  Node operator[](int index) => _this.$dom_childNodes[index];
}

class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
  _ChildNodeListLazy get nodes {
    return new _ChildNodeListLazy(this);
  }

  void set nodes(Collection<Node> value) {
    // Copy list first since we don't want liveness during iteration.
    // TODO(jacobr): there is a better way to do this.
    List copy = new List.from(value);
    text = '';
    for (Node node in copy) {
      $dom_appendChild(node);
    }
  }

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

  /**
   * Replaces this node with another node.
   * @domName Node.replaceChild
   */
  Node replaceWith(Node otherNode) {
    try {
      final Node parent = this.parent;
      parent.$dom_replaceChild(otherNode, this);
    } catch (e) {

    };
    return this;
  }

$!MEMBERS
}