// 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.

// TODO(jacobr): use _Lists.dart to remove some of the duplicated
// functionality.
class _ChildrenElementList implements List {
  // Raw Element.
  final _ElementImpl _element;
  final _HTMLCollectionImpl _childElements;

  _ChildrenElementList._wrap(_ElementImpl element)
    : _childElements = element.$dom_children,
      _element = element;

  List<Element> _toList() {
    final output = new List(_childElements.length);
    for (int i = 0, len = _childElements.length; i < len; i++) {
      output[i] = _childElements[i];
    }
    return output;
  }

  bool contains(Element element) => _childElements.contains(element);

  void forEach(void f(Element element)) {
    for (_ElementImpl element in _childElements) {
      f(element);
    }
  }

  List<Element> filter(bool f(Element element)) {
    final output = [];
    forEach((Element element) {
      if (f(element)) {
        output.add(element);
      }
    });
    return new _FrozenElementList._wrap(output);
  }

  bool every(bool f(Element element)) {
    for (Element element in this) {
      if (!f(element)) {
        return false;
      }
    };
    return true;
  }

  bool some(bool f(Element element)) {
    for (Element element in this) {
      if (f(element)) {
        return true;
      }
    };
    return false;
  }

  Collection map(f(Element element)) {
    final out = [];
    for (Element el in this) {
      out.add(f(el));
    }
    return out;
  }

  bool get isEmpty {
    return _element.$dom_firstElementChild == null;
  }

  int get length {
    return _childElements.length;
  }

  _ElementImpl operator [](int index) {
    return _childElements[index];
  }

  void operator []=(int index, _ElementImpl value) {
    _element.$dom_replaceChild(value, _childElements[index]);
  }

   void set length(int newLength) {
     // TODO(jacobr): remove children when length is reduced.
     throw new UnsupportedError('');
   }

  Element add(_ElementImpl value) {
    _element.$dom_appendChild(value);
    return value;
  }

  Element addLast(_ElementImpl value) => add(value);

  Iterator<Element> iterator() => _toList().iterator();

  void addAll(Collection<Element> collection) {
    for (_ElementImpl element in collection) {
      _element.$dom_appendChild(element);
    }
  }

  void sort([Comparator<Element> compare = Comparable.compare]) {
    throw new UnsupportedError('TODO(jacobr): should we impl?');
  }

  void setRange(int start, int rangeLength, List from, [int startFrom = 0]) {
    throw const NotImplementedException();
  }

  void removeRange(int start, int rangeLength) {
    throw const NotImplementedException();
  }

  void insertRange(int start, int rangeLength, [initialValue = null]) {
    throw const NotImplementedException();
  }

  List getRange(int start, int rangeLength) =>
    new _FrozenElementList._wrap(_Lists.getRange(this, start, rangeLength,
        []));

  int indexOf(Element element, [int start = 0]) {
    return _Lists.indexOf(this, element, start, this.length);
  }

  int lastIndexOf(Element element, [int start = null]) {
    if (start == null) start = length - 1;
    return _Lists.lastIndexOf(this, element, start);
  }

  void clear() {
    // It is unclear if we want to keep non element nodes?
    _element.text = '';
  }

  Element removeLast() {
    final result = this.last;
    if (result != null) {
      _element.$dom_removeChild(result);
    }
    return result;
  }

  Element get last {
    return _element.$dom_lastElementChild;
  }
}

// TODO(jacobr): this is an inefficient implementation but it is hard to see
// a better option given that we cannot quite force NodeList to be an
// ElementList as there are valid cases where a NodeList JavaScript object
// contains Node objects that are not Elements.
class _FrozenElementList implements List {
  final List<Node> _nodeList;

  _FrozenElementList._wrap(this._nodeList);

  Element get first {
    return _nodeList[0];
  }

  bool contains(Element element) {
    for (Element el in this) {
      if (el == element) return true;
    }
    return false;
  }

  void forEach(void f(Element element)) {
    for (Element el in this) {
      f(el);
    }
  }

  Collection map(f(Element element)) {
    final out = [];
    for (Element el in this) {
      out.add(f(el));
    }
    return out;
  }

  List<Element> filter(bool f(Element element)) {
    final out = [];
    for (Element el in this) {
      if (f(el)) out.add(el);
    }
    return out;
  }

  bool every(bool f(Element element)) {
    for(Element element in this) {
      if (!f(element)) {
        return false;
      }
    };
    return true;
  }

  bool some(bool f(Element element)) {
    for(Element element in this) {
      if (f(element)) {
        return true;
      }
    };
    return false;
  }

  bool get isEmpty => _nodeList.isEmpty;

  int get length => _nodeList.length;

  Element operator [](int index) => _nodeList[index];

  void operator []=(int index, Element value) {
    throw new UnsupportedError('');
  }

  void set length(int newLength) {
    _nodeList.length = newLength;
  }

  void add(Element value) {
    throw new UnsupportedError('');
  }

  void addLast(Element value) {
    throw new UnsupportedError('');
  }

  Iterator<Element> iterator() => new _FrozenElementListIterator(this);

  void addAll(Collection<Element> collection) {
    throw new UnsupportedError('');
  }

  void sort([Comparator<Element> compare = Comparable.compare]) {
    throw new UnsupportedError('');
  }

  void setRange(int start, int rangeLength, List from, [int startFrom = 0]) {
    throw new UnsupportedError('');
  }

  void removeRange(int start, int rangeLength) {
    throw new UnsupportedError('');
  }

  void insertRange(int start, int rangeLength, [initialValue = null]) {
    throw new UnsupportedError('');
  }

  List<Element> getRange(int start, int rangeLength) =>
    new _FrozenElementList._wrap(_nodeList.getRange(start, rangeLength));

  int indexOf(Element element, [int start = 0]) =>
    _nodeList.indexOf(element, start);

  int lastIndexOf(Element element, [int start = null]) =>
    _nodeList.lastIndexOf(element, start);

  void clear() {
    throw new UnsupportedError('');
  }

  Element removeLast() {
    throw new UnsupportedError('');
  }

  Element get last => _nodeList.last;
}

class _FrozenElementListIterator implements Iterator<Element> {
  final _FrozenElementList _list;
  int _index = 0;

  _FrozenElementListIterator(this._list);

  /**
   * Gets the next element in the iteration. Throws a
   * [StateError("No more elements")] if no element is left.
   */
  Element next() {
    if (!hasNext) {
      throw new StateError("No more elements");
    }

    return _list[_index++];
  }

  /**
   * Returns whether the [Iterator] has elements left.
   */
  bool get hasNext => _index < _list.length;
}

class _ElementAttributeMap implements AttributeMap {

  final _ElementImpl _element;

  _ElementAttributeMap(this._element);

  bool containsValue(String value) {
    final attributes = _element.$dom_attributes;
    for (int i = 0, len = attributes.length; i < len; i++) {
      if(value == attributes[i].value) {
        return true;
      }
    }
    return false;
  }

  bool containsKey(String key) {
    return _element.$dom_hasAttribute(key);
  }

  String operator [](String key) {
    return _element.$dom_getAttribute(key);
  }

  void operator []=(String key, value) {
    _element.$dom_setAttribute(key, '$value');
  }

  String putIfAbsent(String key, String ifAbsent()) {
    if (!containsKey(key)) {
      this[key] = ifAbsent();
    }
    return this[key];
  }

  String remove(String key) {
    String value = _element.$dom_getAttribute(key);
    _element.$dom_removeAttribute(key);
    return value;
  }

  void clear() {
    final attributes = _element.$dom_attributes;
    for (int i = attributes.length - 1; i >= 0; i--) {
      remove(attributes[i].name);
    }
  }

  void forEach(void f(String key, String value)) {
    final attributes = _element.$dom_attributes;
    for (int i = 0, len = attributes.length; i < len; i++) {
      final item = attributes[i];
      f(item.name, item.value);
    }
  }

  Collection<String> get keys {
    // TODO(jacobr): generate a lazy collection instead.
    final attributes = _element.$dom_attributes;
    final keys = new List<String>(attributes.length);
    for (int i = 0, len = attributes.length; i < len; i++) {
      keys[i] = attributes[i].name;
    }
    return keys;
  }

  Collection<String> get values {
    // TODO(jacobr): generate a lazy collection instead.
    final attributes = _element.$dom_attributes;
    final values = new List<String>(attributes.length);
    for (int i = 0, len = attributes.length; i < len; i++) {
      values[i] = attributes[i].value;
    }
    return values;
  }

  /**
   * The number of {key, value} pairs in the map.
   */
  int get length {
    return _element.$dom_attributes.length;
  }

  /**
   * Returns true if there is no {key, value} pair in the map.
   */
  bool get isEmpty {
    return length == 0;
  }
}

/**
 * Provides a Map abstraction on top of data-* attributes, similar to the
 * dataSet in the old DOM.
 */
class _DataAttributeMap implements AttributeMap {

  final Map<String, String> $dom_attributes;

  _DataAttributeMap(this.$dom_attributes);

  // interface Map

  // TODO: Use lazy iterator when it is available on Map.
  bool containsValue(String value) => values.some((v) => v == value);

  bool containsKey(String key) => $dom_attributes.containsKey(_attr(key));

  String operator [](String key) => $dom_attributes[_attr(key)];

  void operator []=(String key, value) {
    $dom_attributes[_attr(key)] = '$value';
  }

  String putIfAbsent(String key, String ifAbsent()) =>
    $dom_attributes.putIfAbsent(_attr(key), ifAbsent);

  String remove(String key) => $dom_attributes.remove(_attr(key));

  void clear() {
    // Needs to operate on a snapshot since we are mutating the collection.
    for (String key in keys) {
      remove(key);
    }
  }

  void forEach(void f(String key, String value)) {
    $dom_attributes.forEach((String key, String value) {
      if (_matches(key)) {
        f(_strip(key), value);
      }
    });
  }

  Collection<String> get keys {
    final keys = new List<String>();
    $dom_attributes.forEach((String key, String value) {
      if (_matches(key)) {
        keys.add(_strip(key));
      }
    });
    return keys;
  }

  Collection<String> get values {
    final values = new List<String>();
    $dom_attributes.forEach((String key, String value) {
      if (_matches(key)) {
        values.add(value);
      }
    });
    return values;
  }

  int get length => keys.length;

  // TODO: Use lazy iterator when it is available on Map.
  bool get isEmpty => length == 0;

  // Helpers.
  String _attr(String key) => 'data-$key';
  bool _matches(String key) => key.startsWith('data-');
  String _strip(String key) => key.substring(5);
}

class _CssClassSet implements CSSClassSet {

  final _ElementImpl _element;

  _CssClassSet(this._element);

  String toString() => _formatSet(_read());

  // interface Iterable - BEGIN
  Iterator<String> iterator() => _read().iterator();
  // interface Iterable - END

  // interface Collection - BEGIN
  void forEach(void f(String element)) {
    _read().forEach(f);
  }

  Collection map(f(String element)) => _read().map(f);

  Collection<String> filter(bool f(String element)) => _read().filter(f);

  bool every(bool f(String element)) => _read().every(f);

  bool some(bool f(String element)) => _read().some(f);

  bool get isEmpty => _read().isEmpty;

  bool get frozen => false;

  int get length =>_read().length;

  // interface Collection - END

  // interface Set - BEGIN
  bool contains(String value) => _read().contains(value);

  void add(String value) {
    // TODO - figure out if we need to do any validation here
    // or if the browser natively does enough
    _modify((s) => s.add(value));
  }

  bool remove(String value) {
    Set<String> s = _read();
    bool result = s.remove(value);
    _write(s);
    return result;
  }

  bool toggle(String value) {
    Set<String> s = _read();
    bool result = false;
    if (s.contains(value)) {
      s.remove(value);
    } else {
      s.add(value);
      result = true;
    }
    _write(s);
    return result;
  }

  void addAll(Collection<String> collection) {
    // TODO - see comment above about validation
    _modify((s) => s.addAll(collection));
  }

  void removeAll(Collection<String> collection) {
    _modify((s) => s.removeAll(collection));
  }

  bool isSubsetOf(Collection<String> collection) =>
    _read().isSubsetOf(collection);

  bool containsAll(Collection<String> collection) =>
    _read().containsAll(collection);

  Set<String> intersection(Collection<String> other) =>
    _read().intersection(other);

  void clear() {
    _modify((s) => s.clear());
  }
  // interface Set - END

  /**
   * Helper method used to modify the set of css classes on this element.
   *
   *   f - callback with:
   *      s - a Set of all the css class name currently on this element.
   *
   *   After f returns, the modified set is written to the
   *       className property of this element.
   */
  void _modify( f(Set<String> s)) {
    Set<String> s = _read();
    f(s);
    _write(s);
  }

  /**
   * Read the class names from the Element class property,
   * and put them into a set (duplicates are discarded).
   */
  Set<String> _read() {
    // TODO(mattsh) simplify this once split can take regex.
    Set<String> s = new Set<String>();
    for (String name in _classname().split(' ')) {
      String trimmed = name.trim();
      if (!trimmed.isEmpty) {
        s.add(trimmed);
      }
    }
    return s;
  }

  /**
   * Read the class names as a space-separated string. This is meant to be
   * overridden by subclasses.
   */
  String _classname() => _element.$dom_className;

  /**
   * Join all the elements of a set into one string and write
   * back to the element.
   */
  void _write(Set s) {
    _element.$dom_className = _formatSet(s);
  }

  String _formatSet(Set<String> s) {
    // TODO(mattsh) should be able to pass Set to String.joins http:/b/5398605
    List list = new List.from(s);
    return Strings.join(list, ' ');
  }
}

class _SimpleClientRect implements ClientRect {
  final num left;
  final num top;
  final num width;
  final num height;
  num get right => left + width;
  num get bottom => top + height;

  const _SimpleClientRect(this.left, this.top, this.width, this.height);

  bool operator ==(ClientRect other) {
    return other != null && left == other.left && top == other.top
        && width == other.width && height == other.height;
  }

  String toString() => "($left, $top, $width, $height)";
}

// TODO(jacobr): we cannot currently be lazy about calculating the client
// rects as we must perform all measurement queries at a safe point to avoid
// triggering unneeded layouts.
/**
 * All your element measurement needs in one place
 * @domName none
 */
class _ElementRectImpl implements ElementRect {
  final ClientRect client;
  final ClientRect offset;
  final ClientRect scroll;

  // TODO(jacobr): should we move these outside of ElementRect to avoid the
  // overhead of computing them every time even though they are rarely used.
  final _ClientRectImpl _boundingClientRect;
  final _ClientRectListImpl _clientRects;

  _ElementRectImpl(_ElementImpl element) :
    client = new _SimpleClientRect(element.clientLeft,
                                  element.clientTop,
                                  element.clientWidth,
                                  element.clientHeight),
    offset = new _SimpleClientRect(element.offsetLeft,
                                  element.offsetTop,
                                  element.offsetWidth,
                                  element.offsetHeight),
    scroll = new _SimpleClientRect(element.scrollLeft,
                                  element.scrollTop,
                                  element.scrollWidth,
                                  element.scrollHeight),
    _boundingClientRect = element.getBoundingClientRect(),
    _clientRects = element.getClientRects();

  _ClientRectImpl get bounding => _boundingClientRect;

  // TODO(jacobr): cleanup.
  List<ClientRect> get clientRects {
    final out = new List(_clientRects.length);
    for (num i = 0; i < _clientRects.length; i++) {
      out[i] = _clientRects.item(i);
    }
    return out;
  }
}

class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {

  /**
   * @domName Element.hasAttribute, Element.getAttribute, Element.setAttribute,
   *   Element.removeAttribute
   */
  _ElementAttributeMap get attributes => new _ElementAttributeMap(this);

  void set attributes(Map<String, String> value) {
    Map<String, String> attributes = this.attributes;
    attributes.clear();
    for (String key in value.keys) {
      attributes[key] = value[key];
    }
  }

  void set elements(Collection<Element> value) {
    final elements = this.elements;
    elements.clear();
    elements.addAll(value);
  }

  List<Element> get elements => new _ChildrenElementList._wrap(this);

  _ElementImpl query(String selectors) => $dom_querySelector(selectors);

  List<Element> queryAll(String selectors) =>
    new _FrozenElementList._wrap($dom_querySelectorAll(selectors));

  _CssClassSet get classes => new _CssClassSet(this);

  void set classes(Collection<String> value) {
    _CssClassSet classSet = classes;
    classSet.clear();
    classSet.addAll(value);
  }

  Map<String, String> get dataAttributes =>
    new _DataAttributeMap(attributes);

  void set dataAttributes(Map<String, String> value) {
    final dataAttributes = this.dataAttributes;
    dataAttributes.clear();
    for (String key in value.keys) {
      dataAttributes[key] = value[key];
    }
  }

  Future<ElementRect> get rect {
    return _createMeasurementFuture(
        () => new _ElementRectImpl(this),
        new Completer<ElementRect>());
  }

  Future<CSSStyleDeclaration> get computedStyle {
     // TODO(jacobr): last param should be null, see b/5045788
     return getComputedStyle('');
  }

  Future<CSSStyleDeclaration> getComputedStyle(String pseudoElement) {
    return _createMeasurementFuture(
        () => _window.$dom_getComputedStyle(this, pseudoElement),
        new Completer<CSSStyleDeclaration>());
  }

  void addText(String text) {
    this.insertAdjacentText('beforeend', text);
  }

  void addHTML(String text) {
    this.insertAdjacentHTML('beforeend', text);
  }

  // Hooks to support custom WebComponents.
  var xtag;

$if DARTIUM
  noSuchMethod(String name, List args) {
    if (dynamicUnknownElementDispatcher == null) {
      throw new NoSuchMethodError(this, name, args);
    } else {
      return dynamicUnknownElementDispatcher(this, name, args);
    }
  }
$else
  // TODO(vsm): Implement noSuchMethod or similar for dart2js.
$endif

$if DART2JS
  /** @domName Element.insertAdjacentText */
  void insertAdjacentText(String where, String text) {
    if (JS('bool', '!!#.insertAdjacentText', this)) {
      _insertAdjacentText(where, text);
    } else {
      _insertAdjacentNode(where, new Text(text));
    }
  }

  void _insertAdjacentText(String where, String text)
      native 'insertAdjacentText';

  /** @domName Element.insertAdjacentHTML */
  void insertAdjacentHTML(String where, String text) {
    if (JS('bool', '!!#.insertAdjacentHTML', this)) {
      _insertAdjacentHTML(where, text);
    } else {
      _insertAdjacentNode(where, new DocumentFragment.html(text));
    }
  }

  void _insertAdjacentHTML(String where, String text)
      native 'insertAdjacentHTML';

  /** @domName Element.insertAdjacentHTML */
  Element insertAdjacentElement(String where, Element element) {
    if (JS('bool', '!!#.insertAdjacentElement', this)) {
      _insertAdjacentElement(where, element);
    } else {
      _insertAdjacentNode(where, element);
    }
    return element;
  }

  void _insertAdjacentElement(String where, Element element)
      native 'insertAdjacentElement';

  void _insertAdjacentNode(String where, Node node) {
    switch (where.toLowerCase()) {
      case 'beforebegin':
        this.parent.insertBefore(node, this);
        break;
      case 'afterbegin':
        var first = this.nodes.length > 0 ? this.nodes[0] : null;
        this.insertBefore(node, first);
        break;
      case 'beforeend':
        this.nodes.add(node);
        break;
      case 'afterend':
        this.parent.insertBefore(node, this.nextNode);
        break;
      default:
        throw new ArgumentError("Invalid position ${where}");
    }
  }
$else
$endif

$!MEMBERS
}

// Temporary dispatch hook to support WebComponents.
Function dynamicUnknownElementDispatcher;

final _START_TAG_REGEXP = const RegExp('<(\\w+)');
class _ElementFactoryProvider {
  static final _CUSTOM_PARENT_TAG_MAP = const {
    'body' : 'html',
    'head' : 'html',
    'caption' : 'table',
    'td': 'tr',
    'colgroup': 'table',
    'col' : 'colgroup',
    'tr' : 'tbody',
    'tbody' : 'table',
    'tfoot' : 'table',
    'thead' : 'table',
    'track' : 'audio',
  };

  /** @domName Document.createElement */
  static Element createElement_html(String html) {
    // TODO(jacobr): this method can be made more robust and performant.
    // 1) Cache the dummy parent elements required to use innerHTML rather than
    //    creating them every call.
    // 2) Verify that the html does not contain leading or trailing text nodes.
    // 3) Verify that the html does not contain both <head> and <body> tags.
    // 4) Detatch the created element from its dummy parent.
    String parentTag = 'div';
    String tag;
    final match = _START_TAG_REGEXP.firstMatch(html);
    if (match != null) {
      tag = match.group(1).toLowerCase();
      if (_CUSTOM_PARENT_TAG_MAP.containsKey(tag)) {
        parentTag = _CUSTOM_PARENT_TAG_MAP[tag];
      }
    }
    final _ElementImpl temp = new Element.tag(parentTag);
    temp.innerHTML = html;

    Element element;
    if (temp.elements.length == 1) {
      element = temp.elements[0];
    } else if (parentTag == 'html' && temp.elements.length == 2) {
      // Work around for edge case in WebKit and possibly other browsers where
      // both body and head elements are created even though the inner html
      // only contains a head or body element.
      element = temp.elements[tag == 'head' ? 0 : 1];
    } else {
      throw new ArgumentError('HTML had ${temp.elements.length} '
          'top level elements but 1 expected');
    }
    element.remove();
    return element;
  }

  /** @domName Document.createElement */
$if DART2JS
  // Optimization to improve performance until the dart2js compiler inlines this
  // method.
  static Element createElement_tag(String tag) =>
      JS('Element', 'document.createElement(#)', tag);
$else
  static Element createElement_tag(String tag) =>
      _document.$dom_createElement(tag);
$endif
}