/*
 * Copyright (c) 2014, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.dart.engine.internal.html.angular;

import com.google.dart.engine.element.angular.AngularDecoratorElement;
import com.google.dart.engine.element.angular.AngularPropertyElement;
import com.google.dart.engine.element.angular.AngularPropertyKind;
import com.google.dart.engine.element.angular.AngularSelectorElement;
import com.google.dart.engine.html.ast.XmlAttributeNode;
import com.google.dart.engine.html.ast.XmlTagNode;
import com.google.dart.engine.internal.element.angular.HasAttributeSelectorElementImpl;
import com.google.dart.engine.type.Type;

/**
 * {@link NgDecoratorElementProcessor} applies {@link AngularDecoratorElement} by parsing mapped
 * attributes as expressions.
 */
class NgDecoratorElementProcessor extends NgDirectiveProcessor {
  private final AngularDecoratorElement element;

  public NgDecoratorElementProcessor(AngularDecoratorElement element) {
    this.element = element;
  }

  @Override
  public void apply(AngularHtmlUnitResolver resolver, XmlTagNode node) {
    String selectorAttributeName = null;
    {
      AngularSelectorElement selector = element.getSelector();
      if (selector instanceof HasAttributeSelectorElementImpl) {
        selectorAttributeName = ((HasAttributeSelectorElementImpl) selector).getName();
        // resolve attribute expression
        XmlAttributeNode attribute = node.getAttribute(selectorAttributeName);
        if (attribute != null) {
          attribute.setElement(selector);
        }
      }
    }
    //
    for (AngularPropertyElement property : element.getProperties()) {
      // prepare attribute name
      String name = property.getName();
      if (name.equals(".")) {
        name = selectorAttributeName;
      }
      // prepare attribute
      XmlAttributeNode attribute = node.getAttribute(name);
      if (attribute == null) {
        continue;
      }
      // if not resolved as the selector, resolve as a property
      if (!name.equals(selectorAttributeName)) {
        attribute.setElement(property);
      }
      // skip if attribute has no value
      if (!hasValue(attribute)) {
        continue;
      }
      // resolve if binding
      if (property.getPropertyKind() != AngularPropertyKind.ATTR) {
        resolver.pushNameScope();
        try {
          onNgEventDirective(resolver);
          AngularExpression expression = parseAngularExpression(resolver, attribute);
          resolver.resolveExpression(expression);
          setAngularExpression(attribute, expression);
        } finally {
          resolver.popNameScope();
        }
      }
    }
  }

  @Override
  public boolean canApply(XmlTagNode node) {
    return element.getSelector().apply(node);
  }

  /**
   * Support for <code>$event</code> variable in <code>NgEventDirective</code>.
   */
  private void onNgEventDirective(AngularHtmlUnitResolver resolver) {
    if (element.isClass("NgEventDirective")) {
      Type dynamicType = resolver.getTypeProvider().getDynamicType();
      resolver.defineVariable(resolver.createLocalVariableWithName(dynamicType, "$event"));
    }
  }
}