/*
 * Copyright 2000-2010 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * 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 org.jetbrains.android.dom;

import com.android.SdkConstants;
import com.intellij.lang.ASTNode;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.Computable;
import com.intellij.openapi.util.TextRange;
import com.intellij.psi.PsiFile;
import com.intellij.psi.impl.source.xml.SchemaPrefix;
import com.intellij.psi.impl.source.xml.TagNameReference;
import com.intellij.psi.xml.XmlFile;
import com.intellij.psi.xml.XmlTag;
import com.intellij.xml.DefaultXmlExtension;
import org.jetbrains.android.dom.manifest.ManifestDomFileDescription;
import org.jetbrains.android.facet.AndroidFacet;
import org.jetbrains.android.util.AndroidResourceUtil;
import org.jetbrains.annotations.Nullable;

/**
 * @author Eugene.Kudelevsky
 */
public class AndroidXmlExtension extends DefaultXmlExtension {
  @Nullable
  @Override
  public TagNameReference createTagNameReference(ASTNode nameElement, boolean startTagFlag) {
    return AndroidXmlReferenceProvider.areReferencesProvidedByReferenceProvider(nameElement)
           ? null
           : new AndroidClassTagNameReference(nameElement, startTagFlag);
  }

  @Override
  public boolean isAvailable(final PsiFile file) {
    if (file instanceof XmlFile) {
      Project project = file.getProject();
      if (AndroidFacet.getInstance(file) == null) {
        return false;
      }
      return ApplicationManager.getApplication().runReadAction(new Computable<Boolean>() {
        @Override
        public Boolean compute() {
          return AndroidResourceUtil.isInResourceSubdirectory(file, null) ||
                 ManifestDomFileDescription.isManifestFile((XmlFile)file);
        }
      });
    }
    return false;
  }

  @Override
  public SchemaPrefix getPrefixDeclaration(final XmlTag context, String namespacePrefix) {
    SchemaPrefix prefix = super.getPrefixDeclaration(context, namespacePrefix);
    if (prefix != null) {
      return prefix;
    }

    if (namespacePrefix.isEmpty()) {
      // In for example XHTML documents, the root element looks like this:
      //  <html xmlns="http://www.w3.org/1999/xhtml">
      // This means that the IDE can find the namespace for "".
      //
      // However, in Android XML files it's implicit, so just return a dummy SchemaPrefix so
      // // that we don't end up with a
      //      Namespace ''{0}'' is not bound
      // error from {@link XmlUnboundNsPrefixInspection#checkUnboundNamespacePrefix}
      return new SchemaPrefix(null, new TextRange(0, 0), SdkConstants.ANDROID_NS_NAME);
    }

    return null;
  }
}