/*
 * Copyright (c) 2012, 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.tools.ui.internal.testing;

import com.google.dart.tools.core.DartCore;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceChangeEvent;
import org.eclipse.core.resources.IResourceChangeListener;
import org.eclipse.core.resources.IResourceVisitor;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.widgets.Display;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * A tree content provider for the Tests view.
 */
class TestsContentProvider implements ITreeContentProvider, IResourceChangeListener {
  private static final IResource[] NO_CHILDREN = new IResource[0];

//  private IProject project;
  private Viewer viewer;

  TestsContentProvider(IProject project) {
//    this.project = project;

    ResourcesPlugin.getWorkspace().addResourceChangeListener(this);
  }

  @Override
  public void dispose() {
    ResourcesPlugin.getWorkspace().removeResourceChangeListener(this);
  }

  @Override
  public Object[] getChildren(Object element) {
    try {
      if (element instanceof IProject) {
        IProject project = (IProject) element;

        return getChildDartFiles(project);
      } else if (element instanceof IFile) {
        IFile file = (IFile) element;

        return getTestsElementsFor(file).toArray();
      }
    } catch (CoreException ce) {
      // fall through

    }

    return NO_CHILDREN;
  }

  @Override
  public Object[] getElements(Object inputElement) {
    return getChildren(inputElement);
  }

  @Override
  public Object getParent(Object element) {
    if (element instanceof IResource) {
      return ((IResource) element).getProject();
    } else if (element instanceof DartUnitElement) {
      DartUnitElement dartElement = (DartUnitElement) element;

      if (dartElement.getParent() != null) {
        return dartElement.getParent();
      } else {
        return dartElement.getDartFile();
      }
    } else {
      return null;
    }
  }

  @Override
  public boolean hasChildren(Object element) {
    return getChildren(element).length > 0;
  }

  @Override
  public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
    this.viewer = viewer;
  }

  @Override
  public void resourceChanged(IResourceChangeEvent event) {
    // TODO: filter on project

    Display.getDefault().asyncExec(new Runnable() {
      @Override
      public void run() {
        if (viewer != null && !viewer.getControl().isDisposed()) {
          viewer.refresh();
        }
      }
    });
  }

  protected boolean isFiltered(IContainer container) {
    return !DartCore.isAnalyzed(container);
  }

  private IFile[] getChildDartFiles(IProject project) throws CoreException {
    final List<IFile> files = new ArrayList<IFile>();

    project.accept(new IResourceVisitor() {
      @Override
      public boolean visit(IResource resource) throws CoreException {
        if (resource instanceof IContainer) {
          return !isFiltered((IContainer) resource);
        } else if (resource instanceof IFile) {
          IFile file = (IFile) resource;

          if (DartCore.isDartLikeFileName(file.getName())) {
            files.add(file);
          }

          return true;
        } else {

          return false;
        }
      }
    });

    return files.toArray(new IFile[files.size()]);
  }

  private List<DartUnitElement> getTestsElementsFor(IFile file) {
    return Collections.emptyList();
  }
}