/*
 * Copyright 2014 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.tests.swtbot.model;

import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.ViewerColumn;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swtbot.eclipse.finder.SWTWorkbenchBot;
import org.eclipse.swtbot.eclipse.finder.widgets.SWTBotView;
import org.eclipse.swtbot.swt.finder.SWTBot;
import org.eclipse.swtbot.swt.finder.finders.UIThreadRunnable;
import org.eclipse.swtbot.swt.finder.results.BoolResult;
import org.eclipse.swtbot.swt.finder.results.VoidResult;
import org.eclipse.swtbot.swt.finder.utils.TableCollection;
import org.eclipse.swtbot.swt.finder.widgets.SWTBotTree;
import org.eclipse.swtbot.swt.finder.widgets.SWTBotTreeItem;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

abstract public class AbstractTreeBotView extends AbstractBotView {

  public AbstractTreeBotView(SWTWorkbenchBot bot) {
    super(bot);
  }

  /**
   * Select the item at the end of the given tree path.
   * 
   * @param items the names of tree nodes to expand
   * @return the selected item
   */
  public SWTBotTreeItem select(String... items) {
    assertTrue(items.length > 0);
    SWTBotTree tree = tree();
    waitForAnalysis();
    waitForTreeContent(tree);
    SWTBotTreeItem item;
    try {
      item = tree.expandNode(items);
    } catch (Exception ex) {
      // TODO[messick] Remove after dartbug/19563 (danrubel) is fixed
      String last = items[items.length - 1];
      int index = last.indexOf('[');
      if (index > 0) {
        last = last.substring(0, index - 1);
        String[] next = new String[items.length];
        System.arraycopy(items, 0, next, 0, items.length - 1);
        next[next.length - 1] = last;
        item = tree.expandNode(next);
        items = next;
      } else {
        fail();
        throw new RuntimeException(ex);
      }
    }
    tree.select(item);
    waitForAnalysis();
    waitForAsyncDrain();
    TableCollection selection = tree.selection();
    assertNotNull(selection);
    assertEquals(selection.rowCount(), 1);
    assertEquals(items[items.length - 1], selection.get(0, 0));
    return item;
  }

  /**
   * Get the current tree selection. If the tree is empty it is assumed that it has not been updated
   * yet, so loop until it is. DO NOT use this method on a tree that is empty!
   * 
   * @return the tree selection
   */
  public TableCollection selection() {
    SWTBotTree tree = tree();
    waitForTreeContent(tree);
    TableCollection selection = tree.selection();
    return selection;
  }

  /**
   * Perform one of the widget traversal operations specified by the given SWT constant.
   * 
   * @param traversal the SWT constant that identifies the traversal, eg SWT.TRAVERSE_ESCAPE
   */
  public void traverse(final int traversal) {
    UIThreadRunnable.syncExec(new VoidResult() {
      @Override
      public void run() {
        tree().widget.traverse(traversal);
      }
    });
  }

  /**
   * Get the SWTBotTree for this view.
   * 
   * @return the SWTBotTree
   */
  public SWTBotTree tree() {
    SWTBotView files = bot.viewByPartName(viewName());
    SWTBot bot = files.bot();
    SWTBotTree tree = bot.tree();
    return tree;
  }

  /**
   * Get the current tree size. If the tree is empty it is assumed that it has not been updated yet,
   * so loop until it is. DO NOT use this method on a tree that is empty!
   * 
   * @return the tree selection
   */
  public int treeSize() {
    SWTBotTree tree = tree();
    waitForTreeContent(tree);
    int size = tree.visibleRowCount();
    return size;
  }

  /**
   * Change the selection to nothing.
   * 
   * @return the tree item
   */
  public SWTBotTree unselectAll() {
    SWTBotTree tree = tree();
    tree.unselect();
    return tree;
  }

  /**
   * Give the <code>botTree</code> time to update, and return when it is finished.
   * 
   * @param botTable a SWTBotTable
   */
  protected void waitForTreeContent(SWTBotTree botTree) {
    while (isTreeEmpty(botTree) || isTreeBusy(botTree)) {
      waitMillis(1);
    }
  }

  /**
   * Viewers are difficult to work with using SWTBot. The only way to know when a tree has finished
   * updating is to check <code>isBusy()</code> but there's no easy way to get to the viewer from a
   * tree. This technique uses some black magic to determine if the tree is busy.
   * 
   * @param botTree the TreeViewer bot to query
   * @return true if the tree is busy
   */
  private boolean isTreeBusy(final SWTBotTree botTree) {
    return UIThreadRunnable.syncExec(new BoolResult() {
      @Override
      public Boolean run() {
        Tree tree = botTree.widget;
        ViewerColumn col = (ViewerColumn) tree.getData("org.eclipse.jface.columnViewer");
        TreeViewer treeViewer = (TreeViewer) col.getViewer();
        return treeViewer.isBusy();
      }
    });
  }

  private boolean isTreeEmpty(final SWTBotTree botTree) {
    return !botTree.hasItems();
  }
}