/*
 * Copyright (c) 2012-2018 Red Hat, Inc.
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *   Red Hat, Inc. - initial API and implementation
 */
package org.eclipse.che.ide.part.explorer.project.macro;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.Iterables.filter;
import static com.google.common.collect.Iterables.transform;

import com.google.common.annotations.Beta;
import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Predicate;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import java.util.List;
import javax.annotation.Nullable;
import org.eclipse.che.api.promises.client.Promise;
import org.eclipse.che.api.promises.client.PromiseProvider;
import org.eclipse.che.ide.CoreLocalizationConstant;
import org.eclipse.che.ide.api.macro.Macro;
import org.eclipse.che.ide.api.resources.Resource;
import org.eclipse.che.ide.part.explorer.project.ProjectExplorerPresenter;
import org.eclipse.che.ide.resources.tree.ResourceNode;
import org.eclipse.che.ide.ui.smartTree.data.Node;

/**
 * Provider which is responsible for retrieving the resource name from the project explorer.
 *
 * <p>Macro provided: <code>${explorer.current.file.name}</code>
 *
 * <p>In case if project explorer has more than one selected file, comma separated file list is
 * returned.
 *
 * @author Vlad Zhukovskyi
 * @see Macro
 * @see ProjectExplorerPresenter
 * @since 4.7.0
 */
@Beta
@Singleton
public class ExplorerCurrentFileNameMacro implements Macro {

  public static final String KEY = "${explorer.current.file.name}";

  private Predicate<Node> resNodePredicate =
      new Predicate<Node>() {
        @Override
        public boolean apply(@Nullable Node input) {
          checkNotNull(input);

          return input instanceof ResourceNode;
        }
      };

  private Function<Node, Resource> nodeToResourceFun =
      new Function<Node, Resource>() {
        @Nullable
        @Override
        public Resource apply(@Nullable Node input) {
          checkNotNull(input);
          checkState(input instanceof ResourceNode);

          return ((ResourceNode) input).getData();
        }
      };

  private Function<Resource, String> resourceToNameFun =
      new Function<Resource, String>() {
        @Nullable
        @Override
        public String apply(@Nullable Resource input) {
          checkNotNull(input);

          return input.getName();
        }
      };

  private ProjectExplorerPresenter projectExplorer;
  private PromiseProvider promises;
  private final CoreLocalizationConstant localizationConstants;

  @Inject
  public ExplorerCurrentFileNameMacro(
      ProjectExplorerPresenter projectExplorer,
      PromiseProvider promises,
      CoreLocalizationConstant localizationConstants) {
    this.projectExplorer = projectExplorer;
    this.promises = promises;
    this.localizationConstants = localizationConstants;
  }

  /** {@inheritDoc} */
  @Override
  public String getName() {
    return KEY;
  }

  @Override
  public String getDescription() {
    return localizationConstants.macroExplorerCurrentFileNameDescription();
  }

  /** {@inheritDoc} */
  @Override
  public Promise<String> expand() {

    List<Node> selectedNodes = projectExplorer.getTree().getSelectionModel().getSelectedNodes();

    if (selectedNodes.isEmpty()) {
      return promises.resolve("");
    }

    final Iterable<Resource> resources =
        transform(filter(selectedNodes, resNodePredicate), nodeToResourceFun);
    final String commaSeparated = Joiner.on(", ").join(transform(resources, resourceToNameFun));

    return promises.resolve(commaSeparated);
  }
}
