/*
 * Copyright 2016 The Bazel Authors. All rights reserved.
 *
 * 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 com.google.idea.blaze.base.lang.buildfile.completion;

import com.intellij.patterns.ElementPattern;
import com.intellij.patterns.PatternCondition;
import com.intellij.psi.PsiElement;
import com.intellij.util.ProcessingContext;
import org.jetbrains.annotations.NotNull;

import static com.intellij.patterns.PlatformPatterns.psiElement;

/**
 * Filter patterns used by completion contributors.
 */
public class FilterPatterns {

  public static final ElementPattern<PsiElement> indexInParentsChildren(final int childIndex) {
    return psiElement().with(new PatternCondition<PsiElement>("isIndexInParentsChildren") {
      @Override
      public boolean accepts(@NotNull PsiElement psiElement, ProcessingContext context) {
        final PsiElement parent = psiElement.getParent();
        if (parent != null) {
          final PsiElement[] children = parent.getChildren();
          if (childIndex < children.length  && psiElement.equals(children[childIndex])) {
            return true;
          }
        }
        return false;
      }
    });
  }

}