/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.apache.giraph.block_app.framework.block;
  
  import java.util.Iterator;
  
  import org.apache.giraph.block_app.framework.piece.AbstractPiece;
  import org.apache.giraph.function.Consumer;
  import org.apache.giraph.function.Supplier;
  
  /**
   * Block that executes one of two branches based on a condition
   */
  @SuppressWarnings("rawtypes")
  public final class IfBlock implements Block {
    private final Block thenBlock;
    private final Block elseBlock;
    private final Supplier<Boolean> condition;
  
    public IfBlock(
        Supplier<Boolean> condition, Block thenBlock, Block elseBlock) {
      this.condition = condition;
      this.thenBlock = thenBlock;
      this.elseBlock = elseBlock;
    }
  
    public IfBlock(Supplier<Boolean> condition, Block thenBlock) {
      this.condition = condition;
      this.thenBlock = thenBlock;
      this.elseBlock = new EmptyBlock();
    }
  
    @Override
    public Iterator<AbstractPiece> iterator() {
      if (Boolean.TRUE.equals(condition.get())) {
        return thenBlock.iterator();
      } else {
        return elseBlock.iterator();
      }
    }
  
    @Override
    public void forAllPossiblePieces(Consumer<AbstractPiece> consumer) {
      thenBlock.forAllPossiblePieces(consumer);
      elseBlock.forAllPossiblePieces(consumer);
    }
  
    @Override
    public PieceCount getPieceCount() {
      PieceCount thenCount = thenBlock.getPieceCount();
      PieceCount elseCount = elseBlock.getPieceCount();
      return thenCount.equals(elseCount) ?
          thenCount : PieceCount.createUnknownCount();
    }
  
    @Override
    public String toString() {
      if (elseBlock instanceof EmptyBlock) {
        return "IfBlock(" + thenBlock + ")";
      }
      return "IfBlock(" + thenBlock + " , " + elseBlock + ")";
    }
  }