/*
 * Copyright (C) 2012 The Guava Authors
 *
 * 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.common.io;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.io.TestOption.CLOSE_THROWS;
import static com.google.common.io.TestOption.OPEN_THROWS;
import static com.google.common.io.TestOption.READ_THROWS;
import static com.google.common.io.TestOption.SKIP_THROWS;

import com.google.common.collect.ImmutableSet;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;

/**
 * @author Colin Decker
 */
public class TestInputStream extends FilterInputStream {

  private final ImmutableSet<TestOption> options;
  private boolean closed;

  public TestInputStream(InputStream in, TestOption... options) throws IOException {
    this(in, Arrays.asList(options));
  }

  public TestInputStream(InputStream in, Iterable<TestOption> options) throws IOException {
    super(checkNotNull(in));
    this.options = ImmutableSet.copyOf(options);
    throwIf(OPEN_THROWS);
  }

  public boolean closed() {
    return closed;
  }

  @Override
  public int read() throws IOException {
    throwIf(closed);
    throwIf(READ_THROWS);
    return in.read();
  }

  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    throwIf(closed);
    throwIf(READ_THROWS);
    return in.read(b, off, len);
  }

  @Override
  public long skip(long n) throws IOException {
    throwIf(closed);
    throwIf(SKIP_THROWS);
    return in.skip(n);
  }

  @Override
  public int available() throws IOException {
    throwIf(closed);
    return options.contains(TestOption.AVAILABLE_ALWAYS_ZERO) ? 0 : in.available();
  }

  @Override
  public void close() throws IOException {
    closed = true;
    throwIf(CLOSE_THROWS);
    in.close();
  }

  private void throwIf(TestOption option) throws IOException {
    throwIf(options.contains(option));
  }

  private static void throwIf(boolean condition) throws IOException {
    if (condition) {
      throw new IOException();
    }
  }
}
