/*
 * Copyright 2012-present Facebook, Inc.
 *
 * 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.facebook.buck.model;

import com.google.common.base.Objects;
import com.google.common.base.Preconditions;

import javax.annotation.Nullable;

/**
 * A pattern matches build targets that have the specified ancestor directory.
 */
public class SubdirectoryBuildTargetPattern implements BuildTargetPattern {

  private final String basePathWithSlash;

  /**
   * @param basePathWithSlash The base path of the build target in the ancestor directory. It is
   *     expected to match the value returned from a {@link BuildTarget#getBasePathWithSlash()} call.
   */
  public SubdirectoryBuildTargetPattern(String basePathWithSlash) {
    Preconditions.checkNotNull(basePathWithSlash);
    Preconditions.checkArgument(basePathWithSlash.isEmpty() || basePathWithSlash.endsWith("/"),
        "basePathWithSlash must either be the empty string or end with a slash");
    this.basePathWithSlash = basePathWithSlash;
  }

  /**
   *
   * @return true if target not null and is under the directory basePathWithSlash,
   *         otherwise return false.
   */
  @Override
  public boolean apply(@Nullable BuildTarget target) {
    if (target == null) {
      return false;
    } else {
      return target.getBasePathWithSlash().startsWith(basePathWithSlash);
    }
  }

  @Override
  public boolean equals(Object o) {
    if (!(o instanceof SubdirectoryBuildTargetPattern)) {
      return false;
    }
    SubdirectoryBuildTargetPattern that = (SubdirectoryBuildTargetPattern)o;
    return Objects.equal(this.basePathWithSlash, that.basePathWithSlash);
  }

  @Override
  public int hashCode() {
    return Objects.hashCode(basePathWithSlash);
  }
}