/*
 * Copyright 2015-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.facebook.buck.io.MorePaths;
import com.facebook.buck.util.immutables.BuckStyleImmutable;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;

import org.immutables.value.Value;

import java.nio.file.Path;
import java.nio.file.Paths;

import javax.annotation.Nullable;

@BuckStyleImmutable
@Value.Immutable
public abstract class UnflavoredBuildTarget
    implements Comparable<UnflavoredBuildTarget>, HasUnflavoredBuildTarget {

  public static final String BUILD_TARGET_PREFIX = "//";

  @Value.Check
  protected void check() {
    Preconditions.checkArgument(
        getBaseName().startsWith(BUILD_TARGET_PREFIX),
        "baseName must start with %s but was %s",
        BUILD_TARGET_PREFIX,
        getBaseName());

    // On Windows, baseName may contain backslashes, which are not permitted.
    Preconditions.checkArgument(
        !getBaseName().contains("\\"),
        "baseName may not contain backslashes.");

    Preconditions.checkArgument(
        getShortName().lastIndexOf("#") == -1,
        "Build target name cannot contain '#' but was: %s.",
        getShortName());

    Preconditions.checkArgument(
        !getShortName().contains("#"),
        "Build target name cannot contain '#' but was: %s.",
        getShortName());
  }

  @Value.Parameter
  public abstract Optional<String> getRepository();

  /**
   * If this build target were //third_party/java/guava:guava-latest, then this would return
   * "//third_party/java/guava".
   */
  @Value.Parameter
  public abstract String getBaseName();

  /**
   * If this build target were //third_party/java/guava:guava-latest, then this would return
   * "//third_party/java/guava/".
   */
  @Nullable
  public String getBaseNameWithSlash() {
    return getBaseNameWithSlash(getBaseName());
  }

  /**
   * Helper function for getting BuildTarget base names with a trailing slash if needed.
   *
   * If baseName were //third_party/java/guava, then this would return  "//third_party/java/guava/".
   * If it were //, it would return //.
   */
  public static String getBaseNameWithSlash(String baseName) {
    return baseName == null || baseName.equals(BUILD_TARGET_PREFIX) ? baseName : baseName + "/";
  }

  /**
   * If this build target were //third_party/java/guava:guava-latest, then this would return
   * "third_party/java/guava". This does not contain the "//" prefix so that it can be appended to
   * a file path.
   */
  public Path getBasePath() {
    return Paths.get(getBaseName().substring(BUILD_TARGET_PREFIX.length()));
  }

  /**
   * @return the value of {@link #getBasePath()} with a trailing slash, unless
   *     {@link #getBasePath()} returns the empty string, in which case this also returns the empty
   *     string
   */
  public String getBasePathWithSlash() {
    String basePath = MorePaths.pathWithUnixSeparators(getBasePath());
    return basePath.isEmpty() ? "" : basePath + "/";
  }

  @Value.Parameter
  public abstract String getShortName();

  /**
   * If this build target is //third_party/java/guava:guava-latest, then this would return
   * "//third_party/java/guava:guava-latest".
   */
  public String getFullyQualifiedName() {
    return (getRepository().isPresent() ? "@" + getRepository().get() : "") +
        getBaseName() + ":" + getShortName();
  }

  public static ImmutableUnflavoredBuildTarget.Builder builder(UnflavoredBuildTarget buildTarget) {
    return ImmutableUnflavoredBuildTarget
        .builder()
        .setRepository(buildTarget.getRepository())
        .setBaseName(buildTarget.getBaseName())
        .setShortName(buildTarget.getShortName());
  }

  public static ImmutableUnflavoredBuildTarget.Builder builder(String baseName, String shortName) {
    return ImmutableUnflavoredBuildTarget
        .builder()
        .setRepository(Optional.<String>absent())
        .setBaseName(baseName)
        .setShortName(shortName);
  }

  /** @return {@link #getFullyQualifiedName()} */
  @Override
  public String toString() {
    return getFullyQualifiedName();
  }

  @Override
  public int compareTo(@Nullable UnflavoredBuildTarget target) {
    Preconditions.checkNotNull(target);
    return getFullyQualifiedName().compareTo(target.getFullyQualifiedName());
  }

  @Override
  public UnflavoredBuildTarget getUnflavoredBuildTarget() {
    return this;
  }

}