/*
 * Copyright 2014-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.rules.coercer;

import com.facebook.buck.apple.xcode.xcodeproj.SourceTreePath;
import com.facebook.buck.rules.BuildRule;
import com.facebook.buck.rules.RuleKeyAppendable;
import com.facebook.buck.rules.RuleKeyObjectSink;
import com.facebook.buck.rules.SourcePath;
import com.facebook.buck.rules.SourcePathRuleFinder;
import com.facebook.buck.util.OptionalCompat;
import com.facebook.buck.util.immutables.BuckStyleImmutable;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.io.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Optional;
import org.immutables.value.Value;

/**
 * Frameworks can be specified as either a path to a file, or a path prefixed by a build setting.
 */
@Value.Immutable
@BuckStyleImmutable
abstract class AbstractFrameworkPath
    implements Comparable<AbstractFrameworkPath>, RuleKeyAppendable {

  /** The type of framework entry this object represents. */
  protected enum Type {
    /** An Xcode style {@link SourceTreePath}. */
    SOURCE_TREE_PATH,
    /** A Buck style {@link SourcePath}. */
    SOURCE_PATH,
  }

  @Value.Parameter
  protected abstract Type getType();

  @Value.Parameter
  public abstract Optional<SourceTreePath> getSourceTreePath();

  @Value.Parameter
  public abstract Optional<SourcePath> getSourcePath();

  public Iterable<BuildRule> getDeps(SourcePathRuleFinder ruleFinder) {
    return ruleFinder.filterBuildRuleInputs(OptionalCompat.asSet(getSourcePath()));
  }

  public Path getFileName(Function<SourcePath, Path> resolver) {
    switch (getType()) {
      case SOURCE_TREE_PATH:
        return getSourceTreePath().get().getPath().getFileName();
      case SOURCE_PATH:
        return Preconditions.checkNotNull(resolver.apply(getSourcePath().get())).getFileName();
      default:
        throw new RuntimeException("Unhandled type: " + getType());
    }
  }

  public String getName(Function<SourcePath, Path> resolver) {
    String fileName = getFileName(resolver).toString();
    return Files.getNameWithoutExtension(fileName);
  }

  public static Path getUnexpandedSearchPath(
      Function<SourcePath, Path> resolver,
      Function<? super Path, Path> relativizer,
      FrameworkPath input) {
    return convertToPath(resolver, relativizer, input).getParent();
  }

  private static Path convertToPath(
      Function<SourcePath, Path> resolver,
      Function<? super Path, Path> relativizer,
      FrameworkPath input) {
    switch (input.getType()) {
      case SOURCE_TREE_PATH:
        return Paths.get(input.getSourceTreePath().get().toString());
      case SOURCE_PATH:
        return relativizer.apply(
            Preconditions.checkNotNull(resolver.apply(input.getSourcePath().get())));
      default:
        throw new RuntimeException("Unhandled type: " + input.getType());
    }
  }

  @Value.Check
  protected void check() {
    switch (getType()) {
      case SOURCE_TREE_PATH:
        Preconditions.checkArgument(getSourceTreePath().isPresent());
        Preconditions.checkArgument(!getSourcePath().isPresent());
        break;
      case SOURCE_PATH:
        Preconditions.checkArgument(!getSourceTreePath().isPresent());
        Preconditions.checkArgument(getSourcePath().isPresent());
        break;
      default:
        throw new RuntimeException("Unhandled type: " + getType());
    }
  }

  @Override
  public int compareTo(AbstractFrameworkPath o) {
    if (this == o) {
      return 0;
    }

    int typeComparisonResult = getType().ordinal() - o.getType().ordinal();
    if (typeComparisonResult != 0) {
      return typeComparisonResult;
    }
    switch (getType()) {
      case SOURCE_TREE_PATH:
        return getSourceTreePath().get().compareTo(o.getSourceTreePath().get());
      case SOURCE_PATH:
        return getSourcePath().get().compareTo(o.getSourcePath().get());
      default:
        throw new RuntimeException("Unhandled type: " + getType());
    }
  }

  @Override
  public void appendToRuleKey(RuleKeyObjectSink sink) {
    sink.setReflectively("sourcePath", getSourcePath());
    sink.setReflectively("sourceTree", getSourceTreePath().map(Object::toString));
  }

  public static FrameworkPath ofSourceTreePath(SourceTreePath sourceTreePath) {
    return FrameworkPath.of(Type.SOURCE_TREE_PATH, Optional.of(sourceTreePath), Optional.empty());
  }

  public static FrameworkPath ofSourcePath(SourcePath sourcePath) {
    return FrameworkPath.of(Type.SOURCE_PATH, Optional.empty(), Optional.of(sourcePath));
  }
}