// Copyright 2017 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.analysis;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.analysis.config.BuildOptions;
import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
import com.google.devtools.build.lib.analysis.config.FragmentOptions;
import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
import com.google.devtools.build.lib.cmdline.Label;

/** A loader that creates {@link PlatformConfiguration} instances based on command-line options. */
public class PlatformConfigurationLoader implements ConfigurationFragmentFactory {
  @Override
  public ImmutableSet<Class<? extends FragmentOptions>> requiredOptions() {
    return ImmutableSet.<Class<? extends FragmentOptions>>of(PlatformOptions.class);
  }

  @Override
  public PlatformConfiguration create(ConfigurationEnvironment env, BuildOptions buildOptions)
      throws InvalidConfigurationException, InterruptedException {
    PlatformOptions platformOptions = buildOptions.get(PlatformOptions.class);
    return create(platformOptions);
  }

  @Override
  public Class<? extends BuildConfiguration.Fragment> creates() {
    return PlatformConfiguration.class;
  }

  private PlatformConfiguration create(PlatformOptions options)
      throws InvalidConfigurationException {

    if (options.hostPlatform == null) {
      throw new InvalidConfigurationException("Host platform not set");
    }
    Label targetPlatform = Iterables.getFirst(options.platforms, null);
    if (targetPlatform == null) {
      throw new InvalidConfigurationException("Target platform not set");
    }
    return new PlatformConfiguration(
        options.hostPlatform,
        ImmutableList.copyOf(options.extraExecutionPlatforms),
        targetPlatform,
        ImmutableList.copyOf(options.extraToolchains),
        ImmutableList.copyOf(options.enabledToolchainTypes));
  }
}