// Copyright (c) 2019, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8.features;

import com.android.tools.r8.FeatureSplit;
import com.android.tools.r8.ProgramResource;
import com.android.tools.r8.ProgramResourceProvider;
import com.android.tools.r8.ResourceException;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.DexProgramClass;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.naming.ClassNameMapper;
import com.android.tools.r8.utils.DescriptorUtils;
import com.android.tools.r8.utils.Reporter;
import com.google.common.collect.Sets;
import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class FeatureSplitConfiguration {
  private final List<FeatureSplit> featureSplits;

  private final Map<String, FeatureSplit> javaTypeToFeatureSplitMapping = new HashMap<>();

  public FeatureSplitConfiguration(List<FeatureSplit> featureSplits, Reporter reporter) {
    this.featureSplits = featureSplits;
    for (FeatureSplit featureSplit : featureSplits) {
      for (ProgramResourceProvider programResourceProvider :
          featureSplit.getProgramResourceProviders()) {
        try {
          for (ProgramResource programResource : programResourceProvider.getProgramResources()) {
            for (String classDescriptor : programResource.getClassDescriptors()) {
              javaTypeToFeatureSplitMapping.put(
                  DescriptorUtils.descriptorToJavaType(classDescriptor), featureSplit);
            }
          }
        } catch (ResourceException e) {
          throw reporter.fatalError(e.getMessage());
        }
      }
    }
  }

  public Map<FeatureSplit, Set<DexProgramClass>> getFeatureSplitClasses(
      Set<DexProgramClass> classes, ClassNameMapper mapper) {
    Map<FeatureSplit, Set<DexProgramClass>> result = new IdentityHashMap<>();

    for (DexProgramClass programClass : classes) {
      String originalClassName =
          DescriptorUtils.descriptorToJavaType(programClass.type.toDescriptorString(), mapper);
      FeatureSplit featureSplit = javaTypeToFeatureSplitMapping.get(originalClassName);
      if (featureSplit != null) {
        result.computeIfAbsent(featureSplit, f -> Sets.newIdentityHashSet()).add(programClass);
      }
    }
    return result;
  }

  public boolean inSameFeatureOrBase(DexMethod a, DexMethod b) {
    return inSameFeatureOrBase(a.holder, b.holder);
  }

  public boolean inSameFeatureOrBase(DexType a, DexType b) {
    assert a.isClassType() && b.isClassType();
    if (javaTypeToFeatureSplitMapping.isEmpty()) {
      return true;
    }
    // TODO(141451259): Consider doing the mapping from DexType to Feature (with support in mapper)
    return javaTypeToFeatureSplitMapping.get(
            DescriptorUtils.descriptorToJavaType(a.toDescriptorString()))
        == javaTypeToFeatureSplitMapping.get(
            DescriptorUtils.descriptorToJavaType(b.toDescriptorString()));
  }

  public List<FeatureSplit> getFeatureSplits() {
    return featureSplits;
  }
}