// Copyright (c) 2017, 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.utils;

import com.android.tools.r8.dex.ApplicationReader.ProgramClassConflictResolver;
import com.android.tools.r8.errors.DuplicateTypesDiagnostic;
import com.android.tools.r8.graph.ClassKind;
import com.android.tools.r8.graph.DexProgramClass;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.ir.desugar.BackportedMethodRewriter;
import com.android.tools.r8.ir.desugar.DesugaredLibraryWrapperSynthesizer;
import com.android.tools.r8.ir.desugar.InterfaceMethodRewriter;
import com.android.tools.r8.ir.desugar.LambdaRewriter;
import com.android.tools.r8.ir.desugar.NestBasedAccessDesugaring;
import com.android.tools.r8.ir.desugar.TwrCloseResourceRewriter;
import com.android.tools.r8.references.Reference;
import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;

/** Represents a collection of library classes. */
public class ProgramClassCollection extends ClassMap<DexProgramClass> {

  private final ProgramClassConflictResolver conflictResolver;

  public static ProgramClassCollection create(
      List<DexProgramClass> classes, ProgramClassConflictResolver conflictResolver) {
    // We have all classes preloaded, but not necessarily without conflicts.
    ConcurrentHashMap<DexType, Supplier<DexProgramClass>> map = new ConcurrentHashMap<>();
    for (DexProgramClass clazz : classes) {
      map.merge(
          clazz.type, clazz, (a, b) -> conflictResolver.resolveClassConflict(a.get(), b.get()));
    }
    return new ProgramClassCollection(map, conflictResolver);
  }

  private ProgramClassCollection(
      ConcurrentHashMap<DexType, Supplier<DexProgramClass>> classes,
      ProgramClassConflictResolver conflictResolver) {
    super(classes, null);
    this.conflictResolver = conflictResolver;
  }

  @Override
  public String toString() {
    return "program classes: " + super.toString();
  }

  @Override
  DexProgramClass resolveClassConflict(DexProgramClass a, DexProgramClass b) {
    return conflictResolver.resolveClassConflict(a, b);
  }

  @Override
  Supplier<DexProgramClass> getTransparentSupplier(DexProgramClass clazz) {
    return clazz;
  }

  @Override
  ClassKind getClassKind() {
    return ClassKind.PROGRAM;
  }

  public static ProgramClassConflictResolver disallowClassConflictsResolver(Reporter reporter) {
    return (DexProgramClass a, DexProgramClass b) -> {
      assert a.type == b.type;
      // Only allow collapsing synthetic lambda, nest constructor, dispatch and twr-utility classes.
      if (a.originatesFromDexResource()
          && b.originatesFromDexResource()
          && a.accessFlags.isSynthetic()
          && b.accessFlags.isSynthetic()
          && assumeClassesAreEqual(a)) {
        return a;
      }
      throw reporter.fatalError(
          new DuplicateTypesDiagnostic(
              Reference.classFromDescriptor(a.type.toDescriptorString()),
              ImmutableList.of(a.getOrigin(), b.getOrigin())));
    };
  }

  private static boolean assumeClassesAreEqual(DexProgramClass a) {
    return LambdaRewriter.hasLambdaClassPrefix(a.type)
        || BackportedMethodRewriter.hasRewrittenMethodPrefix(a.type)
        || InterfaceMethodRewriter.hasDispatchClassSuffix(a.type)
        || NestBasedAccessDesugaring.isNestConstructor(a.type)
        || DesugaredLibraryWrapperSynthesizer.isSynthesizedWrapper(a.type)
        || a.type.descriptor.toString().equals(TwrCloseResourceRewriter.UTILITY_CLASS_DESCRIPTOR);
  }
}