// 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;

import com.android.tools.r8.utils.AndroidApiLevel;
import com.android.tools.r8.utils.InternalOptions;
import com.android.tools.r8.utils.StringDiagnostic;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import java.util.List;
import java.util.Map;

// TODO(134732760): This is still work in progress.
// The SpecialLibraryConfiguration is a set of flags for experimentation
// with the desugared JDK libraries which should be replaced by a D8/R8
// API level flag --coreLibraryDescriptor
public class SpecialLibraryConfiguration {

  private static Map<String, String> buildPrefixRewritingForProgramCompilationAllAndroid() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.concurrent.ConcurrentHashMap", "j$.util.concurrent.ConcurrentHashMap")
        .putAll(buildPrefixRewritingForProgramCompilationAndroidOPlus())
        .build();
  }

  private static Map<String, String> buildPrefixRewritingForProgramCompilationAndroidOPlus() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.stream.", "j$.util.stream.")
        .put("java.util.function.", "j$.util.function.")
        .put("java.util.DoubleSummaryStatistics", "j$.util.DoubleSummaryStatistics")
        .put("java.util.IntSummaryStatistics", "j$.util.IntSummaryStatistics")
        .put("java.util.LongSummaryStatistics", "j$.util.LongSummaryStatistics")
        .put("java.util.Optional", "j$.util.Optional")
        .put("java.util.PrimitiveIterator", "j$.util.PrimitiveIterator")
        .put("java.util.Spliterator", "j$.util.Spliterator")
        .put("java.util.StringJoiner", "j$.util.StringJoiner")
        .put("java.util.concurrent.ThreadLocalRandom", "j$.util.concurrent.ThreadLocalRandom")
        .put("java.util.concurrent.atomic.DesugarAtomic", "j$.util.concurrent.atomic.DesugarAtomic")
        .putAll(buildPrefixRewritingForProgramCompilationAndroidNPlus())
        .build();
  }

  private static Map<String, String> buildPrefixRewritingForProgramCompilationAndroidNPlus() {
    return ImmutableMap.<String, String>builder()
        .put("java.time.", "j$.time.")
        .put("java.util.Desugar", "j$.util.Desugar")
        .build();
  }

  private static Map<String, String>
      buildRetargetCoreLibraryMemberForProgramCompilationAllAndroid() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.Arrays#stream", "java.util.DesugarArrays")
        .put("java.util.Arrays#spliterator", "java.util.DesugarArrays")
        .put("java.util.LinkedHashSet#spliterator", "java.util.DesugarLinkedHashSet")
        .put(
            "java.util.concurrent.atomic.AtomicInteger#getAndUpdate",
            "java.util.concurrent.atomic.DesugarAtomicInteger")
        .put(
            "java.util.concurrent.atomic.AtomicInteger#updateAndGet",
            "java.util.concurrent.atomic.DesugarAtomicInteger")
        .put(
            "java.util.concurrent.atomic.AtomicInteger#getAndAccumulate",
            "java.util.concurrent.atomic.DesugarAtomicInteger")
        .put(
            "java.util.concurrent.atomic.AtomicInteger#accumulateAndGet",
            "java.util.concurrent.atomic.DesugarAtomicInteger")
        .put(
            "java.util.concurrent.atomic.AtomicLong#getAndUpdate",
            "java.util.concurrent.atomic.DesugarAtomicLong")
        .put(
            "java.util.concurrent.atomic.AtomicLong#updateAndGet",
            "java.util.concurrent.atomic.DesugarAtomicLong")
        .put(
            "java.util.concurrent.atomic.AtomicLong#getAndAccumulate",
            "java.util.concurrent.atomic.DesugarAtomicLong")
        .put(
            "java.util.concurrent.atomic.AtomicLong#accumulateAndGet",
            "java.util.concurrent.atomic.DesugarAtomicLong")
        .put(
            "java.util.concurrent.atomic.AtomicReference#getAndUpdate",
            "java.util.concurrent.atomic.DesugarAtomicReference")
        .put(
            "java.util.concurrent.atomic.AtomicReference#updateAndGet",
            "java.util.concurrent.atomic.DesugarAtomicReference")
        .put(
            "java.util.concurrent.atomic.AtomicReference#getAndAccumulate",
            "java.util.concurrent.atomic.DesugarAtomicReference")
        .put(
            "java.util.concurrent.atomic.AtomicReference#accumulateAndGet",
            "java.util.concurrent.atomic.DesugarAtomicReference")
        .putAll(buildRetargetCoreLibraryMemberForProgramCompilationAndroidNPlus())
        .build();
  }

  private static Map<String, String>
      buildRetargetCoreLibraryMemberForProgramCompilationAndroidNPlus() {
    // --retarget_core_library_member.
    return ImmutableMap.<String, String>builder()
        .put("java.util.Calendar#toInstant", "java.util.DesugarCalendar")
        .put("java.util.Date#from", "java.util.DesugarDate")
        .put("java.util.Date#toInstant", "java.util.DesugarDate")
        .put("java.util.GregorianCalendar#from", "java.util.DesugarGregorianCalendar")
        .put("java.util.GregorianCalendar#toZonedDateTime", "java.util.DesugarGregorianCalendar")
        .build();
  }

  private static Map<String, String> buildPrefixRewritingForCoreLibCompilationAllAndroid() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.concurrent.ConcurrentHashMap", "j$.util.concurrent.ConcurrentHashMap")
        .putAll(buildPrefixRewritingForCoreLibCompilationAndroidOPlus())
        .build();
  }

  private static Map<String, String> buildPrefixRewritingForCoreLibCompilationAndroidOPlus() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.stream.", "j$.util.stream.")
        .put("java.util.function.", "j$.util.function.")
        .put("java.util.Comparators", "j$.util.Comparators")
        .put("java.util.DoubleSummaryStatistics", "j$.util.DoubleSummaryStatistics")
        .put("java.util.IntSummaryStatistics", "j$.util.IntSummaryStatistics")
        .put("java.util.LongSummaryStatistics", "j$.util.LongSummaryStatistics")
        .put("java.util.Objects", "j$.util.Objects")
        .put("java.util.Optional", "j$.util.Optional")
        .put("java.util.PrimitiveIterator", "j$.util.PrimitiveIterator")
        .put("java.util.SortedSet$1", "j$.util.SortedSet$1")
        .put("java.util.Spliterator", "j$.util.Spliterator")
        .put("java.util.StringJoiner", "j$.util.StringJoiner")
        .put("java.util.Tripwire", "j$.util.Tripwire")
        .put("java.util.concurrent.DesugarUnsafe", "j$.util.concurrent.DesugarUnsafe")
        .put("java.util.concurrent.ThreadLocalRandom", "j$.util.concurrent.ThreadLocalRandom")
        .put("java.util.concurrent.atomic.DesugarAtomic", "j$.util.concurrent.atomic.DesugarAtomic")
        .putAll(buildPrefixRewritingForCoreLibCompilationAndroidNPlus())
        .build();
  }

  private static Map<String, String> buildPrefixRewritingForCoreLibCompilationAndroidNPlus() {
    return ImmutableMap.<String, String>builder()
        .put("java.time.", "j$.time.")
        .put("java.util.Desugar", "j$.util.Desugar")
        .build();
  }

  private static Map<String, String> buildRetargetCoreLibraryMemberForCoreLibCompilation() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.LinkedHashSet#spliterator", "java.util.DesugarLinkedHashSet")
        // Following 2 for testing only (core library with extensions).
        .put("java.util.Arrays#stream", "java.util.DesugarArrays")
        .put("java.util.Arrays#spliterator", "java.util.DesugarArrays")
        .build();
  }

  private static List<String> buildDontRewriteInvocations() {
    return ImmutableList.of("java.util.Iterator#remove");
  }

  private static Map<String, String> buildEmulateLibraryInterface() {
    return ImmutableMap.<String, String>builder()
        .put("java.util.Map$Entry", "j$.util.Map$Entry")
        .put("java.util.Collection", "j$.util.Collection")
        .put("java.util.Map", "j$.util.Map")
        .put("java.util.Iterator", "j$.util.Iterator")
        .put("java.util.Comparator", "j$.util.Comparator")
        // Extra flags: in R8 we marked as emulated all interfaces
        // with default methods. Emulated interfaces have their
        // companion class moved to j$ and have a dispatch class.
        // Bazel instead analyzes the class hierarchy.
        .put("java.util.List", "j$.util.List")
        .put("java.util.SortedSet", "j$.util.SortedSet")
        .put("java.util.Set", "j$.util.Set")
        .put("java.util.concurrent.ConcurrentMap", "j$.util.concurrent.ConcurrentMap")
        .build();
  }

  private static Map<String, String> buildBackportCoreLibraryMembers() {
    // R8 specific to deal with *8 removal.
    return ImmutableMap.<String, String>builder()
        .put("java.lang.Double8", "java.lang.Double")
        .put("java.lang.Integer8", "java.lang.Integer")
        .put("java.lang.Long8", "java.lang.Long")
        .put("java.lang.Math8", "java.lang.Math")
        .build();
  }

  public static void configureLibraryDesugaringForProgramCompilation(InternalOptions options) {
    // TODO(b/134732760): Make assertions in D8/R8 commands.
    if (options.minApiLevel >= AndroidApiLevel.O.getLevel()) {
      options.reporter.warning(
          new StringDiagnostic(
              "Desugaring core libraries for Android O and over is possible but not required."));
    }
    options.coreLibraryCompilation = false;
    if (options.minApiLevel < AndroidApiLevel.N.getLevel()) {
      if (options.minApiLevel < AndroidApiLevel.M.getLevel()) {
        options.rewritePrefix = buildPrefixRewritingForProgramCompilationAllAndroid();
      } else {
        options.rewritePrefix = buildPrefixRewritingForProgramCompilationAndroidOPlus();
      }
      options.retargetCoreLibMember =
          buildRetargetCoreLibraryMemberForProgramCompilationAllAndroid();
      options.emulateLibraryInterface = buildEmulateLibraryInterface();
      options.dontRewriteInvocations = buildDontRewriteInvocations();
    } else {
      options.rewritePrefix = buildPrefixRewritingForProgramCompilationAndroidNPlus();
      options.retargetCoreLibMember =
          buildRetargetCoreLibraryMemberForProgramCompilationAndroidNPlus();
    }
  }

  public static void configureLibraryDesugaringForLibraryCompilation(InternalOptions options) {
    // TODO(b/134732760): Make assertions in L8 commands.
    if (options.minApiLevel >= AndroidApiLevel.O.getLevel()) {
      options.reporter.warning(
          new StringDiagnostic(
              "Desugaring core libraries for Android O and over is possible but not required."));
    }
    options.coreLibraryCompilation = true;
    options.backportCoreLibraryMembers = buildBackportCoreLibraryMembers();
    if (options.minApiLevel < AndroidApiLevel.N.getLevel()) {
      options.retargetCoreLibMember = buildRetargetCoreLibraryMemberForCoreLibCompilation();
      options.dontRewriteInvocations = buildDontRewriteInvocations();
      options.emulateLibraryInterface = buildEmulateLibraryInterface();
      if (options.minApiLevel < AndroidApiLevel.M.getLevel()) {
        options.rewritePrefix = buildPrefixRewritingForCoreLibCompilationAllAndroid();
      } else {
        options.rewritePrefix = buildPrefixRewritingForCoreLibCompilationAndroidOPlus();
      }
    } else {
      options.rewritePrefix = buildPrefixRewritingForCoreLibCompilationAndroidNPlus();
    }
  }
}