// 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.ir.analysis.fieldvalueanalysis;

import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.DexClass;
import com.android.tools.r8.graph.DexEncodedField;
import com.android.tools.r8.graph.DexField;
import com.android.tools.r8.graph.GraphLens;
import com.android.tools.r8.graph.PrunedItems;
import com.android.tools.r8.graph.proto.ArgumentInfoCollection;
import com.android.tools.r8.shaking.AppInfoWithLiveness;
import com.android.tools.r8.utils.InternalOptions;
import com.android.tools.r8.utils.SetUtils;
import com.google.common.collect.Sets;
import java.util.Collections;
import java.util.Set;

public class ConcreteMutableFieldSet extends AbstractFieldSet implements KnownFieldSet {

  private final Set<DexEncodedField> fields;

  public ConcreteMutableFieldSet() {
    fields = Sets.newIdentityHashSet();
  }

  public ConcreteMutableFieldSet(DexEncodedField field) {
    fields = SetUtils.newIdentityHashSet(field);
  }

  public void add(DexEncodedField field) {
    fields.add(field);
  }

  public ConcreteMutableFieldSet addAll(ConcreteMutableFieldSet other) {
    fields.addAll(other.fields);
    return this;
  }

  Set<DexEncodedField> getFields() {
    if (InternalOptions.assertionsEnabled()) {
      return Collections.unmodifiableSet(fields);
    }
    return fields;
  }

  @Override
  public boolean isConcreteFieldSet() {
    return true;
  }

  @Override
  public ConcreteMutableFieldSet asConcreteFieldSet() {
    return this;
  }

  @Override
  public boolean isKnownFieldSet() {
    return true;
  }

  @Override
  public ConcreteMutableFieldSet asKnownFieldSet() {
    return this;
  }

  @Override
  public boolean contains(DexEncodedField field) {
    return fields.contains(field);
  }

  @Override
  public AbstractFieldSet fixupReadSetAfterParametersChanged(
      AppView<AppInfoWithLiveness> appView, ArgumentInfoCollection argumentInfoCollection) {
    assert !isEmpty();

    if (argumentInfoCollection.isEmpty()) {
      return this;
    }

    // Find the new field gets that are introduced as a result of constant parameter removal.
    AbstractFieldSet newReadSet =
        EmptyFieldSet.getInstance()
            .fixupReadSetAfterParametersChanged(appView, argumentInfoCollection);
    return newReadSet.isEmpty() ? this : newReadSet.asConcreteFieldSet().addAll(this);
  }

  @Override
  public AbstractFieldSet rewrittenWithLens(
      AppView<?> appView, GraphLens lens, GraphLens codeLens, PrunedItems prunedItems) {
    assert !isEmpty();
    ConcreteMutableFieldSet rewrittenSet = new ConcreteMutableFieldSet();
    for (DexEncodedField field : fields) {
      if (prunedItems.isRemoved(field.getReference())) {
        continue;
      }
      DexField rewrittenFieldReference = lens.lookupField(field.getReference());
      DexClass holder = appView.definitionForHolder(rewrittenFieldReference);
      DexEncodedField rewrittenField = rewrittenFieldReference.lookupOnClass(holder);
      if (rewrittenField == null) {
        assert false;
        continue;
      }
      rewrittenSet.add(rewrittenField);
    }
    return rewrittenSet;
  }

  @Override
  public boolean isEmpty() {
    return fields.isEmpty();
  }

  @Override
  public int size() {
    return fields.size();
  }

  @Override
  public int hashCode() {
    return fields.hashCode();
  }

  @Override
  public boolean equals(Object other) {
    if (other == null) {
      return false;
    }
    if (other.getClass() != getClass()) {
      return false;
    }
    ConcreteMutableFieldSet concreteFieldSet = (ConcreteMutableFieldSet) other;
    return fields.equals(concreteFieldSet.fields);
  }
}