// Copyright (c) 2012, the Dart 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.

library types;

import '../common.dart';
import '../common/backend_api.dart' show Backend;
import '../common/tasks.dart' show CompilerTask;
import '../compiler.dart' show Compiler;
import '../constants/values.dart' show PrimitiveConstantValue;
import '../elements/elements.dart';
import '../inferrer/type_graph_inferrer.dart' show TypeGraphInferrer;
import '../tree/tree.dart';
import '../util/util.dart';
import '../universe/selector.dart' show Selector;
import '../universe/universe.dart'
    show
        ReceiverConstraint,
        UniverseSelectorConstraints,
        SelectorConstraintsStrategy;
import '../world.dart' show ClassWorld, World;

import 'abstract_value_domain.dart' show AbstractValue;

part 'container_type_mask.dart';
part 'dictionary_type_mask.dart';
part 'flat_type_mask.dart';
part 'forwarding_type_mask.dart';
part 'map_type_mask.dart';
part 'type_mask.dart';
part 'union_type_mask.dart';
part 'value_type_mask.dart';

/**
 * Common super class for our type inferrers.
 */
abstract class TypesInferrer {
  void analyzeMain(Element element);
  TypeMask getReturnTypeOfElement(Element element);
  TypeMask getTypeOfElement(Element element);
  TypeMask getTypeOfNode(Element owner, Node node);
  TypeMask getTypeOfSelector(Selector selector, TypeMask mask);
  void clear();
  bool isCalledOnce(Element element);
  bool isFixedArrayCheckedForGrowable(Node node);
}

/**
 * The types task infers guaranteed types globally.
 */
class TypesTask extends CompilerTask {
  final String name = 'Type inference';
  final ClassWorld classWorld;
  TypesInferrer typesInferrer;

  TypesTask(Compiler compiler)
      : this.classWorld = compiler.world,
        super(compiler) {
    typesInferrer = new TypeGraphInferrer(compiler);
  }

  TypeMask dynamicTypeCache;
  TypeMask nonNullTypeCache;
  TypeMask nullTypeCache;
  TypeMask intTypeCache;
  TypeMask uint32TypeCache;
  TypeMask uint31TypeCache;
  TypeMask positiveIntTypeCache;
  TypeMask doubleTypeCache;
  TypeMask numTypeCache;
  TypeMask boolTypeCache;
  TypeMask functionTypeCache;
  TypeMask listTypeCache;
  TypeMask constListTypeCache;
  TypeMask fixedListTypeCache;
  TypeMask growableListTypeCache;
  TypeMask mapTypeCache;
  TypeMask constMapTypeCache;
  TypeMask stringTypeCache;
  TypeMask typeTypeCache;
  TypeMask syncStarIterableTypeCache;
  TypeMask asyncFutureTypeCache;
  TypeMask asyncStarStreamTypeCache;

  TypeMask get dynamicType {
    if (dynamicTypeCache == null) {
      dynamicTypeCache =
          new TypeMask.subclass(classWorld.objectClass, classWorld);
    }
    return dynamicTypeCache;
  }

  TypeMask get nonNullType {
    if (nonNullTypeCache == null) {
      nonNullTypeCache =
          new TypeMask.nonNullSubclass(classWorld.objectClass, classWorld);
    }
    return nonNullTypeCache;
  }

  TypeMask get intType {
    if (intTypeCache == null) {
      intTypeCache = new TypeMask.nonNullSubclass(
          compiler.backend.intImplementation, compiler.world);
    }
    return intTypeCache;
  }

  TypeMask get uint32Type {
    if (uint32TypeCache == null) {
      uint32TypeCache = new TypeMask.nonNullSubclass(
          compiler.backend.uint32Implementation, compiler.world);
    }
    return uint32TypeCache;
  }

  TypeMask get uint31Type {
    if (uint31TypeCache == null) {
      uint31TypeCache = new TypeMask.nonNullExact(
          compiler.backend.uint31Implementation, compiler.world);
    }
    return uint31TypeCache;
  }

  TypeMask get positiveIntType {
    if (positiveIntTypeCache == null) {
      positiveIntTypeCache = new TypeMask.nonNullSubclass(
          compiler.backend.positiveIntImplementation, compiler.world);
    }
    return positiveIntTypeCache;
  }

  TypeMask get doubleType {
    if (doubleTypeCache == null) {
      doubleTypeCache = new TypeMask.nonNullExact(
          compiler.backend.doubleImplementation, compiler.world);
    }
    return doubleTypeCache;
  }

  TypeMask get numType {
    if (numTypeCache == null) {
      numTypeCache = new TypeMask.nonNullSubclass(
          compiler.backend.numImplementation, compiler.world);
    }
    return numTypeCache;
  }

  TypeMask get boolType {
    if (boolTypeCache == null) {
      boolTypeCache = new TypeMask.nonNullExact(
          compiler.backend.boolImplementation, compiler.world);
    }
    return boolTypeCache;
  }

  TypeMask get functionType {
    if (functionTypeCache == null) {
      functionTypeCache = new TypeMask.nonNullSubtype(
          compiler.backend.functionImplementation, classWorld);
    }
    return functionTypeCache;
  }

  TypeMask get listType {
    if (listTypeCache == null) {
      listTypeCache = new TypeMask.nonNullExact(
          compiler.backend.listImplementation, compiler.world);
    }
    return listTypeCache;
  }

  TypeMask get constListType {
    if (constListTypeCache == null) {
      constListTypeCache = new TypeMask.nonNullExact(
          compiler.backend.constListImplementation, compiler.world);
    }
    return constListTypeCache;
  }

  TypeMask get fixedListType {
    if (fixedListTypeCache == null) {
      fixedListTypeCache = new TypeMask.nonNullExact(
          compiler.backend.fixedListImplementation, compiler.world);
    }
    return fixedListTypeCache;
  }

  TypeMask get growableListType {
    if (growableListTypeCache == null) {
      growableListTypeCache = new TypeMask.nonNullExact(
          compiler.backend.growableListImplementation, compiler.world);
    }
    return growableListTypeCache;
  }

  TypeMask get mapType {
    if (mapTypeCache == null) {
      mapTypeCache = new TypeMask.nonNullSubtype(
          compiler.backend.mapImplementation, classWorld);
    }
    return mapTypeCache;
  }

  TypeMask get constMapType {
    if (constMapTypeCache == null) {
      constMapTypeCache = new TypeMask.nonNullSubtype(
          compiler.backend.constMapImplementation, classWorld);
    }
    return constMapTypeCache;
  }

  TypeMask get stringType {
    if (stringTypeCache == null) {
      stringTypeCache = new TypeMask.nonNullExact(
          compiler.backend.stringImplementation, compiler.world);
    }
    return stringTypeCache;
  }

  TypeMask get typeType {
    if (typeTypeCache == null) {
      typeTypeCache = new TypeMask.nonNullExact(
          compiler.backend.typeImplementation, compiler.world);
    }
    return typeTypeCache;
  }

  TypeMask get syncStarIterableType {
    if (syncStarIterableTypeCache == null) {
      syncStarIterableTypeCache = new TypeMask.nonNullExact(
          compiler.backend.syncStarIterableImplementation, compiler.world);
    }
    return syncStarIterableTypeCache;
  }

  TypeMask get asyncFutureType {
    if (asyncFutureTypeCache == null) {
      asyncFutureTypeCache = new TypeMask.nonNullExact(
          compiler.backend.asyncFutureImplementation, compiler.world);
    }
    return asyncFutureTypeCache;
  }

  TypeMask get asyncStarStreamType {
    if (asyncStarStreamTypeCache == null) {
      asyncStarStreamTypeCache = new TypeMask.nonNullExact(
          compiler.backend.asyncStarStreamImplementation, compiler.world);
    }
    return asyncStarStreamTypeCache;
  }

  TypeMask get nullType {
    if (nullTypeCache == null) {
      // TODO(johnniwinther): Assert that the null type has been resolved.
      nullTypeCache = const TypeMask.empty();
    }
    return nullTypeCache;
  }

  /** Helper method for [intersection]. */
  TypeMask _intersection(TypeMask type1, TypeMask type2) {
    if (type1 == null) return type2;
    if (type2 == null) return type1;
    return type1.intersection(type2, classWorld);
  }

  /** Computes the intersection of [type1] and [type2] */
  TypeMask intersection(TypeMask type1, TypeMask type2, element) {
    TypeMask result = _intersection(type1, type2);
    return result;
  }

  /** Returns true if [type1] is strictly better than [type2]. */
  bool better(TypeMask type1, TypeMask type2) {
    if (type1 == null) return false;
    if (type2 == null) {
      return (type1 != null) && (type1 != dynamicType);
    }
    return (type1 != type2) &&
        type2.containsMask(type1, classWorld) &&
        !type1.containsMask(type2, classWorld);
  }

  /**
   * Called when resolution is complete.
   */
  void onResolutionComplete(Element mainElement) {
    measure(() {
      typesInferrer.analyzeMain(mainElement);
      typesInferrer.clear();
    });
  }

  /**
   * Return the (inferred) guaranteed type of [element] or null.
   */
  TypeMask getGuaranteedTypeOfElement(Element element) {
    // TODO(24489): trust some JsInterop types.
    if (compiler.backend.isJsInterop(element)) {
      return dynamicType;
    }
    TypeMask guaranteedType = typesInferrer.getTypeOfElement(element);
    return guaranteedType;
  }

  TypeMask getGuaranteedReturnTypeOfElement(Element element) {
    // TODO(24489): trust some JsInterop types.
    if (compiler.backend.isJsInterop(element)) {
      return dynamicType;
    }

    TypeMask guaranteedType = typesInferrer.getReturnTypeOfElement(element);
    return guaranteedType;
  }

  /**
   * Return the (inferred) guaranteed type of [node] or null.
   * [node] must be an AST node of [owner].
   */
  TypeMask getGuaranteedTypeOfNode(owner, node) {
    TypeMask guaranteedType = typesInferrer.getTypeOfNode(owner, node);
    return guaranteedType;
  }

  /**
   * Return the (inferred) guaranteed type of [selector] or null.
   */
  TypeMask getGuaranteedTypeOfSelector(Selector selector, TypeMask mask) {
    TypeMask guaranteedType = typesInferrer.getTypeOfSelector(selector, mask);
    return guaranteedType;
  }
}