// Copyright (c) 2016, 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 fasta.enum_builder;

import 'package:_fe_analyzer_shared/src/scanner/token.dart';

import 'package:kernel/ast.dart';
import 'package:kernel/class_hierarchy.dart';
import 'package:kernel/reference_from_index.dart' show IndexedClass;

import '../builder/builder.dart';
import '../builder/class_builder.dart';
import '../builder/constructor_reference_builder.dart';
import '../builder/field_builder.dart';
import '../builder/formal_parameter_builder.dart';
import '../builder/library_builder.dart';
import '../builder/member_builder.dart';
import '../builder/metadata_builder.dart';
import '../builder/named_type_builder.dart';
import '../builder/nullability_builder.dart';
import '../builder/procedure_builder.dart';
import '../builder/type_builder.dart';
import '../builder/type_declaration_builder.dart';
import '../builder/type_variable_builder.dart';
import '../fasta_codes.dart'
    show
        LocatedMessage,
        messageNoUnnamedConstructorInObject,
        templateDuplicatedDeclaration,
        templateDuplicatedDeclarationCause,
        templateDuplicatedDeclarationSyntheticCause,
        templateEnumConstantSameNameAsEnclosing;

import '../kernel/body_builder.dart';
import '../kernel/constructor_tearoff_lowering.dart';
import '../kernel/kernel_helper.dart';
import '../kernel/internal_ast.dart';

import '../modifier.dart' show constMask, hasInitializerMask, staticMask;

import '../constant_context.dart';
import '../scope.dart';
import '../type_inference/type_inferrer.dart';
import '../type_inference/type_schema.dart';
import '../util/helpers.dart';
import 'name_scheme.dart';
import 'source_class_builder.dart' show SourceClassBuilder;
import 'source_constructor_builder.dart';
import 'source_field_builder.dart';
import 'source_library_builder.dart' show SourceLibraryBuilder;
import 'source_procedure_builder.dart';

class SourceEnumBuilder extends SourceClassBuilder {
  final List<EnumConstantInfo?>? enumConstantInfos;

  final NamedTypeBuilder intType;

  final NamedTypeBuilder stringType;

  final NamedTypeBuilder objectType;

  final NamedTypeBuilder listType;

  DeclaredSourceConstructorBuilder? synthesizedDefaultConstructorBuilder;

  SourceEnumBuilder.internal(
      List<MetadataBuilder>? metadata,
      String name,
      List<TypeVariableBuilder>? typeVariables,
      TypeBuilder supertypeBuilder,
      List<TypeBuilder>? interfaceBuilders,
      Scope scope,
      ConstructorScope constructors,
      Class cls,
      this.enumConstantInfos,
      this.intType,
      this.listType,
      this.objectType,
      this.stringType,
      SourceLibraryBuilder parent,
      int startCharOffset,
      int charOffset,
      int charEndOffset,
      IndexedClass? referencesFromIndexed)
      : super(
            metadata,
            0,
            name,
            typeVariables,
            supertypeBuilder,
            interfaceBuilders,
            /* onTypes = */ null,
            scope,
            constructors,
            parent,
            /* constructorReferences = */ null,
            startCharOffset,
            charOffset,
            charEndOffset,
            referencesFromIndexed,
            cls: cls);

  factory SourceEnumBuilder(
      List<MetadataBuilder>? metadata,
      String name,
      List<TypeVariableBuilder>? typeVariables,
      TypeBuilder? supertypeBuilder,
      List<TypeBuilder>? interfaceBuilders,
      List<EnumConstantInfo?>? enumConstantInfos,
      SourceLibraryBuilder parent,
      int startCharOffset,
      int charOffset,
      int charEndOffset,
      IndexedClass? referencesFromIndexed,
      Scope scope,
      ConstructorScope constructorScope) {
    assert(enumConstantInfos == null || enumConstantInfos.isNotEmpty);

    Uri fileUri = parent.fileUri;

    // TODO(ahe): These types shouldn't be looked up in scope, they come
    // directly from dart:core.
    NamedTypeBuilder intType = new NamedTypeBuilder(
        "int",
        const NullabilityBuilder.omitted(),
        /* arguments = */ null,
        /* fileUri = */ null,
        /* charOffset = */ null,
        instanceTypeVariableAccess:
            // If "int" resolves to an instance type variable then that we would
            // allowed (the types that we are adding are in instance context
            // after all) but it would be unexpected and we would like an
            // assertion failure, since "int" was meant to be `int` from
            // `dart:core`.
            // TODO(johnniwinther): Add a more robust way of creating named
            // typed builders for dart:core types. This might be needed for the
            // enhanced enums feature where enums can actually declare type
            // variables.
            InstanceTypeVariableAccessState.Unexpected);
    NamedTypeBuilder stringType = new NamedTypeBuilder(
        "String",
        const NullabilityBuilder.omitted(),
        /* arguments = */ null,
        /* fileUri = */ null,
        /* charOffset = */ null,
        instanceTypeVariableAccess: InstanceTypeVariableAccessState.Unexpected);
    NamedTypeBuilder objectType = new NamedTypeBuilder(
        "Object",
        const NullabilityBuilder.omitted(),
        /* arguments = */ null,
        /* fileUri = */ null,
        /* charOffset = */ null,
        instanceTypeVariableAccess: InstanceTypeVariableAccessState.Unexpected);
    supertypeBuilder ??= new NamedTypeBuilder(
        "_Enum",
        const NullabilityBuilder.omitted(),
        /* arguments = */ null,
        /* fileUri = */ null,
        /* charOffset = */ null,
        instanceTypeVariableAccess: InstanceTypeVariableAccessState.Unexpected);
    Class cls = new Class(
        name: name,
        typeParameters:
            TypeVariableBuilder.typeParametersFromBuilders(typeVariables),
        reference: referencesFromIndexed?.cls.reference,
        fileUri: fileUri);
    Map<String, MemberBuilder> members = <String, MemberBuilder>{};
    Map<String, MemberBuilder> setters = <String, MemberBuilder>{};
    Map<String, MemberBuilder> constructors = <String, MemberBuilder>{};
    NamedTypeBuilder selfType = new NamedTypeBuilder(
        name,
        const NullabilityBuilder.omitted(),
        /* arguments = */ null,
        /* fileUri = */ null,
        /* charOffset = */ null,
        instanceTypeVariableAccess: InstanceTypeVariableAccessState.Unexpected);
    NamedTypeBuilder listType = new NamedTypeBuilder(
        "List",
        const NullabilityBuilder.omitted(),
        <TypeBuilder>[selfType],
        /* fileUri = */ null,
        /* charOffset = */ null,
        instanceTypeVariableAccess: InstanceTypeVariableAccessState.Unexpected);

    // metadata class E extends _Enum {
    //   const E(int index, String name) : super(index, name);
    //   static const E id0 = const E(0, 'id0');
    //   ...
    //   static const E id${n-1} = const E(n - 1, 'idn-1');
    //   static const List<E> values = const <E>[id0, ..., id${n-1}];
    //   String toString() {
    //     return "E.${_Enum::_name}";
    //   }
    // }

    NameScheme staticFieldNameScheme = new NameScheme(
        isInstanceMember: false,
        className: name,
        isExtensionMember: false,
        extensionName: null,
        libraryReference: referencesFromIndexed != null
            ? referencesFromIndexed.library.reference
            : parent.library.reference);

    NameScheme procedureNameScheme = new NameScheme(
        isInstanceMember: true,
        className: name,
        isExtensionMember: false,
        extensionName: null,
        libraryReference: referencesFromIndexed != null
            ? referencesFromIndexed.library.reference
            : parent.library.reference);

    Reference? constructorReference;
    Reference? tearOffReference;
    Reference? toStringReference;
    Reference? valuesFieldReference;
    Reference? valuesGetterReference;
    Reference? valuesSetterReference;
    if (referencesFromIndexed != null) {
      constructorReference =
          referencesFromIndexed.lookupConstructorReference(new Name(""));
      tearOffReference = referencesFromIndexed.lookupGetterReference(
          constructorTearOffName("", referencesFromIndexed.library));
      toStringReference =
          referencesFromIndexed.lookupGetterReference(new Name("toString"));
      Name valuesName = new Name("values");
      valuesFieldReference =
          referencesFromIndexed.lookupFieldReference(valuesName);
      valuesGetterReference =
          referencesFromIndexed.lookupGetterReference(valuesName);
      valuesSetterReference =
          referencesFromIndexed.lookupSetterReference(valuesName);
    }

    SourceFieldBuilder valuesBuilder = new SourceFieldBuilder(
        /* metadata = */ null,
        listType,
        "values",
        constMask | staticMask | hasInitializerMask,
        /* isTopLevel = */ false,
        parent,
        charOffset,
        charOffset,
        staticFieldNameScheme,
        fieldReference: valuesFieldReference,
        fieldGetterReference: valuesGetterReference,
        fieldSetterReference: valuesSetterReference);
    members["values"] = valuesBuilder;

    DeclaredSourceConstructorBuilder? synthesizedDefaultConstructorBuilder;
    if (constructorScope.local.isEmpty) {
      synthesizedDefaultConstructorBuilder =
          new DeclaredSourceConstructorBuilder(
              /* metadata = */ null,
              constMask,
              /* returnType = */ null,
              "",
              /* typeParameters = */ null,
              <FormalParameterBuilder>[
                new FormalParameterBuilder(
                    null, 0, intType, "index", parent, charOffset),
                new FormalParameterBuilder(
                    null, 0, stringType, "name", parent, charOffset)
              ],
              parent,
              charOffset,
              charOffset,
              charOffset,
              charEndOffset,
              constructorReference,
              tearOffReference,
              forAbstractClassOrEnum: true);
      synthesizedDefaultConstructorBuilder
          .registerInitializedField(valuesBuilder);
      constructors[""] = synthesizedDefaultConstructorBuilder;
    } else {
      constructorScope.forEach((name, member) {
        if (member is DeclaredSourceConstructorBuilder) {
          member.ensureGrowableFormals();
          member.formals!.insert(
              0,
              new FormalParameterBuilder(
                  null, 0, stringType, "name", parent, charOffset));
          member.formals!.insert(
              0,
              new FormalParameterBuilder(
                  null, 0, intType, "index", parent, charOffset));
        }
      });
    }

    if (scope.lookupLocalMember("toString", setter: false) == null) {
      ProcedureBuilder toStringBuilder = new SourceProcedureBuilder(
          /* metadata = */ null,
          0,
          stringType,
          "toString",
          /* typeVariables = */ null,
          /* formals = */ null,
          ProcedureKind.Method,
          parent,
          charOffset,
          charOffset,
          charOffset,
          charEndOffset,
          toStringReference,
          /* tearOffReference = */ null,
          AsyncMarker.Sync,
          procedureNameScheme,
          isExtensionMember: false,
          isInstanceMember: true);
      members["toString"] = toStringBuilder;
    }
    String className = name;
    if (enumConstantInfos != null) {
      for (int i = 0; i < enumConstantInfos.length; i++) {
        EnumConstantInfo enumConstantInfo = enumConstantInfos[i]!;
        List<MetadataBuilder>? metadata = enumConstantInfo.metadata;
        String name = enumConstantInfo.name;
        MemberBuilder? existing = members[name];
        if (existing != null) {
          // The existing declaration is synthetic if it has the same
          // charOffset as the enclosing enum.
          bool isSynthetic = existing.charOffset == charOffset;
          List<LocatedMessage> context = isSynthetic
              ? <LocatedMessage>[
                  templateDuplicatedDeclarationSyntheticCause
                      .withArguments(name)
                      .withLocation(
                          parent.fileUri, charOffset, className.length)
                ]
              : <LocatedMessage>[
                  templateDuplicatedDeclarationCause
                      .withArguments(name)
                      .withLocation(
                          parent.fileUri, existing.charOffset, name.length)
                ];
          parent.addProblem(templateDuplicatedDeclaration.withArguments(name),
              enumConstantInfo.charOffset, name.length, parent.fileUri,
              context: context);
          enumConstantInfos[i] = null;
        } else if (name == className) {
          parent.addProblem(
              templateEnumConstantSameNameAsEnclosing.withArguments(name),
              enumConstantInfo.charOffset,
              name.length,
              parent.fileUri);
        }
        Reference? fieldReference;
        Reference? getterReference;
        Reference? setterReference;
        if (referencesFromIndexed != null) {
          Name nameName = new Name(name, referencesFromIndexed.library);
          fieldReference = referencesFromIndexed.lookupFieldReference(nameName);
          getterReference =
              referencesFromIndexed.lookupGetterReference(nameName);
          setterReference =
              referencesFromIndexed.lookupSetterReference(nameName);
        }
        FieldBuilder fieldBuilder = new SourceFieldBuilder(
            metadata,
            selfType,
            name,
            constMask | staticMask | hasInitializerMask,
            /* isTopLevel = */ false,
            parent,
            enumConstantInfo.charOffset,
            enumConstantInfo.charOffset,
            staticFieldNameScheme,
            fieldReference: fieldReference,
            fieldGetterReference: getterReference,
            fieldSetterReference: setterReference);
        members[name] = fieldBuilder..next = existing;
      }
    }
    final int startCharOffsetComputed =
        metadata == null ? startCharOffset : metadata.first.charOffset;
    scope.forEachLocalMember((name, member) {
      members[name] = member as MemberBuilder;
    });
    scope.forEachLocalSetter((name, member) {
      setters[name] = member;
    });
    SourceEnumBuilder enumBuilder = new SourceEnumBuilder.internal(
        metadata,
        name,
        typeVariables,
        supertypeBuilder,
        interfaceBuilders,
        new Scope(
            local: members,
            setters: setters,
            parent: scope.parent,
            debugName: "enum $name",
            isModifiable: false),
        constructorScope..local.addAll(constructors),
        cls,
        enumConstantInfos,
        intType,
        listType,
        objectType,
        stringType,
        parent,
        startCharOffsetComputed,
        charOffset,
        charEndOffset,
        referencesFromIndexed)
      ..synthesizedDefaultConstructorBuilder =
          synthesizedDefaultConstructorBuilder;

    void setParent(String name, MemberBuilder? builder) {
      while (builder != null) {
        builder.parent = enumBuilder;
        builder = builder.next as MemberBuilder?;
      }
    }

    members.forEach(setParent);
    constructors.forEach(setParent);
    selfType.bind(enumBuilder);
    return enumBuilder;
  }

  @override
  TypeBuilder? get mixedInTypeBuilder => null;

  @override
  Class build(SourceLibraryBuilder libraryBuilder, LibraryBuilder coreLibrary) {
    cls.isEnum = true;
    intType.resolveIn(coreLibrary.scope, charOffset, fileUri, libraryBuilder);
    stringType.resolveIn(
        coreLibrary.scope, charOffset, fileUri, libraryBuilder);
    objectType.resolveIn(
        coreLibrary.scope, charOffset, fileUri, libraryBuilder);
    TypeBuilder? supertypeBuilder = this.supertypeBuilder;
    NamedTypeBuilder? enumType;

    while (enumType == null && supertypeBuilder is NamedTypeBuilder) {
      TypeDeclarationBuilder? superclassBuilder = supertypeBuilder.declaration;
      if (superclassBuilder is ClassBuilder &&
          superclassBuilder.isMixinApplication) {
        supertypeBuilder = superclassBuilder.supertypeBuilder;
      } else {
        enumType = supertypeBuilder;
      }
    }
    assert(enumType is NamedTypeBuilder && enumType.name == "_Enum");
    enumType!.resolveIn(coreLibrary.scope, charOffset, fileUri, libraryBuilder);

    listType.resolveIn(coreLibrary.scope, charOffset, fileUri, libraryBuilder);

    List<Expression> values = <Expression>[];
    if (enumConstantInfos != null) {
      for (EnumConstantInfo? enumConstantInfo in enumConstantInfos!) {
        if (enumConstantInfo != null) {
          Builder declaration = firstMemberNamed(enumConstantInfo.name)!;
          if (declaration.isField) {
            SourceFieldBuilder fieldBuilder = declaration as SourceFieldBuilder;
            fieldBuilder.build(libraryBuilder);
            values.add(new StaticGet(fieldBuilder.field));
          }
        }
      }
    }
    SourceFieldBuilder valuesBuilder =
        firstMemberNamed("values") as SourceFieldBuilder;
    valuesBuilder.build(libraryBuilder);

    // The super initializer for the synthesized default constructor is
    // inserted here if the enum's supertype is _Enum to preserve the legacy
    // behavior or having the old-style enum constants built in the outlines.
    // Other constructors are handled in [BodyBuilder.finishConstructor] as
    // they are processed via the pipeline for constructor parsing and
    // building.
    if (identical(this.supertypeBuilder, enumType)) {
      if (synthesizedDefaultConstructorBuilder != null) {
        Constructor constructor =
            synthesizedDefaultConstructorBuilder!.build(libraryBuilder);
        ClassBuilder objectClass = objectType.declaration as ClassBuilder;
        ClassBuilder enumClass = enumType.declaration as ClassBuilder;
        MemberBuilder? superConstructor = enumClass.findConstructorOrFactory(
            "", charOffset, fileUri, libraryBuilder);
        if (superConstructor == null || !superConstructor.isConstructor) {
          // TODO(ahe): Ideally, we would also want to check that [Object]'s
          // unnamed constructor requires no arguments. But that information
          // isn't always available at this point, and it's not really a
          // situation that can happen unless you start modifying the SDK
          // sources. (We should add a correct message. We no longer depend on
          // Object here.)
          library.addProblem(
              messageNoUnnamedConstructorInObject,
              objectClass.charOffset,
              objectClass.name.length,
              objectClass.fileUri);
        } else {
          constructor.initializers.add(new SuperInitializer(
              superConstructor.member as Constructor,
              new Arguments.forwarded(
                  constructor.function, libraryBuilder.library))
            ..parent = constructor);
        }
        synthesizedDefaultConstructorBuilder = null;
      }
    }

    return super.build(libraryBuilder, coreLibrary);
  }

  @override
  void buildOutlineExpressions(
      SourceLibraryBuilder libraryBuilder,
      ClassHierarchy classHierarchy,
      List<DelayedActionPerformer> delayedActionPerformers,
      List<SynthesizedFunctionNode> synthesizedFunctionNodes) {
    List<Expression> values = <Expression>[];
    if (enumConstantInfos != null) {
      for (EnumConstantInfo? enumConstantInfo in enumConstantInfos!) {
        if (enumConstantInfo != null) {
          Builder declaration = firstMemberNamed(enumConstantInfo.name)!;
          if (declaration.isField) {
            SourceFieldBuilder fieldBuilder = declaration as SourceFieldBuilder;
            fieldBuilder.build(libraryBuilder);
            values.add(new StaticGet(fieldBuilder.field));
          }
        }
      }
    }
    SourceFieldBuilder valuesBuilder =
        firstMemberNamed("values") as SourceFieldBuilder;
    valuesBuilder.buildBody(
        classHierarchy.coreTypes,
        new ListLiteral(values,
            typeArgument: rawType(library.nonNullable), isConst: true));
    int index = 0;
    if (enumConstantInfos != null) {
      for (EnumConstantInfo? enumConstantInfo in enumConstantInfos!) {
        if (enumConstantInfo != null) {
          String constant = enumConstantInfo.name;
          Builder declaration = firstMemberNamed(constant)!;
          SourceFieldBuilder field;
          if (declaration.isField) {
            field = declaration as SourceFieldBuilder;
          } else {
            continue;
          }

          String constructorName =
              enumConstantInfo.constructorReferenceBuilder?.suffix ?? "";
          MemberBuilder? constructorBuilder =
              constructorScopeBuilder[constructorName];

          if (constructorBuilder == null ||
              constructorBuilder is! SourceConstructorBuilder) {
            // TODO(cstefantsova): Report an error.
          } else {
            Arguments arguments;
            List<Expression> enumSyntheticArguments = <Expression>[
              new IntLiteral(index++),
              new StringLiteral(constant),
            ];
            List<DartType>? typeArguments;
            List<TypeBuilder>? typeArgumentBuilders =
                enumConstantInfo.constructorReferenceBuilder?.typeArguments;
            if (typeArgumentBuilders != null) {
              typeArguments = <DartType>[];
              for (TypeBuilder typeBuilder in typeArgumentBuilders) {
                typeArguments.add(typeBuilder.build(library));
              }
            }
            BodyBuilder? bodyBuilder;
            if (enumConstantInfo.argumentsBeginToken != null ||
                typeArgumentBuilders == null && cls.typeParameters.isNotEmpty) {
              // We need to create a BodyBuilder in two cases: 1) if the
              // arguments token is provided, we'll use the BodyBuilder to
              // parse them and perform inference, 2) if the type arguments
              // aren't provided, but required, we'll use it to infer them.
              bodyBuilder = library.loader
                  .createBodyBuilderForOutlineExpression(
                      library, this, this, scope, fileUri);
              bodyBuilder.constantContext = ConstantContext.required;
            }

            if (enumConstantInfo.argumentsBeginToken != null) {
              arguments = bodyBuilder!
                  .parseArguments(enumConstantInfo.argumentsBeginToken!);
              bodyBuilder.performBacklogComputations(delayedActionPerformers);

              arguments.positional.insertAll(0, enumSyntheticArguments);
            } else {
              arguments = new ArgumentsImpl(enumSyntheticArguments);
            }

            if (typeArguments != null && arguments is ArgumentsImpl) {
              ArgumentsImpl.setNonInferrableArgumentTypes(
                  arguments, typeArguments);
            } else if (cls.typeParameters.isNotEmpty) {
              arguments.types.addAll(new List<DartType>.filled(
                  cls.typeParameters.length, const UnknownType()));
            }
            setParents(enumSyntheticArguments, arguments);

            Expression initializer = new ConstructorInvocation(
                constructorBuilder.constructor, arguments,
                isConst: true)
              ..fileOffset = field.charOffset;
            if (bodyBuilder != null) {
              ExpressionInferenceResult inferenceResult =
                  bodyBuilder.typeInferrer.inferFieldInitializer(
                      bodyBuilder, const UnknownType(), initializer);
              initializer = inferenceResult.expression;
              field.fieldType = inferenceResult.inferredType;
            }
            field.buildBody(classHierarchy.coreTypes, initializer);
          }
        }
      }
    }

    SourceProcedureBuilder toStringBuilder =
        firstMemberNamed("toString") as SourceProcedureBuilder;

    TypeBuilder supertypeBuilder = this.supertypeBuilder!;
    ClassBuilder enumClass = supertypeBuilder.declaration as ClassBuilder;
    MemberBuilder? nameFieldBuilder =
        enumClass.lookupLocalMember("_name") as MemberBuilder?;
    if (nameFieldBuilder != null) {
      Field nameField = nameFieldBuilder.member as Field;

      toStringBuilder.body = new ReturnStatement(new StringConcatenation([
        new StringLiteral("${cls.demangledName}."),
        new InstanceGet.byReference(
            InstanceAccessKind.Instance, new ThisExpression(), nameField.name,
            interfaceTargetReference: nameField.getterReference,
            resultType: nameField.getterType),
      ]));
    }

    super.buildOutlineExpressions(library, classHierarchy,
        delayedActionPerformers, synthesizedFunctionNodes);
  }
}

class EnumConstantInfo {
  final List<MetadataBuilder>? metadata;
  final String name;
  final int charOffset;
  ConstructorReferenceBuilder? constructorReferenceBuilder;
  Token? argumentsBeginToken;

  EnumConstantInfo(this.metadata, this.name, this.charOffset);
}