// Copyright (c) 2022, 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.

import 'package:_fe_analyzer_shared/src/macros/executor/introspection_impls.dart'
    as macro;
import 'package:_fe_analyzer_shared/src/macros/executor/remote_instance.dart'
    as macro;
import 'package:analyzer/dart/ast/ast.dart' as ast;
import 'package:analyzer/dart/ast/token.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/dart/element/nullability_suffix.dart';
import 'package:analyzer/dart/element/type.dart';

class ClassDeclarationImpl extends macro.ClassDeclarationImpl {
  late final ClassElement element;

  ClassDeclarationImpl._({
    required super.id,
    required super.identifier,
    required super.library,
    required super.metadata,
    required super.typeParameters,
    required super.interfaces,
    required super.hasAbstract,
    required super.hasBase,
    required super.hasExternal,
    required super.hasFinal,
    required super.hasInterface,
    required super.hasMixin,
    required super.hasSealed,
    required super.mixins,
    required super.superclass,
  });
}

class DeclarationBuilder {
  final DeclarationBuilderFromNode fromNode = DeclarationBuilderFromNode();

  final DeclarationBuilderFromElement fromElement =
      DeclarationBuilderFromElement();

  /// Associate declarations that were previously created for nodes with the
  /// corresponding elements. So, we can access them uniformly via interfaces,
  /// mixins, etc.
  void transferToElements() {
    // TODO(scheglov) Make sure that these are only declarations?
    for (final entry in fromNode._namedTypeMap.entries) {
      final element = entry.key.element;
      if (element != null) {
        final declaration = entry.value;
        fromElement._identifierMap[element] = declaration;
      }
    }
    for (final entry in fromNode._declaredIdentifierMap.entries) {
      final element = entry.key;
      final declaration = entry.value;
      fromElement._identifierMap[element] = declaration;
    }

    for (final entry in fromNode._classMap.entries) {
      final element = entry.key.declaredElement!;
      final declaration = entry.value;
      declaration.element = element;
      fromElement._classMap[element] = declaration;
    }
  }
}

class DeclarationBuilderFromElement {
  final Map<Element, IdentifierImpl> _identifierMap = Map.identity();
  final Map<Element, LibraryImpl> _libraryMap = Map.identity();

  final Map<ClassElement, IntrospectableClassDeclarationImpl> _classMap =
      Map.identity();

  final Map<FieldElement, FieldDeclarationImpl> _fieldMap = Map.identity();

  final Map<TypeParameterElement, macro.TypeParameterDeclarationImpl>
      _typeParameterMap = Map.identity();

  macro.IntrospectableClassDeclarationImpl classElement(ClassElement element) {
    return _classMap[element] ??= _introspectableClassElement(element);
  }

  macro.FieldDeclarationImpl fieldElement(FieldElement element) {
    return _fieldMap[element] ??= _fieldElement(element);
  }

  macro.IdentifierImpl identifier(Element element) {
    return _identifierMap[element] ??= IdentifierImplFromElement(
      id: macro.RemoteInstance.uniqueId,
      name: element.name!,
      element: element,
    );
  }

  macro.LibraryImpl library(Element element) {
    var library = _libraryMap[element.library];
    if (library == null) {
      final version = element.library!.languageVersion.effective;
      library = LibraryImplFromElement(
          id: macro.RemoteInstance.uniqueId,
          languageVersion:
              macro.LanguageVersionImpl(version.major, version.minor),
          // TODO: Provide metadata annotations.
          metadata: const [],
          uri: element.library!.source.uri,
          element: element);
      _libraryMap[element.library!] = library;
    }
    return library;
  }

  macro.TypeParameterDeclarationImpl typeParameter(
    TypeParameterElement element,
  ) {
    return _typeParameterMap[element] ??= _typeParameter(element);
  }

  macro.TypeAnnotationImpl _dartType(DartType type) {
    switch (type) {
      case InterfaceType():
        return _interfaceType(type);
      case TypeParameterType():
        return macro.NamedTypeAnnotationImpl(
          id: macro.RemoteInstance.uniqueId,
          isNullable: type.nullabilitySuffix == NullabilitySuffix.question,
          identifier: identifier(type.element),
          typeArguments: const [],
        );
      default:
        throw UnimplementedError('(${type.runtimeType}) $type');
    }
  }

  FieldDeclarationImpl _fieldElement(FieldElement element) {
    assert(!_fieldMap.containsKey(element));
    final enclosingClass = element.enclosingElement as ClassElement;
    return FieldDeclarationImpl(
      id: macro.RemoteInstance.uniqueId,
      identifier: identifier(element),
      library: library(element),
      // TODO: Provide metadata annotations.
      metadata: const [],
      hasExternal: element.isExternal,
      hasFinal: element.isFinal,
      hasLate: element.isLate,
      type: _dartType(element.type),
      definingType: identifier(enclosingClass),
      isStatic: element.isStatic,
    );
  }

  macro.NamedTypeAnnotationImpl _interfaceType(InterfaceType type) {
    return macro.NamedTypeAnnotationImpl(
      id: macro.RemoteInstance.uniqueId,
      isNullable: type.nullabilitySuffix == NullabilitySuffix.question,
      identifier: identifier(type.element),
      typeArguments: type.typeArguments.map(_dartType).toList(),
    );
  }

  IntrospectableClassDeclarationImpl _introspectableClassElement(
      ClassElement element) {
    assert(!_classMap.containsKey(element));
    return IntrospectableClassDeclarationImpl._(
      id: macro.RemoteInstance.uniqueId,
      identifier: identifier(element),
      library: library(element),
      // TODO: Provide metadata annotations.
      metadata: const [],
      typeParameters: element.typeParameters.map(_typeParameter).toList(),
      interfaces: element.interfaces.map(_interfaceType).toList(),
      hasAbstract: element.isAbstract,
      hasBase: element.isBase,
      hasExternal: false,
      hasFinal: element.isFinal,
      hasInterface: element.isInterface,
      hasMixin: element.isMixinClass,
      hasSealed: element.isSealed,
      mixins: element.mixins.map(_interfaceType).toList(),
      superclass: element.supertype.mapOrNull(_interfaceType),
    )..element = element;
  }

  macro.TypeParameterDeclarationImpl _typeParameter(
    TypeParameterElement element,
  ) {
    return macro.TypeParameterDeclarationImpl(
      id: macro.RemoteInstance.uniqueId,
      identifier: identifier(element),
      library: library(element),
      // TODO: Provide metadata annotations.
      metadata: const [],
      bound: element.bound.mapOrNull(_dartType),
    );
  }
}

class DeclarationBuilderFromNode {
  final Map<ast.NamedType, IdentifierImpl> _namedTypeMap = Map.identity();

  final Map<Element, IdentifierImpl> _declaredIdentifierMap = Map.identity();
  final Map<Element, LibraryImpl> _libraryMap = Map.identity();

  final Map<ast.ClassDeclaration, IntrospectableClassDeclarationImpl>
      _classMap = Map.identity();

  final Map<ast.MethodDeclaration, MethodDeclarationImpl> _methodMap =
      Map.identity();

  macro.ClassDeclarationImpl classDeclaration(
    ast.ClassDeclaration node,
  ) {
    return _classMap[node] ??= _introspectableClassDeclaration(node);
  }

  macro.LibraryImpl library(Element element) {
    var library = _libraryMap[element.library];
    if (library == null) {
      final version = element.library!.languageVersion.effective;
      library = LibraryImplFromElement(
          id: macro.RemoteInstance.uniqueId,
          languageVersion:
              macro.LanguageVersionImpl(version.major, version.minor),
          // TODO: Provide metadata annotations.
          metadata: const [],
          uri: element.library!.source.uri,
          element: element);
      _libraryMap[element.library!] = library;
    }
    return library;
  }

  macro.MethodDeclarationImpl methodDeclaration(
    ast.MethodDeclaration node,
  ) {
    return _methodMap[node] ??= _methodDeclaration(node);
  }

  macro.IdentifierImpl _declaredIdentifier(Token name, Element element) {
    return _declaredIdentifierMap[element] ??= _DeclaredIdentifierImpl(
      id: macro.RemoteInstance.uniqueId,
      name: name.lexeme,
      element: element,
    );
  }

  macro.FunctionTypeParameterImpl _formalParameter(
    ast.FormalParameter node,
  ) {
    if (node is ast.DefaultFormalParameter) {
      node = node.parameter;
    }

    final macro.TypeAnnotationImpl typeAnnotation;
    if (node is ast.SimpleFormalParameter) {
      typeAnnotation = _typeAnnotation(node.type);
    } else {
      throw UnimplementedError('(${node.runtimeType}) $node');
    }

    return macro.FunctionTypeParameterImpl(
      id: macro.RemoteInstance.uniqueId,
      isNamed: node.isNamed,
      isRequired: node.isRequired,
      name: node.name?.lexeme,
      // TODO: Provide metadata annotations.
      metadata: const [],
      type: typeAnnotation,
    );
  }

  IntrospectableClassDeclarationImpl _introspectableClassDeclaration(
    ast.ClassDeclaration node,
  ) {
    assert(!_classMap.containsKey(node));
    return IntrospectableClassDeclarationImpl._(
      id: macro.RemoteInstance.uniqueId,
      identifier: _declaredIdentifier(node.name, node.declaredElement!),
      library: library(node.declaredElement!),
      // TODO: Provide metadata annotations.
      metadata: const [],
      typeParameters: _typeParameters(node.typeParameters),
      interfaces: _namedTypes(node.implementsClause?.interfaces),
      hasAbstract: node.abstractKeyword != null,
      hasBase: node.baseKeyword != null,
      hasExternal: false,
      hasFinal: node.finalKeyword != null,
      hasInterface: node.interfaceKeyword != null,
      hasMixin: node.mixinKeyword != null,
      hasSealed: node.sealedKeyword != null,
      mixins: _namedTypes(node.withClause?.mixinTypes),
      superclass: node.extendsClause?.superclass.mapOrNull(_namedType),
    );
  }

  MethodDeclarationImpl _methodDeclaration(
    ast.MethodDeclaration node,
  ) {
    assert(!_methodMap.containsKey(node));

    // TODO(scheglov) other parents
    final parentNode = node.parent as ast.ClassDeclaration;
    final parentElement = parentNode.declaredElement!;
    final typeElement = parentElement.augmentationTarget ?? parentElement;
    final definingType = _declaredIdentifier(parentNode.name, typeElement);

    return MethodDeclarationImpl._(
      element: node.declaredElement as MethodElement,
      id: macro.RemoteInstance.uniqueId,
      identifier: _declaredIdentifier(node.name, node.declaredElement!),
      library: library(node.declaredElement!),
      // TODO: Provide metadata annotations.
      metadata: const [],
      hasAbstract: false,
      hasBody: node.body is! ast.EmptyFunctionBody,
      hasExternal: node.externalKeyword != null,
      isGetter: node.isGetter,
      isOperator: node.isOperator,
      isSetter: node.isSetter,
      isStatic: node.isStatic,
      namedParameters: [], // TODO(scheglov) implement
      positionalParameters: [], // TODO(scheglov) implement
      returnType: _typeAnnotation(node.returnType),
      typeParameters: _typeParameters(node.typeParameters),
      definingType: definingType,
    );
  }

  macro.NamedTypeAnnotationImpl _namedType(ast.NamedType node) {
    return macro.NamedTypeAnnotationImpl(
      id: macro.RemoteInstance.uniqueId,
      identifier: _namedTypeIdentifier(node),
      isNullable: node.question != null,
      typeArguments: _typeAnnotations(node.typeArguments?.arguments),
    );
  }

  macro.IdentifierImpl _namedTypeIdentifier(ast.NamedType node) {
    return _namedTypeMap[node] ??= _NamedTypeIdentifierImpl(
      id: macro.RemoteInstance.uniqueId,
      name: node.name2.lexeme,
      node: node,
    );
  }

  List<macro.NamedTypeAnnotationImpl> _namedTypes(
    List<ast.NamedType>? elements,
  ) {
    if (elements != null) {
      return elements.map(_namedType).toList();
    } else {
      return const [];
    }
  }

  macro.TypeAnnotationImpl _typeAnnotation(ast.TypeAnnotation? node) {
    switch (node) {
      case null:
        return macro.OmittedTypeAnnotationImpl(
          id: macro.RemoteInstance.uniqueId,
        );
      case ast.GenericFunctionType():
        return macro.FunctionTypeAnnotationImpl(
          id: macro.RemoteInstance.uniqueId,
          isNullable: node.question != null,
          namedParameters: node.parameters.parameters
              .where((e) => e.isNamed)
              .map(_formalParameter)
              .toList(),
          positionalParameters: node.parameters.parameters
              .where((e) => e.isPositional)
              .map(_formalParameter)
              .toList(),
          returnType: _typeAnnotation(node.returnType),
          typeParameters: _typeParameters(node.typeParameters),
        );
      case ast.NamedType():
        return _namedType(node);
      default:
        throw UnimplementedError('(${node.runtimeType}) $node');
    }
  }

  List<macro.TypeAnnotationImpl> _typeAnnotations(
    List<ast.TypeAnnotation>? elements,
  ) {
    if (elements != null) {
      return List.generate(
          elements.length, (i) => _typeAnnotation(elements[i]));
    } else {
      return const [];
    }
  }

  macro.TypeParameterDeclarationImpl _typeParameter(
    ast.TypeParameter node,
  ) {
    return macro.TypeParameterDeclarationImpl(
      id: macro.RemoteInstance.uniqueId,
      identifier: _declaredIdentifier(node.name, node.declaredElement!),
      library: library(node.declaredElement!),
      // TODO: Provide metadata annotations.
      metadata: const [],
      bound: node.bound.mapOrNull(_typeAnnotation),
    );
  }

  List<macro.TypeParameterDeclarationImpl> _typeParameters(
    ast.TypeParameterList? typeParameterList,
  ) {
    if (typeParameterList != null) {
      return typeParameterList.typeParameters.map(_typeParameter).toList();
    } else {
      return const [];
    }
  }
}

class FieldDeclarationImpl extends macro.FieldDeclarationImpl {
  FieldDeclarationImpl({
    required super.id,
    required super.identifier,
    required super.library,
    required super.metadata,
    required super.hasExternal,
    required super.hasFinal,
    required super.hasLate,
    required super.type,
    required super.definingType,
    required super.isStatic,
  });
}

abstract class IdentifierImpl extends macro.IdentifierImpl {
  IdentifierImpl({
    required super.id,
    required super.name,
  });

  Element? get element;
}

class IdentifierImplFromElement extends IdentifierImpl {
  @override
  final Element element;

  IdentifierImplFromElement({
    required super.id,
    required super.name,
    required this.element,
  });
}

class IntrospectableClassDeclarationImpl
    extends macro.IntrospectableClassDeclarationImpl {
  late final ClassElement element;

  IntrospectableClassDeclarationImpl._({
    required super.id,
    required super.identifier,
    required super.library,
    required super.metadata,
    required super.typeParameters,
    required super.interfaces,
    required super.hasAbstract,
    required super.hasBase,
    required super.hasFinal,
    required super.hasExternal,
    required super.hasInterface,
    required super.hasMixin,
    required super.hasSealed,
    required super.mixins,
    required super.superclass,
  });
}

abstract class LibraryImpl extends macro.LibraryImpl {
  LibraryImpl({
    required super.id,
    required super.languageVersion,
    required super.metadata,
    required super.uri,
  });

  Element? get element;
}

class LibraryImplFromElement extends LibraryImpl {
  @override
  final Element element;

  LibraryImplFromElement({
    required super.id,
    required super.languageVersion,
    required super.metadata,
    required super.uri,
    required this.element,
  });
}

class MethodDeclarationImpl extends macro.MethodDeclarationImpl {
  final MethodElement element;

  MethodDeclarationImpl._({
    required super.id,
    required super.identifier,
    required super.library,
    required super.metadata,
    required super.hasAbstract,
    required super.hasBody,
    required super.hasExternal,
    required super.isGetter,
    required super.isOperator,
    required super.isSetter,
    required super.namedParameters,
    required super.positionalParameters,
    required super.returnType,
    required super.typeParameters,
    required super.definingType,
    required super.isStatic,
    required this.element,
  });
}

class _DeclaredIdentifierImpl extends IdentifierImpl {
  @override
  final Element element;

  _DeclaredIdentifierImpl({
    required super.id,
    required super.name,
    required this.element,
  });
}

class _NamedTypeIdentifierImpl extends IdentifierImpl {
  final ast.NamedType node;

  _NamedTypeIdentifierImpl({
    required super.id,
    required super.name,
    required this.node,
  });

  @override
  Element? get element => node.element;
}

extension<T> on T? {
  R? mapOrNull<R>(R Function(T) mapper) {
    final self = this;
    return self != null ? mapper(self) : null;
  }
}