// Copyright (c) 2020, 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:analyzer/dart/ast/token.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer/src/dart/ast/ast.dart';
import 'package:analyzer/src/dart/element/element.dart';
import 'package:analyzer/src/dart/element/type.dart';
import 'package:analyzer/src/dart/element/type_provider.dart';
import 'package:analyzer/src/dart/resolver/property_element_resolver.dart';
import 'package:analyzer/src/diagnostic/diagnostic.dart' as diag;
import 'package:analyzer/src/error/listener.dart';
import 'package:analyzer/src/generated/inference_log.dart';
import 'package:analyzer/src/generated/resolver.dart';
import 'package:analyzer/src/generated/scope_helpers.dart';

class SimpleIdentifierResolver with ScopeHelpers {
  final ResolverVisitor _resolver;

  var _currentAlreadyResolved = false;

  SimpleIdentifierResolver(this._resolver);

  @override
  DiagnosticReporter get diagnosticReporter => _resolver.diagnosticReporter;

  TypeProviderImpl get _typeProvider => _resolver.typeProvider;

  void resolve(SimpleIdentifierImpl node, {required DartType contextType}) {
    if (node.inDeclarationContext()) {
      inferenceLogWriter?.recordExpressionWithNoType(node);
      return;
    }

    _resolver.checkUnreachableNode(node);

    _resolver.checkReadOfNotAssignedLocalVariable(node, node.element);

    _reportDeprecatedExportUse(node);

    var propertyResult = _resolve1(node, contextType: contextType);
    _resolve2(node, propertyResult, contextType: contextType);
  }

  /// Return the type that should be recorded for a node that resolved to the given accessor.
  ///
  /// @param accessor the accessor that the node resolved to
  /// @return the type that should be recorded for a node that resolved to the given accessor
  ///
  // TODO(scheglov): this is duplicate
  DartType _getTypeOfProperty(PropertyAccessorElement accessor) {
    FunctionType functionType = accessor.type;
    if (accessor is SetterElement) {
      var parameterTypes = functionType.normalParameterTypes;
      if (parameterTypes.isNotEmpty) {
        return parameterTypes[0];
      }
      var getter = accessor.variable.getter;
      if (getter != null) {
        functionType = getter.type;
        return functionType.returnType;
      }
      return DynamicTypeImpl.instance;
    }
    return functionType.returnType;
  }

  /// Return `true` if the given [node] is not a type literal.
  ///
  // TODO(scheglov): this is duplicate
  bool _isExpressionIdentifier(Identifier node) {
    var parent = node.parent;
    if (node is SimpleIdentifier && node.inDeclarationContext()) {
      return false;
    }
    if (parent is ConstructorDeclaration) {
      if (parent.typeName == node) {
        return false;
      }
    }
    if (parent is ConstructorName ||
        parent is MethodInvocation ||
        parent is PrefixedIdentifier && parent.prefix == node ||
        parent is PropertyAccess ||
        parent is NamedType) {
      return false;
    }
    return true;
  }

  /// Return `true` if the given [node] can validly be resolved to a prefix:
  /// * it is the prefix in an import directive, or
  /// * it is the prefix in a prefixed identifier.
  bool _isValidAsPrefix(SimpleIdentifier node) {
    var parent = node.parent;
    if (parent is ImportDirective) {
      return identical(parent.prefix, node);
    } else if (parent is PrefixedIdentifier) {
      return true;
    } else if (parent is MethodInvocation) {
      return identical(parent.target, node) &&
          parent.operator?.type == TokenType.PERIOD;
    }
    return false;
  }

  void _reportDeprecatedExportUse(SimpleIdentifierImpl node) {
    var scopeLookupResult = node.scopeLookupResult;
    if (scopeLookupResult != null) {
      reportDeprecatedExportUseGetter(
        scopeLookupResult: scopeLookupResult,
        nameToken: node.token,
      );
    }
  }

  PropertyElementResolverResult? _resolve1(
    SimpleIdentifierImpl node, {
    required DartType contextType,
  }) {
    _currentAlreadyResolved = false;

    //
    // Synthetic identifiers have been already reported during parsing.
    //
    if (node.isSynthetic) {
      return null;
    }

    //
    // Ignore nodes that should have been resolved before getting here.
    //
    if (node.inDeclarationContext()) {
      return null;
    }
    if (node.element is LocalVariableElement ||
        node.element is FormalParameterElement) {
      return null;
    }
    var parent = node.parent;
    if (parent is FieldFormalParameter) {
      return null;
    } else if (parent is ConstructorFieldInitializer &&
        parent.fieldName == node) {
      return null;
    } else if (parent is Annotation && parent.constructorName == node) {
      return null;
    }

    //
    // Otherwise, the node should be resolved.
    //

    // TODO(scheglov): Special-case resolution of ForStatement, don't use this.
    var hasRead = true;
    var hasWrite = false;
    {
      var parent = node.parent;
      if (parent is ForEachPartsWithIdentifier && parent.identifier == node) {
        hasRead = false;
        hasWrite = true;
      }
    }

    var resolver = PropertyElementResolver(_resolver);
    var result = resolver.resolveSimpleIdentifier(
      node: node,
      hasRead: hasRead,
      hasWrite: hasWrite,
    );

    var callFunctionType = result.functionTypeCallType;
    if (callFunctionType != null) {
      var staticType = _resolver.inferenceHelper.inferTearOff(
        node,
        node,
        callFunctionType,
        contextType: contextType,
      );
      node.recordStaticType(staticType, resolver: _resolver);
      _currentAlreadyResolved = true;
      return null;
    }

    var recordField = result.recordField;
    if (recordField != null) {
      node.recordStaticType(recordField.type, resolver: _resolver);
      _currentAlreadyResolved = true;
      return null;
    }

    var element = hasRead ? result.readElement2 : result.writeElement2;

    var enclosingClass = _resolver.enclosingClass;
    if (_isFactoryConstructorReturnType(node) &&
        !identical(element, enclosingClass)) {
      diagnosticReporter.report(diag.invalidFactoryNameNotAClass.at(node));
    } else if (_isConstructorReturnType(node) &&
        !identical(element, enclosingClass)) {
      // This error is now reported by the parser.
      element = null;
    } else if (element is PrefixElement && !_isValidAsPrefix(node)) {
      if (element.name case var name?) {
        diagnosticReporter.report(
          diag.prefixIdentifierNotFollowedByDot
              .withArguments(name: name)
              .at(node),
        );
      }
    } else if (element == null) {
      // TODO(brianwilkerson): Recover from this error.
      if (node.name == "await" && _resolver.enclosingFunction != null) {
        diagnosticReporter.report(diag.undefinedIdentifierAwait.at(node));
      } else if (!_resolver.libraryFragment.shouldIgnoreUndefinedIdentifier(
        node,
      )) {
        diagnosticReporter.report(
          diag.undefinedIdentifier.withArguments(name: node.name).at(node),
        );
      }
    }
    node.element = element;
    return result;
  }

  void _resolve2(
    SimpleIdentifierImpl node,
    PropertyElementResolverResult? propertyResult, {
    required DartType contextType,
  }) {
    if (_currentAlreadyResolved) {
      return;
    }

    var element = node.element;

    if (element is ExtensionElement) {
      _setExtensionIdentifierType(node);
      inferenceLogWriter?.recordExpressionWithNoType(node);
      return;
    }

    DartType staticType = InvalidTypeImpl.instance;
    if (element is InterfaceElement) {
      if (_isExpressionIdentifier(node)) {
        node.recordStaticType(_typeProvider.typeType, resolver: _resolver);
      } else {
        inferenceLogWriter?.recordExpressionWithNoType(node);
      }
      return;
    } else if (element is TypeAliasElement) {
      if (_isExpressionIdentifier(node) ||
          element.aliasedType is! InterfaceType) {
        node.recordStaticType(_typeProvider.typeType, resolver: _resolver);
      } else {
        inferenceLogWriter?.recordExpressionWithNoType(node);
      }
      return;
    } else if (element is MethodElement) {
      staticType = element.type;
    } else if (element is PropertyAccessorElement) {
      staticType = propertyResult?.getType ?? _getTypeOfProperty(element);
    } else if (element is ExecutableElement) {
      staticType = element.type;
    } else if (element is TypeParameterElement) {
      staticType = _typeProvider.typeType;
    } else if (element is VariableElement) {
      staticType = _resolver.localVariableTypeProvider.getType(
        node,
        isRead: node.inGetterContext(),
      );
    } else if (element is PrefixElement) {
      var parent = node.parent;
      if (parent is PrefixedIdentifier && parent.prefix == node ||
          parent is MethodInvocation && parent.target == node) {
        inferenceLogWriter?.recordExpressionWithNoType(node);
        return;
      }
      staticType = InvalidTypeImpl.instance;
    } else if (element is DynamicElementImpl) {
      staticType = _typeProvider.typeType;
    } else if (element is NeverElementImpl) {
      staticType = _typeProvider.typeType;
    } else {
      staticType = InvalidTypeImpl.instance;
    }

    if (!_resolver.isConstructorTearoffsEnabled) {
      // Only perform a generic function instantiation on a [PrefixedIdentifier]
      // in pre-constructor-tearoffs code. In constructor-tearoffs-enabled code,
      // generic function instantiation is performed at assignability check
      // sites.
      // TODO(srawlins): Switch all resolution to use the latter method, in a
      // breaking change release.
      staticType = _resolver.inferenceHelper.inferTearOff(
        node,
        node,
        staticType,
        contextType: contextType,
      );
    }
    node.recordStaticType(staticType, resolver: _resolver);
  }

  // TODO(scheglov): this is duplicate
  void _setExtensionIdentifierType(IdentifierImpl node) {
    if (node is SimpleIdentifierImpl && node.inDeclarationContext()) {
      return;
    }

    var parent = node.parent;

    if (parent is PrefixedIdentifierImpl && parent.identifier == node) {
      node = parent;
      parent = node.parent;
    }

    if (parent is CommentReference ||
        parent is MethodInvocation && parent.target == node ||
        parent is PrefixedIdentifierImpl && parent.prefix == node ||
        parent is PropertyAccess && parent.target == node) {
      return;
    }

    _resolver.diagnosticReporter.report(
      diag.extensionAsExpression.withArguments(name: node.name).at(node),
    );

    if (node is PrefixedIdentifierImpl) {
      node.identifier.setPseudoExpressionStaticType(DynamicTypeImpl.instance);
      node.setPseudoExpressionStaticType(DynamicTypeImpl.instance);
    } else if (node is SimpleIdentifier) {
      node.setPseudoExpressionStaticType(DynamicTypeImpl.instance);
    }
  }

  /// Return `true` if the given [identifier] is the return type of a
  /// constructor declaration.
  static bool _isConstructorReturnType(SimpleIdentifier identifier) {
    var parent = identifier.parent;
    if (parent is ConstructorDeclaration) {
      return identical(parent.typeName, identifier);
    }
    return false;
  }

  /// Return `true` if the given [identifier] is the return type of a factory
  /// constructor.
  static bool _isFactoryConstructorReturnType(SimpleIdentifier identifier) {
    var parent = identifier.parent;
    if (parent is ConstructorDeclaration) {
      return identical(parent.typeName, identifier) &&
          parent.factoryKeyword != null;
    }
    return false;
  }
}
