// Copyright (c) 2019, 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/ast.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/src/generated/source.dart';
import 'package:nnbd_migration/instrumentation.dart';
import 'package:nnbd_migration/nnbd_migration.dart';

/// The instrumentation information gathered from the migration engine.
class InstrumentationInformation {
  /// The node used for type sources that are always `null`.
  NullabilityNodeInfo always;

  /// A map from elements outside of the code being migrated, to the nullability
  /// nodes associated with the type of the element.
  final Map<Element, DecoratedTypeInfo> externalDecoratedType = {};

  /// A map from the graph edges between nullability nodes, to information about
  /// the edge that was created and why it was created.
  final Map<EdgeInfo, EdgeOriginInfo> edgeOrigin = {};

  /// The node used for type sources that are never `null`.
  NullabilityNodeInfo never;

  /// A list of the steps in the propagation of nullability information through
  /// the nullability graph, to report details of the step that was performed
  /// and why it was performed.
  final List<PropagationInfo> propagationSteps = [];

  /// The instrumentation information that is specific to a single source.
  final Map<Source, SourceInformation> sourceInformation = {};

  /// Initialize a newly created holder of instrumentation information.
  InstrumentationInformation();
}

/// The instrumentation information gathered from the migration engine that is
/// specific to a single source.
class SourceInformation {
  /// A map from the type annotations found in the source code, to the
  /// nullability nodes that are associated with that type.
  final Map<TypeAnnotation, NullabilityNodeInfo> explicitTypeNullability = {};

  /// A map from the fixes that were decided on to the reasons for the fix.
  final Map<SingleNullabilityFix, List<FixReasonInfo>> fixes = {};

  /// A map from AST nodes that have an implicit return type to the nullability
  /// node associated with the implicit return type of the AST node. The node
  /// can be an
  /// - executable declaration,
  /// - function-typed formal parameter declaration,
  /// - function type alias declaration,
  /// - generic function type, or
  /// - function expression.
  final Map<AstNode, DecoratedTypeInfo> implicitReturnType = {};

  /// A map from AST nodes that have an implicit type to the nullability node
  /// associated with the implicit type of the AST node. The node can be a
  /// - formal parameter,
  /// - declared identifier, or
  /// - variable in a variable declaration list.
  final Map<AstNode, DecoratedTypeInfo> implicitType = {};

  /// Called whenever the migration engine encounters an AST node with implicit
  /// type arguments, to report the nullability nodes associated with the
  /// implicit type arguments of the AST node.
  ///
  /// A map from AST nodes that have implicit type arguments to the nullability
  /// nodes associated with the implicit type arguments of the AST node. The
  /// node can be a
  /// - constructor redirection,
  /// - function expression invocation,
  /// - method invocation,
  /// - instance creation expression,
  /// - list/map/set literal, or
  /// - type annotation.
  final Map<AstNode, List<DecoratedTypeInfo>> implicitTypeArguments = {};

  /// Initialize a newly created holder of instrumentation information that is
  /// specific to a single source.
  SourceInformation();
}