public override InputModelType? Read()

in src/AutoRest.CSharp/Common/Input/InputTypes/Serialization/TypeSpecInputModelTypeConverter.cs [21:108]
77 lines of code
20 McCabe index (conditional complexity)

        public override InputModelType? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
            => ReadModelType(ref reader, options, _referenceHandler.CurrentResolver);

        public override void Write(Utf8JsonWriter writer, InputModelType value, JsonSerializerOptions options)
            => throw new NotSupportedException("Writing not supported");

        private static InputModelType? ReadModelType(ref Utf8JsonReader reader, JsonSerializerOptions options, ReferenceResolver resolver)
            => reader.ReadReferenceAndResolve<InputModelType>(resolver) ?? CreateModelType(ref reader, null, null, options, resolver);

        public static InputModelType CreateModelType(ref Utf8JsonReader reader, string? id, string? name, JsonSerializerOptions options, ReferenceResolver resolver)
        {
            var isFirstProperty = id == null && name == null;
            var properties = new List<InputModelProperty>();
            var discriminatedSubtypes = new Dictionary<string, InputModelType>();
            string? crossLanguageDefinitionId = null;
            string? access = null;
            string? deprecation = null;
            string? summary = null;
            string? doc = null;
            string? usageString = null;
            InputModelProperty? discriminatorProperty = null;
            string? discriminatorValue = null;
            InputType? additionalProperties = null;
            InputModelType? baseModel = null;
            InputModelType? model = null;
            IReadOnlyList<InputDecoratorInfo>? decorators = null;

            while (reader.TokenType != JsonTokenType.EndObject)
            {
                var isKnownProperty = reader.TryReadReferenceId(ref isFirstProperty, ref id)
                    || reader.TryReadString("name", ref name)
                    || reader.TryReadString("crossLanguageDefinitionId", ref crossLanguageDefinitionId)
                    || reader.TryReadString("access", ref access)
                    || reader.TryReadString("deprecation", ref deprecation)
                    || reader.TryReadString("summary", ref summary)
                    || reader.TryReadString("doc", ref doc)
                    || reader.TryReadString("usage", ref usageString)
                    || reader.TryReadComplexType("discriminatorProperty", options, ref discriminatorProperty)
                    || reader.TryReadString("discriminatorValue", ref discriminatorValue)
                    || reader.TryReadComplexType("additionalProperties", options, ref additionalProperties)
                    || reader.TryReadComplexType("decorators", options, ref decorators);

                if (isKnownProperty)
                {
                    continue;
                }
                /**
                 * If the model has base model, `BaseModel` and `Properties` should be the last two items in tspCodeModel.
                 * and `BaseModel` should be last but one, and `Properties` should be the last one.
                 */
                if (reader.GetString() == "baseModel")
                {
                    model = CreateInputModelTypeInstance(id, name, crossLanguageDefinitionId, access, deprecation, summary, doc, usageString, discriminatorValue, discriminatorProperty, baseModel, properties, discriminatedSubtypes, additionalProperties, decorators, resolver);
                    reader.TryReadComplexType("baseModel", options, ref baseModel);
                    if (baseModel != null)
                    {
                        model.SetBaseModel(baseModel);
                        var baseModelDerived = (List<InputModelType>)resolver.ResolveReference($"{baseModel.Name}.{nameof(InputModelType.DerivedModels)}");
                        baseModelDerived.Add(model);
                    }
                    continue;
                }
                if (reader.GetString() == "properties")
                {
                    model = model ?? CreateInputModelTypeInstance(id, name, crossLanguageDefinitionId, access, deprecation, summary, doc, usageString, discriminatorValue, discriminatorProperty, baseModel, properties, discriminatedSubtypes, additionalProperties, decorators, resolver);
                    reader.Read();
                    CreateProperties(ref reader, properties, options, name!, model.Usage.HasFlag(InputModelTypeUsage.MultipartFormData));
                    continue;
                }
                if (reader.GetString() == "discriminatedSubtypes")
                {
                    model = model ?? CreateInputModelTypeInstance(id, name, crossLanguageDefinitionId, access, deprecation, summary, doc, usageString, discriminatorValue, discriminatorProperty, baseModel, properties, discriminatedSubtypes, additionalProperties, decorators, resolver);
                    reader.Read();
                    CreateDiscriminatedSubtypes(ref reader, discriminatedSubtypes, options);
                    if (reader.TokenType != JsonTokenType.EndObject)
                    {
                        throw new JsonException($"{nameof(InputModelType)}.{nameof(InputModelType.Properties)} must be the last defined property for id '{id}', name '{name}'");
                    }
                    continue;
                }

                reader.SkipProperty();
            }

            var result = model ?? CreateInputModelTypeInstance(id, name, crossLanguageDefinitionId, access, deprecation,summary, doc, usageString, discriminatorValue, discriminatorProperty, baseModel, properties, discriminatedSubtypes, additionalProperties, decorators, resolver);
            result.Decorators = decorators ?? Array.Empty<InputDecoratorInfo>();
            return result;
        }