public static async Task GetInterfaceAndModelContext()

in codegen/src/Azure.Iot.Operations.ProtocolCompiler/ModelSelector.cs [12:100]
80 lines of code
13 McCabe index (conditional complexity)

        public static async Task<ContextualizedInterface> GetInterfaceAndModelContext(string[] modelTexts, string[] modelNames, Dtmi? modelDtmi, Action<string?> acceptHelpMessage)
        {
            ContextualizedInterface contextualizedInterface = new();

            ParsingOptions parsingOptions = new();

            parsingOptions.ExtensionLimitContexts = new List<Dtmi> { new Dtmi("dtmi:dtdl:limits:onvif") };

            DtdlParseLocator parseLocator = (int parseIndex, int parseLine, out string sourceName, out int sourceLine) =>
            {
                sourceName = modelNames[parseIndex];
                sourceLine = parseLine;
                return true;
            };

            var modelParser = new ModelParser(parsingOptions);

            try
            {
                contextualizedInterface.ModelDict = await modelParser.ParseAsync(EnumerableStringToAsync(modelTexts), parseLocator);
            }
            catch (ParsingException pex)
            {
                StringBuilder errorStringBuilder = new();
                foreach (ParsingError perr in pex.Errors)
                {
                    acceptHelpMessage(perr.Message);
                }

                return contextualizedInterface;
            }
            catch (ResolutionException rex)
            {
                acceptHelpMessage(rex.Message);
                return contextualizedInterface;
            }

            if (modelDtmi != null)
            {
                if (!contextualizedInterface.ModelDict.TryGetValue(modelDtmi, out DTEntityInfo? dtEntity))
                {
                    acceptHelpMessage($"{modelDtmi} not found in model");
                    return contextualizedInterface;
                }
                else if (dtEntity.EntityKind != DTEntityKind.Interface)
                {
                    acceptHelpMessage($"{modelDtmi} is not an Interface");
                    return contextualizedInterface;
                }
                else if (!dtEntity.SupplementalTypes.Any(t => DtdlMqttExtensionValues.MqttAdjunctTypeRegex.IsMatch(t.AbsoluteUri)))
                {
                    acceptHelpMessage($"{modelDtmi} does not have a co-type of {DtdlMqttExtensionValues.GetStandardTerm(DtdlMqttExtensionValues.MqttAdjunctTypePattern)}");
                    return contextualizedInterface;
                }
                else
                {
                    contextualizedInterface.InterfaceId = modelDtmi;
                }
            }
            else
            {
                IEnumerable<DTInterfaceInfo> mqttInterfaces = contextualizedInterface.ModelDict.Values.Where(e => e.EntityKind == DTEntityKind.Interface && e.SupplementalTypes.Any(t => DtdlMqttExtensionValues.MqttAdjunctTypeRegex.IsMatch(t.AbsoluteUri))).Select(e => (DTInterfaceInfo)e);
                switch (mqttInterfaces.Count())
                {
                    case 0:
                        acceptHelpMessage($"No Interface in model has a co-type of {DtdlMqttExtensionValues.GetStandardTerm(DtdlMqttExtensionValues.MqttAdjunctTypePattern)}");
                        break;
                    case 1:
                        contextualizedInterface.InterfaceId = mqttInterfaces.First().Id;
                        break;
                    default:
                        acceptHelpMessage($"More than one Interface has a co-type of {DtdlMqttExtensionValues.GetStandardTerm(DtdlMqttExtensionValues.MqttAdjunctTypePattern)}");
                        acceptHelpMessage($"Resubmit command with one of the following options:");
                        foreach (DTInterfaceInfo mqttInterface in mqttInterfaces)
                        {
                            acceptHelpMessage($"  --modelId {mqttInterface.Id}");
                        }
                        break;
                }
            }

            if (contextualizedInterface.InterfaceId != null)
            {
                Dtmi mqttTypeId = contextualizedInterface.ModelDict[contextualizedInterface.InterfaceId].SupplementalTypes.First(t => DtdlMqttExtensionValues.MqttAdjunctTypeRegex.IsMatch(t.AbsoluteUri));
                contextualizedInterface.MqttVersion = int.Parse(DtdlMqttExtensionValues.MqttAdjunctTypeRegex.Match(mqttTypeId.AbsoluteUri).Groups[1].Captures[0].Value);
            }

            return contextualizedInterface;
        }