private FeatureFlag ParseFeatureFlag()

in src/Microsoft.Extensions.Configuration.AzureAppConfiguration/FeatureManagement/FeatureManagementKeyValueAdapter.cs [342:518]
153 lines of code
38 McCabe index (conditional complexity)

        private FeatureFlag ParseFeatureFlag(string settingKey, string settingValue)
        {
            var featureFlag = new FeatureFlag();

            var reader = new Utf8JsonReader(System.Text.Encoding.UTF8.GetBytes(settingValue));

            try
            {
                if (reader.Read() && reader.TokenType != JsonTokenType.StartObject)
                {
                    throw new FormatException(string.Format(ErrorMessages.FeatureFlagInvalidFormat, settingKey));
                }

                while (reader.Read() && reader.TokenType != JsonTokenType.EndObject)
                {
                    if (reader.TokenType != JsonTokenType.PropertyName)
                    {
                        continue;
                    }

                    string propertyName = reader.GetString();

                    switch (propertyName)
                    {
                        case FeatureManagementConstants.Id:
                            {
                                if (reader.Read() && reader.TokenType == JsonTokenType.String)
                                {
                                    featureFlag.Id = reader.GetString();
                                }
                                else if (reader.TokenType != JsonTokenType.Null)
                                {
                                    throw CreateFeatureFlagFormatException(
                                        FeatureManagementConstants.Id,
                                        settingKey,
                                        reader.TokenType.ToString(),
                                        JsonTokenType.String.ToString());
                                }

                                break;
                            }

                        case FeatureManagementConstants.Enabled:
                            {
                                if (reader.Read() && (reader.TokenType == JsonTokenType.False || reader.TokenType == JsonTokenType.True))
                                {
                                    featureFlag.Enabled = reader.GetBoolean();
                                }
                                else if (reader.TokenType == JsonTokenType.String && bool.TryParse(reader.GetString(), out bool enabled))
                                {
                                    featureFlag.Enabled = enabled;
                                }
                                else
                                {
                                    throw CreateFeatureFlagFormatException(
                                        FeatureManagementConstants.Enabled,
                                        settingKey,
                                        reader.TokenType.ToString(),
                                        $"{JsonTokenType.True}' or '{JsonTokenType.False}");
                                }

                                break;
                            }

                        case FeatureManagementConstants.Conditions:
                            {
                                if (reader.Read() && reader.TokenType == JsonTokenType.StartObject)
                                {
                                    featureFlag.Conditions = ParseFeatureConditions(ref reader, settingKey);
                                }
                                else if (reader.TokenType != JsonTokenType.Null)
                                {
                                    throw CreateFeatureFlagFormatException(
                                        FeatureManagementConstants.Conditions,
                                        settingKey,
                                        reader.TokenType.ToString(),
                                        JsonTokenType.StartObject.ToString());
                                }

                                break;
                            }

                        case FeatureManagementConstants.Allocation:
                            {
                                if (reader.Read() && reader.TokenType == JsonTokenType.StartObject)
                                {
                                    featureFlag.Allocation = ParseFeatureAllocation(ref reader, settingKey);
                                }
                                else if (reader.TokenType != JsonTokenType.Null)
                                {
                                    throw CreateFeatureFlagFormatException(
                                        FeatureManagementConstants.Allocation,
                                        settingKey,
                                        reader.TokenType.ToString(),
                                        JsonTokenType.StartObject.ToString());
                                }

                                break;
                            }

                        case FeatureManagementConstants.Variants:
                            {
                                if (reader.Read() && reader.TokenType == JsonTokenType.StartArray)
                                {
                                    List<FeatureVariant> variants = new List<FeatureVariant>();

                                    while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
                                    {
                                        int i = 0;

                                        if (reader.TokenType == JsonTokenType.StartObject)
                                        {
                                            FeatureVariant featureVariant = ParseFeatureVariant(ref reader, settingKey);

                                            if (featureVariant.Name != null)
                                            {
                                                variants.Add(featureVariant);
                                            }
                                        }
                                        else if (reader.TokenType != JsonTokenType.Null)
                                        {
                                            throw CreateFeatureFlagFormatException(
                                                $"{FeatureManagementConstants.Variants}[{i}]",
                                                settingKey,
                                                reader.TokenType.ToString(),
                                                JsonTokenType.StartObject.ToString());
                                        }

                                        i++;
                                    }

                                    featureFlag.Variants = variants;
                                }
                                else if (reader.TokenType != JsonTokenType.Null)
                                {
                                    throw CreateFeatureFlagFormatException(
                                        FeatureManagementConstants.Variants,
                                        settingKey,
                                        reader.TokenType.ToString(),
                                        JsonTokenType.StartArray.ToString());
                                }

                                break;
                            }

                        case FeatureManagementConstants.Telemetry:
                            {
                                if (reader.Read() && reader.TokenType == JsonTokenType.StartObject)
                                {
                                    featureFlag.Telemetry = ParseFeatureTelemetry(ref reader, settingKey);
                                }
                                else if (reader.TokenType != JsonTokenType.Null)
                                {
                                    throw CreateFeatureFlagFormatException(
                                        FeatureManagementConstants.Telemetry,
                                        settingKey,
                                        reader.TokenType.ToString(),
                                        JsonTokenType.StartObject.ToString());
                                }

                                break;
                            }

                        default:
                            reader.Skip();

                            break;
                    }
                }
            }
            catch (JsonException e)
            {
                throw new FormatException(settingKey, e);
            }

            return featureFlag;
        }