protected virtual bool TryPolicyDefinition()

in src/PSRule.Rules.Azure/Data/Policy/PolicyAssignmentVisitor.cs [887:963]
58 lines of code
21 McCabe index (conditional complexity)

        protected virtual bool TryPolicyDefinition(PolicyAssignmentContext context, JObject definition, string policyDefinitionId, out PolicyDefinition policyDefinition)
        {
            policyDefinition = null;

            // A definition must have properties, policyRule, and a non-disabled effect.
            if (!definition.TryObjectProperty(PROPERTY_PROPERTIES, out var properties) ||
                !properties.TryObjectProperty(PROPERTY_POLICYRULE, out var policyRule) ||
                !policyRule.TryObjectProperty(PROPERTY_IF, out _) ||
                !policyRule.TryObjectProperty(PROPERTY_THEN, out var then))
                return false;

            if (!properties.TryStringProperty(PROPERTY_MODE, out var mode) || !IsPolicyMode(mode, out var policyMode))
            {
                context.Pipeline?.Writer?.VerbosePolicyIgnoreNotApplicable(policyDefinitionId);
                return false;
            }

            properties.TryStringProperty(PROPERTY_DISPLAYNAME, out var displayName);
            properties.TryStringProperty(PROPERTY_DESCRIPTION, out var description);
            var result = new PolicyDefinition(policyDefinitionId, description, definition, displayName);

            // Set annotations
            if (properties.TryObjectProperty(PROPERTY_METADATA, out var metadata))
            {
                if (metadata.TryStringProperty(PROPERTY_CATEGORY, out var category))
                    result.Category = category;

                if (metadata.TryStringProperty(PROPERTY_VERSION, out var version))
                    result.Version = version;
            }

            // Set parameters
            if (properties.TryObjectProperty(PROPERTY_PARAMETERS, out var parameters))
            {
                foreach (var parameter in parameters.Properties())
                    context.SetDefinitionParameterAssignment(result, parameter);

                // Check if definition with same parameters has already been added
                if (context.DefinitionParameterMap.TryGetValue(policyDefinitionId, out var previousDefinitionParameters))
                {
                    var foundDuplicateDefinition = true;
                    foreach (var currentParameter in result.Parameters)
                    {
                        if (previousDefinitionParameters.TryGetValue(currentParameter.Key, out var previousParameterValue))
                        {
                            if (!ParametersEqual(context, previousParameterValue, currentParameter.Value))
                            {
                                foundDuplicateDefinition = false;
                                break;
                            }
                        }
                    }

                    // Skip adding definition if duplicate parameters found
                    if (foundDuplicateDefinition)
                        return false;
                }
                context.DefinitionParameterMap[policyDefinitionId] = result.Parameters;
            }

            if (!TryPolicyRuleEffect(context, then, out var effect) || ShouldFilterRule(context, policyDefinitionId, then, effect))
                return false;

            // Modify policy rule
            TrimPolicyRule(policyRule);
            VisitPolicyRule(context, result, policyRule, effect);
            AddSelectors(result, policyMode);

            // Check for an resulting empty condition.
            if (result.Condition == null || result.Condition.Count == 0)
                throw ThrowEmptyConditionExpandResult(context, policyDefinitionId);

            var policyRuleHash = GetPolicyRuleHash(policyDefinitionId, result.Condition, result.Where);
            result.Name = $"{context.PolicyRulePrefix}.Policy.{policyRuleHash}";
            policyDefinition = result;
            return true;
        }