private Expression BuildValueResolverFunc()

in tools/AutoMapper/Execution/TypeMapPlanBuilder.cs [473:545]
70 lines of code
15 McCabe index (conditional complexity)

        private Expression BuildValueResolverFunc(PropertyMap propertyMap, Expression destValueExpr)
        {
            Expression valueResolverFunc;
            var destinationPropertyType = propertyMap.DestinationPropertyType;
            var valueResolverConfig = propertyMap.ValueResolverConfig;
            var typeMap = propertyMap.TypeMap;

            if (valueResolverConfig != null)
            {
                valueResolverFunc = ToType(BuildResolveCall(destValueExpr, valueResolverConfig),
                    destinationPropertyType);
            }
            else if (propertyMap.CustomResolver != null)
            {
                valueResolverFunc =
                    propertyMap.CustomResolver.ConvertReplaceParameters(Source, _destination, destValueExpr, Context);
            }
            else if (propertyMap.CustomExpression != null)
            {
                var nullCheckedExpression = propertyMap.CustomExpression.ReplaceParameters(Source)
                    .NullCheck(destinationPropertyType);
                var destinationNullable = destinationPropertyType.IsNullableType();
                var returnType = destinationNullable && destinationPropertyType.GetTypeOfNullable() ==
                                 nullCheckedExpression.Type
                    ? destinationPropertyType
                    : nullCheckedExpression.Type;
                valueResolverFunc =
                    TryCatch(
                        ToType(nullCheckedExpression, returnType),
                        Catch(typeof(NullReferenceException), Default(returnType)),
                        Catch(typeof(ArgumentNullException), Default(returnType))
                    );
            }
            else if (propertyMap.SourceMembers.Any()
                     && propertyMap.SourceType != null
            )
            {
                var last = propertyMap.SourceMembers.Last();
                if (last is PropertyInfo pi && pi.GetGetMethod(true) == null)
                {
                    valueResolverFunc = Default(last.GetMemberType());
                }
                else
                {
                    valueResolverFunc = Chain(propertyMap.SourceMembers, destinationPropertyType);
                }
            }
            else if (propertyMap.SourceMember != null)
            {
                valueResolverFunc = MakeMemberAccess(Source, propertyMap.SourceMember);
            }
            else
            {
                valueResolverFunc = Throw(Constant(new Exception("I done blowed up")));
            }

            if (propertyMap.NullSubstitute != null)
            {
                var nullSubstitute = Constant(propertyMap.NullSubstitute);
                valueResolverFunc = Coalesce(valueResolverFunc, ToType(nullSubstitute, valueResolverFunc.Type));
            }
            else if (!typeMap.Profile.AllowNullDestinationValues)
            {
                var toCreate = propertyMap.SourceType ?? destinationPropertyType;
                if (!toCreate.IsAbstract() && toCreate.IsClass())
                    valueResolverFunc = Coalesce(
                        valueResolverFunc,
                        ToType(DelegateFactory.GenerateNonNullConstructorExpression(toCreate), propertyMap.SourceType)
                    );
            }

            return valueResolverFunc;
        }