HLTech / pact-gen

import com.hltech.pact.gen.domain.client.model.Param;

import org.springframework.http.HttpHeaders;

import org.springframework.util.MultiValueMap;

import org.springframework.web.bind.annotation.RequestHeader;

import org.springframework.web.bind.annotation.ValueConstants;

import java.lang.reflect.Method;

import java.lang.reflect.Parameter;

import java.util.Arrays;

import java.util.List;

import java.util.Map;

import java.util.Optional;

import java.util.stream.Collectors;

public final class RequestHeaderParamsExtractor {

    public static List<Param> extractAll(Method feignClientMethod) {

        return Arrays.stream(feignClientMethod.getParameters())

            .filter(param -> param.getAnnotation(RequestHeader.class) != null)

            .filter(param -> param.getType() != Map.class

                && param.getType() != MultiValueMap.class

                && param.getType() != HttpHeaders.class)

            .map(RequestHeaderParamsExtractor::extract)

            .collect(Collectors.toList());

    }

    private static Param extract(Parameter param) {

        Param.ParamBuilder builder = Param.builder();

        extractHeaderDefaultValue(param).ifPresent(builder::defaultValue);

        List<Class<?>> paramTypes = TypeExtractor.extractParameterTypesFromType(param.getParameterizedType());

        return builder

            .name(extractHeaderName(param))

            .type(param.getType())

            .genericArgumentType(paramTypes.isEmpty() ? null : paramTypes.get(0))

            .build();

    }

    private static Optional<Object> extractHeaderDefaultValue(Parameter param) {

        RequestHeader annotation = param.getAnnotation(RequestHeader.class);

        if (annotation.defaultValue().equals(ValueConstants.DEFAULT_NONE) || annotation.defaultValue().isEmpty()) {

            return Optional.empty();

        }

        return Optional.of(annotation.defaultValue());

    }

    private static String extractHeaderName(Parameter param) {

        RequestHeader annotation = param.getAnnotation(RequestHeader.class);

        if (!annotation.name().isEmpty()) {

            return annotation.name();

        } else if (!annotation.value().isEmpty()) {

            return annotation.value();

        }

        return param.getName();

    }

}