package cn.licoy.encryptbody.advice;

import cn.licoy.encryptbody.annotation.encrypt.*;
import cn.licoy.encryptbody.bean.EncryptAnnotationInfoBean;
import cn.licoy.encryptbody.enums.EncryptBodyMethod;
import cn.licoy.encryptbody.enums.SHAEncryptType;
import cn.licoy.encryptbody.exception.EncryptBodyFailException;
import cn.licoy.encryptbody.exception.EncryptMethodNotFoundException;
import cn.licoy.encryptbody.util.*;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import cn.licoy.encryptbody.config.EncryptBodyConfig;
import jodd.util.ReflectUtil;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.MethodParameter;
import org.springframework.core.annotation.Order;
import org.springframework.http.MediaType;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;


/**
 * 响应数据的加密处理<br>
 * 本类只对控制器参数中含有<strong>{@link org.springframework.web.bind.annotation.ResponseBody}</strong>
 * 或者控制类上含有<strong>{@link org.springframework.web.bind.annotation.RestController}</strong>
 * 以及package为<strong><code>cn.licoy.encryptbody.annotation.encrypt</code></strong>下的注解有效
 *
 * @author licoy.cn
 * @version 2018/9/4
 * @see ResponseBodyAdvice
 */
@Order(1)
@ControllerAdvice
@Slf4j
public class EncryptResponseBodyAdvice implements ResponseBodyAdvice {

    private final ObjectMapper objectMapper;

    private final EncryptBodyConfig config;

    @Value("${encrypt.enable}")
    private boolean enableEncrypt;


    @Autowired
    public EncryptResponseBodyAdvice(ObjectMapper objectMapper, EncryptBodyConfig config) {
        this.objectMapper = objectMapper;
        this.config = config;
    }


    @Override
    public boolean supports(MethodParameter returnType, Class converterType) {
        if (!enableEncrypt) return false;
        Annotation[] annotations = returnType.getDeclaringClass().getAnnotations();
        if (annotations != null && annotations.length > 0) {
            for (Annotation annotation : annotations) {
                if (annotation instanceof EncryptBody ||
                        annotation instanceof AESEncryptBody ||
                        annotation instanceof DESEncryptBody ||
                        annotation instanceof RSAEncryptBody ||
                        annotation instanceof MD5EncryptBody ||
                        annotation instanceof SHAEncryptBody) {
                    return true;
                }
            }
        }
        if (Arrays.stream(ReflectUtil.getSuperclasses(returnType.getDeclaringClass()))
                  .flatMap(clazz -> Arrays.stream(clazz.getAnnotations()))
                  .anyMatch(annotation -> annotation instanceof EncryptBody ||
                          annotation instanceof AESEncryptBody ||
                          annotation instanceof DESEncryptBody ||
                          annotation instanceof RSAEncryptBody ||
                          annotation instanceof MD5EncryptBody ||
                          annotation instanceof SHAEncryptBody)) {
            return true;
        }
        return returnType.getMethod().isAnnotationPresent(EncryptBody.class) ||
                returnType.getMethod().isAnnotationPresent(AESEncryptBody.class) ||
                returnType.getMethod().isAnnotationPresent(DESEncryptBody.class) ||
                returnType.getMethod().isAnnotationPresent(RSAEncryptBody.class) ||
                returnType.getMethod().isAnnotationPresent(MD5EncryptBody.class) ||
                returnType.getMethod().isAnnotationPresent(SHAEncryptBody.class);
    }

    @SneakyThrows
    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
                                  Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
        if (body == null) return null;
        response.getHeaders().add("Content-Encrypted", "true");
        String str = null;
        try {
            str = objectMapper.writeValueAsString(body);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        EncryptAnnotationInfoBean classAnnotation = getClassAnnotation(returnType.getDeclaringClass());
        if (classAnnotation != null) {
            return switchEncrypt(str, classAnnotation);
        }
        EncryptAnnotationInfoBean methodAnnotation = getMethodAnnotation(returnType);
        if (methodAnnotation != null) {
            return switchEncrypt(str, methodAnnotation);
        }
        throw new EncryptBodyFailException();
    }

    /**
     * 获取方法控制器上的加密注解信息
     *
     * @param methodParameter 控制器方法
     * @return 加密注解信息
     */
    private EncryptAnnotationInfoBean getMethodAnnotation(MethodParameter methodParameter) {
        if (methodParameter.getMethod().isAnnotationPresent(EncryptBody.class)) {
            EncryptBody encryptBody = methodParameter.getMethodAnnotation(EncryptBody.class);
            return EncryptAnnotationInfoBean.builder()
                                            .encryptBodyMethod(encryptBody.value())
                                            .key(encryptBody.otherKey())
                                            .shaEncryptType(encryptBody.shaType())
                                            .build();
        }
        if (methodParameter.getMethod().isAnnotationPresent(MD5EncryptBody.class)) {
            return EncryptAnnotationInfoBean.builder()
                                            .encryptBodyMethod(EncryptBodyMethod.MD5)
                                            .build();
        }
        if (methodParameter.getMethod().isAnnotationPresent(SHAEncryptBody.class)) {
            return EncryptAnnotationInfoBean.builder()
                                            .encryptBodyMethod(EncryptBodyMethod.SHA)
                                            .shaEncryptType(methodParameter.getMethodAnnotation(SHAEncryptBody.class).value())
                                            .build();
        }
        if (methodParameter.getMethod().isAnnotationPresent(DESEncryptBody.class)) {
            return EncryptAnnotationInfoBean.builder()
                                            .encryptBodyMethod(EncryptBodyMethod.DES)
                                            .key(methodParameter.getMethodAnnotation(DESEncryptBody.class).otherKey())
                                            .build();
        }
        if (methodParameter.getMethod().isAnnotationPresent(AESEncryptBody.class)) {
            return EncryptAnnotationInfoBean.builder()
                                            .encryptBodyMethod(EncryptBodyMethod.AES)
                                            .key(methodParameter.getMethodAnnotation(AESEncryptBody.class).otherKey())
                                            .build();
        }
        return null;
    }

    /**
     * 获取类控制器上的加密注解信息
     *
     * @param clazz 控制器类
     * @return 加密注解信息
     */
    private EncryptAnnotationInfoBean getClassAnnotation(Class clazz) {
        List<Annotation> annotations = new ArrayList<>(Arrays.asList(clazz.getSuperclass().getDeclaredAnnotations()));
        annotations.addAll(Arrays.asList(clazz.getDeclaredAnnotations()));
        for (Annotation annotation : annotations) {
            if (annotation instanceof EncryptBody) {
                EncryptBody encryptBody = (EncryptBody) annotation;
                return EncryptAnnotationInfoBean.builder()
                                                .encryptBodyMethod(encryptBody.value())
                                                .key(encryptBody.otherKey())
                                                .shaEncryptType(encryptBody.shaType())
                                                .build();
            }
            if (annotation instanceof MD5EncryptBody) {
                return EncryptAnnotationInfoBean.builder()
                                                .encryptBodyMethod(EncryptBodyMethod.MD5)
                                                .build();
            }
            if (annotation instanceof SHAEncryptBody) {
                return EncryptAnnotationInfoBean.builder()
                                                .encryptBodyMethod(EncryptBodyMethod.SHA)
                                                .shaEncryptType(((SHAEncryptBody) annotation).value())
                                                .build();
            }
            if (annotation instanceof DESEncryptBody) {
                return EncryptAnnotationInfoBean.builder()
                                                .encryptBodyMethod(EncryptBodyMethod.DES)
                                                .key(((DESEncryptBody) annotation).otherKey())
                                                .build();
            }
            if (annotation instanceof AESEncryptBody) {
                return EncryptAnnotationInfoBean.builder()
                                                .encryptBodyMethod(EncryptBodyMethod.AES)
                                                .key(((AESEncryptBody) annotation).otherKey())
                                                .build();
            }
        }
        return null;
    }


    /**
     * 选择加密方式并进行加密
     *
     * @param formatStringBody 目标加密字符串
     * @param infoBean         加密信息
     * @return 加密结果
     */
    private String switchEncrypt(String formatStringBody, EncryptAnnotationInfoBean infoBean) throws Exception {
        EncryptBodyMethod method = infoBean.getEncryptBodyMethod();
        if (method == null) {
            throw new EncryptMethodNotFoundException();
        }
        if (method == EncryptBodyMethod.MD5) {
            return MD5EncryptUtil.encrypt(formatStringBody);
        }
        if (method == EncryptBodyMethod.SHA) {
            SHAEncryptType shaEncryptType = infoBean.getShaEncryptType();
            if (shaEncryptType == null) shaEncryptType = SHAEncryptType.SHA256;
            return SHAEncryptUtil.encrypt(formatStringBody, shaEncryptType);
        }
        String key = infoBean.getKey();
        if (method == EncryptBodyMethod.DES) {
            key = CheckUtils.checkAndGetKey(config.getDesKey(), key, "DES-KEY");
            return DESEncryptUtil.encrypt(formatStringBody, key);
        }
        if (method == EncryptBodyMethod.AES) {
            key = CheckUtils.checkAndGetKey(config.getAesKey(), key, "AES-KEY");
            return AESEncryptUtil.encrypt(formatStringBody, key);
        }
        throw new EncryptBodyFailException();
    }


}