package com.xiaopeng.operation.config.log;

import com.alibaba.fastjson2.JSON;
import com.xiaopeng.common.log.config.LogHeaderProperties;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.util.*;

/**
 * Feign 调用日志切面
 *
 * <p>拦截所有带 @FeignClient 注解的接口方法，记录：
 * <ul>
 *   <li>调用的接口类名 + 方法名</li>
 *   <li>入参（JSON 序列化）</li>
 *   <li>出参（JSON 序列化）</li>
 *   <li>耗时（ms）</li>
 *   <li>异常信息（含完整堆栈）</li>
 * </ul>
 */
@Slf4j
@Aspect
@Component
public class FeignLoggingAspect {

    @Autowired
    private LogHeaderProperties logHeaderProperties;

    /**
     * 拦截所有带 @FeignClient 注解的接口的所有方法
     */
    @Around("within(@org.springframework.cloud.openfeign.FeignClient *)")
    public Object logFeignCall(ProceedingJoinPoint pjp) throws Throwable {
        return doLog(pjp);
    }

    private Object doLog(ProceedingJoinPoint pjp) throws Throwable {
        MethodSignature signature = (MethodSignature) pjp.getSignature();
        Method method = signature.getMethod();
        // 使用接口声明类名，避免打印动态代理类名（如 $Proxy270）
        String className = signature.getDeclaringType().getSimpleName();
        String methodName = method.getName();
        String fullMethod = className + "#" + methodName;

        Object[] args = pjp.getArgs();
        String argsJson = safeToJson(args);
        String headerStr = extractCurrentHeaders();

        if (headerStr != null) {
            log.info("[Feign] >>> 调用开始 | method={} | headers={} | args={}", fullMethod, headerStr, argsJson);
        } else {
            log.info("[Feign] >>> 调用开始 | method={} | args={}", fullMethod, argsJson);
        }

        long start = System.currentTimeMillis();
        try {
            Object result = pjp.proceed();
            long elapsed = System.currentTimeMillis() - start;
            String resultJson = safeToJson(result);
            log.info("[Feign] <<< 调用成功 | method={} | elapsed={}ms | result={}", fullMethod, elapsed, resultJson);
            return result;
        } catch (Throwable ex) {
            long elapsed = System.currentTimeMillis() - start;
            log.error("[Feign] <<< 调用异常 | method={} | elapsed={}ms | error={} | args={}",
                    fullMethod, elapsed, ex.getMessage(), argsJson, ex);
            throw ex;
        }
    }

    /**
     * 安全序列化为 JSON，避免序列化失败导致日志切面本身抛异常
     */
    private String safeToJson(Object obj) {
        if (obj == null) {
            return "null";
        }
        try {
            if (obj instanceof Object[]) {
                return JSON.toJSONString(Arrays.asList((Object[]) obj));
            }
            return JSON.toJSONString(obj);
        } catch (Exception e) {
            return "[序列化失败: " + obj.getClass().getSimpleName() + "]";
        }
    }

    /**
     * 从当前请求上下文中提取请求头信息
     */
    private String extractCurrentHeaders() {
        if (!logHeaderProperties.isEnabled()) {
            return null;
        }
        try {
            ServletRequestAttributes attrs = (ServletRequestAttributes)
                    RequestContextHolder.getRequestAttributes();
            if (attrs == null) return "{}";
            HttpServletRequest request = attrs.getRequest();
            List<String> names = logHeaderProperties.getNames();
            StringBuilder sb = new StringBuilder("{");
            boolean first = true;
            if (names != null && !names.isEmpty()) {
                for (String name : names) {
                    String value = request.getHeader(name);
                    if (value != null) {
                        if (!first) sb.append(", ");
                        first = false;
                        sb.append(name).append("=").append(value);
                    }
                }
            } else {
                Enumeration<String> headerNames = request.getHeaderNames();
                while (headerNames != null && headerNames.hasMoreElements()) {
                    String name = headerNames.nextElement();
                    String value = request.getHeader(name);
                    if (!first) sb.append(", ");
                    first = false;
                    sb.append(name).append("=").append(value);
                }
            }
            return sb.append("}").toString();
        } catch (Exception e) {
            return "{error: " + e.getMessage() + "}";
        }
    }
}