package com.yunhai.userhome.loadtestmetrics;

/* =============================================================================
 * [LOADTEST-METRICS] 临时埋点 —— 《压测与oapi埋点统计方案.md》阶段二(方案 §3.2)
 * 压测结束后整体移除:删除 loadtestmetrics 包 + 回退 pom.xml/application.yml
 * 中 [LOADTEST-METRICS] 标记段 + DROP TABLE api_metrics。
 * 移除步骤详见仓库根《埋点移除清单.md》。
 * ============================================================================= */

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;

/**
 * [LOADTEST-METRICS] 出站 UserBase oapi 调用计数(direction=out,方案 §3.2)。<br>
 * 切在 yh-openapi-client 的 {@code YschOpenCall}(SDK 重构后所有出站开放接口调用的唯一
 * 公共入口,Spring Bean)上:YschBaseOpenApi 静态门面、OpenApiUserClient / OpenApiAppClient
 * 注入式调用全部经它发出,一处切面覆盖全部出站,不改动任何业务 Service 代码。<br>
 * 入站请求数(direction=in)与出站调用数(direction=out)相除即「放大系数」,
 * 是缓存层次决策的直接依据(方案 §5)。
 */
@Slf4j
@Aspect
@Component
public class OutboundOapiMetricsAspect {

    private static final int MAX_URI_LEN = 200;

    private final ApiMetricsCollector collector;

    public OutboundOapiMetricsAspect(ApiMetricsCollector collector) {
        this.collector = collector;
    }

    /**
     * 拦截 YschOpenCall 全部公开调用方法(get/getList/post/postMultipart/download)。<br>
     * 按名重载第 2 参均为 path(如 /oapi/app/list),据此归一化记 uri。
     */
    @Around("execution(* com.yunhai.platform.openapi.core.YschOpenCall.*(..))")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        String uri = resolveUri(point);
        String method = resolveHttpMethod(point.getSignature().getName());
        boolean loadTest = inheritLoadTestFlag();

        long start = System.currentTimeMillis();
        boolean error = false;
        try {
            return point.proceed();
        } catch (Throwable e) {
            error = true;
            throw e;
        } finally {
            try {
                collector.record(uri, method, ApiMetricsEntity.DIRECTION_OUT,
                        System.currentTimeMillis() - start, error, loadTest);
            } catch (Exception recordEx) {
                // 埋点自身绝不影响出站调用
                log.warn("[LOADTEST-METRICS] 出站计数失败: {}", recordEx.getMessage());
            }
        }
    }

    /** 方法名 → HTTP 方法(getJson/get→GET,postJson/post/postMultipart→POST) */
    private String resolveHttpMethod(String signatureName) {
        return signatureName.startsWith("post") ? "POST" : "GET";
    }

    /** 取第 2 参 path 归一化;防御签名变化时记方法名兜底,不抛错 */
    private String resolveUri(ProceedingJoinPoint point) {
        try {
            Object[] args = point.getArgs();
            if (args.length >= 2 && args[1] instanceof String) {
                return normalize((String) args[1]);
            }
        } catch (Exception ignore) {
            // 兜底
        }
        return "oapi:" + point.getSignature().getName();
    }

    /** 出站 path 归一化:保证前导 /、纯数字段归一为 {id}、截断 200 */
    private String normalize(String path) {
        String p = path == null ? "" : path.trim();
        if (p.isEmpty()) {
            return "/";
        }
        if (!p.startsWith("/")) {
            p = "/" + p;
        }
        int q = p.indexOf('?');
        if (q >= 0) {
            p = p.substring(0, q);
        }
        String[] segs = p.split("/");
        StringBuilder sb = new StringBuilder(p.length());
        for (String seg : segs) {
            if (seg.length() > 0 && isDigits(seg)) {
                seg = "{id}";
            }
            sb.append('/').append(seg);
        }
        p = sb.toString();
        return p.length() > MAX_URI_LEN ? p.substring(0, MAX_URI_LEN) : p;
    }

    private boolean isDigits(String s) {
        for (int i = 0; i < s.length(); i++) {
            if (!Character.isDigit(s.charAt(i))) {
                return false;
            }
        }
        return true;
    }

    /** 出站调用的压测标记继承自触发它的入站请求(X-Load-Test 头);定时任务等无请求上下文则为 false */
    private boolean inheritLoadTestFlag() {
        if (RequestContextHolder.getRequestAttributes() instanceof ServletRequestAttributes) {
            HttpServletRequest req = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
            String v = req.getHeader(ApiMetricsFilter.HEADER_LOAD_TEST);
            if (v != null && !v.trim().isEmpty()) {
                v = v.trim();
                return !"0".equals(v) && !"false".equalsIgnoreCase(v);
            }
        }
        return false;
    }

}