// loadtest/lib/helpers.js —— k6 公共助手（P5-prep Task 3）。
// 被 read-feed.js / upload-burst.js 复用：登录 / 建相册 / 上传全链 / 公开读
// 分页 / 点赞批次 / 浏览上报 / 公开可见轮询。端点与请求体形态对齐
// scripts/prod-smoke.sh（契约权威 = packages/contracts/openapi.yaml）。
//
// 内置测试图与 prod-smoke.sh 同一张：800x600 JPEG（quality 55，3118 字节），
// base64 内嵌（下方 JPEG_B64 由 scripts/prod-smoke.sh 同步生成，勿手改），
// k6 侧用 k6/encoding 解码为二进制。刻意不用 1x1——避免变体流水线踩最小
// 尺寸边界。
import http from 'k6/http';
import { sleep } from 'k6';
import encoding from 'k6/encoding';

export const JPEG_B64 = '/9j/2wBDAA4KCw0LCQ4NDA0QDw4RFiQXFhQUFiwgIRokNC43NjMuMjI6QVNGOj1OPjIySGJJTlZYXV5dOEVmbWVabFNbXVn/2wBDAQ8QEBYTFioXFypZOzI7WVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVlZWVn/wAARCAJYAyADASIAAhEBAxEB/8QAFQABAQAAAAAAAAAAAAAAAAAAAAX/xAAUEAEAAAAAAAAAAAAAAAAAAAAA/8QAFQEBAQAAAAAAAAAAAAAAAAAAAAX/xAAUEQEAAAAAAAAAAAAAAAAAAAAA/9oADAMBAAIRAxEAPwCsAkKIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD//2Q==';

/** 解码一次，全脚本复用（ArrayBuffer 可直接作 k6 http 请求体）。 */
export const JPEG_BYTES = encoding.b64decode(JPEG_B64, true);

// ── env 参数读取（--env KEY=VALUE → __ENV.KEY；缺省回退）──

export function envStr(name, fallback) {
  const v = __ENV[name];
  return v === undefined || v === '' ? fallback : v;
}

export function envInt(name, fallback) {
  const raw = __ENV[name];
  if (raw === undefined || raw === '') {
    return fallback;
  }
  const n = Number.parseInt(raw, 10);
  return Number.isFinite(n) && n > 0 ? n : fallback;
}

export function envFloat(name, fallback) {
  const raw = __ENV[name];
  if (raw === undefined || raw === '') {
    return fallback;
  }
  const n = Number.parseFloat(raw);
  return Number.isFinite(n) && n >= 0 ? n : fallback;
}

/** 压测内唯一键（clientTaskId/batchId/requestId 等幂等键；时间戳+随机足够）。 */
export function uniqId(prefix) {
  return `${prefix}-${Date.now().toString(36)}-${Math.floor(Math.random() * 1e9).toString(36)}`;
}

// ── 认证与相册 ──

export function authHeaders(token) {
  return { Authorization: `Bearer ${token}`, 'Content-Type': 'application/json' };
}

/** 密码登录 → sessionToken（响应体 {sessionToken,...}，同 prod-smoke ②）。 */
export function login(base, account, password) {
  const res = http.post(
    `${base}/v1/auth/password`,
    JSON.stringify({ account, password }),
    { headers: { 'Content-Type': 'application/json' }, tags: { name: 'auth_password' } },
  );
  if (res.status !== 200) {
    throw new Error(`登录失败 HTTP ${res.status}: ${res.body}`);
  }
  const token = res.json('sessionToken');
  if (!token) {
    throw new Error(`登录响应缺 sessionToken: ${res.body}`);
  }
  return token;
}

/** 建时间戳相册 → { albumId, publicToken }（同 prod-smoke ③）。 */
export function createAlbum(base, token, title, description) {
  const res = http.post(
    `${base}/v1/albums`,
    JSON.stringify({
      translations: [
        { locale: 'zh-CN', title, description: description || 'k6 loadtest fixture' },
      ],
      defaultLocale: 'zh-CN',
      startAt: new Date().toISOString(),
    }),
    { headers: authHeaders(token), tags: { name: 'albums_create' } },
  );
  if (res.status !== 201) {
    throw new Error(`建相册失败 HTTP ${res.status}: ${res.body}`);
  }
  return { albumId: res.json('id'), publicToken: res.json('publicToken') };
}

// ── 上传全链（presign → OSS PUT → complete）──

/**
 * 单照片全链上传。返回逐步耗时（毫秒，k6 timings）与 id，供脚本各自打点：
 * { photoId, uploadId, timings: { presign, put, complete, chainMs } }
 * 任一步非预期状态码即抛错（k6 计一次 error 并终止单迭代）。
 */
export function uploadPhoto(base, token, albumId, clientTaskId) {
  const started = Date.now();
  const presign = http.post(
    `${base}/v1/uploads`,
    JSON.stringify({
      albumId,
      clientTaskId,
      filename: 'k6.jpg',
      bytes: JPEG_BYTES.byteLength,
      contentType: 'image/jpeg',
    }),
    { headers: authHeaders(token), tags: { name: 'uploads_presign' } },
  );
  if (presign.status !== 201) {
    throw new Error(`presign 失败 HTTP ${presign.status}: ${presign.body}`);
  }
  const uploadId = presign.json('uploadId');
  const photoId = presign.json('photoId');
  const url = presign.json('url');
  if (!uploadId || !url) {
    throw new Error(`presign 响应缺 uploadId/url: ${presign.body}`);
  }
  // PUT 目标是 presigned 对象存储 URL（staging=MinIO / 生产=OSS），非被测 API 域。
  const put = http.put(url, JPEG_BYTES, {
    headers: { 'Content-Type': 'image/jpeg' },
    tags: { name: 'oss_put' },
  });
  if (put.status < 200 || put.status > 299) {
    throw new Error(`OSS PUT 失败 HTTP ${put.status}`);
  }
  const complete = http.post(
    `${base}/v1/uploads/${uploadId}/complete`,
    '',
    { headers: authHeaders(token), tags: { name: 'uploads_complete' } },
  );
  if (complete.status !== 200) {
    throw new Error(`complete 失败 HTTP ${complete.status}: ${complete.body}`);
  }
  return {
    photoId,
    uploadId,
    timings: {
      presign: presign.timings.duration,
      put: put.timings.duration,
      complete: complete.timings.duration,
      chainMs: Date.now() - started,
    },
  };
}

// ── 观众端四类操作（ov 域公开端点；亦可打 cn 做对照）──

/**
 * 公开照片列表一页（契约：limit 1..60 缺省 30；cursor 不透明需 encode；
 * sort=latest|hot 仅 ov 实现非法值 400）。tag 参数让脚本能按 name 分组统计。
 */
export function fetchFeedPage(base, albumToken, options) {
  const opts = options || {};
  let qs = `limit=${opts.limit || 30}`;
  if (opts.cursor) {
    qs += `&cursor=${encodeURIComponent(opts.cursor)}`;
  }
  if (opts.sort) {
    qs += `&sort=${opts.sort}`;
  }
  return http.get(`${base}/v1/public/albums/${albumToken}/photos?${qs}`, {
    tags: { name: opts.tag || 'list_public_photos' },
  });
}

/** 浏览上报（匿名；visitorId 客户端持久 8..128 字符，requestId 幂等键）。 */
export function reportVisit(base, albumToken, visitorId, requestId) {
  return http.post(
    `${base}/v1/public/albums/${albumToken}/visits`,
    JSON.stringify({ visitorId, requestId }),
    {
      headers: { 'Content-Type': 'application/json' },
      tags: { name: 'visit_report' },
    },
  );
}

/** 点赞批次（匿名；sessionId 限速键 / batchId 幂等键 / delta 1..20 整数）。 */
export function likeBatch(base, albumToken, photoId, sessionId, batchId, delta) {
  return http.post(
    `${base}/v1/public/albums/${albumToken}/photos/${photoId}/likes`,
    JSON.stringify({ sessionId, batchId, delta }),
    {
      headers: { 'Content-Type': 'application/json' },
      tags: { name: 'like_batch' },
    },
  );
}

/**
 * 轮询公开列表直到 photoId 可见（worker 发布事务异步 + cn→ov 推送 2s 间隔；
 * 同 prod-smoke ④ 口径）。返回 { found, waitedMs, polls }。
 */
export function pollUntilVisible(
  base,
  albumToken,
  photoId,
  timeoutSec,
  intervalSec,
  tag,
) {
  const started = Date.now();
  let polls = 0;
  for (;;) {
    polls += 1;
    const res = fetchFeedPage(base, albumToken, { limit: 30, tag: tag || 'public_read_poll' });
    if (res.status === 200) {
      const items = res.json('items');
      if (Array.isArray(items) && items.some((it) => it.photoId === photoId)) {
        return { found: true, waitedMs: Date.now() - started, polls };
      }
    }
    if (Date.now() - started > timeoutSec * 1000) {
      return { found: false, waitedMs: Date.now() - started, polls };
    }
    sleep(intervalSec);
  }
}