// deploy/m2_probe3.js —— 浏览器 fetch chunk 级探针（PM 使用，在远端运行）
// 目的：确定 progress 帧丢失发生在哪一层（Vite proxy 缓冲？fetch 读取？parser？）
const { chromium } = require('playwright');

(async () => {
  const browser = await chromium.launch();
  const ctx = await browser.newContext({ viewport: { width: 1440, height: 900 } });
  const page = await ctx.newPage();

  // 在页面上下文里直接发起 fetch 并记录 chunk 到达时间线与内容
  const result = await page.evaluate(async () => {
    const t0 = Date.now();
    const log = [];
    const ctrl = new AbortController();
    const timeout = setTimeout(() => ctrl.abort(), 90000);
    try {
      const resp = await fetch('http://127.0.0.1:5180/api/qa/chat/stream', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          question: 'SPL gene family in rice',
          use_llm: true, debug: false,
          chain_top_k: 3, chain_hops: 2, chain_max_edges: 12, chain_max_nodes: 10,
          native_chain_enabled: true, native_chain_max_hops: 3, native_chain_top_k: 5,
        }),
        signal: ctrl.signal,
      });
      log.push(`T+${Math.round((Date.now() - t0) / 1000)}s headers: status=${resp.status} ct=${resp.headers.get('content-type')}`);
      const reader = resp.body.getReader();
      const decoder = new TextDecoder();
      let nChunks = 0;
      for (;;) {
        const { done, value } = await reader.read();
        if (done) break;
        nChunks++;
        const text = decoder.decode(value, { stream: true });
        const events = (text.match(/event: \w+/g) || []).join(',');
        log.push(`T+${Math.round((Date.now() - t0) / 1000)}s chunk#${nChunks} len=${value.length} [${events}] preview=${text.slice(0, 80).replace(/\n/g, '↵')}`);
      }
      log.push(`T+${Math.round((Date.now() - t0) / 1000)}s stream done, ${nChunks} chunks total`);
    } catch (e) {
      log.push(`ERROR: ${e.name}: ${e.message}`);
    }
    clearTimeout(timeout);
    return log;
  });

  result.forEach((l) => console.log(l));
  await browser.close();
})();