/**
 * 票 26 消融实验：拦截 `/map-snapshot`（让 freshness tick 的 refresh 拿不到新页），
 * 其余端点与 GIS 资源照常。若 30s/60s 周期性帧 stall 消失 → 「refresh→重建」因果链成立。
 *
 * 运行：node .scratch/cockpit-real-data-wayfinding/verify/artifacts/t26/probe-jitter-ablate.mjs
 */
import { cdpLaunch } from '../../../../cockpit-shell-panel-layout/verify/cdp-driver.mjs'

const CHROME = process.env.CHROME_PATH || 'C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe'
const TARGET_URL = process.env.T26_URL || 'http://127.0.0.1:8000/#/cockpit'
const WAIT_MS = Number(process.env.T26_WAIT_MS || 70000)
const POLL_MS = 250

const sleep = (ms) => new Promise((r) => setTimeout(r, ms))

function stats(values) {
    if (!values.length) return null
    const sorted = [...values].sort((a, b) => a - b)
    const at = (q) => sorted[Math.min(sorted.length - 1, Math.floor(q * sorted.length))]
    return { n: sorted.length, p50: at(0.5), p95: at(0.95), max: sorted[sorted.length - 1] }
}

const browser = await cdpLaunch({ executablePath: CHROME, width: 1280, height: 800 })
console.log(`Chrome: ${await browser.version()}  [消融：map-snapshot 全程 500]`)
const page = await browser.newPage()

await page.goto(TARGET_URL, { timeout: 60000 })
await page.waitForSelector('.cockpit-shell', { timeout: 20000 })

// 采样器 + 消融补丁：map-snapshot 请求直接失败（fetch 与 XHR 两条路径都拦）。
await page.evaluate(() => {
    window.__t26 = { frames: [], longTasks: [], blocked: 0 }
    let last = performance.now()
    const tick = (now) => {
        window.__t26.frames.push({ t: now, dt: now - last })
        last = now
        requestAnimationFrame(tick)
    }
    requestAnimationFrame(tick)
    try {
        new PerformanceObserver((list) => {
            for (const entry of list.getEntries()) window.__t26.longTasks.push({ start: entry.startTime, dur: entry.duration })
        }).observe({ entryTypes: ['longtask'] })
    } catch { /* 忽略 */ }

    const blocked = (url) => String(url).includes('map-snapshot')
    // 只拦 15s 之后的 map-snapshot：首屏加载与 auto-batch（0–8s）照常，
    // 消融目标是 30s 起的 freshness refresh 轮 —— 这样图上对象仍在，只有"重载"被摘除。
    const armAt = performance.now() + 15000
    const shouldBlock = () => performance.now() > armAt
    const nativeFetch = window.fetch.bind(window)
    window.fetch = async (...args) => {
        const url = String((args[0] && args[0].url) || args[0])
        if (blocked(url) && shouldBlock()) {
            window.__t26.blocked += 1
            return { ok: false, status: 500, json: async () => ({ code: 500, msg: 'ablated' }), headers: { get: () => null } }
        }
        return nativeFetch(...args)
    }
    const XHR = XMLHttpRequest.prototype
    const nativeOpen = XHR.open
    XHR.open = function (method, url, ...rest) {
        this.__t26blocked = blocked(url)
        return nativeOpen.call(this, method, url, ...rest)
    }
    const nativeSend = XHR.send
    XHR.send = function (...args) {
        if (this.__t26blocked && shouldBlock()) {
            window.__t26.blocked += 1
            Object.defineProperty(this, 'readyState', { configurable: true, get: () => 4 })
            Object.defineProperty(this, 'status', { configurable: true, get: () => 500 })
            Object.defineProperty(this, 'responseText', { configurable: true, get: () => '{"code":500,"msg":"ablated"}' })
            Object.defineProperty(this, 'response', { configurable: true, get: () => '{"code":500,"msg":"ablated"}' })
            setTimeout(() => {
                this.dispatchEvent(new Event('readystatechange'))
                this.dispatchEvent(new Event('load'))
                this.dispatchEvent(new Event('loadend'))
            }, 20)
            return undefined
        }
        return nativeSend.apply(this, args)
    }
})

if (await page.$('[data-cockpit-intro]')) {
    await page.click('[data-cockpit-intro]')
    await page.waitForSelector('[data-cockpit-intro]', { hidden: true, timeout: 10000 }).catch(() => {})
}
await page.waitForFunction(
    () => ['ready', 'failed', 'disabled'].includes(document.querySelector('.cockpit-shell__map .map-canvas')?.dataset.mapEngine),
    { timeout: 40000 },
).catch(() => {})
await sleep(3000)

console.log(`静置采样 ${(WAIT_MS / 1000).toFixed(0)}s…`)
const deadline = Date.now() + WAIT_MS
while (Date.now() < deadline) await sleep(POLL_MS)

const result = await page.evaluate(() => {
    const frames = window.__t26.frames
    const start = frames.length ? frames[0].t : 0
    const out = []
    let bucket = []
    let bucketStart = start
    for (const frame of frames) {
        if (frame.t - bucketStart >= 5000) {
            out.push({ from: bucketStart - start, dts: bucket.map((f) => f.dt) })
            bucket = []
            bucketStart = frame.t
        }
        bucket.push(frame)
    }
    if (bucket.length) out.push({ from: bucketStart - start, dts: bucket.map((f) => f.dt) })
    return {
        windows: out.map((w) => ({ from: w.from, dts: w.dts })),
        longTasks: window.__t26.longTasks,
        blocked: window.__t26.blocked,
    }
})

console.log(`被拦截的 map-snapshot 请求数：${result.blocked}`)
console.log('fps 窗口：')
for (const w of result.windows) {
    const s = stats(w.dts)
    console.log(`  ${(w.from / 1000).toFixed(1)}s p50=${s.p50} p95=${s.p95} max=${s.max}`)
}
const big = result.longTasks.filter((t) => t.dur >= 100)
console.log(`长任务(≥100ms)：${big.length} 个 ${JSON.stringify(big.slice(0, 8))}`)

await browser.close()