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| 1 | +import { useEffect, useMemo, useState } from "react"; |
| 2 | + |
| 3 | +const FRAME_COUNT = 6; |
| 4 | +const FRAME_INTERVAL = 1200; |
| 5 | + |
| 6 | +function getStatusLabel(state) { |
| 7 | + switch (state) { |
| 8 | + case "loading": |
| 9 | + return "Loading…"; |
| 10 | + case "ready": |
| 11 | + return "Rendered"; |
| 12 | + case "error": |
| 13 | + return "Blocked"; |
| 14 | + default: |
| 15 | + return "Queued"; |
| 16 | + } |
| 17 | +} |
| 18 | + |
| 19 | +function PreviewFrame({ url, index, delayMs }) { |
| 20 | + const [source, setSource] = useState(""); |
| 21 | + const [state, setState] = useState("queued"); |
| 22 | + const [startedAt, setStartedAt] = useState(null); |
| 23 | + const [loadedAt, setLoadedAt] = useState(null); |
| 24 | + |
| 25 | + useEffect(() => { |
| 26 | + if (!url) { |
| 27 | + setSource(""); |
| 28 | + setState("idle"); |
| 29 | + setStartedAt(null); |
| 30 | + setLoadedAt(null); |
| 31 | + return; |
| 32 | + } |
| 33 | + |
| 34 | + setState("queued"); |
| 35 | + const timer = setTimeout(() => { |
| 36 | + setSource(url); |
| 37 | + setStartedAt(performance.now()); |
| 38 | + setState("loading"); |
| 39 | + }, delayMs); |
| 40 | + |
| 41 | + return () => { |
| 42 | + clearTimeout(timer); |
| 43 | + setSource(""); |
| 44 | + setState("queued"); |
| 45 | + setStartedAt(null); |
| 46 | + setLoadedAt(null); |
| 47 | + }; |
| 48 | + }, [url, delayMs]); |
| 49 | + |
| 50 | + const handleLoad = () => { |
| 51 | + setState("ready"); |
| 52 | + setLoadedAt(performance.now()); |
| 53 | + }; |
| 54 | + |
| 55 | + const handleError = () => { |
| 56 | + setState("error"); |
| 57 | + }; |
| 58 | + |
| 59 | + const deltaMs = |
| 60 | + startedAt && loadedAt ? Math.max(0, loadedAt - startedAt).toFixed(0) : null; |
| 61 | + |
| 62 | + return ( |
| 63 | + <div className={`preview-frame ${state}`}> |
| 64 | + {source ? ( |
| 65 | + <iframe |
| 66 | + src={source} |
| 67 | + title={`preview-${index}`} |
| 68 | + onLoad={handleLoad} |
| 69 | + onError={handleError} |
| 70 | + sandbox="allow-same-origin allow-scripts allow-forms" |
| 71 | + loading="lazy" |
| 72 | + referrerPolicy="no-referrer" |
| 73 | + /> |
| 74 | + ) : ( |
| 75 | + <div className="preview-placeholder">Awaiting snapshot…</div> |
| 76 | + )} |
| 77 | + <footer> |
| 78 | + <div> |
| 79 | + <span>Frame {index + 1}</span> |
| 80 | + <small>{getStatusLabel(state)}</small> |
| 81 | + </div> |
| 82 | + <div className="latency-badge"> |
| 83 | + {deltaMs ? `${deltaMs} ms` : "—"} |
| 84 | + </div> |
| 85 | + </footer> |
| 86 | + </div> |
| 87 | + ); |
| 88 | +} |
| 89 | + |
| 90 | +export default function PreviewGrid({ url }) { |
| 91 | + const frames = useMemo( |
| 92 | + () => Array.from({ length: FRAME_COUNT }, (_, idx) => idx), |
| 93 | + [] |
| 94 | + ); |
| 95 | + |
| 96 | + if (!url) { |
| 97 | + return null; |
| 98 | + } |
| 99 | + |
| 100 | + return ( |
| 101 | + <section className="preview-grid"> |
| 102 | + <header> |
| 103 | + <div> |
| 104 | + <p className="eyebrow">Live stability preview</p> |
| 105 | + <h2>How does the page settle?</h2> |
| 106 | + </div> |
| 107 | + <p> |
| 108 | + We reload the site multiple times in quick succession to surface |
| 109 | + layout shifts, blocking assets, and other instability indicators. |
| 110 | + </p> |
| 111 | + </header> |
| 112 | + <div className="preview-grid__frames"> |
| 113 | + {frames.map((idx) => ( |
| 114 | + <PreviewFrame |
| 115 | + key={`${url}-${idx}`} |
| 116 | + url={url} |
| 117 | + index={idx} |
| 118 | + delayMs={idx * FRAME_INTERVAL} |
| 119 | + /> |
| 120 | + ))} |
| 121 | + </div> |
| 122 | + </section> |
| 123 | + ); |
| 124 | +} |
| 125 | + |
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