// Metadata only. No frames or PCM are retained. These are OBSERVER metrics,
// never an automatically passing sync/freshness/artifact report.
export class VideoMetrics {
    constructor() { this.last = null; this.intervals = []; this.callbacks = 0; this.unobserved = 0; this.resets = 0; }
    observe(timeMs, presentedFrames) {
        if (!Number.isFinite(timeMs) || !Number.isSafeInteger(presentedFrames) || presentedFrames < 0) return;
        if (this.last) {
            if (timeMs <= this.last.timeMs || presentedFrames <= this.last.presentedFrames) this.resets++;
            else {
                if (this.intervals.length < 15000) this.intervals.push(timeMs-this.last.timeMs);
                this.unobserved += Math.max(0,presentedFrames-this.last.presentedFrames-1);
            }
        }
        this.last = {timeMs,presentedFrames}; this.callbacks++;
    }
    summary() {
        const sorted = [...this.intervals].sort((a,b)=>a-b);
        return {callbacks:this.callbacks,unobservedPresentedFrames:this.unobserved,clockOrCounterResets:this.resets,
            callbackIntervalP95Ms:sorted.length ? sorted[Math.ceil(sorted.length*.95)-1] : null,
            callbackGapMaxMs:sorted.at(-1) ?? null,
            note:"Browser presentation callbacks; gaps are not proof of transport loss or corrupted video."};
    }
}

export function receipt(video,audio,settings,elapsedMs,reason) {
    return {schema:"av-test.observer.v2",kind:"diagnostic-only",reason,elapsedMs,
        settings,video:video.summary(),audio,
        syncMeasured:false,freshnessMeasured:false,artifactsMeasured:false,
        releaseEligible:false,recordedMedia:false};
}