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| 1 | +export type ClockAnomalyReason = |
| 2 | + | "evidence-after-receipt" |
| 3 | + | "evidence-time-regression" |
| 4 | + | "append-receipt-regression" |
| 5 | + | "elapsed-time-divergence"; |
| 6 | + |
| 7 | +export type ClockAnomaly = { |
| 8 | + creditEventId: string; |
| 9 | + outcomeId: string; |
| 10 | + reason: ClockAnomalyReason; |
| 11 | + evidenceTime: string; |
| 12 | + appendReceiptAt: string; |
| 13 | + previousEvidenceTime: string | null; |
| 14 | + previousAppendReceiptAt: string | null; |
| 15 | +}; |
| 16 | + |
| 17 | +export type EvidenceTime = { |
| 18 | + evidenceTime: number; |
| 19 | + appendReceiptAt: number; |
| 20 | +}; |
| 21 | + |
| 22 | +export function parseEvidenceTime(evidenceTime: unknown, appendReceiptAt: unknown): EvidenceTime { |
| 23 | + const parsed = { |
| 24 | + evidenceTime: Date.parse(String(evidenceTime)), |
| 25 | + appendReceiptAt: Date.parse(String(appendReceiptAt)), |
| 26 | + }; |
| 27 | + if (!Number.isFinite(parsed.evidenceTime) || !Number.isFinite(parsed.appendReceiptAt)) { |
| 28 | + throw new Error("evidence timestamps must be valid ISO timestamps"); |
| 29 | + } |
| 30 | + return parsed; |
| 31 | +} |
| 32 | + |
| 33 | +export function evidenceAvailabilityTime(value: EvidenceTime): number { |
| 34 | + return Math.max(value.evidenceTime, value.appendReceiptAt); |
| 35 | +} |
| 36 | + |
| 37 | +export function clockAnomalies( |
| 38 | + current: EvidenceTime, |
| 39 | + input: { |
| 40 | + creditEventId: string; |
| 41 | + outcomeId: string; |
| 42 | + previous: EvidenceTime | null; |
| 43 | + delayed: boolean; |
| 44 | + maximumFutureSkewSeconds: number; |
| 45 | + maximumElapsedDivergenceSeconds: number; |
| 46 | + }, |
| 47 | +): ClockAnomaly[] { |
| 48 | + const reasons: ClockAnomalyReason[] = []; |
| 49 | + if (current.evidenceTime > current.appendReceiptAt + input.maximumFutureSkewSeconds * 1_000) { |
| 50 | + reasons.push("evidence-after-receipt"); |
| 51 | + } |
| 52 | + if (input.previous !== null) { |
| 53 | + if (current.evidenceTime < input.previous.evidenceTime) reasons.push("evidence-time-regression"); |
| 54 | + if (current.appendReceiptAt < input.previous.appendReceiptAt) reasons.push("append-receipt-regression"); |
| 55 | + if ( |
| 56 | + input.delayed |
| 57 | + && Math.abs( |
| 58 | + (current.evidenceTime - input.previous.evidenceTime) |
| 59 | + - (current.appendReceiptAt - input.previous.appendReceiptAt), |
| 60 | + ) > input.maximumElapsedDivergenceSeconds * 1_000 |
| 61 | + ) { |
| 62 | + reasons.push("elapsed-time-divergence"); |
| 63 | + } |
| 64 | + } |
| 65 | + return reasons.map((reason) => ({ |
| 66 | + creditEventId: input.creditEventId, |
| 67 | + outcomeId: input.outcomeId, |
| 68 | + reason, |
| 69 | + evidenceTime: new Date(current.evidenceTime).toISOString(), |
| 70 | + appendReceiptAt: new Date(current.appendReceiptAt).toISOString(), |
| 71 | + previousEvidenceTime: input.previous === null |
| 72 | + ? null |
| 73 | + : new Date(input.previous.evidenceTime).toISOString(), |
| 74 | + previousAppendReceiptAt: input.previous === null |
| 75 | + ? null |
| 76 | + : new Date(input.previous.appendReceiptAt).toISOString(), |
| 77 | + })); |
| 78 | +} |
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