Sven (AAMOS AI)
53 lines
1.8 KiB
TypeScript
53 lines
1.8 KiB
TypeScript
/**
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* Pantry Forecast (spec §40): "Ni brukar använda mjölk var sjätte dag."
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* Enkel deterministisk konsumtionstakt ur transaktionshistorik.
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* Prognoser märks ALLTID som prognoser i UI.
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*/
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export interface ConsumptionEvent {
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/** ISO-datum */
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date: string;
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quantity: number;
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}
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export interface ForecastResult {
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/** Genomsnittlig förbrukning per dag (i postens enhet). */
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dailyRate: number;
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/** Dagar tills nuvarande saldo beräknas ta slut. */
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daysUntilEmpty: number | null;
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/** Föreslaget inköpsdatum (2 dagars marginal). */
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suggestedRestockDate: string | null;
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confidence: "low" | "medium" | "high";
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}
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export function forecastDepletion(
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currentBalance: number,
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consumption: ConsumptionEvent[],
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today: Date = new Date(),
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): ForecastResult {
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if (consumption.length < 2) {
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return { dailyRate: 0, daysUntilEmpty: null, suggestedRestockDate: null, confidence: "low" };
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}
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const sorted = [...consumption].sort((a, b) => a.date.localeCompare(b.date));
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const first = Date.parse(sorted[0]!.date);
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const last = Date.parse(sorted[sorted.length - 1]!.date);
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const spanDays = Math.max(1, (last - first) / 86_400_000);
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const total = sorted.reduce((sum, e) => sum + Math.abs(e.quantity), 0);
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const dailyRate = total / spanDays;
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if (dailyRate <= 0) {
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return { dailyRate: 0, daysUntilEmpty: null, suggestedRestockDate: null, confidence: "low" };
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}
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const daysUntilEmpty = currentBalance / dailyRate;
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const restock = new Date(today.getTime() + Math.max(0, daysUntilEmpty - 2) * 86_400_000);
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const confidence = consumption.length >= 6 ? "high" : consumption.length >= 4 ? "medium" : "low";
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return {
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dailyRate: Math.round(dailyRate * 1000) / 1000,
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daysUntilEmpty: Math.round(daysUntilEmpty * 10) / 10,
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suggestedRestockDate: restock.toISOString().slice(0, 10),
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confidence,
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};
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}
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