Fas 2 steg 1: Inventory Trust Engine - trust states pa inventory_items

packages/inventory-engine/src/index.ts

@@ -3,3 +3,4 @@ export * from "./balance.js";
 export * from "./fefo.js";
 export * from "./dedup.js";
 export * from "./forecast.js";
+export * from "./trust.js";

packages/inventory-engine/src/trust.ts

@@ -0,0 +1,94 @@
+import type { TrustState } from "@app/shared-types";
+
+export interface TrustInput {
+  confidence: number;
+  verifiedByUser: boolean;
+  lastVerifiedAt: Date | string | null;
+  quantity: number;
+  updatedAt: Date | string;
+}
+
+export interface InventoryItemLike {
+  confidence: number;
+  verifiedByUser: boolean;
+  lastVerifiedAt: Date | string | null;
+  quantity: number;
+  updatedAt: Date | string;
+}
+
+export interface TrustResult {
+  state: TrustState;
+  score: number; // 0–100
+}
+
+/**
+ * Compute the trust state of an inventory item.
+ *
+ * - unverified: quantity is present but never verified.
+ * - trusted: user verified or high confidence and recently touched.
+ * - decaying: confidence is dropping / not verified for a while.
+ * - stale: very old, unverified, or confidence critically low.
+ *
+ * Decay affects TRUST, not edibility (mjölkprincipen – spec D-035).
+ */
+export function computeTrust(input: TrustInput): TrustResult {
+  const now = Date.now();
+  const lastVerified = input.lastVerifiedAt ? new Date(input.lastVerifiedAt).getTime() : null;
+  const updated = new Date(input.updatedAt).getTime();
+  const daysSinceVerification = lastVerified ? (now - lastVerified) / 86_400_000 : null;
+  const daysSinceUpdate = (now - updated) / 86_400_000;
+
+  // Base score from confidence (0–80 points)
+  let score = Math.round(input.confidence * 80);
+
+  // Verification bonus (0–20 points)
+  if (input.verifiedByUser && daysSinceVerification !== null && daysSinceVerification <= 7) {
+    score += 20;
+  } else if (input.verifiedByUser && daysSinceVerification !== null && daysSinceVerification <= 30) {
+    score += 10;
+  } else if (input.verifiedByUser) {
+    score += 5;
+  }
+
+  // Decay penalties (only affect trust score)
+  if (daysSinceVerification !== null && daysSinceVerification > 7) {
+    score -= Math.min(20, Math.floor((daysSinceVerification - 7) / 7) * 5);
+  }
+  if (daysSinceUpdate > 14) {
+    score -= Math.min(15, Math.floor((daysSinceUpdate - 14) / 7) * 5);
+  }
+  if (input.quantity <= 0) {
+    score -= 10; // depleted items are less interesting for trust
+  }
+
+  score = Math.max(0, Math.min(100, score));
+
+  let state: TrustState;
+  if (input.verifiedByUser && score >= 80) {
+    state = "trusted";
+  } else if (score >= 60) {
+    state = "trusted";
+  } else if (score >= 30) {
+    state = "decaying";
+  } else if (lastVerified === null && daysSinceUpdate <= 1) {
+    state = "unverified";
+  } else {
+    state = "stale";
+  }
+
+  return { state, score };
+}
+
+/** Convenience wrapper that returns just the state for an inventory row. */
+export function itemTrustState(item: InventoryItemLike): TrustState {
+  return computeTrust(item).state;
+}
+
+/** Pick the most urgent trust state from a list (used for household summary). */
+export function worstTrustState(states: TrustState[]): TrustState {
+  const order: TrustState[] = ["stale", "decaying", "unverified", "trusted"];
+  for (const s of order) {
+    if (states.includes(s)) return s;
+  }
+  return "unverified";
+}