Update: 2026-07-06 19:27:17

backend/pricing-engine/src/utils/math.ts

@@ -209,6 +209,30 @@ export function twoStageRegression(
   return { baseFare, kmRate: rates.kmRate, minRate: rates.minRate };
 }
 
+/**
+ * Simple distance-only model: price = kmRate × dist
+ * Returns null if data is degenerate.
+ */
+export function simpleDistanceModel(
+  samples: Array<{ distance_km: number; duration_min: number; price: number }>
+): { baseFare: number; kmRate: number; minRate: number } | null {
+  const dists  = samples.map(s => s.distance_km);
+  const prices = samples.map(s => s.price);
+
+  // Mean of price/distance ratios, weighted by distance
+  let sumRatio = 0, count = 0;
+  for (let i = 0; i < dists.length; i++) {
+    if (dists[i] > 0 && prices[i] > 0) {
+      sumRatio += prices[i] / dists[i];
+      count++;
+    }
+  }
+  if (count < 3) return null;
+
+  const kmRate = Math.round((sumRatio / count) * 1000) / 1000;
+  return { baseFare: 0, kmRate, minRate: 0 };
+}
+
 // ─────────────────────────────────────────────
 // Robust regression (iterative outlier removal)
 // ─────────────────────────────────────────────