From 2a548e9ebc2a9aca0167b44138e9ef34f2fa6408 Mon Sep 17 00:00:00 2001
From: DEls <davide.els1@outlook.com>
Date: Sat, 29 Aug 2026 20:04:51 +0200
Subject: [PATCH] refactor(fuel): build rows from the shared variance pass
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No behaviour change — deletes the duplicate group/sort/pairwise walk now
that computeFuelLogStatuses does it. computeFuelVariance now has exactly
one caller.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 src/app/dashboard/fuel/page.tsx | 47 +++++++++++++--------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

diff --git a/src/app/dashboard/fuel/page.tsx b/src/app/dashboard/fuel/page.tsx
index 3bda595..c27ba49 100644
--- a/src/app/dashboard/fuel/page.tsx
+++ b/src/app/dashboard/fuel/page.tsx
@@ -1,6 +1,11 @@
 import { pbAdmin } from "@/lib/pb";
-import { computeFuelVariance, parseFuelLimit } from "@/lib/fuel-variance";
-import { RATE_PER_LITRE } from "@/lib/metrics";
+import { parseFuelLimit } from "@/lib/fuel-variance";
+import {
+  computeFuelLogStatuses,
+  RATE_PER_LITRE,
+  type AttentionFuelLogLike,
+  type AttentionVehicleLike,
+} from "@/lib/metrics";
 import { FuelView, type FuelRow, type VehicleSummary } from "./fuel-view";
 
 export const dynamic = "force-dynamic";
@@ -23,21 +28,13 @@ export default async function FuelPage() {
     };
   }
 
-  // Build per-row data + sort each vehicle's logs by date so we can find
-  // the previous reading for variance computation.
-  const logsByVehicle = new Map<string, (typeof fuelLogs)[number][]>();
-  for (const log of fuelLogs) {
-    const list = logsByVehicle.get(log.vehicle) ?? [];
-    list.push(log);
-    logsByVehicle.set(log.vehicle, list);
-  }
-  for (const list of logsByVehicle.values()) {
-    list.sort((a, b) => {
-      const d = (a.date_logged ?? "").localeCompare(b.date_logged ?? "");
-      if (d !== 0) return d;
-      return (a.odo_reading ?? 0) - (b.odo_reading ?? 0);
-    });
-  }
+  // One shared variance pass; index it so the row map is a lookup.
+  const statusByLogId = new Map(
+    computeFuelLogStatuses({
+      vehicles: vehicles as unknown as AttentionVehicleLike[],
+      fuelLogs: fuelLogs as unknown as AttentionFuelLogLike[],
+    }).map((s) => [s.logId, s]),
+  );
 
   const rows: FuelRow[] = fuelLogs.map((log) => {
     const veh = log.expand?.vehicle
@@ -56,17 +53,11 @@ export default async function FuelPage() {
       fuelLimits: "",
     };
 
-    const peers = logsByVehicle.get(log.vehicle) ?? [];
-    const idx = peers.findIndex((p) => p.id === log.id);
-    const previous = idx > 0 ? peers[idx - 1] : undefined;
-
-    const { variance, status, limitTarget, limitUnit } = computeFuelVariance(
-      log.litres,
-      log.odo_reading,
-      previous?.odo_reading,
-      previous?.litres,
-      vehicleRow.fuelLimits,
-    );
+    const st = statusByLogId.get(log.id);
+    const variance = st?.variance ?? null;
+    const status = st?.status ?? "no-limit";
+    const limitTarget = st?.limitTarget ?? null;
+    const limitUnit = st?.limitUnit ?? null;
 
     return {
       id: log.id,