feat(vendor): switch BSR charts to daily resolution for smoother trend lines

- Add date? field to BSRRecord (ISO string YYYY-MM-DD)
- processBSRExcel now extracts and stores the Date column as an ISO date
  (handles both Excel serial numbers and string dates)
- VendorDataView groups chart data by date (daily) when dates are available,
  falling back to weekly buckets — eliminates straight-line charts caused
  by only 2 weekly data points

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/VendorDataView.tsx

@@ -15,8 +15,9 @@ interface VendorDataViewProps {
   bsrData: BSRRecord[];
 }
 
-interface WeeklyChartPoint {
+interface ChartPoint {
-  weekLabel: string;
+  label: string;
+  sortKey: string;
   [key: string]: number | string | null;
 }
 
@@ -73,30 +74,48 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
     return Array.from(m).sort();
   }, [filteredData]);
 
-  // Aggregate Data for Charts
+  // Determine if daily resolution is available (>= half the records have a date)
+  const useDailyResolution = useMemo(() => {
+    const withDate = filteredData.filter(r => r.date).length;
+    return withDate > filteredData.length / 2;
+  }, [filteredData]);
+
+  // Aggregate Data for Charts — daily if dates available, else weekly
   const { topBsrChartData, detailBsrChartData, ratingChartData } = useMemo(() => {
-    const byWeek = new Map<number, BSRRecord[]>();
+    // Group by date string (YYYY-MM-DD) or by week number
+    const byBucket = new Map<string, BSRRecord[]>();
+
     filteredData.forEach(r => {
-      if (!byWeek.has(r.week)) byWeek.set(r.week, []);
+      const key = useDailyResolution && r.date ? r.date : `W${String(r.week).padStart(2, '0')}`;
-      byWeek.get(r.week)!.push(r);
+      if (!byBucket.has(key)) byBucket.set(key, []);
+      byBucket.get(key)!.push(r);
     });
 
-    const sortedWeeks = Array.from(byWeek.keys()).sort((a, b) => a - b);
+    const sortedKeys = Array.from(byBucket.keys()).sort();
 
-    const topBsrChartData: WeeklyChartPoint[] = [];
+    const topBsrChartData: ChartPoint[] = [];
-    const detailBsrChartData: WeeklyChartPoint[] = [];
+    const detailBsrChartData: ChartPoint[] = [];
-    const ratingChartData: WeeklyChartPoint[] = [];
+    const ratingChartData: ChartPoint[] = [];
 
-    sortedWeeks.forEach(week => {
+    sortedKeys.forEach(key => {
-      const row = byWeek.get(week)!;
+      const rows = byBucket.get(key)!;
-      const weekLabel = `Week ${week}`;
 
-      const topPoint: WeeklyChartPoint = { weekLabel };
+      // Human-readable label
-      const detailPoint: WeeklyChartPoint = { weekLabel };
+      let label: string;
-      const ratingPoint: WeeklyChartPoint = { weekLabel };
+      if (useDailyResolution && key.includes('-')) {
+        // YYYY-MM-DD → "DD MMM"
+        const d = new Date(key + 'T12:00:00Z');
+        label = d.toLocaleDateString('en-GB', { day: '2-digit', month: 'short' });
+      } else {
+        label = key; // e.g. "W08"
+      }
+
+      const topPoint: ChartPoint = { label, sortKey: key };
+      const detailPoint: ChartPoint = { label, sortKey: key };
+      const ratingPoint: ChartPoint = { label, sortKey: key };
 
       activeMarkets.forEach(m => {
-        const marketRows = row.filter(r => r.market === m);
+        const marketRows = rows.filter(r => r.market === m);
 
         // Top BSR
         const topBsrRows = marketRows.filter(r => r.topLevelBSR != null);
@@ -123,7 +142,7 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
     });
 
     return { topBsrChartData, detailBsrChartData, ratingChartData };
-  }, [filteredData, activeMarkets]);
+  }, [filteredData, activeMarkets, useDailyResolution]);
 
   if (bsrData.length === 0) {
     return (
@@ -141,6 +160,8 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
     );
   }
 
+  const resolutionLabel = useDailyResolution ? 'Daily Avg' : 'Weekly Avg';
+
   return (
     <div className="space-y-6 p-4 pb-24 md:pb-4">
       {/* Filters */}
@@ -188,12 +209,12 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
 
       {/* Top Level BSR Trend Chart */}
       <div className="bg-slate-900/50 border border-slate-800 rounded-xl p-4">
-        <h3 className="text-lg font-bold text-slate-200 mb-4">Top Level BSR Trend (Weekly Avg)</h3>
+        <h3 className="text-lg font-bold text-slate-200 mb-4">Top Level BSR Trend ({resolutionLabel})</h3>
         <p className="text-xs text-slate-500 mb-3">Lower rank = better position. Averaged across filtered ASINs per market.</p>
         <ResponsiveContainer width="100%" height={350}>
           <LineChart data={topBsrChartData}>
             <CartesianGrid strokeDasharray="3 3" stroke="#334155" />
-            <XAxis dataKey="weekLabel" tick={{ fill: '#94a3b8', fontSize: 11 }} interval="preserveStartEnd" />
+            <XAxis dataKey="label" tick={{ fill: '#94a3b8', fontSize: 11 }} interval="preserveStartEnd" />
             <YAxis reversed tick={{ fill: '#94a3b8', fontSize: 11 }} />
             <Tooltip
               contentStyle={{ backgroundColor: '#1e293b', border: '1px solid #334155', borderRadius: '8px' }}
@@ -218,12 +239,12 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
 
       {/* Detail Level BSR Trend Chart */}
       <div className="bg-slate-900/50 border border-slate-800 rounded-xl p-4">
-        <h3 className="text-lg font-bold text-slate-200 mb-4">Detail Level BSR Trend (Weekly Avg)</h3>
+        <h3 className="text-lg font-bold text-slate-200 mb-4">Detail Level BSR Trend ({resolutionLabel})</h3>
         <p className="text-xs text-slate-500 mb-3">Lower rank = better position. Averaged across filtered ASINs per market.</p>
         <ResponsiveContainer width="100%" height={350}>
           <LineChart data={detailBsrChartData}>
             <CartesianGrid strokeDasharray="3 3" stroke="#334155" />
-            <XAxis dataKey="weekLabel" tick={{ fill: '#94a3b8', fontSize: 11 }} interval="preserveStartEnd" />
+            <XAxis dataKey="label" tick={{ fill: '#94a3b8', fontSize: 11 }} interval="preserveStartEnd" />
             <YAxis reversed tick={{ fill: '#94a3b8', fontSize: 11 }} />
             <Tooltip
               contentStyle={{ backgroundColor: '#1e293b', border: '1px solid #334155', borderRadius: '8px' }}
@@ -248,12 +269,12 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
 
       {/* Average Rating Chart */}
       <div className="bg-slate-900/50 border border-slate-800 rounded-xl p-4">
-        <h3 className="text-lg font-bold text-slate-200 mb-4">Average Rating (Weekly Avg)</h3>
+        <h3 className="text-lg font-bold text-slate-200 mb-4">Average Rating ({resolutionLabel})</h3>
         <p className="text-xs text-slate-500 mb-3">Averaged across filtered ASINs per market.</p>
         <ResponsiveContainer width="100%" height={350}>
           <LineChart data={ratingChartData}>
             <CartesianGrid strokeDasharray="3 3" stroke="#334155" />
-            <XAxis dataKey="weekLabel" tick={{ fill: '#94a3b8', fontSize: 11 }} interval="preserveStartEnd" />
+            <XAxis dataKey="label" tick={{ fill: '#94a3b8', fontSize: 11 }} interval="preserveStartEnd" />
             <YAxis domain={[0, 5]} tick={{ fill: '#94a3b8', fontSize: 11 }} />
             <Tooltip
               contentStyle={{ backgroundColor: '#1e293b', border: '1px solid #334155', borderRadius: '8px' }}

services/dataProcessor.ts

@@ -682,15 +682,25 @@ export const processBSRExcel = async (fileOrBuffer: File | ArrayBuffer): Promise
 
                 // Week: try direct week column first, else derive from Date column
                 let week = 0;
+                let isoDate: string | undefined;
                 const weekRaw = getColumnValue(row, ['week', 'woche', 'semana', 'week number', 'weeknumber', 'Week', 'Week Number']);
                 if (weekRaw) {
                     week = parseInt(String(weekRaw).match(/\d+/)?.[0] || '0', 10);
                 }
-                if (!week) {
                 const dateRaw = getColumnValue(row, ['date', 'fecha', 'datum', 'Date']);
                 if (dateRaw) {
-                        const d = new Date(dateRaw);
+                    // Handle Excel serial date numbers
+                    let d: Date;
+                    const dateNum = Number(dateRaw);
+                    if (!isNaN(dateNum) && dateNum > 1000) {
+                        // Excel serial date: days since 1899-12-30
+                        d = new Date((dateNum - 25569) * 86400 * 1000);
+                    } else {
+                        d = new Date(dateRaw);
+                    }
                     if (!isNaN(d.getTime())) {
+                        isoDate = d.toISOString().slice(0, 10); // "YYYY-MM-DD"
+                        if (!week) {
                             // ISO week number
                             const tmp = new Date(d);
                             tmp.setHours(0, 0, 0, 0);
@@ -704,6 +714,7 @@ export const processBSRExcel = async (fileOrBuffer: File | ArrayBuffer): Promise
 
                 allData.push({
                     week,
+                    date: isoDate,
                     market: String(marketRaw).trim(),
                     asin: String(asinRaw).trim(),
                     topLevelBSR: parseIntSafe(getColumnValue(row, [

types.ts

@@ -282,6 +282,7 @@ export interface VendorCSVRow {
 
 export interface BSRRecord {
   week: number;
+  date?: string; // ISO date string (YYYY-MM-DD) when available — enables daily resolution charts
   market: string;
   asin: string;
   topLevelBSR: number | null;