Add baseline comparison for discount simulator

inventory/src/components/discount-simulator/SummaryCard.tsx

@@ -1,9 +1,12 @@
+import { differenceInDays } from "date-fns";
 import { Card, CardContent } from "@/components/ui/card";
 import { formatCurrency } from "@/utils/productUtils";
 import { DiscountSimulationResponse } from "@/types/discount-simulator";
 import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
 import { Skeleton } from "@/components/ui/skeleton";
 import { Separator } from "@/components/ui/separator";
+import { Bookmark, X } from "lucide-react";
 
 // Utility function to interpolate between two colors
 const interpolateColor = (color1: [number, number, number], color2: [number, number, number], ratio: number): [number, number, number] => {
@@ -49,6 +52,37 @@ const getProfitPercentageColor = (percentage: number): string => {
 interface SummaryCardProps {
   result?: DiscountSimulationResponse;
   isLoading: boolean;
+  baselineResult?: DiscountSimulationResponse;
+  onSaveAsBaseline?: () => void;
+  onClearBaseline?: () => void;
+}
+
+function calculateAnnualizedProfitDiff(
+  current: DiscountSimulationResponse,
+  baseline: DiscountSimulationResponse
+): number | null {
+  const currentTotals = current.totals;
+  const baselineTotals = baseline.totals;
+
+  if (!currentTotals || !baselineTotals) return null;
+
+  // Calculate days in the current simulation period
+  const startDate = new Date(current.dateRange.start);
+  const endDate = new Date(current.dateRange.end);
+  const daysInPeriod = differenceInDays(endDate, startDate) + 1; // +1 to include both start and end days
+
+  if (daysInPeriod <= 0) return null;
+
+  // Profit difference per order
+  const profitDiffPerOrder = currentTotals.weightedProfitAmount - baselineTotals.weightedProfitAmount;
+
+  // Total profit difference for the period
+  const totalProfitDiff = profitDiffPerOrder * currentTotals.orders;
+
+  // Annualize: scale to 365 days
+  const annualizedDiff = (totalProfitDiff / daysInPeriod) * 365;
+
+  return annualizedDiff;
 }
 
 const formatPercent = (value: number) => {
@@ -56,16 +90,23 @@ const formatPercent = (value: number) => {
   return `${(value * 100).toFixed(2)}%`;
 };
 
-export function SummaryCard({ result, isLoading }: SummaryCardProps) {
+export function SummaryCard({
+  result,
+  isLoading,
+  baselineResult,
+  onSaveAsBaseline,
+  onClearBaseline
+}: SummaryCardProps) {
   if (isLoading && !result) {
     return (
-      <Card className="pt-6">
-        <CardContent>
-          <div className="h-72 flex flex-col items-center justify-center gap-8">
+      <Card>
+        <CardContent className="py-4">
+          <div className="flex items-center justify-center gap-8">
             <div className="text-center space-y-2">
               <Skeleton className="h-4 w-24 mx-auto" />
-              <Skeleton className="h-10 w-20 mx-auto" />
+              <Skeleton className="h-8 w-20 mx-auto" />
             </div>
+            <Separator orientation="vertical" className="h-12" />
             <div className="text-center space-y-2">
               <Skeleton className="h-4 w-32 mx-auto" />
               <Skeleton className="h-8 w-24 mx-auto" />
@@ -89,32 +130,84 @@ export function SummaryCard({ result, isLoading }: SummaryCardProps) {
       : "destructive"
     : "secondary";
 
+  // Calculate annualized profit difference if baseline exists
+  const annualizedDiff = result && baselineResult
+    ? calculateAnnualizedProfitDiff(result, baselineResult)
+    : null;
+  const hasBaseline = !!baselineResult;
+  const isPositiveDiff = annualizedDiff !== null && annualizedDiff >= 0;
+
   return (
-    <Card className="pt-6">
-      <CardContent>
-        <div className="h-72 flex flex-col items-center justify-center gap-5">
+    <Card>
+      <CardContent className="py-4">
+        <div className="flex items-center justify-center gap-6">
+          {/* Weighted Average Profit */}
           <div className="text-center">
-            <p className="text-sm text-muted-foreground mb-3">Weighted Average Profit</p>
+            <p className="text-sm text-muted-foreground mb-2">Weighted Average Profit</p>
             {totals ? (
               <span
-                className="inline-block px-4 py-2 rounded text-white font-semibold text-2xl"
+                className="inline-block px-3 py-1.5 rounded text-white font-semibold text-lg"
                 style={{ backgroundColor: profitPercentageColor }}
               >
                 {weightedProfitPercent}
               </span>
             ) : (
-              <Badge variant={weightedBadgeVariant} className="text-2xl py-2 px-4 font-semibold">
+              <Badge variant={weightedBadgeVariant} className="text-lg py-1.5 px-3 font-semibold">
                 {weightedProfitPercent}
               </Badge>
             )}
           </div>
-          <Separator orientation="horizontal" />
+
+          <Separator orientation="vertical" className="h-12" />
+
+          {/* Weighted Profit Per Order */}
           <div className="text-center">
-            <p className="text-sm text-muted-foreground mb-3">Weighted Profit Per Order</p>
-            <Badge variant="secondary" className="text-2xl py-2 px-4 font-semibold">
+            <p className="text-sm text-muted-foreground mb-2">Weighted Profit Per Order</p>
+            <Badge variant="secondary" className="text-lg py-1.5 px-3 font-semibold">
               {weightedProfitAmount}
             </Badge>
           </div>
+
+          {/* Baseline comparison section */}
+          {hasBaseline && annualizedDiff !== null && (
+            <>
+              <Separator orientation="vertical" className="h-12" />
+              <div className="text-center">
+                <p className="text-sm text-muted-foreground mb-2">Annual Change vs Baseline</p>
+                <span
+                  className={`inline-block px-3 py-1.5 rounded bg-secondary font-semibold text-lg ${
+                    isPositiveDiff ? 'text-green-600' : 'text-red-600'
+                  }`}
+                >
+                  {isPositiveDiff ? '+' : ''}{formatCurrency(annualizedDiff)}
+                </span>
+              </div>
+              <Button
+                variant="ghost"
+                size="sm"
+                className="text-xs text-muted-foreground hover:text-foreground"
+                onClick={onClearBaseline}
+              >
+                <X className="h-3 w-3 mr-1" />
+                Clear
+              </Button>
+            </>
+          )}
+
+          {/* Save as baseline button */}
+          {result && !hasBaseline && (
+            <>
+              <Separator orientation="vertical" className="h-12" />
+              <Button
+                variant="outline"
+                size="sm"
+                onClick={onSaveAsBaseline}
+              >
+                <Bookmark className="h-3 w-3 mr-1" />
+                Set as baseline
+              </Button>
+            </>
+          )}
         </div>
       </CardContent>
     </Card>

inventory/src/pages/DiscountSimulator.tsx

@@ -62,6 +62,7 @@ export function DiscountSimulator() {
   const [pointDollarValue, setPointDollarValue] = useState(DEFAULT_POINT_VALUE);
   const [pointDollarTouched, setPointDollarTouched] = useState(false);
   const [simulationResult, setSimulationResult] = useState<DiscountSimulationResponse | undefined>(undefined);
+  const [baselineResult, setBaselineResult] = useState<DiscountSimulationResponse | undefined>(undefined);
   const [isSimulating, setIsSimulating] = useState(false);
   const [hasLoadedConfig, setHasLoadedConfig] = useState(false);
   const [loadedFromStorage, setLoadedFromStorage] = useState(false);
@@ -402,6 +403,16 @@ export function DiscountSimulator() {
     }
   };
 
+  const handleSaveAsBaseline = useCallback(() => {
+    if (simulationResult) {
+      setBaselineResult(simulationResult);
+    }
+  }, [simulationResult]);
+
+  const handleClearBaseline = useCallback(() => {
+    setBaselineResult(undefined);
+  }, []);
+
   const resetConfig = useCallback(() => {
     skipAutoRunRef.current = true;
     const defaultRange = getDefaultDateRange();
@@ -478,17 +489,21 @@ export function DiscountSimulator() {
 
         {/* Right Side - Results */}
         <div className="space-y-4 min-w-0 flex-1 overflow-hidden">
-          {/* Top Right - Summary and Chart */}
-          <div className="grid gap-4 lg:grid-cols-[160px,1fr] min-w-0">
-            <div className="w-full min-w-0">
-              <SummaryCard result={simulationResult} isLoading={isLoading} />
-            </div>
+          {/* Top - Summary (horizontal) */}
+          <SummaryCard
+            result={simulationResult}
+            isLoading={isLoading}
+            baselineResult={baselineResult}
+            onSaveAsBaseline={handleSaveAsBaseline}
+            onClearBaseline={handleClearBaseline}
+          />
+
+          {/* Chart */}
           <div className="w-full min-w-0 overflow-hidden">
             <ResultsChart buckets={simulationResult?.buckets ?? []} isLoading={isSimulating} />
           </div>
-          </div>
 
-          {/* Bottom Right - Table */}
+          {/* Table */}
           <div className="w-full min-w-0 overflow-hidden">
             <ResultsTable buckets={simulationResult?.buckets ?? []} isLoading={isSimulating} />
           </div>