feat: add duplicate transaction detection and display in transactions page, enhancing user experience with visual indicators for duplicates

app/api/banking/duplicates/ids/route.ts

@@ -0,0 +1,20 @@
+import { NextResponse } from "next/server";
+import { transactionService } from "@/services/transaction.service";
+import { requireAuth } from "@/lib/auth-utils";
+
+export async function GET() {
+  const authError = await requireAuth();
+  if (authError) return authError;
+
+  try {
+    const duplicateIds = await transactionService.getDuplicateIds();
+    return NextResponse.json({ duplicateIds: Array.from(duplicateIds) });
+  } catch (error) {
+    console.error("Error finding duplicate IDs:", error);
+    return NextResponse.json(
+      { error: "Failed to find duplicate IDs" },
+      { status: 500 },
+    );
+  }
+}
+

app/api/banking/transactions/route.ts

@@ -125,9 +125,6 @@ export async function DELETE(request: Request) {
     console.error("Error deleting transaction:", error);
     const errorMessage =
       error instanceof Error ? error.message : "Failed to delete transaction";
-    return NextResponse.json(
+    return NextResponse.json({ error: errorMessage }, { status: 500 });
-      { error: errorMessage },
-      { status: 500 },
-    );
   }
 }

app/rules/page.tsx

@@ -42,7 +42,7 @@ export default function RulesPage() {
       offset: 0,
       includeUncategorized: true,
     },
-    !!metadata
+    !!metadata,
   );
 
   const refresh = useCallback(() => {
@@ -56,7 +56,7 @@ export default function RulesPage() {
   const [filterMinCount, setFilterMinCount] = useState(2);
   const [expandedGroups, setExpandedGroups] = useState<Set<string>>(new Set());
   const [selectedGroup, setSelectedGroup] = useState<TransactionGroup | null>(
-    null
+    null,
   );
   const [isDialogOpen, setIsDialogOpen] = useState(false);
   const [isAutoCategorizing, setIsAutoCategorizing] = useState(false);
@@ -87,7 +87,7 @@ export default function RulesPage() {
           totalAmount: transactions.reduce((sum, t) => sum + t.amount, 0),
           suggestedKeyword: suggestKeyword(descriptions),
         };
-      }
+      },
     );
 
     // Filter by search query
@@ -98,7 +98,7 @@ export default function RulesPage() {
         (g) =>
           g.displayName.toLowerCase().includes(query) ||
           g.key.includes(query) ||
-          g.suggestedKeyword.toLowerCase().includes(query)
+          g.suggestedKeyword.toLowerCase().includes(query),
       );
     }
 
@@ -167,7 +167,7 @@ export default function RulesPage() {
 
       // 1. Add keyword to category
       const category = metadata.categories.find(
-        (c: { id: string }) => c.id === ruleData.categoryId
+        (c: { id: string }) => c.id === ruleData.categoryId,
       );
       if (!category) {
         throw new Error("Category not found");
@@ -175,7 +175,7 @@ export default function RulesPage() {
 
       // Check if keyword already exists
       const keywordExists = category.keywords.some(
-        (k: string) => k.toLowerCase() === ruleData.keyword.toLowerCase()
+        (k: string) => k.toLowerCase() === ruleData.keyword.toLowerCase(),
       );
 
       if (!keywordExists) {
@@ -193,14 +193,14 @@ export default function RulesPage() {
               method: "PUT",
               headers: { "Content-Type": "application/json" },
               body: JSON.stringify({ id, categoryId: ruleData.categoryId }),
-            })
+            }),
-          )
+          ),
         );
       }
 
       refresh();
     },
-    [metadata, refresh]
+    [metadata, refresh],
   );
 
   const handleAutoCategorize = useCallback(async () => {
@@ -214,7 +214,7 @@ export default function RulesPage() {
       for (const transaction of uncategorized) {
         const categoryId = autoCategorize(
           transaction.description + " " + (transaction.memo || ""),
-          metadata.categories
+          metadata.categories,
         );
         if (categoryId) {
           await fetch("/api/banking/transactions", {
@@ -228,7 +228,7 @@ export default function RulesPage() {
 
       refresh();
       alert(
-        `${categorizedCount} transaction(s) catégorisée(s) automatiquement`
+        `${categorizedCount} transaction(s) catégorisée(s) automatiquement`,
       );
     } catch (error) {
       console.error("Error auto-categorizing:", error);
@@ -247,8 +247,8 @@ export default function RulesPage() {
               method: "PUT",
               headers: { "Content-Type": "application/json" },
               body: JSON.stringify({ ...t, categoryId }),
-            })
+            }),
-          )
+          ),
         );
         refresh();
       } catch (error) {
@@ -256,7 +256,7 @@ export default function RulesPage() {
         alert("Erreur lors de la catégorisation");
       }
     },
-    [refresh]
+    [refresh],
   );
 
   if (

app/transactions/page.tsx

@@ -15,6 +15,7 @@ import {
   useBankingMetadata,
   useTransactions,
   getTransactionsQueryKey,
+  useDuplicateIds,
 } from "@/lib/hooks";
 import { updateCategory } from "@/lib/store-db";
 import { useQueryClient } from "@tanstack/react-query";
@@ -83,6 +84,7 @@ export default function TransactionsPage() {
   const [updatingTransactionIds, setUpdatingTransactionIds] = useState<
     Set<string>
   >(new Set());
+  const [showDuplicates, setShowDuplicates] = useState(false);
 
   // Get start date based on period
   const startDate = useMemo(() => {
@@ -164,6 +166,9 @@ export default function TransactionsPage() {
     invalidate: invalidateTransactions,
   } = useTransactions(transactionParams, !!metadata);
 
+  // Fetch duplicate IDs
+  const { data: duplicateIds = new Set<string>() } = useDuplicateIds();
+
   // For filter comboboxes, we'll use empty arrays for now
   // They can be enhanced later with separate queries if needed
   const transactionsForAccountFilter: Transaction[] = [];
@@ -593,6 +598,8 @@ export default function TransactionsPage() {
         }}
         isCustomDatePickerOpen={isCustomDatePickerOpen}
         onCustomDatePickerOpenChange={setIsCustomDatePickerOpen}
+        showDuplicates={showDuplicates}
+        onShowDuplicatesChange={setShowDuplicates}
         accounts={metadata.accounts}
         folders={metadata.folders}
         categories={metadata.categories}
@@ -631,6 +638,8 @@ export default function TransactionsPage() {
             formatCurrency={formatCurrency}
             formatDate={formatDate}
             updatingTransactionIds={updatingTransactionIds}
+            duplicateIds={duplicateIds}
+            highlightDuplicates={showDuplicates}
           />
 
           {/* Pagination controls */}

components/dashboard/sidebar.tsx

@@ -77,10 +77,7 @@ function SidebarContent({
         </div>
       )}
 
-      <nav className={cn(
+      <nav className={cn("flex-1 space-y-2", collapsed ? "p-2" : "p-4")}>
-        "flex-1 space-y-2",
-        collapsed ? "p-2" : "p-4"
-      )}>
         {navItems.map((item) => {
           const isActive = pathname === item.href;
           return (
@@ -117,10 +114,12 @@ function SidebarContent({
         })}
       </nav>
 
-      <div className={cn(
+      <div
-        "border-t border-border/30 space-y-2",
+        className={cn(
-        collapsed ? "p-2" : "p-4"
+          "border-t border-border/30 space-y-2",
-      )}>
+          collapsed ? "p-2" : "p-4",
+        )}
+      >
         <Link href="/settings" onClick={handleLinkClick}>
           <Button
             variant="ghost"
@@ -186,10 +185,12 @@ export function Sidebar({ open, onOpenChange }: SidebarProps) {
         collapsed ? "w-16" : "w-64",
       )}
     >
-      <div className={cn(
+      <div
-        "flex items-center border-b border-border/30 transition-all duration-300",
+        className={cn(
-        collapsed ? "justify-center p-4" : "justify-between p-6"
+          "flex items-center border-b border-border/30 transition-all duration-300",
-      )}>
+          collapsed ? "justify-center p-4" : "justify-between p-6",
+        )}
+      >
         {!collapsed && (
           <div className="flex items-center gap-3">
             <div className="w-12 h-12 rounded-2xl bg-gradient-to-br from-primary via-primary/90 to-primary/80 flex items-center justify-center shadow-xl shadow-primary/30 backdrop-blur-sm">
@@ -206,7 +207,7 @@ export function Sidebar({ open, onOpenChange }: SidebarProps) {
           onClick={() => setCollapsed(!collapsed)}
           className={cn(
             "hover:bg-muted/60 rounded-xl transition-all duration-300 hover:scale-110",
-            collapsed ? "" : "ml-auto"
+            collapsed ? "" : "ml-auto",
           )}
         >
           {collapsed ? (

components/layout/page-header.tsx

@@ -40,9 +40,7 @@ export function PageHeader({
             <h1 className="text-2xl md:text-4xl lg:text-5xl font-black text-foreground tracking-tight leading-tight flex-1 min-w-0">
               {title}
             </h1>
-            {rightContent && (
+            {rightContent && <div className="shrink-0">{rightContent}</div>}
-              <div className="shrink-0">{rightContent}</div>
-            )}
           </div>
           {description && (
             <div className="text-base md:text-lg text-muted-foreground/70 font-semibold">

components/transactions/transaction-filters.tsx

@@ -28,10 +28,12 @@ import {
   SheetTitle,
   SheetTrigger,
 } from "@/components/ui/sheet";
-import { Search, X, Filter, Wallet, Calendar } from "lucide-react";
+import { Search, X, Filter, Wallet, Calendar, Copy } from "lucide-react";
 import { format } from "date-fns";
 import { fr } from "date-fns/locale";
 import { useIsMobile } from "@/hooks/use-mobile";
+import { Checkbox } from "@/components/ui/checkbox";
+import { Label } from "@/components/ui/label";
 import type { Account, Category, Folder, Transaction } from "@/lib/types";
 
 type Period = "1month" | "3months" | "6months" | "12months" | "custom" | "all";
@@ -53,6 +55,8 @@ interface TransactionFiltersProps {
   onCustomEndDateChange: (date: Date | undefined) => void;
   isCustomDatePickerOpen: boolean;
   onCustomDatePickerOpenChange: (open: boolean) => void;
+  showDuplicates: boolean;
+  onShowDuplicatesChange: (show: boolean) => void;
   accounts: Account[];
   folders: Folder[];
   categories: Category[];
@@ -77,6 +81,8 @@ export function TransactionFilters({
   onCustomEndDateChange,
   isCustomDatePickerOpen,
   onCustomDatePickerOpenChange,
+  showDuplicates,
+  onShowDuplicatesChange,
   accounts,
   folders,
   categories,
@@ -153,6 +159,23 @@ export function TransactionFilters({
           </SelectContent>
         </Select>
 
+        <div className="flex items-center gap-2 px-3 py-2 rounded-md border border-border bg-card">
+          <Checkbox
+            id="show-duplicates"
+            checked={showDuplicates}
+            onCheckedChange={(checked) =>
+              onShowDuplicatesChange(checked === true)
+            }
+          />
+          <Label
+            htmlFor="show-duplicates"
+            className="text-sm font-normal cursor-pointer flex items-center gap-2"
+          >
+            <Copy className="h-4 w-4 text-muted-foreground" />
+            Afficher les doublons
+          </Label>
+        </div>
+
         {period === "custom" && (
           <Popover
             open={isCustomDatePickerOpen}
@@ -256,7 +279,7 @@ export function TransactionFilters({
         onRemoveCategory={(id) => {
           const newCategories = selectedCategories.filter((c) => c !== id);
           onCategoriesChange(
-            newCategories.length > 0 ? newCategories : ["all"],
+            newCategories.length > 0 ? newCategories : ["all"]
           );
         }}
         onClearCategories={() => onCategoriesChange(["all"])}
@@ -282,7 +305,8 @@ export function TransactionFilters({
       (!selectedAccounts.includes("all") ? selectedAccounts.length : 0) +
       (!selectedCategories.includes("all") ? selectedCategories.length : 0) +
       (showReconciled !== "all" ? 1 : 0) +
-      (period !== "all" ? 1 : 0);
+      (period !== "all" ? 1 : 0) +
+      (showDuplicates ? 1 : 0);
 
     return (
       <>
@@ -367,7 +391,7 @@ function ActiveFilters({
 
   const selectedAccs = accounts.filter((a) => selectedAccounts.includes(a.id));
   const selectedCats = categories.filter((c) =>
-    selectedCategories.includes(c.id),
+    selectedCategories.includes(c.id)
   );
   const isUncategorized = selectedCategories.includes("uncategorized");
 

components/transactions/transaction-table.tsx

@@ -25,6 +25,7 @@ import {
   Wand2,
   Trash2,
   Loader2,
+  AlertTriangle,
 } from "lucide-react";
 import { DropdownMenuSeparator } from "@/components/ui/dropdown-menu";
 import { cn } from "@/lib/utils";
@@ -52,6 +53,8 @@ interface TransactionTableProps {
   formatCurrency: (amount: number) => string;
   formatDate: (dateStr: string) => string;
   updatingTransactionIds?: Set<string>;
+  duplicateIds?: Set<string>;
+  highlightDuplicates?: boolean;
 }
 
 const ROW_HEIGHT = 72; // Hauteur approximative d'une ligne
@@ -145,6 +148,8 @@ export function TransactionTable({
   formatCurrency,
   formatDate,
   updatingTransactionIds = new Set(),
+  duplicateIds = new Set(),
+  highlightDuplicates = false,
 }: TransactionTableProps) {
   const [focusedIndex, setFocusedIndex] = useState<number | null>(null);
   const parentRef = useRef<HTMLDivElement>(null);
@@ -247,6 +252,8 @@ export function TransactionTable({
                   const account = getAccount(transaction.accountId);
                   const _category = getCategory(transaction.categoryId);
                   const isFocused = focusedIndex === virtualRow.index;
+                  const isDuplicate =
+                    highlightDuplicates && duplicateIds.has(transaction.id);
 
                   return (
                     <div
@@ -259,6 +266,10 @@ export function TransactionTable({
                         left: 0,
                         width: "100%",
                         transform: `translateY(${virtualRow.start}px)`,
+                        ...(isDuplicate && {
+                          backgroundColor: "rgb(254 252 232)", // yellow-50
+                          borderLeft: "4px solid rgb(234 179 8)", // yellow-500
+                        }),
                       }}
                       onClick={() => {
                         // Désactiver le pointage au clic sur mobile
@@ -269,7 +280,8 @@ export function TransactionTable({
                       className={cn(
                         "p-4 space-y-3 hover:bg-muted/50 cursor-pointer border-b border-border",
                         transaction.isReconciled && "bg-emerald-500/5",
-                        isFocused && "bg-primary/10 ring-1 ring-primary/30"
+                        isFocused && "bg-primary/10 ring-1 ring-primary/30",
+                        isDuplicate && "shadow-sm"
                       )}
                     >
                       <div className="flex items-start justify-between gap-2">
@@ -282,9 +294,23 @@ export function TransactionTable({
                             onClick={(e) => e.stopPropagation()}
                           />
                           <div className="flex-1 min-w-0">
-                            <p className="font-medium text-xs md:text-sm truncate">
+                            <div className="flex items-center gap-2">
-                              {transaction.description}
+                              <p className="font-medium text-xs md:text-sm truncate">
-                            </p>
+                                {transaction.description}
+                              </p>
+                              {isDuplicate && (
+                                <Tooltip delayDuration={200}>
+                                  <TooltipTrigger asChild>
+                                    <AlertTriangle className="h-3 w-3 md:h-4 md:w-4 text-[var(--warning)] shrink-0" />
+                                  </TooltipTrigger>
+                                  <TooltipContent>
+                                    <p>
+                                      Transaction en double (même somme et date)
+                                    </p>
+                                  </TooltipContent>
+                                </Tooltip>
+                              )}
+                            </div>
                             {transaction.memo && (
                               <p className="text-[10px] md:text-xs text-muted-foreground truncate mt-1">
                                 {transaction.memo}
@@ -455,6 +481,8 @@ export function TransactionTable({
                   const transaction = transactions[virtualRow.index];
                   const account = getAccount(transaction.accountId);
                   const isFocused = focusedIndex === virtualRow.index;
+                  const isDuplicate =
+                    highlightDuplicates && duplicateIds.has(transaction.id);
 
                   return (
                     <div
@@ -467,6 +495,10 @@ export function TransactionTable({
                         left: 0,
                         width: "100%",
                         transform: `translateY(${virtualRow.start}px)`,
+                        ...(isDuplicate && {
+                          backgroundColor: "rgb(254 252 232)", // yellow-50
+                          borderLeft: "4px solid rgb(234 179 8)", // yellow-500
+                        }),
                       }}
                       onClick={() =>
                         handleRowClick(virtualRow.index, transaction.id)
@@ -474,7 +506,8 @@ export function TransactionTable({
                       className={cn(
                         "grid grid-cols-[auto_120px_2fr_150px_180px_140px_auto_auto] gap-0 border-b border-border hover:bg-muted/50 cursor-pointer",
                         transaction.isReconciled && "bg-emerald-500/5",
-                        isFocused && "bg-primary/10 ring-1 ring-primary/30"
+                        isFocused && "bg-primary/10 ring-1 ring-primary/30",
+                        isDuplicate && "shadow-sm"
                       )}
                     >
                       <div className="p-3">
@@ -492,9 +525,23 @@ export function TransactionTable({
                         className="p-3 min-w-0 overflow-hidden"
                         onClick={(e) => e.stopPropagation()}
                       >
-                        <p className="font-medium text-sm truncate">
+                        <div className="flex items-center gap-2">
-                          {transaction.description}
+                          <p className="font-medium text-sm truncate">
-                        </p>
+                            {transaction.description}
+                          </p>
+                          {isDuplicate && (
+                            <Tooltip delayDuration={200}>
+                              <TooltipTrigger asChild>
+                                <AlertTriangle className="h-4 w-4 text-[var(--warning)] shrink-0" />
+                              </TooltipTrigger>
+                              <TooltipContent>
+                                <p>
+                                  Transaction en double (même somme et date)
+                                </p>
+                              </TooltipContent>
+                            </Tooltip>
+                          )}
+                        </div>
                         {transaction.memo && (
                           <DescriptionWithTooltip
                             description={transaction.memo}

components/ui/account-filter-combobox.tsx

@@ -182,9 +182,7 @@ export function AccountFilterCombobox({
             {isFolderPartiallySelected(folder.id) && (
               <div className="h-3 w-3 rounded-sm bg-primary/50 mr-1" />
             )}
-            {isFolderSelected(folder.id) && (
+            {isFolderSelected(folder.id) && <Check className="h-4 w-4" />}
-              <Check className="h-4 w-4" />
-            )}
           </div>
         </CommandItem>
 
@@ -306,9 +304,7 @@ export function AccountFilterCombobox({
                     )
                   </span>
                 )}
-                {isAll && (
+                {isAll && <Check className="ml-auto h-4 w-4" />}
-                  <Check className="ml-auto h-4 w-4" />
-                )}
               </CommandItem>
             </CommandGroup>
 

components/ui/category-filter-combobox.tsx

@@ -193,7 +193,11 @@ export function CategoryFilterCombobox({
         align="start"
         onOpenAutoFocus={(e) => e.preventDefault()}
       >
-        <Command value={isAll ? "all" : isUncategorized ? "uncategorized" : value.join(",")}>
+        <Command
+          value={
+            isAll ? "all" : isUncategorized ? "uncategorized" : value.join(",")
+          }
+        >
           <CommandInput placeholder="Rechercher..." />
           <CommandList className="max-h-[300px]">
             <CommandEmpty>Aucune catégorie trouvée.</CommandEmpty>
@@ -212,9 +216,7 @@ export function CategoryFilterCombobox({
                     ({filteredTransactions.length})
                   </span>
                 )}
-                {isAll && (
+                {isAll && <Check className="ml-auto h-4 w-4 shrink-0" />}
-                  <Check className="ml-auto h-4 w-4 shrink-0" />
-                )}
               </CommandItem>
               <CommandItem
                 value="uncategorized"

hooks/use-mobile.ts

@@ -4,7 +4,7 @@ const MOBILE_BREAKPOINT = 768;
 
 export function useIsMobile() {
   const [isMobile, setIsMobile] = React.useState<boolean | undefined>(
-    undefined
+    undefined,
   );
 
   React.useEffect(() => {

lib/hooks.ts

@@ -205,3 +205,18 @@ export function useAccountsWithStats() {
     staleTime: 60 * 1000, // 1 minute
   });
 }
+
+export function useDuplicateIds() {
+  return useQuery({
+    queryKey: ["duplicate-ids"],
+    queryFn: async (): Promise<Set<string>> => {
+      const response = await fetch("/api/banking/duplicates/ids");
+      if (!response.ok) {
+        throw new Error("Failed to fetch duplicate IDs");
+      }
+      const data = await response.json();
+      return new Set(data.duplicateIds || []);
+    },
+    staleTime: 30 * 1000, // 30 seconds
+  });
+}

services/transaction.service.ts

@@ -41,14 +41,14 @@ export const transactionService = {
 
     // Create sets for fast lookup
     const existingFitIdSet = new Set(
-      existingByFitId.map((t) => `${t.accountId}-${t.fitId}`),
+      existingByFitId.map((t) => `${t.accountId}-${t.fitId}`)
     );
 
     // Create set for duplicates by amount + date + description
     const existingCriteriaSet = new Set(
       allExistingTransactions.map(
-        (t) => `${t.accountId}-${t.date}-${t.amount}-${t.description}`,
+        (t) => `${t.accountId}-${t.date}-${t.amount}-${t.description}`
-      ),
+      )
     );
 
     // Filter out duplicates based on fitId OR (amount + date + description)
@@ -85,7 +85,7 @@ export const transactionService = {
 
   async update(
     id: string,
-    data: Partial<Omit<Transaction, "id">>,
+    data: Partial<Omit<Transaction, "id">>
   ): Promise<Transaction> {
     const updated = await prisma.transaction.update({
       where: { id },
@@ -123,14 +123,67 @@ export const transactionService = {
       await prisma.transaction.delete({
         where: { id },
       });
-    } catch (error: any) {
+    } catch (error: unknown) {
-      if (error.code === "P2025") {
+      if (
+        error &&
+        typeof error === "object" &&
+        "code" in error &&
+        error.code === "P2025"
+      ) {
         throw new Error(`Transaction with id ${id} not found`);
       }
       throw error;
     }
   },
 
+  async getDuplicateIds(): Promise<Set<string>> {
+    // Get all transactions grouped by account
+    const allTransactions = await prisma.transaction.findMany({
+      orderBy: [
+        { accountId: "asc" },
+        { date: "asc" },
+        { createdAt: "asc" }, // Oldest first
+      ],
+      select: {
+        id: true,
+        accountId: true,
+        date: true,
+        amount: true,
+      },
+    });
+
+    // Group by account for efficient processing
+    const transactionsByAccount = new Map<string, typeof allTransactions>();
+    for (const transaction of allTransactions) {
+      if (!transactionsByAccount.has(transaction.accountId)) {
+        transactionsByAccount.set(transaction.accountId, []);
+      }
+      transactionsByAccount.get(transaction.accountId)!.push(transaction);
+    }
+
+    const duplicateIds = new Set<string>();
+    const seenKeys = new Map<string, string>(); // key -> first transaction ID
+
+    // For each account, find duplicates by amount + date only
+    for (const [accountId, transactions] of transactionsByAccount.entries()) {
+      for (const transaction of transactions) {
+        const key = `${accountId}-${transaction.date}-${transaction.amount}`;
+
+        if (seenKeys.has(key)) {
+          // This is a duplicate - mark both the first and this one
+          const firstId = seenKeys.get(key)!;
+          duplicateIds.add(firstId);
+          duplicateIds.add(transaction.id);
+        } else {
+          // First occurrence
+          seenKeys.set(key, transaction.id);
+        }
+      }
+    }
+
+    return duplicateIds;
+  },
+
   async deduplicate(): Promise<{
     deletedCount: number;
     duplicatesFound: number;