export functionality added for friends section (#123)

* export functionality added

* added export button next to add expence

src/components/Friend/Export.tsx

@@ -0,0 +1,120 @@
+import React from 'react';
+import { Button } from '~/components/ui/button';
+import { format } from 'date-fns';
+import { SplitType } from '@prisma/client';
+import { Download } from 'lucide-react';
+import { toUIString } from '~/utils/numbers';
+
+interface ExpenseParticipant {
+  expenseId: string;
+  userId: number;
+  amount: number;
+}
+
+interface Expense {
+  id: string;
+  paidBy: number;
+  addedBy: number;
+  name: string;
+  category: string;
+  amount: number;
+  splitType: SplitType;
+  expenseDate: Date;
+  createdAt: Date;
+  updatedAt: Date;
+  currency: string;
+  fileKey: string | null;
+  groupId: number | null;
+  deletedAt: Date | null;
+  deletedBy: number | null;
+  expenseParticipants: ExpenseParticipant[];
+}
+
+interface ExportCSVProps {
+  expenses: Expense[];
+  fileName: string;
+  currentUserId: number;
+  friendName: string;
+  friendId: string | number;
+  disabled?: boolean;
+}
+
+export const Export: React.FC<ExportCSVProps> = ({
+  expenses,
+  fileName,
+  currentUserId,
+  friendName,
+  friendId,
+  disabled = false,
+}) => {
+  const headers = [
+    'Paid By',
+    'Name',
+    'Category',
+    'Amount',
+    'Split Type',
+    'Expense Date',
+    'Currency',
+    'You Lent',
+    'You Owe',
+    'Settlement',
+  ];
+
+  const exportToCSV = () => {
+    const csvHeaders = headers.join(',');
+    const csvData = expenses.map((expense) => {
+      const youPaid = expense.paidBy === currentUserId;
+      const yourExpense = expense.expenseParticipants.find(
+        (p) => p.userId === (youPaid ? friendId : currentUserId),
+      );
+
+      const isSettlement = expense.splitType === SplitType.SETTLEMENT;
+
+      return [
+        expense.paidBy === currentUserId ? 'You' : friendName,
+        expense.name,
+        expense.category,
+        toUIString(expense?.amount ?? 0),
+        expense.splitType,
+        format(new Date(expense.expenseDate), 'yyyy-MM-dd HH:mm:ss'),
+        expense.currency,
+        youPaid && !isSettlement ? toUIString(yourExpense?.amount ?? 0) : 0,
+        !youPaid && !isSettlement ? toUIString(yourExpense?.amount ?? 0) : 0,
+        isSettlement ? toUIString(yourExpense?.amount ?? 0) : 0,
+      ];
+    });
+
+    const csvContent = [
+      csvHeaders,
+      ...csvData.map((row) =>
+        row
+          .map((cell) => (typeof cell === 'string' && cell.includes(',') ? `"${cell}"` : cell))
+          .join(','),
+      ),
+    ].join('\n');
+
+    const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' });
+    const link = document.createElement('a');
+    if (link.download !== undefined) {
+      const url = URL.createObjectURL(blob);
+      link.setAttribute('href', url);
+      link.setAttribute('download', `${fileName}.csv`);
+      link.style.visibility = 'hidden';
+      document.body.appendChild(link);
+      link.click();
+      document.body.removeChild(link);
+    }
+  };
+
+  return (
+    <Button
+      size="sm"
+      variant="secondary"
+      className="w-[150px] gap-1 text-sm lg:w-[180px]"
+      onClick={exportToCSV}
+      disabled={disabled}
+    >
+      <Download className="h-4 w-4 text-white" size={20} /> Export
+    </Button>
+  );
+};

src/pages/balances/[friendId].tsx

@@ -15,6 +15,7 @@ import { useRouter } from 'next/router';
 import { type NextPageWithUser } from '~/types';
 import { motion } from 'framer-motion';
 import { DeleteFriend } from '~/components/Friend/DeleteFriend';
+import { Export } from '~/components/Friend/Export';
 
 const FriendPage: NextPageWithUser = ({ user }) => {
   const router = useRouter();
@@ -138,6 +139,14 @@ const FriendPage: NextPageWithUser = ({ user }) => {
                   <PlusIcon className="h-4 w-4 text-gray-400" /> Add Expense
                 </Button>
               </Link>
+              <Export
+                expenses={expenses.data ?? []}
+                fileName={`expenses_with_${friendQuery.data?.name}`}
+                currentUserId={user.id}
+                friendName={friendQuery.data?.name ?? ''}
+                friendId={friendQuery.data?.id ?? ''}
+                disabled={!expenses.data || expenses.data.length === 0}
+              />
               {/* <Button size="sm" className="gap-1 text-sm lg:w-[180px]" variant="secondary">
                 <Bell className="h-4 w-4 text-gray-400" />
                 Remind