feat: category import from CSV + budget auto-assign rules

Category:
- Add categoryColumn to NormalizerConfig and NormalizedRow
- Map 'Category' column for Discover CC profile
- Write category to Transaction on upload

Budget rules:
- Add BudgetRule model (userId, budgetId, pattern)
- API: GET/POST /api/budget-rules, DELETE /api/budget-rules/:id
- Apply rules during upload (first case-insensitive match wins)
- Budgets page fetches and passes rules per budget
- BudgetCard 'Rules' menu item opens BudgetRulesDialog for add/delete

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

prisma/schema.prisma

@@ -8,13 +8,14 @@ datasource db {
 }
 
 model User {
-  id           String    @id @default(cuid())
-  email        String    @unique
+  id           String       @id @default(cuid())
+  email        String       @unique
   passwordHash String
-  createdAt    DateTime  @default(now())
-  updatedAt    DateTime  @updatedAt
+  createdAt    DateTime     @default(now())
+  updatedAt    DateTime     @updatedAt
   accounts     Account[]
   budgets      Budget[]
+  budgetRules  BudgetRule[]
 }
 
 enum AccountType {
@@ -80,10 +81,24 @@ model Budget {
   createdAt    DateTime      @default(now())
   updatedAt    DateTime      @updatedAt
   transactions Transaction[]
+  rules        BudgetRule[]
 
   @@index([userId])
 }
 
+model BudgetRule {
+  id        String   @id @default(cuid())
+  userId    String
+  user      User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  budgetId  String
+  budget    Budget   @relation(fields: [budgetId], references: [id], onDelete: Cascade)
+  pattern   String
+  createdAt DateTime @default(now())
+
+  @@index([userId])
+  @@index([budgetId])
+}
+
 model CsvUpload {
   id            String        @id @default(cuid())
   accountId     String

src/app/(app)/budgets/page.tsx

@@ -6,29 +6,41 @@ export default async function BudgetsPage() {
   const session = await auth()
   if (!session?.user?.id) return null
 
+  const userId = session.user.id
   const now = new Date()
   const monthStart = new Date(now.getFullYear(), now.getMonth(), 1)
   const monthEnd = new Date(now.getFullYear(), now.getMonth() + 1, 0, 23, 59, 59, 999)
 
-  const [budgets, spendRows] = await Promise.all([
+  const [budgets, spendRows, rules] = await Promise.all([
     prisma.budget.findMany({
-      where: { userId: session.user.id },
+      where: { userId },
       orderBy: { createdAt: 'asc' },
     }),
     prisma.$queryRaw<{ budgetId: string; total: bigint }[]>`
       SELECT t."budgetId", COALESCE(SUM(t."amountCents"), 0)::bigint AS total
       FROM "Transaction" t
       JOIN "Account" a ON t."accountId" = a.id
-      WHERE a."userId" = ${session.user.id}
+      WHERE a."userId" = ${userId}
         AND t."budgetId" IS NOT NULL
         AND t.type = 'DEBIT'
         AND t.date >= ${monthStart}
         AND t.date <= ${monthEnd}
       GROUP BY t."budgetId"
     `,
+    prisma.budgetRule.findMany({
+      where: { userId },
+      orderBy: { createdAt: 'asc' },
+      select: { id: true, budgetId: true, pattern: true },
+    }),
   ])
 
   const spendMap = new Map(spendRows.map((r) => [r.budgetId, Number(r.total)]))
+  const rulesMap = new Map<string, { id: string; pattern: string }[]>()
+  for (const rule of rules) {
+    const existing = rulesMap.get(rule.budgetId) ?? []
+    existing.push({ id: rule.id, pattern: rule.pattern })
+    rulesMap.set(rule.budgetId, existing)
+  }
 
   const budgetsWithSpend = budgets.map((b) => ({
     id: b.id,
@@ -37,6 +49,7 @@ export default async function BudgetsPage() {
     color: b.color,
     isActive: b.isActive,
     spendCents: spendMap.get(b.id) ?? 0,
+    rules: rulesMap.get(b.id) ?? [],
   }))
 
   return (

src/app/api/budget-rules/[id]/route.ts

@@ -0,0 +1,16 @@
+import { NextResponse } from 'next/server'
+import { auth } from '@/lib/auth'
+import { prisma } from '@/lib/prisma'
+
+export async function DELETE(_req: Request, { params }: { params: Promise<{ id: string }> }) {
+  const session = await auth()
+  if (!session?.user?.id) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const { id } = await params
+
+  const rule = await prisma.budgetRule.findFirst({ where: { id, userId: session.user.id } })
+  if (!rule) return NextResponse.json({ error: 'Not found' }, { status: 404 })
+
+  await prisma.budgetRule.delete({ where: { id } })
+  return new NextResponse(null, { status: 204 })
+}

src/app/api/budget-rules/route.ts

@@ -0,0 +1,37 @@
+import { NextResponse } from 'next/server'
+import { auth } from '@/lib/auth'
+import { prisma } from '@/lib/prisma'
+import { createBudgetRuleSchema } from '@/lib/validations/budget-rule'
+
+export async function GET() {
+  const session = await auth()
+  if (!session?.user?.id) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const rules = await prisma.budgetRule.findMany({
+    where: { userId: session.user.id },
+    orderBy: { createdAt: 'asc' },
+    select: { id: true, budgetId: true, pattern: true },
+  })
+  return NextResponse.json(rules)
+}
+
+export async function POST(req: Request) {
+  const session = await auth()
+  if (!session?.user?.id) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const body = await req.json()
+  const parsed = createBudgetRuleSchema.safeParse(body)
+  if (!parsed.success) return NextResponse.json({ error: parsed.error.flatten() }, { status: 400 })
+
+  const { budgetId, pattern } = parsed.data
+
+  // Verify budget belongs to this user
+  const budget = await prisma.budget.findFirst({ where: { id: budgetId, userId: session.user.id } })
+  if (!budget) return NextResponse.json({ error: 'Budget not found' }, { status: 404 })
+
+  const rule = await prisma.budgetRule.create({
+    data: { userId: session.user.id, budgetId, pattern },
+    select: { id: true, budgetId: true, pattern: true },
+  })
+  return NextResponse.json(rule, { status: 201 })
+}

src/app/api/upload/route.ts

@@ -76,6 +76,22 @@ export async function POST(req: Request) {
 
   const normalized = normalizeRows(allRows, accountId, config)
 
+  // Apply budget auto-assign rules (first match wins)
+  const budgetRules = await prisma.budgetRule.findMany({
+    where: { userId: session.user.id },
+    orderBy: { createdAt: 'asc' },
+    select: { pattern: true, budgetId: true },
+  })
+  const rowsWithBudgets = normalized.map((row) => {
+    const desc = row.description.toLowerCase()
+    for (const rule of budgetRules) {
+      if (desc.includes(rule.pattern.toLowerCase())) {
+        return { ...row, budgetId: rule.budgetId }
+      }
+    }
+    return { ...row, budgetId: null }
+  })
+
   const upload = await prisma.csvUpload.create({
     data: {
       accountId,
@@ -89,13 +105,15 @@ export async function POST(req: Request) {
 
   try {
     const { count: importedCount } = await prisma.transaction.createMany({
-      data: normalized.map((r) => ({
+      data: rowsWithBudgets.map((r) => ({
         accountId,
         uploadId: upload.id,
         date: r.date,
         description: r.description,
         amountCents: r.amountCents,
         type: r.type,
+        category: r.category ?? null,
+        budgetId: r.budgetId,
         dedupeHash: r.dedupeHash,
       })),
       skipDuplicates: true,
@@ -118,7 +136,7 @@ export async function POST(req: Request) {
     // Upsert balance snapshots for each affected month
     const months = [
       ...new Map(
-        normalized.map((r) => {
+        rowsWithBudgets.map((r) => {
           const y = r.date.getFullYear()
           const m = r.date.getMonth() + 1
           return [`${y}-${m}`, { year: y, month: m }]

src/components/budgets/BudgetCard.tsx

@@ -7,11 +7,17 @@ import {
   DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuSeparator,
   DropdownMenuTrigger,
 } from '@/components/ui/dropdown-menu'
-import { MoreHorizontal, Pencil, Trash2, EyeOff, Eye } from 'lucide-react'
+import { MoreHorizontal, Pencil, Trash2, EyeOff, Eye, ListFilter } from 'lucide-react'
 import { BudgetProgress } from './BudgetProgress'
 import { CreateBudgetDialog } from './CreateBudgetDialog'
+import { BudgetRulesDialog } from './BudgetRulesDialog'
 import { formatCents } from '@/lib/utils/currency'
 
+export interface BudgetRule {
+  id: string
+  pattern: string
+}
+
 export interface BudgetWithSpend {
   id: string
   name: string
@@ -19,11 +25,13 @@ export interface BudgetWithSpend {
   color: string | null
   isActive: boolean
   spendCents: number
+  rules?: BudgetRule[]
 }
 
 export function BudgetCard({ budget }: { budget: BudgetWithSpend }) {
   const router = useRouter()
   const [editOpen, setEditOpen] = useState(false)
+  const [rulesOpen, setRulesOpen] = useState(false)
 
   async function handleToggle() {
     await fetch(`/api/budgets/${budget.id}`, {
@@ -62,6 +70,9 @@ export function BudgetCard({ budget }: { budget: BudgetWithSpend }) {
               <DropdownMenuItem onClick={() => setEditOpen(true)}>
                 <Pencil className="h-4 w-4 mr-2" />Edit
               </DropdownMenuItem>
+              <DropdownMenuItem onClick={() => setRulesOpen(true)}>
+                <ListFilter className="h-4 w-4 mr-2" />Rules
+              </DropdownMenuItem>
               <DropdownMenuItem onClick={handleToggle}>
                 {budget.isActive
                   ? <><EyeOff className="h-4 w-4 mr-2" />Deactivate</>
@@ -102,6 +113,13 @@ export function BudgetCard({ budget }: { budget: BudgetWithSpend }) {
       </Card>
 
       <CreateBudgetDialog open={editOpen} onOpenChange={setEditOpen} budget={budget} />
+      <BudgetRulesDialog
+        open={rulesOpen}
+        onOpenChange={setRulesOpen}
+        budgetId={budget.id}
+        budgetName={budget.name}
+        rules={budget.rules ?? []}
+      />
     </>
   )
 }

src/components/budgets/BudgetRulesDialog.tsx

@@ -0,0 +1,96 @@
+'use client'
+
+import { useState } from 'react'
+import { useRouter } from 'next/navigation'
+import { Dialog, DialogContent, DialogHeader, DialogTitle } from '@/components/ui/dialog'
+import { Button } from '@/components/ui/button'
+import { Input } from '@/components/ui/input'
+import { Trash2, Plus } from 'lucide-react'
+
+interface Rule {
+  id: string
+  pattern: string
+}
+
+interface Props {
+  open: boolean
+  onOpenChange: (open: boolean) => void
+  budgetId: string
+  budgetName: string
+  rules: Rule[]
+}
+
+export function BudgetRulesDialog({ open, onOpenChange, budgetId, budgetName, rules }: Props) {
+  const router = useRouter()
+  const [pattern, setPattern] = useState('')
+  const [adding, setAdding] = useState(false)
+
+  async function handleAdd(e: React.FormEvent) {
+    e.preventDefault()
+    if (!pattern.trim()) return
+    setAdding(true)
+    await fetch('/api/budget-rules', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ budgetId, pattern: pattern.trim() }),
+    })
+    setPattern('')
+    setAdding(false)
+    router.refresh()
+  }
+
+  async function handleDelete(id: string) {
+    await fetch(`/api/budget-rules/${id}`, { method: 'DELETE' })
+    router.refresh()
+  }
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="max-w-md">
+        <DialogHeader>
+          <DialogTitle>Auto-assign rules — {budgetName}</DialogTitle>
+        </DialogHeader>
+
+        <p className="text-sm text-muted-foreground">
+          Transactions whose description contains a pattern (case-insensitive) are automatically
+          assigned to this budget on upload. First matching rule wins.
+        </p>
+
+        {rules.length === 0 ? (
+          <p className="text-sm text-muted-foreground text-center py-2">No rules yet.</p>
+        ) : (
+          <ul className="space-y-1.5">
+            {rules.map((rule) => (
+              <li
+                key={rule.id}
+                className="flex items-center justify-between gap-2 rounded-md border px-3 py-2 text-sm"
+              >
+                <span className="font-mono truncate">{rule.pattern}</span>
+                <button
+                  onClick={() => handleDelete(rule.id)}
+                  className="shrink-0 text-muted-foreground hover:text-destructive transition-colors"
+                  aria-label="Delete rule"
+                >
+                  <Trash2 className="h-3.5 w-3.5" />
+                </button>
+              </li>
+            ))}
+          </ul>
+        )}
+
+        <form onSubmit={handleAdd} className="flex gap-2">
+          <Input
+            placeholder="e.g. Amazon, Netflix, Starbucks"
+            value={pattern}
+            onChange={(e) => setPattern(e.target.value)}
+            className="flex-1"
+          />
+          <Button type="submit" disabled={adding || !pattern.trim()} size="sm">
+            <Plus className="h-4 w-4 mr-1" />
+            Add
+          </Button>
+        </form>
+      </DialogContent>
+    </Dialog>
+  )
+}

src/lib/csv/bank-profiles.ts

@@ -4,6 +4,7 @@ export interface NormalizerConfig {
   strategy: ParseStrategy
   dateColumn: string
   descriptionColumn: string
+  categoryColumn?: string
   // Strategy A
   amountColumn?: string
   invertAmountSign?: boolean
@@ -40,6 +41,7 @@ export const bankProfiles: BankProfile[] = [
     descriptionColumn: 'Description',
     amountColumn: 'Amount',
     invertAmountSign: false, // positive = DEBIT (charge), negative = CREDIT (payment)
+    categoryColumn: 'Category',
     detectColumns: ['Trans. Date', 'Post Date', 'Description', 'Amount', 'Category'],
   },
   {

src/lib/csv/normalizer.ts

@@ -6,6 +6,7 @@ export interface NormalizedRow {
   description: string
   amountCents: number
   type: 'DEBIT' | 'CREDIT'
+  category?: string
   dedupeHash: string
 }
 
@@ -92,11 +93,13 @@ export function normalizeRows(
 
       if (amountCents === 0) continue
 
+      const rawCategory = config.categoryColumn ? (row[config.categoryColumn] ?? '').trim() : ''
       out.push({
         date,
         description,
         amountCents,
         type,
+        category: rawCategory || undefined,
         dedupeHash: dedupeHash(accountId, date, description, amountCents),
       })
     } catch {

src/lib/validations/budget-rule.ts

@@ -0,0 +1,6 @@
+import { z } from 'zod'
+
+export const createBudgetRuleSchema = z.object({
+  budgetId: z.string().cuid(),
+  pattern: z.string().min(1).max(200).trim(),
+})