refactor: consolidate AI analyzers into shared lib/ai module and add journal entry reversal columns

Extract shared vision/document analysis logic into lib/ai (vision-client, document-analyzer, image preprocessing, validation helpers), simplifying invoice-analyzer, receipt-analyzer, and document classifier. Add migration 046 for journal entry reversal/correction link columns (reversed_by_id, reverses_id, correction_of_id) required by storno service. Update extension components and shared UI. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-26 17:14:44 +01:00
parent 6d647b956c
commit 3f255ea201
42 changed files with 2090 additions and 1127 deletions
@@ -0,0 +1,666 @@
+/**
+ * Unified Document Analyzer
+ *
+ * SERVER-ONLY: Uses the shared vision client (Anthropic SDK).
+ *
+ * Provides four modes:
+ * - analyzeDocument(): Single Claude call that classifies AND extracts
+ * - extractReceipt(): Standalone receipt extraction
+ * - extractInvoice(): Standalone invoice extraction
+ * - classifyDocument(): Lightweight classify-only
+ */
+
+import 'server-only'
+import type {
+  DocumentClassificationType,
+  ReceiptExtractionResult,
+  InvoiceExtractionResult,
+  ExtractedInvoiceLineItem,
+  VatBreakdownItem,
+} from '@/types'
+import { callVision } from './vision-client'
+import {
+  validateString,
+  validateNumber,
+  validateDate,
+  validateTime,
+  validateOrgNumber,
+  validateVatNumber,
+  validateAccountNumber,
+} from './validation-helpers'
+import { buildTemplatePromptSection } from '@/lib/bookkeeping/template-prompt'
+
+// ============================================================
+// Types
+// ============================================================
+
+export interface DocumentClassification {
+  type: DocumentClassificationType
+  confidence: number
+  reasoning: string
+  isReverseCharge?: boolean
+}
+
+export interface UnifiedExtractionResult {
+  classification: DocumentClassification
+  receipt?: ReceiptExtractionResult
+  invoice?: InvoiceExtractionResult
+}
+
+interface ConsistencyResult {
+  valid: boolean
+  issues: string[]
+}
+
+// ============================================================
+// Prompts
+// ============================================================
+
+const CLASSIFY_SYSTEM_PROMPT = `Du är expert på att klassificera svenska affärsdokument.
+Din uppgift är att avgöra vilken typ av dokument som visas.
+
+DOKUMENTTYPER:
+- supplier_invoice: Leverantörsfaktura (har fakturanummer, bankgiro/plusgiro, förfallodatum, leverantörsuppgifter)
+- receipt: Kvitto (butiks-/restaurangkvitto, kort betalningsbevis med artikelrader)
+- government_letter: Myndighetspost (från Skatteverket, Bolagsverket, Försäkringskassan, kommun, etc.)
+- unknown: Annat dokument som inte passar ovan
+
+FÖR LEVERANTÖRSFAKTUROR - kontrollera även:
+- Är fakturan från en utländsk/EU-leverantör utan svensk moms?
+- Nämner dokumentet "reverse charge", "omvänd skattskyldighet", eller "artikel 196"?
+- Har leverantören ett VAT-nummer som INTE börjar med SE?
+Om ja: flagga isReverseCharge = true`
+
+const RECEIPT_SYSTEM_PROMPT = `Du är expert på att extrahera data från svenska kvitton och fakturor.
+Din uppgift är att noggrant analysera kvittobilden och extrahera all relevant information.
+
+VIKTIGT:
+- Extrahera VARJE artikelrad, inte bara summan
+- Identifiera momssats per rad om möjligt (25%, 12%, 6%)
+- Flagga om detta är: restaurang, Systembolaget, eller utländsk handlare
+- Svenska organisationsnummer är i format XXXXXX-XXXX
+- Momsregistreringsnummer börjar med SE
+- Datum ska vara i ISO-format (YYYY-MM-DD)
+- Belopp ska vara numeriska värden utan valutasymboler
+- Ange konfidenstal (0.0-1.0) för hela extraheringen baserat på bildkvalitet`
+
+const INVOICE_SYSTEM_PROMPT = `Du är expert på att extrahera data från svenska leverantörsfakturor.
+Din uppgift är att noggrant analysera fakturan och extrahera all relevant information.
+
+VIKTIGT:
+- Extrahera leverantörens organisationsnummer (XXXXXX-XXXX format)
+- Extrahera bankgiro och/eller plusgiro
+- Extrahera varje fakturaradspost med belopp, moms
+- Identifiera momssatser (25%, 12%, 6%, 0%)
+- Extrahera OCR-nummer eller betalningsreferens
+- Datum ska vara i ISO-format (YYYY-MM-DD)
+- Belopp ska vara numeriska värden utan valutasymboler
+- Ange konfidenstal (0.0-1.0) för hela extraheringen`
+
+function buildReceiptUserPrompt(): string {
+  const templateSection = buildTemplatePromptSection()
+
+  return `Analysera detta kvitto och extrahera strukturerad data.
+
+Returnera ett JSON-objekt med följande struktur:
+
+{
+  "merchant": {
+    "name": "Handlarens namn",
+    "orgNumber": "XXXXXX-XXXX eller null",
+    "vatNumber": "SE... eller null",
+    "isForeign": false
+  },
+  "receipt": {
+    "date": "YYYY-MM-DD",
+    "time": "HH:MM eller null",
+    "currency": "SEK"
+  },
+  "lineItems": [
+    {
+      "description": "Artikelbeskrivning",
+      "quantity": 1,
+      "unitPrice": 100.00,
+      "lineTotal": 100.00,
+      "vatRate": 25,
+      "suggestedCategory": "equipment|software|travel|office|marketing|professional_services|education|other",
+      "suggestedTemplateId": "mall-id eller null"
+    }
+  ],
+  "totals": {
+    "subtotal": 100.00,
+    "vatAmount": 25.00,
+    "total": 125.00
+  },
+  "flags": {
+    "isRestaurant": false,
+    "isSystembolaget": false,
+    "isForeignMerchant": false
+  },
+  "confidence": 0.95,
+  "suggestedTemplateId": "mall-id för hela kvittot eller null"
+}
+
+${templateSection}
+
+KATEGORIER för suggestedCategory (backup om ingen mall matchar):
+- equipment: Datorer, telefoner, kameror, teknikprylar
+- software: Program, appar, molntjänster, prenumerationer
+- travel: Flyg, tåg, hotell, taxi
+- office: Kontorsmaterial, möbler, hyra
+- marketing: Reklam, marknadsföring, PR
+- professional_services: Konsulter, redovisning, juridik
+- education: Kurser, böcker, utbildning
+- other: Övrigt
+
+Returnera ENDAST JSON-objektet, ingen annan text.`
+}
+
+function buildInvoiceUserPrompt(): string {
+  const templateSection = buildTemplatePromptSection()
+
+  return `Analysera denna leverantörsfaktura och extrahera strukturerad data.
+
+Returnera ett JSON-objekt med följande struktur:
+
+{
+  "supplier": {
+    "name": "Leverantörens namn",
+    "orgNumber": "XXXXXX-XXXX eller null",
+    "vatNumber": "SE... eller null",
+    "address": "Fullständig adress eller null",
+    "bankgiro": "XXX-XXXX eller null",
+    "plusgiro": "XXXXXX-X eller null"
+  },
+  "invoice": {
+    "invoiceNumber": "Fakturanummer",
+    "invoiceDate": "YYYY-MM-DD",
+    "dueDate": "YYYY-MM-DD",
+    "paymentReference": "OCR-nummer eller referens eller null",
+    "currency": "SEK"
+  },
+  "lineItems": [
+    {
+      "description": "Beskrivning av rad",
+      "quantity": 1,
+      "unitPrice": 100.00,
+      "lineTotal": 100.00,
+      "vatRate": 25,
+      "accountSuggestion": "BAS-kontonummer som 5410 eller null",
+      "suggestedTemplateId": "mall-id eller null"
+    }
+  ],
+  "totals": {
+    "subtotal": 100.00,
+    "vatAmount": 25.00,
+    "total": 125.00
+  },
+  "vatBreakdown": [
+    {
+      "rate": 25,
+      "base": 100.00,
+      "amount": 25.00
+    }
+  ],
+  "confidence": 0.95,
+  "suggestedTemplateId": "mall-id för hela fakturan eller null"
+}
+
+${templateSection}
+
+KONTOKATEGORIER (BAS, backup om ingen mall matchar):
+- 4000-4999: Varuinköp, material
+- 5010: Lokalhyra
+- 5410: Förbrukningsinventarier
+- 5420: Programvaror
+- 5800-5899: Resekostnader
+- 6100-6199: Kontorsmaterial
+- 6200-6299: Telefon, internet
+- 6310: Företagsförsäkringar
+- 6530: Redovisningstjänster
+- 6570: Bankkostnader
+
+Returnera ENDAST JSON-objektet, ingen annan text.`
+}
+
+function buildUnifiedUserPrompt(): string {
+  const templateSection = buildTemplatePromptSection()
+
+  return `Analysera detta dokument. Gör BÅDA stegen:
+
+STEG 1: Klassificera dokumenttypen.
+STEG 2: Om det är ett kvitto eller leverantörsfaktura, extrahera all data.
+
+Returnera ett JSON-objekt med följande struktur:
+
+{
+  "classification": {
+    "type": "supplier_invoice" | "receipt" | "government_letter" | "unknown",
+    "confidence": 0.95,
+    "reasoning": "Kort förklaring",
+    "isReverseCharge": false
+  },
+  "receipt": null,
+  "invoice": null
+}
+
+Om type = "receipt", fyll i "receipt" med:
+{
+  "merchant": { "name": "...", "orgNumber": "XXXXXX-XXXX eller null", "vatNumber": "SE... eller null", "isForeign": false },
+  "receipt": { "date": "YYYY-MM-DD", "time": "HH:MM eller null", "currency": "SEK" },
+  "lineItems": [{ "description": "...", "quantity": 1, "unitPrice": 100, "lineTotal": 100, "vatRate": 25, "suggestedCategory": "equipment|software|travel|office|marketing|professional_services|education|other", "suggestedTemplateId": null }],
+  "totals": { "subtotal": 100, "vatAmount": 25, "total": 125 },
+  "flags": { "isRestaurant": false, "isSystembolaget": false, "isForeignMerchant": false },
+  "confidence": 0.95,
+  "suggestedTemplateId": null
+}
+
+Om type = "supplier_invoice", fyll i "invoice" med:
+{
+  "supplier": { "name": "...", "orgNumber": "XXXXXX-XXXX eller null", "vatNumber": "SE... eller null", "address": "...", "bankgiro": "...", "plusgiro": "..." },
+  "invoice": { "invoiceNumber": "...", "invoiceDate": "YYYY-MM-DD", "dueDate": "YYYY-MM-DD", "paymentReference": "...", "currency": "SEK" },
+  "lineItems": [{ "description": "...", "quantity": 1, "unitPrice": 100, "lineTotal": 100, "vatRate": 25, "accountSuggestion": "5410", "suggestedTemplateId": null }],
+  "totals": { "subtotal": 100, "vatAmount": 25, "total": 125 },
+  "vatBreakdown": [{ "rate": 25, "base": 100, "amount": 25 }],
+  "confidence": 0.95,
+  "suggestedTemplateId": null
+}
+
+${templateSection}
+
+Om type = "government_letter" eller "unknown": lämna receipt och invoice som null.
+
+Returnera ENDAST JSON-objektet, ingen annan text.`
+}
+
+// ============================================================
+// Validation
+// ============================================================
+
+const VALID_CLASSIFICATION_TYPES: DocumentClassificationType[] = [
+  'supplier_invoice',
+  'receipt',
+  'government_letter',
+  'unknown',
+]
+
+const VALID_VAT_RATES = [0, 6, 12, 25]
+
+function validateClassification(raw: unknown): DocumentClassification {
+  if (!raw || typeof raw !== 'object') {
+    throw new Error('Invalid classification result: not an object')
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const data = raw as any
+
+  const type = VALID_CLASSIFICATION_TYPES.includes(data.type) ? data.type : 'unknown'
+  const confidence = typeof data.confidence === 'number' ? data.confidence : 0.5
+  const reasoning = typeof data.reasoning === 'string' ? data.reasoning : ''
+  const isReverseCharge = type === 'supplier_invoice' ? Boolean(data.isReverseCharge) : undefined
+
+  return { type, confidence, reasoning, isReverseCharge }
+}
+
+function validateReceiptExtraction(raw: unknown): ReceiptExtractionResult {
+  if (!raw || typeof raw !== 'object') {
+    throw new Error('Invalid receipt extraction: not an object')
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const data = raw as any
+
+  const merchant = data.merchant || {}
+  const receipt = data.receipt || {}
+  const totals = data.totals || {}
+  const flags = data.flags || {}
+
+  return {
+    merchant: {
+      name: validateString(merchant.name),
+      orgNumber: validateOrgNumber(merchant.orgNumber),
+      vatNumber: validateVatNumber(merchant.vatNumber),
+      isForeign: Boolean(flags.isForeignMerchant || merchant.isForeign),
+    },
+    receipt: {
+      date: validateDate(receipt.date),
+      time: validateTime(receipt.time),
+      currency: validateString(receipt.currency) || 'SEK',
+    },
+    lineItems: validateReceiptLineItems(data.lineItems),
+    totals: {
+      subtotal: validateNumber(totals.subtotal),
+      vatAmount: validateNumber(totals.vatAmount),
+      total: validateNumber(totals.total),
+    },
+    flags: {
+      isRestaurant: Boolean(flags.isRestaurant),
+      isSystembolaget: Boolean(flags.isSystembolaget),
+      isForeignMerchant: Boolean(flags.isForeignMerchant || merchant.isForeign),
+    },
+    confidence: validateNumber(data.confidence) || 0.5,
+    suggestedTemplateId: validateString(data.suggestedTemplateId) || undefined,
+  }
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+function validateReceiptLineItems(data: any): ReceiptExtractionResult['lineItems'] {
+  if (!Array.isArray(data)) return []
+
+  return data
+    .filter((item: unknown) => item && typeof item === 'object')
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    .map((item: any) => ({
+      description: String(item.description || '').trim(),
+      quantity: validateNumber(item.quantity) || 1,
+      unitPrice: validateNumber(item.unitPrice),
+      lineTotal: validateNumber(item.lineTotal) || 0,
+      vatRate: validateNumber(item.vatRate),
+      suggestedCategory: validateString(item.suggestedCategory),
+      suggestedTemplateId: validateString(item.suggestedTemplateId) || undefined,
+      confidence: validateNumber(item.confidence) || undefined,
+    }))
+    .filter((item: { lineTotal: number; description: string }) => item.lineTotal > 0 || item.description.length > 0)
+}
+
+function validateInvoiceExtraction(raw: unknown): InvoiceExtractionResult {
+  if (!raw || typeof raw !== 'object') {
+    throw new Error('Invalid invoice extraction: not an object')
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const data = raw as any
+
+  const supplier = data.supplier || {}
+  const invoice = data.invoice || {}
+  const totals = data.totals || {}
+
+  return {
+    supplier: {
+      name: validateString(supplier.name),
+      orgNumber: validateOrgNumber(supplier.orgNumber),
+      vatNumber: validateVatNumber(supplier.vatNumber),
+      address: validateString(supplier.address),
+      bankgiro: validateString(supplier.bankgiro),
+      plusgiro: validateString(supplier.plusgiro),
+    },
+    invoice: {
+      invoiceNumber: validateString(invoice.invoiceNumber),
+      invoiceDate: validateDate(invoice.invoiceDate),
+      dueDate: validateDate(invoice.dueDate),
+      paymentReference: validateString(invoice.paymentReference),
+      currency: validateString(invoice.currency) || 'SEK',
+    },
+    lineItems: validateInvoiceLineItems(data.lineItems),
+    totals: {
+      subtotal: validateNumber(totals.subtotal),
+      vatAmount: validateNumber(totals.vatAmount),
+      total: validateNumber(totals.total),
+    },
+    vatBreakdown: validateVatBreakdown(data.vatBreakdown),
+    confidence: validateNumber(data.confidence) || 0.5,
+    suggestedTemplateId: validateString(data.suggestedTemplateId) || undefined,
+  }
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+function validateInvoiceLineItems(data: any): ExtractedInvoiceLineItem[] {
+  if (!Array.isArray(data)) return []
+
+  return data
+    .filter((item: unknown) => item && typeof item === 'object')
+    .map((item: Record<string, unknown>) => ({
+      description: String(item.description || '').trim(),
+      quantity: validateNumber(item.quantity) || 1,
+      unitPrice: validateNumber(item.unitPrice),
+      lineTotal: validateNumber(item.lineTotal) || 0,
+      vatRate: validateNumber(item.vatRate),
+      accountSuggestion: validateAccountNumber(item.accountSuggestion as string | undefined),
+      suggestedTemplateId: validateString(item.suggestedTemplateId as string | undefined) || undefined,
+    }))
+    .filter((item: ExtractedInvoiceLineItem) => item.lineTotal > 0 || item.description.length > 0)
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+function validateVatBreakdown(data: any): VatBreakdownItem[] {
+  if (!Array.isArray(data)) return []
+
+  return data
+    .filter((item: unknown) => item && typeof item === 'object')
+    .map((item: Record<string, unknown>) => ({
+      rate: validateNumber(item.rate) || 0,
+      base: validateNumber(item.base) || 0,
+      amount: validateNumber(item.amount) || 0,
+    }))
+    .filter((item: VatBreakdownItem) => item.amount > 0 || item.base > 0)
+}
+
+// ============================================================
+// Consistency Validation
+// ============================================================
+
+/**
+ * Post-extraction validation that catches AI hallucinations.
+ */
+export function validateExtractionConsistency(
+  extraction: ReceiptExtractionResult | InvoiceExtractionResult,
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  _type: 'receipt' | 'invoice'
+): ConsistencyResult {
+  const issues: string[] = []
+
+  const total = extraction.totals.total
+  const lineItems = extraction.lineItems
+
+  // Check: total > 0
+  if (total !== null && total <= 0) {
+    issues.push(`Total is ${total} — expected positive value`)
+  }
+
+  // Check: line item totals sum to receipt/invoice total (±1 SEK tolerance)
+  if (total !== null && lineItems.length > 0) {
+    const lineSum = lineItems.reduce((sum, item) => sum + item.lineTotal, 0)
+    const diff = Math.abs(lineSum - total)
+    if (diff > 1) {
+      issues.push(`Line items sum to ${lineSum} but total is ${total} (diff: ${diff})`)
+    }
+  }
+
+  // Check: VAT rates are valid (0, 6, 12, 25)
+  for (const item of lineItems) {
+    if (item.vatRate !== null && !VALID_VAT_RATES.includes(item.vatRate)) {
+      issues.push(`Invalid VAT rate ${item.vatRate} on "${item.description}"`)
+    }
+  }
+
+  // Check: descriptions aren't empty
+  for (const item of lineItems) {
+    if (!item.description || item.description.trim().length === 0) {
+      issues.push('Line item has empty description')
+    }
+  }
+
+  return {
+    valid: issues.length === 0,
+    issues,
+  }
+}
+
+// ============================================================
+// Public API
+// ============================================================
+
+/**
+ * Unified document analysis: classifies AND extracts in a single Claude call.
+ * Falls back to dedicated extraction if misclassification detected.
+ */
+export async function analyzeDocument(
+  base64: string,
+  mimeType: string
+): Promise<UnifiedExtractionResult> {
+  const raw = await callVision({
+    base64,
+    mimeType,
+    systemPrompt: `${CLASSIFY_SYSTEM_PROMPT}\n\n${RECEIPT_SYSTEM_PROMPT}\n\n${INVOICE_SYSTEM_PROMPT}`,
+    userPrompt: buildUnifiedUserPrompt(),
+    maxTokens: 4096,
+  })
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const data = raw as any
+
+  const classification = validateClassification(data.classification || data)
+
+  const result: UnifiedExtractionResult = { classification }
+
+  if (classification.type === 'receipt') {
+    if (data.receipt) {
+      result.receipt = validateReceiptExtraction(data.receipt)
+      const consistency = validateExtractionConsistency(result.receipt, 'receipt')
+      if (!consistency.valid && result.receipt.confidence > 0.5) {
+        // Retry with dedicated extraction
+        try {
+          result.receipt = await extractReceipt(base64, mimeType)
+        } catch {
+          // Keep original with reduced confidence
+          result.receipt = { ...result.receipt, confidence: result.receipt.confidence * 0.7 }
+        }
+      }
+    } else {
+      // Misclassification fallback: type says receipt but no receipt data
+      try {
+        result.receipt = await extractReceipt(base64, mimeType)
+      } catch {
+        // Classification only — no extraction available
+      }
+    }
+  } else if (classification.type === 'supplier_invoice') {
+    if (data.invoice) {
+      result.invoice = validateInvoiceExtraction(data.invoice)
+      const consistency = validateExtractionConsistency(result.invoice, 'invoice')
+      if (!consistency.valid && result.invoice.confidence > 0.5) {
+        try {
+          result.invoice = await extractInvoice(base64, mimeType)
+        } catch {
+          result.invoice = { ...result.invoice, confidence: result.invoice.confidence * 0.7 }
+        }
+      }
+    } else {
+      try {
+        result.invoice = await extractInvoice(base64, mimeType)
+      } catch {
+        // Classification only
+      }
+    }
+  }
+
+  return result
+}
+
+/**
+ * Standalone receipt extraction.
+ * For use when caller already knows it's a receipt.
+ */
+export async function extractReceipt(
+  base64: string,
+  mimeType: string
+): Promise<ReceiptExtractionResult> {
+  const raw = await callVision({
+    base64,
+    mimeType,
+    systemPrompt: RECEIPT_SYSTEM_PROMPT,
+    userPrompt: buildReceiptUserPrompt(),
+    maxTokens: 4096,
+  })
+
+  const result = validateReceiptExtraction(raw)
+
+  const consistency = validateExtractionConsistency(result, 'receipt')
+  if (!consistency.valid && result.confidence > 0.5) {
+    // Retry with correction prompt
+    try {
+      const correctionPrompt = `Föregående extraheringen hade dessa problem: ${consistency.issues.join('; ')}. Var god extrahera igen med korrigeringar.\n\n${buildReceiptUserPrompt()}`
+      const retryRaw = await callVision({
+        base64,
+        mimeType,
+        systemPrompt: RECEIPT_SYSTEM_PROMPT,
+        userPrompt: correctionPrompt,
+        maxTokens: 4096,
+      })
+      return validateReceiptExtraction(retryRaw)
+    } catch {
+      // Return original with reduced confidence
+      return { ...result, confidence: result.confidence * 0.7 }
+    }
+  }
+
+  return result
+}
+
+/**
+ * Standalone invoice extraction.
+ * For use when caller already knows it's an invoice.
+ */
+export async function extractInvoice(
+  base64: string,
+  mimeType: string
+): Promise<InvoiceExtractionResult> {
+  const raw = await callVision({
+    base64,
+    mimeType,
+    systemPrompt: INVOICE_SYSTEM_PROMPT,
+    userPrompt: buildInvoiceUserPrompt(),
+    maxTokens: 4096,
+  })
+
+  const result = validateInvoiceExtraction(raw)
+
+  const consistency = validateExtractionConsistency(result, 'invoice')
+  if (!consistency.valid && result.confidence > 0.5) {
+    try {
+      const correctionPrompt = `Föregående extraheringen hade dessa problem: ${consistency.issues.join('; ')}. Var god extrahera igen med korrigeringar.\n\n${buildInvoiceUserPrompt()}`
+      const retryRaw = await callVision({
+        base64,
+        mimeType,
+        systemPrompt: INVOICE_SYSTEM_PROMPT,
+        userPrompt: correctionPrompt,
+        maxTokens: 4096,
+      })
+      return validateInvoiceExtraction(retryRaw)
+    } catch {
+      return { ...result, confidence: result.confidence * 0.7 }
+    }
+  }
+
+  return result
+}
+
+/**
+ * Lightweight classify-only (no extraction).
+ * Kept for backward compatibility.
+ */
+export async function classifyDocument(
+  base64: string,
+  mimeType: string
+): Promise<DocumentClassification> {
+  const userPrompt = `Klassificera detta dokument. Returnera ENDAST ett JSON-objekt:
+
+{
+  "type": "supplier_invoice" | "receipt" | "government_letter" | "unknown",
+  "confidence": 0.95,
+  "reasoning": "Kort förklaring",
+  "isReverseCharge": false
+}
+
+Returnera ENDAST JSON-objektet, ingen annan text.`
+
+  const raw = await callVision({
+    base64,
+    mimeType,
+    systemPrompt: CLASSIFY_SYSTEM_PROMPT,
+    userPrompt,
+    maxTokens: 1024,
+  })
+
+  return validateClassification(raw)
+}