import { describe, it, expect } from 'vitest'
import {
  CANDIDATE_MIN_CONFIDENCE,
  scoreUnderlagCandidates,
} from '../underlag-candidates'
import type { InboxChannelContext, InvoiceExtractionResult } from '@/types'

function ctx(partial: Partial<InboxChannelContext>): InboxChannelContext {
  return { channel: 'whatsapp', ...partial }
}

function extraction(partial: {
  supplier?: string | null
  date?: string | null
  total?: number | null
  vat?: number | null
  currency?: string
}): InvoiceExtractionResult {
  return {
    supplier: {
      name: partial.supplier ?? null,
      orgNumber: null, vatNumber: null, address: null, bankgiro: null, plusgiro: null,
    },
    invoice: {
      invoiceNumber: null, invoiceDate: partial.date ?? null, dueDate: null,
      paymentReference: null, currency: partial.currency ?? 'SEK',
    },
    lineItems: [],
    totals: { subtotal: null, vatAmount: partial.vat ?? null, total: partial.total ?? null },
    vatBreakdown: [],
    confidence: 0.9,
  } as InvoiceExtractionResult
}

describe('scoreUnderlagCandidates', () => {
  const tx = {
    id: 'tx-1',
    date: '2026-05-12',
    description: 'ESPRESSO HOUSE 1234 STOCKHOLM',
    merchant_name: 'Espresso House',
    amount: -184,
    currency: 'SEK',
    amount_sek: null,
    exchange_rate: null,
  }

  it('surfaces an unmatched WhatsApp receipt that matches the transaction', () => {
    // The reported bug: this item is real, sitting in the inbox, and invisible
    // to every lookup because matched_transaction_id is NULL.
    const out = scoreUnderlagCandidates(tx, [
      {
        id: 'item-1',
        document_id: 'doc-1',
        extracted_data: extraction({
          supplier: 'Espresso House',
          date: '2026-05-12',
          total: 184,
        }),
        channel_context: ctx({
          representation: {
            participants: [{ name: 'Anna Berg', company: 'Volvo' }],
            purpose: 'kundmöte',
            event_date: null,
            raw_answer: 'jag och Anna',
            answered_at: '2026-05-12T13:00:00Z',
          },
        }),
      },
    ])

    expect(out).toHaveLength(1)
    expect(out[0].inbox_item_id).toBe('item-1')
    expect(out[0].confidence).toBeGreaterThanOrEqual(CANDIDATE_MIN_CONFIDENCE)
    // and it brings the captured answers along with it
    expect(out[0].channelContext?.representation?.purpose).toBe('kundmöte')
  })

  it('rejects a same-amount receipt from a different month', () => {
    const out = scoreUnderlagCandidates(tx, [
      {
        id: 'item-2',
        document_id: 'doc-2',
        extracted_data: extraction({ supplier: 'Okänd', date: '2026-01-02', total: 184 }),
        channel_context: null,
      },
    ])
    expect(out).toEqual([])
  })

  it('does not propose a receipt whose amount cannot be compared', () => {
    // 184 EUR is not 184 SEK, and with no stored rate the two are not
    // comparable at all. Without an amount signal the score would rest on date
    // + merchant alone and come back as a confident match, so an uncomparable
    // amount disqualifies the candidate outright. Same-merchant same-day is a
    // ranking hint for a human, not evidence of the same economic event.
    const out = scoreUnderlagCandidates(tx, [
      {
        id: 'item-3',
        document_id: 'doc-3',
        extracted_data: extraction({
          supplier: 'Espresso House',
          date: '2026-05-12',
          total: 184,
          currency: 'EUR',
        }),
        channel_context: null,
      },
    ])
    expect(out).toEqual([])
  })

  it('skips extractions with no usable signal', () => {
    const out = scoreUnderlagCandidates(tx, [
      {
        id: 'item-4',
        document_id: 'doc-4',
        extracted_data: extraction({ supplier: 'Espresso House' }),
        channel_context: null,
      },
    ])
    expect(out).toEqual([])
  })

  it('returns the strongest candidates first', () => {
    const out = scoreUnderlagCandidates(tx, [
      {
        id: 'weak',
        document_id: 'doc-w',
        extracted_data: extraction({ supplier: null, date: '2026-05-13', total: 184 }),
        channel_context: null,
      },
      {
        id: 'strong',
        document_id: 'doc-s',
        extracted_data: extraction({ supplier: 'Espresso House', date: '2026-05-12', total: 184 }),
        channel_context: null,
      },
    ])
    expect(out[0].inbox_item_id).toBe('strong')
  })

  it('returns nothing for a transaction with no date or amount', () => {
    expect(
      scoreUnderlagCandidates({ ...tx, date: null }, [
        {
          id: 'item-5',
          document_id: 'doc-5',
          extracted_data: extraction({ supplier: 'Espresso House', date: '2026-05-12', total: 184 }),
          channel_context: null,
        },
      ]),
    ).toEqual([])
  })
})