// apps/hq/test/due-dates.test.ts — go-live cluster WS-A: invoice due dates (D18)
import { describe, it, expect } from 'vitest'
import { openDb } from '../src/db'
import { seedIfEmpty } from '../src/seed'
import { createClient } from '../src/repos-clients'
import { assignModule, createModule, setPrice } from '../src/repos-modules'
import { createRecurringPlan } from '../src/repos-recurring'
import { convertDocument, createDraft, getDocument, issueDocument, listDocuments } from '../src/repos-documents'
import { getReminder, listReminders, setSetting, upsertReminder } from '../src/repos-reminders'
import { reminderContext } from '../src/send-reminder'
import { reminderEmail } from '../src/reminder-templates'
import { runDailyScan, type ScanDeps } from '../src/scheduler'

const deps: ScanDeps = {
  gmail: { f: (async () => new Response('{}')) as typeof fetch, clientId: '', clientSecret: '', keyHex: '' },
  renderPdf: async () => Buffer.from('%PDF-'), company: () => ({ 'company.name': 'Tecnostac' }),
  now: () => '2026-07-17T00:00:00Z',
}

function addDaysIso(iso: string, days: number): string {
  const d = new Date(`${iso}T00:00:00Z`)
  d.setUTCDate(d.getUTCDate() + days)
  return d.toISOString().slice(0, 10)
}

function world() {
  const db = openDb(':memory:'); seedIfEmpty(db) // seeds billing.payment_terms_days=15
  const c = createClient(db, 'u1', { name: 'Acme', stateCode: '32', contacts: [{ name: 'R', email: 'r@acme.in' }] })
  const m = createModule(db, 'u1', { code: 'POS', name: 'POS' })
  setPrice(db, 'u1', { moduleId: m.id, kind: 'yearly', pricePaise: 10_000_00, effectiveFrom: '2026-01-01' })
  const invoiceDraft = () => createDraft(db, 'u1', {
    docType: 'INVOICE', clientId: c.id, lines: [{ moduleId: m.id, qty: 1, kind: 'yearly' }],
  })
  return { db, c, m, invoiceDraft }
}

describe('due dates (D18)', () => {
  it('issue stamps doc_date + terms on an invoice without one (manual issue path)', () => {
    const { db, invoiceDraft } = world()
    const draft = invoiceDraft()
    expect(draft.dueDate).toBeNull()
    db.prepare(`UPDATE document SET doc_date='2026-07-01' WHERE id=?`).run(draft.id)
    const inv = issueDocument(db, 'u1', draft.id)
    expect(inv.dueDate).toBe('2026-07-16') // 2026-07-01 + 15
  })

  it('a caller-provided due date survives issue untouched', () => {
    const { db, c, m } = world()
    const draft = createDraft(db, 'u1', {
      docType: 'INVOICE', clientId: c.id, dueDate: '2026-09-30',
      lines: [{ moduleId: m.id, qty: 1, kind: 'yearly' }],
    })
    expect(draft.dueDate).toBe('2026-09-30')
    expect(issueDocument(db, 'u1', draft.id).dueDate).toBe('2026-09-30')
  })

  it('the terms setting is honoured when changed (dated behavior lives in the stamp)', () => {
    const { db, invoiceDraft } = world()
    setSetting(db, 'u1', 'billing.payment_terms_days', '30')
    const draft = invoiceDraft()
    db.prepare(`UPDATE document SET doc_date='2026-07-01' WHERE id=?`).run(draft.id)
    expect(issueDocument(db, 'u1', draft.id).dueDate).toBe('2026-07-31')
  })

  it('quotes and proformas never get a due date — at draft or at issue', () => {
    const { db, c, m } = world()
    expect(() => createDraft(db, 'u1', {
      docType: 'QUOTATION', clientId: c.id, dueDate: '2026-08-01',
      lines: [{ moduleId: m.id, qty: 1, kind: 'yearly' }],
    })).toThrow(/INVOICE/)
    const pi = createDraft(db, 'u1', {
      docType: 'PROFORMA', clientId: c.id, lines: [{ moduleId: m.id, qty: 1, kind: 'yearly' }],
    })
    expect(issueDocument(db, 'u1', pi.id).dueDate).toBeNull()
  })

  it('proforma → invoice conversion gets stamped at issue (convert-and-send path)', () => {
    const { db, c, m } = world()
    const pi = issueDocument(db, 'u1', createDraft(db, 'u1', {
      docType: 'PROFORMA', clientId: c.id, lines: [{ moduleId: m.id, qty: 1, kind: 'yearly' }],
    }).id)
    const invDraft = convertDocument(db, 'u1', pi.id, 'INVOICE')
    const inv = issueDocument(db, 'u1', invDraft.id)
    expect(inv.dueDate).not.toBeNull() // stamped from terms on the invoice's own doc_date
  })

  it('recurring generation stamps the due date on the invoice it issues (third issue path)', async () => {
    const { db, c, m } = world()
    setPrice(db, 'u1', { moduleId: m.id, kind: 'monthly', pricePaise: 2_000_00, effectiveFrom: '2026-01-01' })
    const cm = assignModule(db, 'u1', { clientId: c.id, moduleId: m.id, kind: 'monthly' })
    createRecurringPlan(db, 'u1', { clientId: c.id, clientModuleId: cm.id, cadence: 'monthly', nextRun: '2026-07-17', policy: 'manual' })
    await runDailyScan(db, deps, '2026-07-17')
    const [inv] = listDocuments(db, { clientId: c.id, type: 'INVOICE' }).documents
    expect(inv).toBeDefined()
    expect(inv!.dueDate).toBe(addDaysIso(inv!.docDate, 15)) // doc_date + seeded 15-day terms
  })

  it('bad dueDate format is rejected at draft', () => {
    const { db, c, m } = world()
    expect(() => createDraft(db, 'u1', {
      docType: 'INVOICE', clientId: c.id, dueDate: '17-07-2026',
      lines: [{ moduleId: m.id, qty: 1, kind: 'yearly' }],
    })).toThrow(/YYYY-MM-DD/)
  })

  it('overdue scan anchors on the due date: not yet due ⇒ silent, past due ⇒ milestone from due_date', async () => {
    const { db, invoiceDraft } = world()
    // Old issue date but due date in the future → NOT overdue.
    const a = issueDocument(db, 'u1', invoiceDraft().id)
    db.prepare(`UPDATE document SET doc_date='2026-05-01', due_date='2026-08-01' WHERE id=?`).run(a.id)
    // Due 16 days ago → d15 milestone (7/15/30 ladder), counted from due_date not doc_date.
    const b = issueDocument(db, 'u1', invoiceDraft().id)
    db.prepare(`UPDATE document SET doc_date='2026-05-01', due_date='2026-07-01' WHERE id=?`).run(b.id)
    await runDailyScan(db, deps, '2026-07-17')
    const rows = listReminders(db, {}).filter((r) => r.ruleKind === 'invoice_overdue')
    expect(rows).toHaveLength(1)
    expect(rows[0]).toMatchObject({ subjectId: b.id, duePeriod: 'd15' })
  })

  it('the reminder email says "was due on X and is now N day(s) overdue"', () => {
    const { db, c, invoiceDraft } = world()
    const inv = issueDocument(db, 'u1', invoiceDraft().id)
    db.prepare(`UPDATE document SET due_date='2026-07-02' WHERE id=?`).run(inv.id)
    const { id } = upsertReminder(db, { ruleKind: 'invoice_overdue', subjectId: inv.id, duePeriod: 'd15', clientId: c.id, docId: inv.id, now: '2026-07-17T00:00:00Z' })
    const { ctx } = reminderContext(db, getReminder(db, id)!, 'Tecnostac', '2026-07-17')
    expect(ctx.dueDate).toBe('2026-07-02')
    expect(ctx.daysOverdue).toBe(15)
    expect(reminderEmail('invoice_overdue', ctx).bodyText).toMatch(/was due on 2026-07-02 and is now 15 day\(s\) overdue/)
  })

  it('legacy invoices without a due date keep the past-due-since-issue wording and doc_date anchor', () => {
    const { db, c, invoiceDraft } = world()
    const inv = issueDocument(db, 'u1', invoiceDraft().id)
    db.prepare(`UPDATE document SET doc_date='2026-07-07', due_date=NULL WHERE id=?`).run(inv.id)
    const { id } = upsertReminder(db, { ruleKind: 'invoice_overdue', subjectId: inv.id, duePeriod: 'd7', clientId: c.id, docId: inv.id, now: '2026-07-17T00:00:00Z' })
    const { ctx } = reminderContext(db, getReminder(db, id)!, 'Tecnostac', '2026-07-17')
    expect(ctx.dueDate).toBeUndefined()
    expect(reminderEmail('invoice_overdue', ctx).bodyText).toMatch(/is outstanding and is now 10 day\(s\) past due/)
  })
})