// apps/hq/test/preview-route.test.ts
import { describe, it, expect, beforeAll, afterAll } from 'vitest'
import express from 'express'
import { openDb } from '../src/db'
import { seedIfEmpty } from '../src/seed'
import { createStaff } from '../src/auth'
import { createClient } from '../src/repos-clients'
import { createModule, setPrice } from '../src/repos-modules'
import { apiRouter } from '../src/api'

async function appWith() {
  const db = openDb(':memory:'); await seedIfEmpty(db) // company.state_code=32, GST18
  await createStaff(db, { email: 'owner@test.in', displayName: 'Owner', role: 'owner', password: 'owner-password' })
  const c = await createClient(db, 'u1', { name: 'Acme', code: 'ACME', stateCode: '32' })
  const kar = await createClient(db, 'u1', { name: 'BLR Co', code: 'BLR', stateCode: '29' })
  const m = await createModule(db, 'u1', { code: 'POS', name: 'POS Billing' })
  await setPrice(db, 'u1', { moduleId: m.id, kind: 'yearly', pricePaise: 10_000_00, effectiveFrom: '2026-04-01' })
  const noPrice = await createModule(db, 'u1', { code: 'ANALYTICS', name: 'Analytics' })
  const app = express(); app.use(express.json()); app.locals['db'] = db; app.use('/api', apiRouter(db))
  const server = app.listen(0)
  const base = `http://localhost:${(server.address() as { port: number }).port}/api`
  return { db, server, base, c, kar, m, noPrice }
}

describe('POST /documents/preview', () => {
  let ctx: Awaited<ReturnType<typeof appWith>>
  beforeAll(async () => { ctx = await appWith() })
  afterAll(() => ctx.server.close())
  const login = async () =>
    (await (await fetch(`${ctx.base}/auth/login`, { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ email: 'owner@test.in', password: 'owner-password' }) })).json() as any).token
  const preview = async (token: string | null, body: unknown) => {
    const res = await fetch(`${ctx.base}/documents/preview`, {
      method: 'POST', headers: { 'content-type': 'application/json', ...(token ? { authorization: `Bearer ${token}` } : {}) },
      body: JSON.stringify(body),
    })
    return { status: res.status, json: await res.json() as any }
  }
  const save = async (token: string, body: unknown) => {
    const res = await fetch(`${ctx.base}/documents`, {
      method: 'POST', headers: { 'content-type': 'application/json', authorization: `Bearer ${token}` }, body: JSON.stringify(body),
    })
    return { status: res.status, json: await res.json() as any }
  }

  it('requires auth', async () => {
    expect((await preview(null, { docType: 'QUOTATION', clientId: ctx.c.id, lines: [] })).status).toBe(401)
  })

  it('returns real letterhead HTML + server totals for a priced line', async () => {
    const token = await login()
    const out = await preview(token, { docType: 'INVOICE', clientId: ctx.c.id, lines: [{ moduleId: ctx.m.id, qty: 1, kind: 'yearly' }] })
    expect(out.status).toBe(200)
    expect(out.json.ok).toBe(true)
    expect(out.json.html).toContain('TAX INVOICE')
    expect(out.json.html).toContain('DRAFT')          // unsaved → docNo prints DRAFT
    expect(out.json.totals.payablePaise).toBe(11_800_00)
    expect(out.json.totals.cgstPaise).toBe(900_00)
    expect(out.json.warnings).toEqual([])
    // Persisted nothing:
    expect((await ctx.db.get(`SELECT COUNT(*) AS n FROM document`) as any).n).toBe(0)
    expect((await ctx.db.get(`SELECT COUNT(*) AS n FROM audit_log WHERE entity='document'`) as any).n).toBe(0)
  })

  it('shows the IGST split live for an out-of-state client', async () => {
    const token = await login()
    const out = await preview(token, { docType: 'INVOICE', clientId: ctx.kar.id, lines: [{ moduleId: ctx.m.id, qty: 1, kind: 'yearly' }] })
    expect(out.json.totals.igstPaise).toBe(1_800_00)
    expect(out.json.totals.cgstPaise).toBe(0)
  })

  it('PERMISSIVE preview vs STRICT save diverge on a price gap', async () => {
    const token = await login()
    const body = { docType: 'QUOTATION', clientId: ctx.c.id, lines: [{ moduleId: ctx.noPrice.id, qty: 1, kind: 'yearly' }] }
    const pv = await preview(token, body)
    expect(pv.status).toBe(200)
    expect(pv.json.totals.payablePaise).toBe(0)                 // forgiven at ₹0
    expect(pv.json.warnings.some((w: string) => /ANALYTICS/.test(w))).toBe(true)
    const sv = await save(token, body)
    expect(sv.status).toBe(400)                                 // save refuses
    expect(sv.json.error).toMatch(/No price for module ANALYTICS/)
  })

  it('previews with no client picked — placeholder letterhead, GST total still authoritative', async () => {
    const token = await login()
    const out = await preview(token, { docType: 'QUOTATION', clientId: '', lines: [{ moduleId: ctx.m.id, qty: 1, kind: 'yearly' }] })
    expect(out.status).toBe(200)
    expect(out.json.html).toContain('— pick a client —')
    expect(out.json.totals.payablePaise).toBe(11_800_00)       // 18% invariant
    expect(out.json.warnings.some((w: string) => /client/i.test(w))).toBe(true)
  })

  it('empty composer previews an empty table at ₹0', async () => {
    const token = await login()
    const out = await preview(token, { docType: 'QUOTATION', clientId: ctx.c.id, lines: [] })
    expect(out.status).toBe(200)
    expect(out.json.totals.payablePaise).toBe(0)
  })
})