import http from 'node:http'

/**
 * Stripe-Nachbau für Tests. stripe-node spricht ihn über config.stripe.apiBase (STRIPE_API_BASE)
 * an. Objekte werden vorab in die Maps gelegt; jeder Aufruf landet in calls als
 * { method, path, query, body } (Formular-Schlüssel flach, z. B. 'items[0][price]').
 */
export async function startFakeStripe() {
  const subscriptions = new Map()
  const prices = new Map()
  const invoices = new Map()
  const calls = []

  const flat = (params) => Object.fromEntries(params.entries())
  const noSuch = (what, id) => [404, { error: { type: 'invalid_request_error', code: 'resource_missing', message: `No such ${what}: '${id}'` } }]
  const listOf = (data) => ({ object: 'list', data, has_more: false, url: '/v1/list' })

  const readBody = (req) =>
    new Promise((resolve) => {
      let raw = ''
      req.on('data', (chunk) => (raw += chunk))
      req.on('end', () => resolve(new URLSearchParams(raw)))
    })

  const route = (method, path, query) => {
    let m
    if (method === 'GET' && (m = path.match(/^\/v1\/subscriptions\/([^/]+)$/))) {
      return subscriptions.has(m[1]) ? [200, subscriptions.get(m[1])] : noSuch('subscription', m[1])
    }
    if (method === 'GET' && (m = path.match(/^\/v1\/prices\/([^/]+)$/))) {
      return prices.has(m[1]) ? [200, prices.get(m[1])] : noSuch('price', m[1])
    }
    if (method === 'GET' && path === '/v1/prices') {
      const keys = [...query.entries()].filter(([k]) => /^lookup_keys\[\d*\]$/.test(k)).map(([, v]) => v)
      const active = query.get('active')
      const found = [...prices.values()].filter(
        (p) => (!keys.length || keys.includes(p.lookup_key)) && (active === null || String(p.active !== false) === active)
      )
      return [200, listOf(found)]
    }
    if (method === 'GET' && (m = path.match(/^\/v1\/invoices\/([^/]+)$/))) {
      return invoices.has(m[1]) ? [200, invoices.get(m[1])] : noSuch('invoice', m[1])
    }
    return [404, { error: { type: 'invalid_request_error', message: `No such route: ${method} ${path}` } }]
  }

  const server = http.createServer(async (req, res) => {
    const url = new URL(req.url, 'http://127.0.0.1')
    const body = await readBody(req)
    calls.push({ method: req.method, path: url.pathname, query: flat(url.searchParams), body: flat(body) })
    const [status, payload] = route(req.method, url.pathname, url.searchParams)
    res.writeHead(status, { 'Content-Type': 'application/json', 'Request-Id': `req_test_${calls.length}` })
    res.end(JSON.stringify(payload))
  })
  await new Promise((resolve) => server.listen(0, '127.0.0.1', resolve))

  return {
    url: `http://127.0.0.1:${server.address().port}`,
    calls,
    subscriptions,
    prices,
    invoices,
    close: () => new Promise((resolve) => server.close(resolve)),
  }
}