// A small node:http stand-in for the anonymous menu API (/_menu/api/v1),
// answering GET /menus/<code> from testing/fixtures/menus/<code>.json and
// 404 {"error":"Menu not found"} otherwise. It records every request so a
// smoke run can assert header forwarding.
//
// Plain .mjs with JSDoc types: Node does not strip TypeScript under
// node_modules, and consuming apps may import this file from there.

import { createServer } from 'node:http'
import { readFileSync } from 'node:fs'
import { join } from 'node:path'

const PREFIX = '/_menu/api/v1'

/**
 * @typedef {{ method: string, url: string, xff: string | null }} FixtureRequest
 * @typedef {{ url: string, requests: FixtureRequest[], close: () => Promise<void> }} FixtureApi
 */

/**
 * Starts the fixture API on 127.0.0.1.
 * @param {{ dir: string, port?: number }} opts
 * @returns {Promise<FixtureApi>}
 */
export function startFixtureApi({ dir, port = 0 }) {
  /** @type {FixtureRequest[]} */
  const requests = []

  /** @param {import('node:http').IncomingMessage} req */
  const route = (req) => {
    const url = new URL(req.url ?? '/', 'http://fixture.local')
    if (req.method !== 'GET' && req.method !== 'HEAD') return { status: 405, body: { error: 'Method not allowed' } }
    const m = /^\/menus\/([A-Za-z0-9_-]+)$/.exec(url.pathname.slice(PREFIX.length))
    if (!url.pathname.startsWith(PREFIX + '/') || !m) return { status: 404, body: { error: 'Menu not found' } }
    try {
      return { status: 200, body: JSON.parse(readFileSync(join(dir, 'menus', `${m[1]}.json`), 'utf8')) }
    } catch (err) {
      if (/** @type {any} */ (err).code === 'ENOENT') return { status: 404, body: { error: 'Menu not found' } }
      throw err
    }
  }

  const server = createServer((req, res) => {
    const xff = req.headers['x-forwarded-for']
    requests.push({ method: req.method ?? 'GET', url: req.url ?? '/', xff: Array.isArray(xff) ? xff.join(', ') : (xff ?? null) })
    let out
    try {
      out = route(req)
    } catch (err) {
      out = { status: 500, body: { error: String(err) } }
    }
    res.writeHead(out.status, { 'content-type': 'application/json' })
    res.end(req.method === 'HEAD' ? undefined : JSON.stringify(out.body))
  })

  return new Promise((resolve, reject) => {
    server.once('error', reject)
    server.listen(port, '127.0.0.1', () => {
      const addr = /** @type {import('node:net').AddressInfo} */ (server.address())
      resolve({
        url: `http://127.0.0.1:${addr.port}`,
        requests,
        close: () => new Promise((done) => server.close(() => done())),
      })
    })
  })
}