// This module's own rate-limit policy, built on core's plumbing.
//
// `ctx.middleware.rateLimit` is core's `makeLimiter` (MODULE_API.md §2.3, API
// 1.1.0): the module states the window, the cap and the message, and core
// supplies the `express-rate-limit` instance, its store and the logging that
// records a breach. That division is the point. The policy is the module's —
// only the module knows what its endpoints cost — but there is one limiter
// library in the process and one place a breach is written down. A module that
// resolved `express-rate-limit` for itself would get a second store, and a limit
// enforced by two independent counters is not the limit either of them states.
//
// Built lazily, for the reason `core.js` explains: `core.middleware` resolves
// `ctx`, so touching it at require time would run before `register()`. The
// routers ask for these while they are being built, which is inside
// `register()`, and the result is memoised so a limiter is created once and the
// counter is not reset by a second call.

const core = require('../core')

let limiters = null

function build() {
  if (limiters) return limiters
  limiters = {
    // The player-vendor market search. The first genuinely expensive PUBLIC
    // endpoint on the site: every call is a LIKE scan plus a COUNT over the
    // listings table, which on a large shard is the biggest table there is, and
    // it is anonymous by default. Generous for a human browsing shops (a typed
    // search is debounced to one request, and paging is a click), tight enough
    // that it cannot be used as a cheap way to load the database.
    //
    // This lived in core's `middleware/rateLimit.js` and is UO policy, so it
    // came here with the route it guards.
    marketLimiter: core.middleware.rateLimit({
      windowMs: 60 * 1000,
      max: 60,
      label: 'market',
      message: 'Too many searches. Please slow down.',
    }),
  }
  return limiters
}

module.exports = {
  get marketLimiter() { return build().marketLimiter },
}