rewrite ratelimiting and api route builder (#1667)

* rewrite ratelimiting and api route builder

* more stuff

* let people pass their own handlers

* Update burst.js

* Update RequestHandler.js

* Update burst.js

* Update sequential.js

* Update RequestHandler.js

src/client/rest/APIRouter.js

@@ -1,32 +1,34 @@
 const util = require('util');
 
+const noop = () => {}; // eslint-disable-line no-empty-function
 const methods = ['get', 'post', 'delete', 'patch', 'put'];
 const reflectors = [
   'toString', 'valueOf', 'inspect', 'constructor',
   Symbol.toPrimitive, util.inspect.custom,
 ];
 
-module.exports = restManager => {
+function buildRoute(manager) {
+  const route = [''];
   const handler = {
-    get(list, name) {
-      if (name === 'opts') {
-        function toReturn(...args) { // eslint-disable-line no-inner-declarations
-          list.push(...args.filter(x => x !== null && typeof x !== 'undefined'));
-          return new Proxy(list, handler);
-        }
-        const directJoin = () => `${list.join('/')}/${name}`;
-        for (const r of reflectors) toReturn[r] = directJoin;
-        for (const method of methods) {
-          toReturn[method] = options => restManager.request(method, directJoin(), options);
-        }
-        return toReturn;
+    get(target, name) {
+      if (reflectors.includes(name)) return () => route.join('/');
+      if (methods.includes(name)) {
+        return options => manager.request(name, route.join('/'), Object.assign({
+          route: route.map((r, i) => {
+            if (/\d{16,19}/g.test(r)) return /channels|guilds/.test(route[i - 1]) ? r : ':id';
+            return r;
+          }).join('/'),
+        }, options));
       }
-      if (reflectors.includes(name)) return () => list.join('/');
-      if (methods.includes(name)) return options => restManager.request(name, list.join('/'), options);
-      list.push(name);
-      return new Proxy(list, handler);
+      route.push(name);
+      return new Proxy(noop, handler);
+    },
+    apply(target, _, args) {
+      route.push(...args.filter(x => x != null)); // eslint-disable-line eqeqeq
+      return new Proxy(noop, handler);
     },
   };
+  return new Proxy(noop, handler);
+}
 
-  return new Proxy([''], handler);
-};
+module.exports = buildRoute;