(require '[schema.core :as s])
(require '[schema.coerce :as coerce])
(require '[schema.utils :as utils])

(defn filter-schema-keys
  [m schema-keys extra-keys-walker]
  (reduce-kv (fn [m k v]
               (if (or (contains? schema-keys k)
                       (and extra-keys-walker
                            (not (utils/error? (extra-keys-walker k)))))
                 m
                 (dissoc m k)))
             m
             m))

(defn map-filter-matcher
  [s]
  (when (or (instance? clojure.lang.PersistentArrayMap s)
            (instance? clojure.lang.PersistentHashMap s))
    (let [extra-keys-schema (#'s/find-extra-keys-schema s)
          extra-keys-walker (when extra-keys-schema (s/walker extra-keys-schema))
          explicit-keys (some->> (dissoc s extra-keys-schema)
                                 keys
                                 (mapv s/explicit-schema-key)
                                 (into #{}))]
      (when (or extra-keys-walker (seq explicit-keys))
        (fn [x]
          (if (map? x)
            (filter-schema-keys x explicit-keys extra-keys-walker)
            x))))))