(ns frontend.search.browser
  "Browser implementation of search protocol"
  (:require [cljs-bean.core :as bean]
            [frontend.search.db :as search-db :refer [indices]]
            [frontend.search.protocol :as protocol]
            [goog.object :as gobj]
            [promesa.core :as p]))

;; fuse.js

(defn search-blocks
  [repo q {:keys [limit page]
            :or {limit 20}}]
  (let [indice (or (get-in @indices [repo :blocks])
                   (search-db/make-blocks-indice! repo))
        result
        (if page
          (.search indice
                   (clj->js {:$and [{"page" page} {"content" q}]})
                   (clj->js {:limit limit}))
          (.search indice q (clj->js {:limit limit})))
        result (bean/->clj result)]
    (->>
     (map
       (fn [{:keys [item matches]}]
         (let [{:keys [content uuid page]} item]
           {:block/uuid uuid
            :block/content content
            :block/page page
            :search/matches matches}))
       result)
     (remove nil?))))

(defrecord Browser [repo]
  protocol/Engine
  (query [_this q option]
    (p/promise (search-blocks repo q option)))
  (rebuild-blocks-indice! [_this]
    (let [indice (search-db/make-blocks-indice! repo)]
      (p/promise indice)))
  (transact-blocks! [_this {:keys [blocks-to-remove-set
                                  blocks-to-add]}]
    (swap! search-db/indices update-in [repo :blocks]
           (fn [indice]
             (when indice
               (doseq [block-id blocks-to-remove-set]
                 (.remove indice
                          (fn [block]
                            (= block-id (gobj/get block "id")))))
               (when (seq blocks-to-add)
                 (doseq [block blocks-to-add]
                   (.add indice (bean/->js block)))))
             indice)))
  (transact-pages! [_this _data] nil) ;; Page index is not available with fuse.js until sufficient performance benchmarking
  (truncate-blocks! [_this]
    (swap! indices assoc-in [repo :blocks] nil))
  (remove-db! [_this]
    nil))