(ns dom.core
  (:require [clojure.string :as str]
            [clojure.set :refer [difference union]]))

; sample usage:
; (-> (all ".class") (hide) (+css "titi") (clear) (html "<span>zob</span>") (show))


(defn- nodelist-coll [nodelist]
 (doall (map #(.item nodelist %) (range (.-length nodelist)))))

(defn- coll! [item]
  (cond
    (coll? item) item
    (nil? item) [] 
    [item]))

(defn +css 
  "add classname(s) to given nodes"
  [nodes css]
  (let [cnodes (coll! nodes)
        +cn (set (str/split css #"\s+"))]
    (doseq [n cnodes]
      (let [c (union (set (str/split (.-className n) #"\s+")) +cn)]
        (set! (.-className n) (str/join " " c))))
    nodes))

(defn -css 
  "remove classname(s) of given nodes"
  [nodes css]
  (let [cnodes (coll! nodes)
        -cn (set (str/split css #"\s+"))]
    (doseq [n cnodes]
      (let [c (difference (set (str/split (.-className n) #"\s+")) -cn)]
        (set! (.-className n) (str/join " " c))))
    nodes))

(defn hide 
  "hide the given nodes"
  [nodes]
  (doseq [n (coll! nodes)] 
    (set! (.-display (.-style n)) "none"))
  nodes)

(defn show
  "display the given nodes"
  [nodes]
  (doseq [n (coll! nodes)] 
    (set! (.-display (.-style n)) "block"))
  nodes)

(defn html 
  ([nodes html]
    "setup inner html of given nodes"
    (doseq [n (coll! nodes)] 
      (set! (.-innerHTML n) (or html "")))
    nodes)
  ([html]
    "create html element from an html string,
     returning generated nodes"
    (let [div (.createElement js/document "div")]
      (set! (.-innerHTML div) (or html ""))
      (nodelist-coll (.childNodes div)))))

(defn clear 
  "remove children of given nodes"
  [nodes]
  (html nodes ""))

(defn all 
  "return an HTMLElement collection matching the given selector"
  [selector]
  (let [nodelist (.querySelectorAll js/document selector)]
    (nodelist-coll nodelist)))

(defn one 
  "return the first HTMLElement matching the given selector"
  [selector]
  (first (all selector)))

(defn append-to
  "append nodes to the first match of given selector"
  [nodes selector]
  (let [dst-node (one selector)]
    (if (not (nil? dst-node))
      (doseq [n (coll! nodes)] 
        (.appendChild dst-node n)))
    nodes))