;; This Source Code Form is subject to the terms of the Mozilla Public
;; License, v. 2.0. If a copy of the MPL was not distributed with this
;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
;;
;; Copyright (c) KALEIDOS INC

(ns app.util.text.content.from-dom
  (:require
   [app.common.data :as d]
   [app.common.types.text :as txt]
   [app.util.dom :as dom]
   [app.util.text.content.styles :as styles]))

(defn is-text-node
  [node]
  (= (.-nodeType node) js/Node.TEXT_NODE))

(defn is-element
  [node tag]
  (and (= (.-nodeType node) js/Node.ELEMENT_NODE)
       (= (.-nodeName node) (.toUpperCase tag))))

(defn is-line-break
  [node]
  (is-element node "br"))

(defn is-text-span-child
  [node]
  (or (is-line-break node)
      (is-text-node node)))

(defn get-text-span-text
  [element]
  (when-not (is-text-span-child (.-firstChild element))
    (throw (js/TypeError. "Invalid text span child")))
  (if (is-line-break (.-firstChild element))
    ""
    (.-textContent element)))

(defn get-attrs-from-styles
  [element attrs defaults]
  (let [attrs (or attrs [])
        value-empty? (fn [v]
                       (or (nil? v)
                           (and (string? v) (empty? v))
                           (and (coll? v) (empty? v))))]
    (reduce (fn [acc key]
              (let [style (.-style element)
                    value (if (contains? styles/mapping key)
                            (let [style-name (styles/get-style-name-as-css-variable key)
                                  [_ style-decode] (get styles/mapping key)]
                              (style-decode (.getPropertyValue style style-name)))
                            (let [style-name (styles/get-style-name key)]
                              (styles/normalize-attr-value key (.getPropertyValue style style-name))))]
                (assoc acc key (if (value-empty? value) (get defaults key) value))))
            {} attrs)))

(defn get-text-span-styles
  [element]
  (get-attrs-from-styles element txt/text-node-attrs (txt/get-default-text-attrs)))

(defn get-paragraph-styles
  [element]
  (let [styles (get-attrs-from-styles element
                                      (d/concat-set txt/paragraph-attrs txt/text-node-attrs)
                                      (d/merge txt/default-paragraph-attrs txt/default-text-attrs))
        ;; Recover real font-size from data attribute, which to_dom/get-paragraph-styles may have
        ;; changed to "0" ("0" trick to avoid it interfering with height calculation in the browser).
        saved-font-size (dom/get-data element "saved-font-size")]
    (cond-> styles
      (some? saved-font-size)
      (assoc :font-size saved-font-size))))

(defn get-root-styles
  [element]
  (get-attrs-from-styles element txt/root-attrs txt/default-root-attrs))

(defn create-text-span
  [element]
  (let [text (get-text-span-text element)]
    (d/merge {:text text
              :key (.-id element)}
             (get-text-span-styles element))))

(defn create-paragraph
  [element]
  (d/merge {:type "paragraph"
            :key (.-id element)
            :children (mapv create-text-span (.-children element))}
           (get-paragraph-styles element)))

(defn create-root
  [element]
  (let [root-styles (get-root-styles element)]
    (d/merge {:type "root"
              :key (.-id element)
              :children [{:type "paragraph-set"
                          :children (mapv create-paragraph (.-children element))}]}
             root-styles)))