/**
 * This file originates from https://github.com/ProseMirror/prosemirror-menu
 * and is hence subject to the MIT license found here:
 * https://github.com/ProseMirror/prosemirror-menu/blob/master/LICENSE
 * @copyright Marijn Haverbeke and others
 */

const SVG = "http://www.w3.org/2000/svg"
const XLINK = "http://www.w3.org/1999/xlink"

const prefix = "ProseMirror-icon"

function hashPath(path) {
  let hash = 0
  for (let i = 0; i < path.length; i++)
    hash = (((hash << 5) - hash) + path.charCodeAt(i)) | 0
  return hash
}

export function getIcon(icon) {
  let node = document.createElement("div")
  node.className = prefix
  if (icon.path) {
    let name = "pm-icon-" + hashPath(icon.path).toString(16)
    if (!document.getElementById(name)) buildSVG(name, icon)
    let svg = node.appendChild(document.createElementNS(SVG, "svg"))
    svg.style.width = (icon.width / icon.height) + "em"
    let use = svg.appendChild(document.createElementNS(SVG, "use"))
    use.setAttributeNS(XLINK, "href", /([^#]*)/.exec(document.location)[1] + "#" + name)
  } else if (icon.dom) {
    node.appendChild(icon.dom.cloneNode(true))
  } else {
    node.appendChild(document.createElement("span")).textContent = icon.text || ''
    if (icon.css) node.firstChild.style.cssText = icon.css
  }
  return node
}

function buildSVG(name, data) {
  let collection = document.getElementById(prefix + "-collection")
  if (!collection) {
    collection = document.createElementNS(SVG, "svg")
    collection.id = prefix + "-collection"
    collection.style.display = "none"
    document.body.insertBefore(collection, document.body.firstChild)
  }
  let sym = document.createElementNS(SVG, "symbol")
  sym.id = name
  sym.setAttribute("viewBox", "0 0 " + data.width + " " + data.height)
  let path = sym.appendChild(document.createElementNS(SVG, "path"))
  path.setAttribute("d", data.path)
  collection.appendChild(sym)
}