const U200D = String.fromCharCode(8205)
const UFE0Fg = /\uFE0F/g

export function getIconCode(char: string) {
  return toCodePoint(char.indexOf(U200D) < 0 ? char.replace(UFE0Fg, "") : char)
}

function toCodePoint(unicodeSurrogates: string) {
  const r = []
  let c = 0,
    p = 0,
    i = 0

  while (i < unicodeSurrogates.length) {
    c = unicodeSurrogates.charCodeAt(i++)
    if (p) {
      r.push((65536 + ((p - 55296) << 10) + (c - 56320)).toString(16))
      p = 0
    } else if (55296 <= c && c <= 56319) {
      p = c
    } else {
      r.push(c.toString(16))
    }
  }
  return r.join("-")
}

const twemoji = (code: string) =>
  `https://cdnjs.cloudflare.com/ajax/libs/twemoji/15.1.0/svg/${code.toLowerCase()}.svg`
const emojiCache: Record<string, Promise<any>> = {}

export function loadEmoji(code: string) {
  const type = "twemoji"
  const key = type + ":" + code
  if (key in emojiCache) return emojiCache[key]

  return (emojiCache[key] = fetch(twemoji(code)).then((r) => r.text()))
}