// https://github.com/google/closure-library/blob/e877b1eac410c0d842bcda118689759512e0e26f/closure/goog/crypt/crypt.js

//tslint:disable

/**
 * Converts a JS string to a UTF-8 "byte" array.
 * @param {string} str 16-bit unicode string.
 * @return {!Array<number>} UTF-8 byte array.
 */
export function stringToUtf8ByteArray(str: string): Uint8Array {
  // TODO(user): Use native implementations if/when available
  let out: any[] = [],
    p: number = 0;
  for (let i = 0; i < str.length; i++) {
    let c = str.charCodeAt(i);
    if (c < 128) {
      out[p++] = c;
    } else if (c < 2048) {
      out[p++] = (c >> 6) | 192;
      out[p++] = (c & 63) | 128;
    } else if (
      (c & 0xfc00) == 0xd800 &&
      i + 1 < str.length &&
      (str.charCodeAt(i + 1) & 0xfc00) == 0xdc00
    ) {
      // Surrogate Pair
      c = 0x10000 + ((c & 0x03ff) << 10) + (str.charCodeAt(++i) & 0x03ff);
      out[p++] = (c >> 18) | 240;
      out[p++] = ((c >> 12) & 63) | 128;
      out[p++] = ((c >> 6) & 63) | 128;
      out[p++] = (c & 63) | 128;
    } else {
      out[p++] = (c >> 12) | 224;
      out[p++] = ((c >> 6) & 63) | 128;
      out[p++] = (c & 63) | 128;
    }
  }
  return new Uint8Array(out);
}