// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// Copyright Mathias Bynens <https://mathiasbynens.be/>

// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:

// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

// Adapted from https://github.com/mathiasbynens/punycode.js

// TODO(cmorten): migrate punycode logic to "icu" internal binding and/or "url"
// internal module so there can be re-use within the "url" module etc.

"use strict";

/**
 * Creates an array containing the numeric code points of each Unicode
 * character in the string. While JavaScript uses UCS-2 internally,
 * this function will convert a pair of surrogate halves (each of which
 * UCS-2 exposes as separate characters) into a single code point,
 * matching UTF-16.
 *
 * @param str The Unicode input string (UCS-2).
 * @return The new array of code points.
 */
function ucs2decode(str: string) {
  const output = [];
  let counter = 0;
  const length = str.length;

  while (counter < length) {
    const value = str.charCodeAt(counter++);

    if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
      // It's a high surrogate, and there is a next character.
      const extra = str.charCodeAt(counter++);

      if ((extra & 0xFC00) == 0xDC00) { // Low surrogate.
        output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
      } else {
        // It's an unmatched surrogate; only append this code unit, in case the
        // next code unit is the high surrogate of a surrogate pair.
        output.push(value);
        counter--;
      }
    } else {
      output.push(value);
    }
  }

  return output;
}

/**
 * Creates a string based on an array of numeric code points.
 * @see `punycode.ucs2.decode`
 * @memberOf punycode.ucs2
 * @name encode
 * @param codePoints The array of numeric code points.
 * @returns The new Unicode string (UCS-2).
 */
function ucs2encode(array: number[]) {
  return String.fromCodePoint(...array);
}

export const ucs2 = {
  decode: ucs2decode,
  encode: ucs2encode,
};