'use strict';

(function exposeWellFormedString(root, factory) {
  const api = factory();
  if (typeof module !== 'undefined' && module.exports) module.exports = api;
  if (root) root.AptWellFormedString = api;
}(typeof window !== 'undefined' ? window : undefined, function wellFormedStringFactory() {
  function manualToWellFormed(value) {
    let result = '';
    for (let index = 0; index < value.length; index += 1) {
      const codeUnit = value.charCodeAt(index);
      if (codeUnit >= 0xd800 && codeUnit <= 0xdbff) {
        const next = value.charCodeAt(index + 1);
        if (next >= 0xdc00 && next <= 0xdfff) {
          result += value[index] + value[index + 1];
          index += 1;
        } else {
          result += '\ufffd';
        }
      } else if (codeUnit >= 0xdc00 && codeUnit <= 0xdfff) {
        result += '\ufffd';
      } else {
        result += value[index];
      }
    }
    return result;
  }

  function toWellFormedString(value, fallback = '') {
    let string;
    try {
      string = String(value);
    } catch {
      string = String(fallback);
    }
    return typeof string.toWellFormed === 'function'
      ? string.toWellFormed()
      : manualToWellFormed(string);
  }

  return Object.freeze({ toWellFormedString });
}));