((root) => {
  function decodeKey(value) {
    try { return decodeURIComponent(value.replace(/\+/g, ' ')); }
    catch (_) { return value; }
  }

  function detectLinkType(link) {
    const pathname = new URL(link).pathname.toLowerCase();
    return /(?:^|\/)imp(?:\/|$)/.test(pathname) ? 'imp' : 'click';
  }

  function convertTrackingLink(originalLink, template) {
    const original = originalLink.trim();
    const parsed = new URL(original);
    if (!['http:', 'https:'].includes(parsed.protocol)) throw new Error('仅支持 HTTP 或 HTTPS 链接');
    if (!parsed.search) throw new Error('链接中没有可转换的查询参数');

    const type = detectLinkType(original);
    const linkTemplate = template.links[type];
    if (!linkTemplate) {
      const typeLabel = type === 'imp' ? 'Impression' : 'Click';
      throw new Error(`${template.name} 暂未配置 ${typeLabel} 宏模板`);
    }

    const hashIndex = original.indexOf('#');
    const hash = hashIndex >= 0 ? original.slice(hashIndex) : '';
    const withoutHash = hashIndex >= 0 ? original.slice(0, hashIndex) : original;
    const queryIndex = withoutHash.indexOf('?');
    const base = withoutHash.slice(0, queryIndex);
    const query = withoutHash.slice(queryIndex + 1);
    const replacements = { platform: template.platformCode, ...linkTemplate.mappings };
    const changes = [];
    let parameterCount = 0;

    const convertedSegments = query.split('&').map((segment) => {
      if (!segment) return segment;
      parameterCount += 1;
      const equalIndex = segment.indexOf('=');
      const rawKey = equalIndex >= 0 ? segment.slice(0, equalIndex) : segment;
      const rawValue = equalIndex >= 0 ? segment.slice(equalIndex + 1) : '';
      const key = decodeKey(rawKey);
      if (!Object.prototype.hasOwnProperty.call(replacements, key)) return segment;

      const replacement = String(replacements[key] ?? '');
      if (rawValue !== replacement) changes.push({ key, from: rawValue, to: replacement });
      return `${rawKey}=${replacement}`;
    });

    return {
      url: `${base}?${convertedSegments.join('&')}${hash}`,
      type,
      changes,
      parameterCount,
      preservedCount: parameterCount - changes.length
    };
  }

  root.TrackingLinkConverter = { detectLinkType, convertTrackingLink };
})(typeof window === 'undefined' ? globalThis : window);