/**
 * AKSRT Share Data Builder
 *
 * Single source of truth for share payloads. Every share surface
 * (dropdown links, copy, WeChat bridge, poster) resolves its data through
 * window.AksrtShareData so no script assembles title/url/cover/qrcode on its
 * own.
 *
 * Canonical payload shape:
 *   { title, url, desc, text, image, qrcode, author, date, siteName }
 *
 * Data is read from the nearest [data-share-*] context (falling back to
 * #share-dropdown), then to OpenGraph/meta tags and document defaults.
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  function metaContent(selectors) {
    for (var i = 0; i < selectors.length; i += 1) {
      var node = document.querySelector(selectors[i]);
      var content = node ? node.getAttribute('content') : '';
      if (content) return content;
    }
    return '';
  }

  function siteName() {
    return (
      metaContent(['meta[property="og:site_name"]']) ||
      (document.querySelector('.site-title, .logo-text, .site-nav__logo') || {}).textContent ||
      document.title ||
      ''
    ).trim();
  }

  /**
   * Find the element that carries the share data attributes for a node.
   */
  function context(node) {
    var source = node && typeof node.closest === 'function'
      ? node.closest('[data-share-url], [data-share-title], [data-share-desc], [data-share-image], [data-aksrt-poster]')
      : null;
    return source || document.getElementById('share-dropdown');
  }

  /**
   * Generate a QR data URL for a link, reusing the WeChat share encoder
   * when available. Returns '' if no encoder is loaded.
   */
  function qrcode(url) {
    if (window.AksrtShare && typeof window.AksrtShare.buildQrDataUrl === 'function' && url) {
      return window.AksrtShare.buildQrDataUrl(url, 200) || '';
    }
    return '';
  }

  /**
   * Resolve a canonical share payload for a triggering node.
   *
   * @param {Element} node Triggering element (button/link).
   * @param {Object}  [overrides] Optional explicit overrides.
   * @returns {Object}
   */
  function resolve(node, overrides) {
    var ctx = context(node);

    function attr(name) {
      return (node && node.getAttribute && node.getAttribute(name)) ||
        (ctx && ctx.getAttribute && ctx.getAttribute(name)) || '';
    }

    var url = attr('data-share-url') || window.location.href;
    var payload = {
      title: attr('data-share-title') || document.title,
      url: url,
      desc: attr('data-share-desc') || metaContent(['meta[property="og:description"]', 'meta[name="description"]']),
      text: attr('data-share-text') || '',
      image: attr('data-share-image') || metaContent(['meta[property="og:image"]']),
      qrcode: attr('data-share-qrcode') || '',
      author: attr('data-share-author') || '',
      date: attr('data-share-date') || '',
      siteName: attr('data-share-site') || siteName()
    };

    if (!payload.qrcode) {
      payload.qrcode = qrcode(payload.url);
    }

    if (overrides && typeof overrides === 'object') {
      Object.keys(overrides).forEach(function (key) {
        if (overrides[key] !== undefined && overrides[key] !== null && overrides[key] !== '') {
          payload[key] = overrides[key];
        }
      });
    }

    return payload;
  }

  window.AksrtShareData = {
    resolve: resolve,
    qrcode: qrcode,
    siteName: siteName
  };
})();