(function (root, factory) {
  // 行政区划模块同时支持浏览器页面和 Node 单元测试。
  if (typeof module === 'object' && module.exports) {
    module.exports = factory(root);
    return;
  }

  root.RegionPages = factory(root);
  if (root.document) {
    root.document.addEventListener('DOMContentLoaded', function () {
      root.RegionPages.init();
    });
  }
})(typeof globalThis !== 'undefined' ? globalThis : window, function (root) {
  'use strict';

  var documentRef = root.document;

  function normalizeList(data) {
    // 行政区划接口使用通用 ListResult，兼容常见数组包裹字段。
    if (Array.isArray(data)) return data;
    if (!data || typeof data !== 'object') return [];
    if (Array.isArray(data.rows)) return data.rows;
    if (Array.isArray(data.records)) return data.records;
    if (Array.isArray(data.list)) return data.list;
    if (Array.isArray(data.data)) return data.data;
    return [];
  }

  function pick(item, keys, fallback) {
    var source = item || {};
    var index;
    var value;

    for (index = 0; index < keys.length; index += 1) {
      value = source[keys[index]];
      if (value !== undefined && value !== null && value !== '') return value;
    }

    return fallback || '';
  }

  function escapeHtml(value) {
    // 地区名称和编码进入 option 前统一转义。
    return String(value === undefined || value === null ? '' : value)
      .replace(/&/g, '&amp;')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;')
      .replace(/'/g, '&#39;');
  }

  function getRegionCode(item) {
    return pick(item, ['regionCode', 'code', 'value'], '');
  }

  function getRegionName(item) {
    return pick(item, ['regionName', 'name', 'label'], '未命名地区');
  }

  function buildRegionOption(item) {
    return '<option value="' + escapeHtml(getRegionCode(item)) + '">' + escapeHtml(getRegionName(item)) + '</option>';
  }

  function buildPathText(items) {
    return normalizeList(items).map(function (item) {
      return getRegionName(item);
    }).filter(Boolean).join(' / ');
  }

  function getFinalRegionCode(values) {
    var source = values || {};

    return source.districtCode || source.cityCode || source.provinceCode || '';
  }

  function trimOrUndefined(value) {
    var text = String(value === undefined || value === null ? '' : value).trim();

    return text || undefined;
  }

  function buildProfileRegionBody(values) {
    var source = values || {};

    return {
      provinceCode: trimOrUndefined(source.provinceCode),
      cityCode: trimOrUndefined(source.cityCode),
      districtCode: trimOrUndefined(source.districtCode)
    };
  }

  function getApi() {
    return root.GenealogyApi && root.GenealogyApi.defaultClient;
  }

  function query(selector, rootNode) {
    return (rootNode || documentRef).querySelector(selector);
  }

  function queryAll(selector, rootNode) {
    return Array.prototype.slice.call((rootNode || documentRef).querySelectorAll(selector));
  }

  function showMessage(message) {
    if (root.layui && root.layui.layer) {
      root.layui.layer.msg(message);
      return;
    }

    root.alert(message);
  }

  function getFormValues(form) {
    var values = {};

    queryAll('[name]', form).forEach(function (field) {
      values[field.name] = field.value;
    });

    return values;
  }

  function setOptions(select, items, placeholder) {
    var list = normalizeList(items);

    if (!select) return;
    select.innerHTML = '<option value="">' + escapeHtml(placeholder) + '</option>' + list.map(buildRegionOption).join('');
    select.disabled = false;
  }

  function resetSelect(select, placeholder) {
    if (!select) return;
    select.innerHTML = '<option value="">' + escapeHtml(placeholder) + '</option>';
    select.disabled = true;
  }

  function updateTargetCode(picker) {
    var values = {
      provinceCode: query('[data-region-level="province"]', picker).value,
      cityCode: query('[data-region-level="city"]', picker).value,
      districtCode: query('[data-region-level="district"]', picker).value
    };
    var target = query('[data-region-code]', picker);

    if (target) target.value = getFinalRegionCode(values);
  }

  async function loadChildrenInto(select, parentCode, placeholder) {
    var api = getApi();

    if (!api || !select) return;
    setOptions(select, await api.regionChildren(parentCode || '0'), placeholder);
  }

  async function initPicker(picker) {
    var province = query('[data-region-level="province"]', picker);
    var city = query('[data-region-level="city"]', picker);
    var district = query('[data-region-level="district"]', picker);

    resetSelect(city, '请选择市');
    resetSelect(district, '请选择区县');
    await loadChildrenInto(province, '0', '请选择省');

    province.addEventListener('change', async function () {
      resetSelect(city, '请选择市');
      resetSelect(district, '请选择区县');
      updateTargetCode(picker);
      if (province.value) await loadChildrenInto(city, province.value, '请选择市');
    });

    city.addEventListener('change', async function () {
      resetSelect(district, '请选择区县');
      updateTargetCode(picker);
      if (city.value) await loadChildrenInto(district, city.value, '请选择区县');
    });

    district.addEventListener('change', function () {
      updateTargetCode(picker);
    });
  }

  async function submitProfileRegion(form) {
    var api = getApi();
    var values = getFormValues(form);
    var body = buildProfileRegionBody(values);

    if (!api) return;
    if (!body.provinceCode) {
      showMessage('请选择省份');
      return;
    }

    try {
      await api.updateProfile(body);
      showMessage('地区资料已保存');
    } catch (error) {
      showMessage(error.message || '地区资料保存失败');
    }
  }

  function bindProfileForms() {
    queryAll('[data-region-profile-form]').forEach(function (form) {
      form.addEventListener('submit', function (event) {
        event.preventDefault();
        submitProfileRegion(form);
      });
    });
  }

  function init() {
    if (!documentRef) return;

    queryAll('[data-region-picker]').forEach(function (picker) {
      initPicker(picker);
    });
    bindProfileForms();
  }

  return {
    normalizeList: normalizeList,
    buildRegionOption: buildRegionOption,
    buildPathText: buildPathText,
    getFinalRegionCode: getFinalRegionCode,
    buildProfileRegionBody: buildProfileRegionBody,
    init: init
  };
});