/* global wx, getCurrentPages */

const SUBSCRIBE_RESULT_STORAGE_KEY = 'genarrative:wechat-subscribe-result';

function appendSubscribeResult(url, result) {
  const hashIndex = String(url || '').indexOf('#');
  const baseUrl =
    hashIndex >= 0 ? String(url).slice(0, hashIndex) : String(url || '');
  const rawHash = hashIndex >= 0 ? String(url).slice(hashIndex + 1) : '';
  const nextHash = rawHash
    .split('&')
    .filter((part) => part && !part.startsWith('wx_subscribe_result='))
    .concat(`wx_subscribe_result=${encodeURIComponent(result)}`)
    .join('&');
  return `${baseUrl}#${nextHash}`;
}

function buildSubscribeResultValue(requestId, status, reason) {
  const segments = [requestId, status];
  if (reason) {
    segments.push(encodeURIComponent(reason));
  }
  return segments.join(':');
}

function notifyPreviousWebView(requestId, status, reason) {
  const result = buildSubscribeResultValue(requestId, status, reason);
  wx.setStorageSync(SUBSCRIBE_RESULT_STORAGE_KEY, result);
  const pages = getCurrentPages();
  const previousPage = pages.length >= 2 ? pages[pages.length - 2] : null;
  if (previousPage && typeof previousPage.setData === 'function') {
    previousPage.setData({
      webViewUrl: appendSubscribeResult(previousPage.data.webViewUrl, result),
    });
  }
}

function resolveSubscribeStatus(result, templateId) {
  return result && result[templateId] === 'accept'
    ? 'success'
    : 'skip';
}

function createSubscribeMessagePage(pageContext, options = {}) {
  const templateId = String(options.templateId || '').trim();
  const notifyPageResult = (methodThis, status, reason) => {
    const page = pageContext ?? methodThis;
    const requestId = page.requestId || '';
    if (!requestId || page.hasNotifiedSubscribeResult) {
      return;
    }
    page.hasNotifiedSubscribeResult = true;
    notifyPreviousWebView(requestId, status, reason);
  };

  return {
    data: {
      title: '接收生成结果通知',
      errorMessage: '',
      requesting: false,
    },

    onLoad(query) {
      const page = pageContext ?? this;
      page.requestId = String(query.requestId || '');
      page.hasNotifiedSubscribeResult = false;
    },

    notifyResult(status, reason) {
      notifyPageResult(this, status, reason);
    },

    requestSubscribe() {
      const page = pageContext ?? this;
      const requestId = page.requestId || '';
      if (!requestId) {
        page.setData({
          errorMessage: '缺少订阅请求参数。',
        });
        return;
      }
      if (!templateId) {
        notifyPageResult(this, 'skip', 'missing_template_id');
        wx.navigateBack();
        return;
      }
      if (typeof wx.requestSubscribeMessage !== 'function') {
        notifyPageResult(this, 'skip', 'unsupported');
        wx.navigateBack();
        return;
      }

      page.setData({
        requesting: true,
        errorMessage: '',
      });
      wx.requestSubscribeMessage({
        tmplIds: [templateId],
        success(result) {
          notifyPageResult(
            page,
            resolveSubscribeStatus(result, templateId),
            '',
          );
          wx.navigateBack();
        },
        fail(error) {
          notifyPageResult(
            page,
            'skip',
            error && error.errMsg ? error.errMsg : 'failed',
          );
          wx.navigateBack();
        },
      });
    },

    handleSkip() {
      notifyPageResult(this, 'skip', 'user_skip');
      wx.navigateBack();
    },

    onUnload() {
      notifyPageResult(this, 'skip', 'page_unload');
    },
  };
}

module.exports = {
  SUBSCRIBE_RESULT_STORAGE_KEY,
  appendSubscribeResult,
  buildSubscribeResultValue,
  createSubscribeMessagePage,
  resolveSubscribeStatus,
};