suspend fun loginTsinghua(username: String, password: String): String {
    //login
    val LEARN_PREFIX = "https://learn2018.tsinghua.edu.cn";
    baseList.clear()
    detailList.clear()
    val course = ArrayList<String>()
    var cookies: Map<String, String>?
    val ticket = Jsoup.connect("https://id.tsinghua.edu.cn/do/off/ui/auth/login/post/bb5df85216504820be7bba2b0ae1535b/0?/login.do")
            .data("i_user", username).data("i_pass", password).data("atOnce", true.toString())
            .timeout(10000).post()
            .body().select("a").attr("href").split('=').last()
    val loginResponse = Jsoup.connect("$LEARN_PREFIX/b/j_spring_security_thauth_roaming_entry?ticket=$ticket")
            .execute().let {
              cookies = it.cookies()
              it.statusCode() in 200..299
            }
    if (!loginResponse) throw Exception("Incorrect username or password.")
    //getSemesterIdList
    val semesterIdArray = JSONArray(Jsoup.connect("$LEARN_PREFIX/b/wlxt/kc/v_wlkc_xs_xktjb_coassb/queryxnxq")
            .cookies(cookies).execute().body()).let {
      Array<String>(it.length()) { i: Int -> it.getString(i) }
    }
    //getCurrentSemester
    var currentSemester = JSONObject(Jsoup.connect("$LEARN_PREFIX/b/kc/zhjw_v_code_xnxq/getCurrentAndNextSemester")
            .cookies(cookies).execute().body())
            .getJSONObject("result").getString("id")
    if (currentSemester.split("-").last() == "3" && semesterIdArray.indexOf(currentSemester) > 0)
      currentSemester = semesterIdArray[semesterIdArray.indexOf(currentSemester) - 1]
    //getCourseList
    val courseList = JSONObject(Jsoup.connect("$LEARN_PREFIX/b/wlxt/kc/v_wlkc_xs_xkb_kcb_extend/student/loadCourseBySemesterId/$currentSemester")
            .cookies(cookies).execute().body())
            .getJSONArray("resultList")
    val courseDetailList = Array<Array<String>>(courseList.length()) { i ->
      JSONArray(Jsoup.connect("$LEARN_PREFIX/b/kc/v_wlkc_xk_sjddb/detail?id=${courseList.getJSONObject(i).getString("wlkcid")}")
              .cookies(cookies).execute().body()).let {
        Array(it.length()) { idx ->
          it.getString(idx)
        }
      }
    }
    for (i in 0 until courseList.length()) {
      baseList.add(CourseBaseBean(i,
              courseName = courseList.getJSONObject(i).getString("kcm"),
              color = "#${Integer.toHexString(ViewUtils.getCustomizedColor(getApplication(), i % 9))}",
              tableId = importId
      ))
      for (j in 0 until courseDetailList[i].size) {
        val matcher = Pattern.compile("星期([一二三四五六七日])第([1-6])节\\((.*?)\\)，(.*)")
                .matcher(courseDetailList[i][j])
        if (matcher.find()) {
          val matchRs = matcher.toMatchResult()

          detailList.add(CourseDetailBean(i,
                  day = "一二三四五六七日".indexOf(matchRs.group(1)) + 1,
                  room = matchRs.group(4),
                  teacher = courseList.getJSONObject(i).getString("jsm"),
                  tableId = importId,
                  startNode = when (matchRs.group(2).toInt()) {
                    1 -> 1; 2 -> 3;3 -> 6;4 -> 8;5 -> 10;6 -> 12
                    else -> 0
                  },
                  step = when (matchRs.group(2).toInt()) {
                    2, 6 -> 3
                    else -> 2
                  },
                  startWeek = if (matchRs.group(3).contains("后")) 9 else 1,
                  endWeek = if (matchRs.group(3).contains("前")) 8 else 16,
                  type = 0
          ))
        }
      }
    }
    return write2DB()
  }

val split = source.split(" ".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()