ワークフローの最適化：代替休暇日の自動提案

/*
 * Questetra スクリプトタスク
 * 代替の取得可能休暇期間を提案
 *
 * 以下の両方に対応:
 * - 単日（1日のみ）の休暇申請
 * - 複数日の休暇申請
 *
 * Input:
 *   q_start_date
 *   q_end_date
 *
 * Output:
 *   q_suggested_dates  String / Text data item
 */
const CALENDAR_ID = "INSERT_YOUR_CALENDAR_ID";
const AUTH_SETTING_NAME = "INSERT_YOUR_AUTH_SETTING_NAME";
const THRESHOLD = 3;          // fewer than 3 events per day = available
const DAYS_BEFORE = 14;        // search up to 14 days before requested start date
const DAYS_AFTER = 30;         // search up to 30 days after requested start date
const MAX_SUGGESTIONS = 5;    // return up to 5 suggested periods
// 1) 日付の読み込み
const startDate = engine.findDataByVarName("q_start_date");
const endDate   = engine.findDataByVarName("q_end_date");
if (startDate === null || endDate === null) {
  throw new Error("q_start_date or q_end_date is empty.");
}
// 2) ヘルパー関数
function toJsDate(qDate) {
  return new Date(qDate.toString() + "T00:00:00+09:00");
}
function formatDate(date) {
  const y = date.getFullYear();
  const m = ("0" + (date.getMonth() + 1)).slice(-2);
  const d = ("0" + date.getDate()).slice(-2);
  return y + "-" + m + "-" + d;
}
function addDays(date, days) {
  const newDate = new Date(date.getTime());
  newDate.setDate(newDate.getDate() + days);
  return newDate;
}
function daysBetweenInclusive(start, end) {
  return Math.round((end - start) / (1000 * 60 * 60 * 24)) + 1;
}
function isWeekend(date) {
  const day = date.getDay();
  return day === 0 || day === 6;
}
// 3) 申請日付の変換
const requestedStart = toJsDate(startDate);
const requestedEnd   = toJsDate(endDate);
if (requestedEnd < requestedStart) {
  throw new Error("q_end_date is earlier than q_start_date.");
}
const leaveLengthDays = daysBetweenInclusive(requestedStart, requestedEnd);
// 4) 検索範囲の決定
const MIN_ADVANCE_FOR_BACKWARD_SEARCH = 5;
const today = new Date();
today.setHours(0, 0, 0, 0);
const earliestAllowedSuggestion = addDays(today, 1);
// Only search backwards if the requested leave starts
// at least MIN_ADVANCE_FOR_BACKWARD_SEARCH days from today
const thresholdDate =
  addDays(today, MIN_ADVANCE_FOR_BACKWARD_SEARCH);
let searchStart;
if (requestedStart >= thresholdDate) {
  searchStart = addDays(requestedStart, -DAYS_BEFORE);
  // Never suggest dates in the past
  if (searchStart < earliestAllowedSuggestion) {
    searchStart = earliestAllowedSuggestion;
  }
} else {
  searchStart = requestedStart;
}
// Need to extend search end enough to fit a full replacement leave period
const latestCandidateStart = addDays(requestedStart, DAYS_AFTER);
const searchEnd = addDays(latestCandidateStart, leaveLengthDays - 1);
engine.log("Requested leave length: " + leaveLengthDays + " day(s)");
engine.log("Search start: " + formatDate(searchStart));
engine.log("Search end: " + formatDate(searchEnd));
// 5) 検索範囲全体の全イベントを一括取得
const timeMin = formatDate(searchStart) + "T00:00:00+09:00";
const timeMax = formatDate(searchEnd)   + "T23:59:59+09:00";
const url =
  "https://www.googleapis.com/calendar/v3/calendars/" +
  encodeURIComponent(CALENDAR_ID) +
  "/events";
const authSetting = httpClient.findAuthSetting(AUTH_SETTING_NAME, false);
let request = httpClient.begin();
request = request.authSetting(authSetting);
request = request.queryParam("timeMin", timeMin);
request = request.queryParam("timeMax", timeMax);
request = request.queryParam("singleEvents", "true");
request = request.queryParam("orderBy", "startTime");
const response = request.get(url);
const status = response.getStatusCode() + "";
const body = response.getResponseAsString() + "";
engine.log("Calendar API status: " + status);
if (status !== "200") {
  throw new Error("Google Calendar API error: " + status + "\n" + body);
}
const json = JSON.parse(body);
const events = json.items || [];
engine.log("Total events found: " + events.length);
// 6) 1日ごとのイベント数を集計
const countsByDate = {};
function incrementDateCount(dateString) {
  if (!countsByDate[dateString]) {
    countsByDate[dateString] = 0;
  }
  countsByDate[dateString]++;
}
for (let i = 0; i < events.length; i++) {
  const event = events[i];
  let eventDate;
  if (event.start && event.start.date) {
    eventDate = event.start.date;
  } else if (event.start && event.start.dateTime) {
    eventDate = event.start.dateTime.substring(0, 10);
  } else {
    continue;
  }
  incrementDateCount(eventDate);
}
// 7) 候補期間が取得可能か確認
function isPeriodAvailable(candidateStart, candidateEnd) {
  let cursor = new Date(candidateStart.getTime());
  while (cursor <= candidateEnd) {
    const dateString = formatDate(cursor);
    // Optional: reject leave periods that include weekends
    if (isWeekend(cursor)) {
      return false;
    }
    const count = countsByDate[dateString] || 0;
    if (count >= THRESHOLD) {
      return false;
    }
    cursor = addDays(cursor, 1);
  }
  return true;
}
// 8) 候補の休暇期間を検索
const suggestions = [];
const candidateStartEnd = latestCandidateStart;
let candidateStart = new Date(searchStart.getTime());
while (candidateStart <= candidateStartEnd) {
  const candidateEnd = addDays(candidateStart, leaveLengthDays - 1);
  if (isPeriodAvailable(candidateStart, candidateEnd)) {
    if (leaveLengthDays === 1) {
      suggestions.push(formatDate(candidateStart));
    } else {
      suggestions.push(formatDate(candidateStart) + " to " + formatDate(candidateEnd));
    }
  }
  if (suggestions.length >= MAX_SUGGESTIONS) {
    break;
  }
  candidateStart = addDays(candidateStart, 1);
}
// 9) 提案された日付の保存
let outputText;
if (suggestions.length === 0) {
  outputText =
     formatDate(searchStart) + " から " + formatDate(searchEnd) + " の間に利用可能な休暇期間は見つかりませんでした。";
} else {
  outputText =
    "利用可能な休暇期間の候補：\n- " +
    suggestions.join("\n- ");
}
engine.setDataByVarName("q_suggested_dates", outputText);
engine.log(outputText);