/**
 * Network requests: duties and calendar events.
 */

import { FETCH_TIMEOUT_MS } from "./constants.js";
import { getInitData } from "./auth.js";

/**
 * Build fetch options with init data header and timeout abort.
 * @param {string} initData - Telegram init data
 * @returns {{ headers: object, signal: AbortSignal, timeoutId: number }}
 */
export function buildFetchOptions(initData) {
  const headers = {};
  if (initData) headers["X-Telegram-Init-Data"] = initData;
  const controller = new AbortController();
  const timeoutId = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
  return { headers, signal: controller.signal, timeoutId };
}

/**
 * Fetch duties for date range. Throws ACCESS_DENIED error on 403.
 * @param {string} from - YYYY-MM-DD
 * @param {string} to - YYYY-MM-DD
 * @returns {Promise<object[]>}
 */
export async function fetchDuties(from, to) {
  const base = window.location.origin;
  const url =
    base +
    "/api/duties?from=" +
    encodeURIComponent(from) +
    "&to=" +
    encodeURIComponent(to);
  const initData = getInitData();
  const opts = buildFetchOptions(initData);
  try {
    const res = await fetch(url, { headers: opts.headers, signal: opts.signal });
    if (res.status === 403) {
      let detail = "Доступ запрещён";
      try {
        const body = await res.json();
        if (body && body.detail !== undefined) {
          detail =
            typeof body.detail === "string"
              ? body.detail
              : (body.detail.msg || JSON.stringify(body.detail));
        }
      } catch (parseErr) {
        /* ignore */
      }
      const err = new Error("ACCESS_DENIED");
      err.serverDetail = detail;
      throw err;
    }
    if (!res.ok) throw new Error("Ошибка загрузки");
    return res.json();
  } catch (e) {
    if (e.name === "AbortError") {
      throw new Error("Не удалось загрузить данные. Проверьте интернет.");
    }
    throw e;
  } finally {
    clearTimeout(opts.timeoutId);
  }
}

/**
 * Fetch calendar events for range. Returns [] on non-200 or error. Does not throw for 403.
 * @param {string} from - YYYY-MM-DD
 * @param {string} to - YYYY-MM-DD
 * @returns {Promise<object[]>}
 */
export async function fetchCalendarEvents(from, to) {
  const base = window.location.origin;
  const url =
    base +
    "/api/calendar-events?from=" +
    encodeURIComponent(from) +
    "&to=" +
    encodeURIComponent(to);
  const initData = getInitData();
  const opts = buildFetchOptions(initData);
  try {
    const res = await fetch(url, { headers: opts.headers, signal: opts.signal });
    if (!res.ok) return [];
    return res.json();
  } catch (e) {
    return [];
  } finally {
    clearTimeout(opts.timeoutId);
  }
}