import express from "express";
import { fileURLToPath } from "node:url";
import multer from "multer";
import { parseWord, PARSER_VERSION } from "./parser.js";
import { scheduleFor } from "./schedules.js";
import { timetable } from "./timetable.js";
import {
  getIndex,
  indexStatus,
  search,
  dayOf,
  freeRooms,
  examsOf,
  findGroups,
  directoryCalendar,
  todayIso,
} from "./directory.js";
import {
  getCatalog,
  getCalendar,
  documentFor,
  request,
  sourceStatus,
} from "./source.js";
const app = express();
app.disable("x-powered-by");
app.use("/api", (_req, res, next) => {
  res.set("Cache-Control", "no-store");
  next();
});
// Raised whenever an endpoint is added or changed, so a deployment is easy to verify:
// 2 — /api/timetable for the Android client; 3 — its range=semester.
const API_VERSION = 3;

// Liveness plus what the server currently reads from the university, without network calls.
app.get("/api/health", async (_req, res) => {
  const sources = await sourceStatus().catch((e) => ({ error: e.message }));
  res.json({
    ok: true,
    apiVersion: API_VERSION,
    parserVersion: PARSER_VERSION,
    ...sources,
    directory: indexStatus(),
  });
});
const isDate = (s) => /^\d{4}-\d{2}-\d{2}$/.test(s || "");
const badRequest = (res, error) => res.status(400).json({ error });
// University-wide lookups over every catalog document.
app.get("/api/directory/search", async (req, res, next) => {
  try {
    res.json(search(await getIndex(), String(req.query.q || "").slice(0, 60)));
  } catch (e) {
    next(e);
  }
});
app.get("/api/directory/day", async (req, res, next) => {
  try {
    const date = req.query.date || todayIso();
    const teacher = String(req.query.teacher || "").slice(0, 80),
      room = String(req.query.room || "").slice(0, 20);
    if (!isDate(date)) return badRequest(res, "Дата должна быть в формате ГГГГ-ММ-ДД.");
    if (!teacher && !room) return badRequest(res, "Укажите преподавателя или аудиторию.");
    res.json(dayOf(await getIndex(), await directoryCalendar(), { teacher, room }, date));
  } catch (e) {
    next(e);
  }
});
app.get("/api/directory/free", async (req, res, next) => {
  try {
    const date = req.query.date || todayIso(),
      pair = Number(req.query.pair);
    if (!isDate(date)) return badRequest(res, "Дата должна быть в формате ГГГГ-ММ-ДД.");
    const calendar = await directoryCalendar();
    const result = freeRooms(await getIndex(), calendar, date, pair);
    if (!result) return badRequest(res, "Нет такой пары в расписании звонков.");
    res.json(result);
  } catch (e) {
    next(e);
  }
});
app.get("/api/groups", async (req, res, next) => {
  try {
    const text = (name) => String(req.query[name] || "").slice(0, 120);
    res.json(
      findGroups(await getIndex(), {
        q: text("q"),
        faculty: text("faculty"),
        course: text("course"),
        form: text("form"),
      }),
    );
  } catch (e) {
    next(e);
  }
});
// A group's lessons by date with weeks applied: for native and other clients.
app.get("/api/timetable", async (req, res, next) => {
  try {
    const doc = String(req.query.doc || ""),
      group = String(req.query.group || "").slice(0, 40),
      from = req.query.from || todayIso();
    if (!doc || !group) return badRequest(res, "Укажите документ (doc) и группу (group).");
    if (!isDate(from)) return badRequest(res, "Дата должна быть в формате ГГГГ-ММ-ДД.");
    const file = await documentFor(doc);
    res.json(
      timetable({
        file,
        schedule: await scheduleFor(file),
        calendar: await directoryCalendar(),
        group,
        from,
        days: req.query.days,
        range: req.query.range === "semester" ? "semester" : undefined,
        today: todayIso(),
      }),
    );
  } catch (e) {
    next(e);
  }
});
app.get("/api/exams", async (req, res, next) => {
  try {
    const group = String(req.query.group || "").slice(0, 40);
    if (!group) return badRequest(res, "Укажите группу.");
    res.json({
      group,
      exams: examsOf(await getIndex(), group, String(req.query.faculty || "") || null),
    });
  } catch (e) {
    next(e);
  }
});
app.get("/api/catalog", async (req, res, next) => {
  try {
    res.json(await getCatalog(req.query.refresh === "1"));
  } catch (e) {
    next(e);
  }
});
app.get("/api/calendar", async (req, res, next) => {
  try {
    res.json(await getCalendar(req.query.refresh === "1"));
  } catch (e) {
    next(e);
  }
});
app.get("/api/schedule/:id", async (req, res, next) => {
  try {
    const file = await documentFor(req.params.id);
    res.json(await scheduleFor(file, { refresh: req.query.refresh === "1" }));
  } catch (e) {
    next(e);
  }
});
app.get("/api/original/:id", async (req, res, next) => {
  try {
    const file = await documentFor(req.params.id);
    res.set("Content-Type", "application/octet-stream");
    res.set(
      "Content-Disposition",
      `attachment; filename*=UTF-8''${encodeURIComponent(file.name)}`,
    );
    res.send(await request(file.path));
  } catch (e) {
    next(e);
  }
});
const upload = multer({
  storage: multer.memoryStorage(),
  limits: { fileSize: 10 * 1024 * 1024, files: 1, fields: 0 },
});
app.post("/api/import", upload.single("file"), async (req, res, next) => {
  try {
    if (!req.file)
      return res.status(400).json({ error: "Выберите файл Word." });
    // Multer decodes multipart names as latin1 by default.
    const name = Buffer.from(req.file.originalname, "latin1").toString("utf8");
    if (!/\.docx?$/i.test(name))
      return res
        .status(400)
        .json({ error: "Поддерживаются файлы .docx и .doc." });
    res.json(await parseWord(req.file.buffer, { name, uploaded: true }));
  } catch (e) {
    e.status = 422;
    next(e);
  }
});
const dist = fileURLToPath(new URL("../dist/", import.meta.url));
app.use(express.static(dist, { maxAge: 0 }));
app.get("/{*path}", (req, res, next) =>
  req.path.startsWith("/api/")
    ? res.status(404).json({ error: "Адрес не найден." })
    : res.sendFile(dist + "index.html", (err) => err && next(err)),
);
app.use((error, _req, res, _next) => {
  console.error(error.message);
  res
    .status(error.code === "LIMIT_FILE_SIZE" ? 413 : error.status || 503)
    .json({
      error:
        error.code === "LIMIT_FILE_SIZE"
          ? "Файл больше 10 МБ. Выберите документ меньшего размера."
          : error.status === 422
            ? error.message
            : error.status === 404
              ? error.message
              : "Не удалось загрузить расписание. Проверьте подключение и попробуйте ещё раз.",
    });
});
const port = Number(process.env.PORT || 3001);
app.listen(port, process.env.HOST || "127.0.0.1", () => {
  console.log(`API и PWA: http://127.0.0.1:${port}`);
  // Read the week table and parse the whole catalog in the background,
  // so the first visit and the first search do not wait for the university.
  getCalendar().catch((e) => console.error(`Таблица недель: ${e.message}`));
  getIndex().catch((e) => console.error(`Индекс: ${e.message}`));
});