From 86c2a3097debf268cada95d72b55e4bdb9129368 Mon Sep 17 00:00:00 2001
From: Vladislav Kopnin <vlad.kopnen@mail.ru>
Date: Wed, 9 Sep 2026 11:33:03 +0300
Subject: [PATCH] =?UTF-8?q?=D0=91=D1=8D=D0=BA=D0=B5=D0=BD=D0=B4:=20=D0=BF?=
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- xlsx.py: чтение книги (мержи, скрытые столбцы, красный текст), фикс дат до 1900
- lessons.py: общая схема ролей (предмет/преподаватель/аудитория/заметка)
  вместо ветвлений по числу строк; маркеры к.в., многострочные заметки,
  ФИО с/без отчества, организации, локации, метки групп -> заметки
- source.py: загрузка с Яндекс.Диска с понятными ошибками
- parsing.py: листы -> расписание, недели семестра, индексы преподов/аудиторий
- cache.py: lock, TTL, проверка modified, stale-while-error с retry cooldown
- main.py: create_app, /healthz, логирование; force-обновление убрано (вернётся с авторизацией)
- переменная окружения SCHEDULE_LINK
---
 .env.example                     |   3 +-
 src/backend/main.py              | 486 +++++++++----------
 src/backend/schedule/__init__.py |  14 +
 src/backend/schedule/cache.py    | 170 +++++++
 src/backend/schedule/errors.py   |   5 +
 src/backend/schedule/lessons.py  | 511 ++++++++++++++++++++
 src/backend/schedule/parsing.py  | 390 +++++++++++++++
 src/backend/schedule/source.py   |  45 ++
 src/backend/schedule/xlsx.py     | 235 +++++++++
 src/backend/schedule_parser.py   | 799 -------------------------------
 10 files changed, 1601 insertions(+), 1057 deletions(-)
 create mode 100644 src/backend/schedule/__init__.py
 create mode 100644 src/backend/schedule/cache.py
 create mode 100644 src/backend/schedule/errors.py
 create mode 100644 src/backend/schedule/lessons.py
 create mode 100644 src/backend/schedule/parsing.py
 create mode 100644 src/backend/schedule/source.py
 create mode 100644 src/backend/schedule/xlsx.py
 delete mode 100644 src/backend/schedule_parser.py

diff --git a/.env.example b/.env.example
index cff39dd..570529b 100644
--- a/.env.example
+++ b/.env.example
@@ -1,5 +1,6 @@
-schedule_link=
+SCHEDULE_LINK=
 SCHEDULE_CACHE_TTL=900
+SCHEDULE_RETRY_AFTER=60
 API_PORT=8000
 FRONTEND_PORT=8080
 SCHEDULE_API=http://api:8000
diff --git a/src/backend/main.py b/src/backend/main.py
index 3fba284..c911a3b 100644
--- a/src/backend/main.py
+++ b/src/backend/main.py
@@ -1,33 +1,27 @@
+"""API-приложение расписания (FastAPI)."""
+
+from __future__ import annotations
+
+import logging
 import os
-import time
+import threading
 from contextlib import asynccontextmanager
-from datetime import datetime
+from datetime import date
 from pathlib import Path
 
 import uvicorn
 from dotenv import load_dotenv
 from fastapi import FastAPI, HTTPException, Query
 
-from schedule_parser import (
-    DAYS,
-    ScheduleError,
-    build_day_times,
-    build_group_schedule,
-    build_room_schedule,
-    build_teacher_room_index,
-    build_teacher_schedule,
-    current_parity,
-    download_schedule,
-    extract_week_ranges,
-    fetch_table_modified,
-    parse_rooms_info,
-    parse_schedule,
-    parse_teachers_full,
-    parse_workbook,
-    sort_rooms,
-)
+from schedule import ScheduleCache, ScheduleError
+from schedule import parsing
 
-def _find_dotenv():
+log = logging.getLogger(__name__)
+logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(name)s: %(message)s")
+
+
+def _find_dotenv() -> Path | None:
+    """Ищем .env вверх от каталога модуля (локальная разработка)."""
     path = Path(__file__).resolve().parent
     for _ in range(5):
         env = path / ".env"
@@ -43,256 +37,234 @@ _dotenv_path = _find_dotenv()
 if _dotenv_path:
     load_dotenv(_dotenv_path)
 
-SCHEDULE_LINK = os.getenv("schedule_link") or os.getenv("SCHEDULE_LINK", "").strip()
-CACHE_TTL = int(os.getenv("SCHEDULE_CACHE_TTL", "900"))
-
-_cache = {
-    "data": None,
-    "weeks": None,
-    "modified": None,
-    "loaded_at": 0.0,
-    "error": None,
-    "index": None,
-    "teacher_full": {},
-    "room_info": {},
-}
+SCHEDULE_LINK = (os.getenv("SCHEDULE_LINK") or "").strip()
+CACHE_TTL = float(os.getenv("SCHEDULE_CACHE_TTL", "900"))
+RETRY_AFTER = float(os.getenv("SCHEDULE_RETRY_AFTER", "60"))
 
 
-@asynccontextmanager
-async def lifespan(app: FastAPI):
+def _default_cache() -> ScheduleCache:
     try:
-        _load_data()
-    except Exception:
-        pass
-    yield
+        return ScheduleCache(SCHEDULE_LINK, ttl_seconds=CACHE_TTL, retry_after=RETRY_AFTER)
+    except ScheduleError:
+        log.error("SCHEDULE_LINK не задан — API данных работать не будет")
+        return _BrokenCache()
 
 
-app = FastAPI(
-    title="Расписание",
-    description="Расписание групп из Яндекс.Таблицы",
-    lifespan=lifespan,
-)
+class _BrokenCache(ScheduleCache):
+    """Кэш без ссылки: все запросы данных отвечают понятной ошибкой."""
+
+    def __init__(self) -> None:
+        self._link = None
+        self._ttl = CACHE_TTL
+        self._retry_after = RETRY_AFTER
+        self._lock = threading.RLock()
+        self._data = None
+        self._weeks = []
+        self._index = None
+        self._day_times = {}
+        self._teacher_full = {}
+        self._room_info = {}
+        self._loaded_at = 0.0
+        self._modified = None
+        self._error = "Не задана переменная окружения SCHEDULE_LINK"
+        self._last_failed = 0.0
+
+    def _ensure_fresh(self) -> None:
+        raise ScheduleError(self._error)
 
 
-def _load_data(force: bool = False):
-    if not SCHEDULE_LINK:
-        raise ScheduleError("Ссылка schedule_link не задана в .env")
-    now = time.time()
-    if (
-        not force
-        and _cache["data"] is not None
-        and now - _cache["loaded_at"] < CACHE_TTL
-        and _cache["error"] is None
-    ):
-        return _cache["data"], _cache["weeks"]
-
-    modified = fetch_table_modified(SCHEDULE_LINK)
-
-    if (
-        not force
-        and modified
-        and modified == _cache["modified"]
-        and _cache["data"] is not None
-        and _cache["error"] is None
-    ):
-        _cache["loaded_at"] = now
-        return _cache["data"], _cache["weeks"]
-
-    xlsx = download_schedule(SCHEDULE_LINK)
-    sheets = parse_workbook(xlsx)
-    data = parse_schedule(sheets)
-    weeks = extract_week_ranges(sheets)
-    _cache["data"] = data
-    _cache["weeks"] = weeks
-    _cache["modified"] = modified
-    _cache["loaded_at"] = now
-    _cache["error"] = None
-    _cache["index"] = None
-    _cache["teacher_full"] = parse_teachers_full(sheets)
-    _cache["room_info"] = parse_rooms_info(sheets)
-    return data, weeks
+def _day_arg(day: str) -> str:
+    normalized = day.strip().lower()
+    if normalized not in parsing.DAYS:
+        raise HTTPException(
+            status_code=400,
+            detail=f"День должен быть одним из: {', '.join(parsing.DAYS)}",
+        )
+    return normalized
 
 
-def _get_index(force: bool = False):
-    data, _ = _get_data(force=force)
-    if _cache["index"] is None:
-        _cache["index"] = build_teacher_room_index(data)
-    return _cache["index"]
+def create_app(cache: ScheduleCache | None = None) -> FastAPI:
+    cache = cache or _default_cache()
 
+    @asynccontextmanager
+    async def lifespan(app: FastAPI):
+        cache.warmup()
+        yield
 
-def _get_data(force: bool = False):
-    try:
-        return _load_data(force=force)
-    except ScheduleError as exc:
-        _cache["error"] = str(exc)
-        raise HTTPException(status_code=502, detail=str(exc))
-
-
-@app.get("/")
-def index():
-    return {
-        "title": "Расписание",
-        "endpoints": {
-            "/groups": "Список групп",
-            "/schedule/{group}": "Расписание группы",
-            "/schedule/{group}/{day}": "Расписание группы на день",
-            "/today?group={group}": "Расписание группы на сегодня",
-        },
-    }
-
-
-@app.get("/groups")
-def groups(force: bool = Query(False)):
-    data, _ = _get_data(force=force)
-    return sorted(
-        data.keys(),
-        key=lambda g: (
-            0 if g.endswith("БО") else (1 if g.endswith("МО") else 2),
-            g,
-        ),
+    app = FastAPI(
+        title="Расписание",
+        description="Расписание групп из Яндекс.Таблицы",
+        lifespan=lifespan,
     )
+    app.state.cache = cache
+
+    def _data() -> tuple[dict, list[dict]]:
+        try:
+            return cache.get()
+        except ScheduleError as exc:
+            raise HTTPException(status_code=502, detail=str(exc))
+
+    def _index() -> tuple[dict, dict]:
+        try:
+            return cache.get_index()
+        except ScheduleError as exc:
+            raise HTTPException(status_code=502, detail=str(exc))
+
+    # --- обслуживание -----------------------------------------------------------
+
+    @app.get("/healthz")
+    def healthz() -> dict:
+        """Живость процесса; не зависит от доступности таблицы."""
+        return {"ok": True}
+
+    @app.get("/status")
+    def status() -> dict:
+        return cache.status()
+
+    # --- справочники -------------------------------------------------------------
+
+    @app.get("/")
+    def index() -> dict:
+        return {
+            "title": "Расписание",
+            "endpoints": {
+                "/groups": "Список групп",
+                "/schedule/{group}": "Расписание группы",
+                "/schedule/{group}/{day}": "Расписание группы на день",
+                "/today?group={group}": "Расписание группы на сегодня",
+                "/teachers": "Список преподавателей",
+                "/teacher/{name}": "Расписание преподавателя",
+                "/rooms": "Список аудиторий",
+                "/room/{label}": "Занятость аудитории",
+                "/rooms-day?day={день}": "Занятость всех аудиторий на день",
+                "/rooms-free?day={день}&period={N}": "Свободные аудитории",
+                "/week": "Недели семестра и текущая чётность",
+                "/status": "Состояние кэша",
+            },
+        }
+
+    @app.get("/groups")
+    def groups() -> list[str]:
+        data, _ = _data()
+        return sorted(
+            data.keys(),
+            key=lambda g: (0 if g.endswith("БО") else (1 if g.endswith("МО") else 2), g),
+        )
+
+    @app.get("/teachers")
+    def teachers() -> list[str]:
+        teachers_map, _ = _index()
+        return sorted(teachers_map.keys())
+
+    @app.get("/rooms")
+    def rooms() -> list[str]:
+        _, rooms_map = _index()
+        return parsing.sort_rooms(set(rooms_map) | set(cache.room_info))
+
+    # --- занятия -----------------------------------------------------------------
+
+    @app.get("/schedule/{group}")
+    def schedule(group: str) -> dict:
+        data, _ = _data()
+        if group not in data:
+            raise HTTPException(status_code=404, detail=f"Группа «{group}» не найдена")
+        return parsing.build_group_schedule(data, group)
+
+    @app.get("/schedule/{group}/{day}")
+    def schedule_day(group: str, day: str) -> dict:
+        data, _ = _data()
+        if group not in data:
+            raise HTTPException(status_code=404, detail=f"Группа «{group}» не найдена")
+        normalized = _day_arg(day)
+        sched = parsing.build_group_schedule(data, group)
+        day_data = sched["days"].get(normalized, {})
+        return {"group": group, "day": normalized, "periods": day_data}
+
+    @app.get("/today")
+    def today(group: str) -> dict:
+        data, _ = _data()
+        if group not in data:
+            raise HTTPException(status_code=404, detail=f"Группа «{group}» не найдена")
+        day_name = parsing.DAYS[date.today().weekday()]
+        sched = parsing.build_group_schedule(data, group)
+        return {
+            "group": group,
+            "date": date.today().isoformat(),
+            "day": day_name,
+            "periods": sched["days"].get(day_name, {}),
+        }
+
+    @app.get("/teacher/{name}")
+    def teacher(name: str) -> dict:
+        teachers_map, _ = _index()
+        result = parsing.build_teacher_schedule(teachers_map, name)
+        if result is None:
+            raise HTTPException(status_code=404, detail=f"Преподаватель «{name}» не найден")
+        result["full_name"] = cache.teacher_full.get(name, name)
+        return result
+
+    @app.get("/room/{label}")
+    def room(label: str) -> dict:
+        _, rooms_map = _index()
+        result = parsing.build_room_schedule(rooms_map, label, cache.get_day_times())
+        if result is None:
+            raise HTTPException(status_code=404, detail=f"Аудитория «{label}» не найдена")
+        result["info"] = cache.room_info.get(label, {}).get("info", "")
+        return result
+
+    @app.get("/rooms-free")
+    def rooms_free(day: str, period: int) -> list[dict]:
+        normalized = _day_arg(day)
+        if period < 1 or period > 8:
+            raise HTTPException(status_code=400, detail="Пара должна быть от 1 до 8")
+        _, rooms_map = _index()
+        room_info = cache.room_info
+        free = []
+        for label in parsing.sort_rooms(set(rooms_map) | set(room_info)):
+            occupied = rooms_map.get(label, {}).get(normalized, {}).get(str(period), {})
+            busy = bool((occupied.get("ч") or []) or (occupied.get("з") or []))
+            if not busy:
+                free.append({"room": label, "info": room_info.get(label, {}).get("info", "")})
+        return free
+
+    @app.get("/rooms-day")
+    def rooms_day(day: str) -> dict:
+        normalized = _day_arg(day)
+        _, rooms_map = _index()
+        room_info = cache.room_info
+        day_times = cache.get_day_times().get(normalized, {})
+        rooms_out = []
+        for label in parsing.sort_rooms(set(rooms_map) | set(room_info)):
+            info = room_info.get(label, {}).get("info", "")
+            occupied_day = rooms_map.get(label, {}).get(normalized, {})
+            periods = {}
+            for period in sorted(set(occupied_day) | set(day_times), key=int):
+                slot = occupied_day.get(period, {})
+                periods[period] = {
+                    "time": slot.get("time") or day_times.get(period, ""),
+                    "ч": slot.get("ч") or [],
+                    "з": slot.get("з") or [],
+                }
+            rooms_out.append({"room": label, "info": info, "periods": periods})
+        return {"day": normalized, "rooms": rooms_out}
+
+    @app.get("/week")
+    def week() -> dict:
+        _, weeks = _data()
+        today = date.today()
+        return {
+            "today": today.isoformat(),
+            "parity": parsing.current_parity(weeks, today),
+            "weeks": [
+                {"parity": w["parity"], "start": w["start"].isoformat(), "end": w["end"].isoformat()}
+                for w in weeks
+            ],
+        }
+
+    return app
 
 
-@app.get("/teachers")
-def teachers(force: bool = Query(False)):
-    teachers_map, _ = _get_index(force=force)
-    return sorted(teachers_map.keys())
-
-
-@app.get("/rooms")
-def rooms(force: bool = Query(False)):
-    _, rooms_map = _get_index(force=force)
-    return sort_rooms(rooms_map.keys())
-
-
-@app.get("/teacher/{name}")
-def teacher(name: str, force: bool = Query(False)):
-    teachers_map, _ = _get_index(force=force)
-    result = build_teacher_schedule(teachers_map, name)
-    if result is None:
-        raise HTTPException(status_code=404, detail=f"Преподаватель «{name}» не найден")
-    result["full_name"] = _cache.get("teacher_full", {}).get(name, name)
-    return result
-
-
-@app.get("/room/{label}")
-def room(label: str, force: bool = Query(False)):
-    data, _ = _get_data(force=force)
-    _, rooms_map = _get_index(force=force)
-    result = build_room_schedule(rooms_map, label, build_day_times(data))
-    if result is None:
-        raise HTTPException(status_code=404, detail=f"Аудитория «{label}» не найдена")
-    result["info"] = _cache.get("room_info", {}).get(label, {}).get("info", "")
-    return result
-
-
-@app.get("/rooms-free")
-def rooms_free(
-    day: str,
-    period: int,
-    force: bool = Query(False),
-):
-    normalized = day.strip().lower()
-    if normalized not in DAYS:
-        raise HTTPException(status_code=400, detail=f"День должен быть одним из: {', '.join(DAYS)}")
-    if period < 1 or period > 8:
-        raise HTTPException(status_code=400, detail="Пара должна быть от 1 до 8")
-    _, rooms_map = _get_index(force=force)
-    room_info = _cache.get("room_info", {})
-    free = []
-    for label in sort_rooms(room_info.keys()):
-        occupied = rooms_map.get(label, {}).get(normalized, {}).get(str(period), {})
-        busy = bool((occupied.get("ч") or []) or (occupied.get("з") or []))
-        if not busy:
-            free.append({"room": label, "info": room_info[label].get("info", "")})
-    return free
-
-
-@app.get("/rooms-day")
-def rooms_day(day: str, force: bool = Query(False)):
-    normalized = day.strip().lower()
-    if normalized not in DAYS:
-        raise HTTPException(status_code=400, detail=f"День должен быть одним из: {', '.join(DAYS)}")
-    data, _ = _get_data(force=force)
-    _, rooms_map = _get_index(force=force)
-    room_info = _cache.get("room_info", {})
-    day_times = build_day_times(data).get(normalized, {})
-
-    labels = set(rooms_map.keys()) | set(room_info.keys())
-    rooms_out = []
-    for label in sort_rooms(labels):
-        info = room_info.get(label, {}).get("info", "")
-        occupied_day = rooms_map.get(label, {}).get(normalized, {})
-        periods = {}
-        keys = set(occupied_day.keys()) | set(day_times.keys())
-        for period in sorted(keys, key=lambda p: int(p)):
-            slot = occupied_day.get(period, {})
-            periods[str(period)] = {
-                "time": day_times.get(period, slot.get("time", "")),
-                "ч": slot.get("ч", []) or [],
-                "з": slot.get("з", []) or [],
-            }
-        rooms_out.append({"room": label, "info": info, "periods": periods})
-    return {"day": normalized, "rooms": rooms_out}
-
-
-@app.get("/week")
-def week(force: bool = Query(False)):
-    _, weeks = _get_data(force=force)
-    today = datetime.now().date()
-    return {
-        "today": today.isoformat(),
-        "parity": current_parity(weeks, today),
-        "weeks": [
-            {"parity": w["parity"], "start": w["start"].isoformat(), "end": w["end"].isoformat()}
-            for w in weeks
-        ],
-    }
-
-
-@app.get("/status")
-def status(force: bool = Query(False)):
-    _get_data(force=force)
-    return {
-        "cache_ttl_seconds": CACHE_TTL,
-        "last_updated": (
-            datetime.fromtimestamp(_cache["loaded_at"], datetime.now().astimezone().tzinfo).isoformat() if _cache["loaded_at"] else None
-        ),
-        "table_modified": _cache["modified"],
-    }
-
-
-@app.get("/schedule/{group}")
-def schedule(group: str, force: bool = Query(False)):
-    data, _ = _get_data(force=force)
-    if group not in data:
-        raise HTTPException(status_code=404, detail=f"Группа «{group}» не найдена")
-    return build_group_schedule(data, group)
-
-
-@app.get("/schedule/{group}/{day}")
-def schedule_day(group: str, day: str, force: bool = Query(False)):
-    data, _ = _get_data(force=force)
-    if group not in data:
-        raise HTTPException(status_code=404, detail=f"Группа «{group}» не найдена")
-    normalized = day.strip().lower()
-    if normalized not in DAYS:
-        raise HTTPException(status_code=400, detail=f"День должен быть одним из: {', '.join(DAYS)}")
-    sched = build_group_schedule(data, group)
-    day_data = sched["days"].get(normalized, {})
-    return {"group": group, "day": normalized, "periods": day_data}
-
-
-@app.get("/today")
-def today(group: str, force: bool = Query(False)):
-    data, _ = _get_data(force=force)
-    if group not in data:
-        raise HTTPException(status_code=404, detail=f"Группа «{group}» не найдена")
-    weekday = datetime.now().weekday()
-    day_name = DAYS[weekday]
-    sched = build_group_schedule(data, group)
-    return {"group": group, "date": datetime.now().date().isoformat(), "day": day_name, "periods": sched["days"].get(day_name, {})}
-
+app = create_app()
 
 if __name__ == "__main__":
     uvicorn.run("main:app", host="127.0.0.1", port=8000, reload=True)
diff --git a/src/backend/schedule/__init__.py b/src/backend/schedule/__init__.py
new file mode 100644
index 0000000..9346326
--- /dev/null
+++ b/src/backend/schedule/__init__.py
@@ -0,0 +1,14 @@
+"""Пакет для загрузки и разбора расписания из Яндекс.Таблиц (xlsx).
+
+Структура:
+    xlsx      — чтение xlsx-рабочей книги (ячейки, мержи, скрытые столбцы, красный текст);
+    source    — загрузка файла по публичной ссылке Яндекс.Диска;
+    lessons   — разбор текста ячейки занятия (предмет/преподаватель/аудитория/заметки);
+    parsing   — разбор листов: группы, недели, индексы преподавателей и аудиторий;
+    cache     — кэш загруженной таблицы (TTL, перезагрузка, stale-while-error).
+"""
+
+from .cache import ScheduleCache
+from .errors import ScheduleError
+
+__all__ = ["ScheduleCache", "ScheduleError"]
diff --git a/src/backend/schedule/cache.py b/src/backend/schedule/cache.py
new file mode 100644
index 0000000..13042b7
--- /dev/null
+++ b/src/backend/schedule/cache.py
@@ -0,0 +1,170 @@
+"""Кэш загруженного расписания.
+
+- однопоточная перезагрузка (lock): параллельные запросы во время загрузки
+  ждут один download вместо N скачиваний;
+- TTL, а также проверка modified таблицы: если таблица не менялась,
+  скачивание не повторяется;
+- stale-while-error: если таблица перестала скачиваться, отдаём последнее
+  удачное состояние и повторяем попытку не чаще, чем раз в retry_after секунд
+  (вместо скачивания на каждый запрос).
+"""
+
+from __future__ import annotations
+
+import logging
+import threading
+import time
+from datetime import datetime
+
+from . import parsing
+from .errors import ScheduleError
+from .source import download_schedule, fetch_table_modified
+from .xlsx import parse_workbook
+
+log = logging.getLogger(__name__)
+
+
+class ScheduleCache:
+    def __init__(
+        self,
+        link: str | None,
+        ttl_seconds: float = 900.0,
+        retry_after: float = 60.0,
+    ) -> None:
+        if not link:
+            raise ScheduleError("Не задана переменная окружения SCHEDULE_LINK")
+        self._link = link
+        self._ttl = ttl_seconds
+        self._retry_after = retry_after
+        self._lock = threading.RLock()
+
+        self._data: dict | None = None
+        self._weeks: list[dict] = []
+        self._index: tuple[dict, dict] | None = None
+        self._day_times: dict = {}
+        self._teacher_full: dict = {}
+        self._room_info: dict = {}
+        self._loaded_at: float = 0.0
+        self._modified: str | None = None
+        self._error: str | None = None
+        self._last_failed: float = 0.0
+
+    # --- публичное API ---------------------------------------------------------
+
+    @property
+    def teacher_full(self) -> dict:
+        return self._teacher_full
+
+    @property
+    def room_info(self) -> dict:
+        return self._room_info
+
+    def get(self) -> tuple[dict, list[dict]]:
+        """(data, weeks); бросает ScheduleError, если данных нет совсем."""
+        with self._lock:
+            self._ensure_fresh()
+            assert self._data is not None
+            return self._data, self._weeks
+
+    def get_index(self) -> tuple[dict, dict]:
+        """(teachers, rooms) — индексы занятий по преподавателям и аудиториям."""
+        with self._lock:
+            self._ensure_fresh()
+            assert self._index is not None
+            return self._index
+
+    def get_day_times(self) -> dict:
+        with self._lock:
+            self._ensure_fresh()
+            return self._day_times
+
+    def status(self) -> dict:
+        with self._lock:
+            return {
+                "cache_ttl_seconds": self._ttl,
+                "last_updated": self._iso(self._loaded_at),
+                "table_modified": self._modified,
+                "error": self._error,
+            }
+
+    def warmup(self) -> None:
+        """Первый запуск данных на старте приложения (ошибка не фатальна)."""
+        try:
+            self.get()
+        except ScheduleError as exc:
+            log.warning("Начальная загрузка расписания не удалась: %s", exc)
+
+    # --- internals --------------------------------------------------------------
+
+    @staticmethod
+    def _iso(ts: float) -> str | None:
+        if not ts:
+            return None
+        return datetime.fromtimestamp(ts, datetime.now().astimezone().tzinfo).isoformat()
+
+    def _ensure_fresh(self) -> None:
+        now = time.time()
+        fresh = (
+            self._data is not None
+            and self._loaded_at
+            and self._error is None
+            and now - self._loaded_at < self._ttl
+        )
+        if fresh:
+            return
+        self._reload(now)
+
+    def _reload(self, now: float) -> None:
+        # служим старые данные, пока не истекло время повторной попытки
+        if (
+            self._data is not None
+            and self._error is not None
+            and now - self._last_failed < self._retry_after
+        ):
+            return
+        modified = fetch_table_modified(self._link)
+        if (
+            self._data is not None
+            and modified is not None
+            and modified == self._modified
+        ):
+            # таблица не менялась — источник доступен, данные актуальны
+            self._loaded_at = now
+            self._error = None
+            return
+        try:
+            log.info("Загружаю расписание по ссылке %s ...", self._link)
+            started = time.time()
+            xlsx = download_schedule(self._link)
+            sheets = parse_workbook(xlsx)
+            data = parsing.parse_schedule(sheets)
+            weeks = parsing.extract_week_ranges(sheets)
+            index = parsing.build_teacher_room_index(data)
+            self._data = data
+            self._weeks = weeks
+            self._index = index
+            self._day_times = parsing.build_day_times(data)
+            self._teacher_full = parsing.parse_teachers_full(sheets)
+            self._room_info = parsing.parse_rooms_info(sheets)
+            self._modified = modified
+            self._loaded_at = now
+            self._error = None
+            log.info(
+                "Расписание загружено: %d групп за %.1f с", len(data), time.time() - started
+            )
+        except ScheduleError as exc:
+            self._fail(exc, now)
+        except Exception as exc:  # непредвиденное в парсинге/сети
+            log.exception("Ошибка при загрузке расписания")
+            self._fail(ScheduleError(f"Не удалось обработать таблицу: {exc}"), now)
+
+    def _fail(self, exc: ScheduleError, now: float) -> None:
+        self._error = str(exc)
+        self._last_failed = now
+        if self._data is None:
+            raise exc
+        log.warning(
+            "Обновление не удалось (%s), отдам предыдущее состояние ещё %.0f с",
+            exc,
+            self._retry_after,
+        )
diff --git a/src/backend/schedule/errors.py b/src/backend/schedule/errors.py
new file mode 100644
index 0000000..307653a
--- /dev/null
+++ b/src/backend/schedule/errors.py
@@ -0,0 +1,5 @@
+"""Исключения пакета schedule, которые показывают пользователю как текст ошибки."""
+
+
+class ScheduleError(Exception):
+    """Ошибка загрузки или разбора расписания (ссылка, сеть, xlsx, лист)."""
diff --git a/src/backend/schedule/lessons.py b/src/backend/schedule/lessons.py
new file mode 100644
index 0000000..8ba44de
--- /dev/null
+++ b/src/backend/schedule/lessons.py
@@ -0,0 +1,511 @@
+"""Разбор текста ячейки занятия.
+
+В одной ячейке может быть одно или несколько занятий, оформлено строго
+необязательное: маркер, время, локация, примечания пишутся как придумается.
+Поэтому разбор не ветвится по количеству строк, а проходит один конвейер:
+
+1. красные фрагменты таблицы (⟪...⟫) выносятся в заметки и удаляются из текста —
+   они служат только примечаниями, даже если внутри «вложено» другое занятие;
+2. извлекается маркер «к.в.» (своя строка или префикс первой строки);
+3. каждая строка классифицируется по ролям:
+     - аудитория   — есть «ауд.»/«каб.», URL, «онлайн», «зал...» (вместе с названием
+                     корпуса, номерами вариантов, временем начала);
+     - преподаватель — фамилия + инициалы или полное ФИО, организация;
+                       в строке с преподавателем может присутствовать аудитория;
+     - предмет     — всё, что идёт до преподавателя/аудитории;
+     - заметка     — время/даты/ссылки;
+     - организация — короткое имя капсом («НПО Криста», «ПравоТех»): преподаватель,
+                     если преподавателя ещё нет, иначе — место проведения.
+4. остаток собирается по позиции: предмет сначала, после преподавателя/аудитории
+   неклассифицированное без аудитории — локация (аудитория), дальше — заметки.
+"""
+
+from __future__ import annotations
+
+import re
+from dataclasses import asdict, dataclass, replace
+from typing import Optional
+
+from .xlsx import RED_CLOSE, RED_OPEN
+
+# --- маркер недели занятия («к.в.» = курсовая/ведомостная неделя) ---------------
+_MARKER_LINE_RE = re.compile(r"^\s*к\.в\.?\s*[-–—]?\s*(\d{1,2})?\s*$", re.I)
+_MARKER_PREFIX_RE = re.compile(r"^\s*(к\.в\.?\s*[-–—]?\s*(\d{1,2})?)\s+(?=\S)", re.I)
+
+# --- роли -------------------------------------------------------------------
+_TIME_RE = re.compile(r"\d{1,2}:\d{2}|\d{1,2}\.\d{1,2}\.\d{2,4}")
+_URL_RE = re.compile(r"https?://\S+")
+_ROOM_REF_RE = re.compile(r"(?:ауд|каб)\.?\s*[\w\-]*", re.I)
+_ONLINE_RE = re.compile(r"\bонлайн\b", re.I)
+_ROOM_START_RE = re.compile(r"^\s*(?:зал|каб)\b", re.I)
+# время в начале строки: «начало в 12:00», «с 13:45 до 15:15»
+_TIME_PREFIX_RE = re.compile(
+    r"^(?P<time>.*?\d{1,2}:\d{2}(?:\s*(?:до|—|–|-)\s*\d{1,2}:\d{2})?)\s+(?P<rest>.*)$"
+)
+
+# Имя: «Фамилия И.И.», «Фамилия А.М.», «Фамилия Г.К» — минимум одна точка
+# (чтобы «Группа Б» не принималась за преподавателя)
+_NAME_INITIALS_RE = re.compile(
+    r"[А-ЯЁ][а-яё-]{1,}\s+(?:[А-ЯЁ]\.(?:\s*[А-ЯЁ]\.{0,1}){0,1}|[А-ЯЁ]\.{0,1}\s+[А-ЯЁ]\.)"
+)
+# Полное ФИО в начале строки: три и более слова, каждое с большой и не короче 3 букв
+# (под предлогами «с/в/и/по» предметы не путаются)
+_FULL_NAME_RE = re.compile(
+    r"^[А-ЯЁ][а-яё-]{2,}(?:\s+[А-ЯЁ][а-яё-]{2,}){2,}(?:\s*\([^()]*\))?"
+)
+# Организация/локация: «НПО Криста», «ПравоТех», «МАИС»
+_ORG_WORD_RE = re.compile(r"^[A-ZА-ЯЁ][A-Za-zА-ЯЁа-яё0-9&\-]*$")
+
+
+def _is_org_line(line: str) -> bool:
+    """Организация или аббревиатура-локация (но не «Деловое общение»)."""
+    if len(line) > 30 or _TIME_RE.search(line):
+        return False
+    words = line.split()
+    if not 1 <= len(words) <= 3:
+        return False
+    if any(not _ORG_WORD_RE.match(w) for w in words):
+        return False
+    if len(words) == 1:
+        # одно слово: аббревиатура (МАИС, ДСП) или camelcase-название (ПравоТех)
+        return words[0].isupper() and len(words[0]) <= 12 or re.search(
+            r"[a-zа-яё][A-ZА-ЯЁ]", words[0]
+        )
+    # несколько слов: первое — короче 6 букв и все заглавные (НПО, НИУ)
+    return words[0].isupper() and len(words[0]) <= 6
+
+_PAREN_RE = re.compile(r"\(([^()]*)\)")
+_ROOM_WORD_RE = re.compile(r"(?:ауд|каб)\.?\s*", re.I)
+
+
+@dataclass(frozen=True)
+class Lesson:
+    marker: str = ""
+    subject: str = ""
+    teacher: str = ""
+    room: str = ""
+    note: str = ""
+
+    def to_dict(self) -> dict:
+        return asdict(self)
+
+
+def _normalize_marker(num: Optional[str]) -> str:
+    return f"к.в. - {num}" if num else "к.в."
+
+
+def _squish(text: str) -> str:
+    return re.sub(r"\s{2,}", " ", text).strip()
+
+
+def _clean_name_parens(line: str) -> tuple[str, list[str]]:
+    """Скобки в строке преподавателя: со временем/датой -> заметка, остальное остаётся."""
+    notes: list[str] = []
+
+    def repl(m: re.Match) -> str:
+        inner = m.group(1).strip()
+        if not inner:
+            return ""  # пустые скобки после выноса красного фрагмента
+        if inner and _TIME_RE.search(inner):
+            notes.append(inner)
+            return ""
+        return m.group(0)
+
+    return _squish(_PAREN_RE.sub(repl, line)), notes
+
+
+def _clean_room_parens(line: str) -> tuple[str, list[str]]:
+    """Скобки в строке аудитории: «(221)»/«(л)» остаются, пояснения -> заметки."""
+    notes: list[str] = []
+
+    def repl(m: re.Match) -> str:
+        inner = m.group(1).strip()
+        keep = (
+            not inner
+            or len(inner) <= 2
+            or inner.isupper()
+            or not re.search(r"[а-яёА-ЯЁ]", inner)
+        )
+        if keep:
+            return m.group(0)
+        notes.append(inner)
+        return ""
+
+    cleaned = _PAREN_RE.sub(repl, line)
+    cleaned = _ROOM_WORD_RE.sub(
+        lambda m: "ауд. " if m.group(0)[:3].lower() == "ауд" else "каб. ", cleaned
+    )
+    return _squish(cleaned).strip(" ,"), notes
+
+
+@dataclass
+class _LineRoles:
+    subject: str = ""
+    teacher: str = ""
+    room: str = ""
+    org: str = ""
+    notes: tuple[str, ...] = ()
+
+
+def _line_is_room(line: str) -> bool:
+    core = _PAREN_RE.sub("", line)  # «… (онлайн)» — маркер предмета, не аудитория
+    return bool(
+        _ROOM_REF_RE.search(core)
+        or _URL_RE.search(line)
+        or _ONLINE_RE.search(core)
+        or _ROOM_START_RE.match(core)
+    )
+
+
+def _classify_line(line: str) -> _LineRoles:
+    roles = _LineRoles()
+
+    if _line_is_room(line):
+        rest = line
+        # «начало занятия в 18:30 онлайн» -> время в заметку, аудитория отдельно
+        prefix_m = _TIME_PREFIX_RE.match(rest)
+        if prefix_m and _line_is_room(prefix_m.group("rest")):
+            roles.notes = (prefix_m.group("time").strip(),)
+            rest = prefix_m.group("rest")
+        initial_matches = list(_NAME_INITIALS_RE.finditer(rest))
+        full_m = _FULL_NAME_RE.match(rest)
+        # инициалы весомее полного имени: «Сети Петри Башкин В.А. ауд. 224» —
+        # три слова предмета, а не ФИО
+        if initial_matches:
+            first = initial_matches[0].start()
+            tail = initial_matches[-1].end()
+            teacher_text = _squish(" ".join(m.group(0) for m in initial_matches))
+        elif full_m is not None:
+            first, tail = 0, full_m.end()
+            teacher_text = full_m.group(0)
+        else:
+            first, tail, teacher_text = -1, 0, ""
+            # до аудитории без имени: предмет и (реже) организация-преподаватель
+            anchors = [
+                m.start()
+                for m in (
+                    _ROOM_REF_RE.search(rest),
+                    _URL_RE.search(rest),
+                    _ONLINE_RE.search(rest),
+                    _ROOM_START_RE.match(rest),
+                )
+                if m is not None
+            ]
+            if anchors:
+                pos = min(anchors)
+                if pos > 0 and rest[:1].isupper():
+                    pre = _squish(rest[:pos])
+                    # «Методы сжатия КрасновМ.В.» — инициалы без пробела
+                    m_unsp = re.search(
+                        r"([А-ЯЁ][А-ЯЁа-яё\-]*\s*[А-ЯЁ]\.\s*[А-ЯЁ]?\.*)$", pre
+                    )
+                    if m_unsp:
+                        teacher_text = m_unsp.group(1).strip()
+                        pre = _squish(pre[: m_unsp.start()])
+                    words = pre.split()
+                    last = words[-1] if words else ""
+                    if len(words) >= 3 and len(last) >= 4 and not last.isupper():
+                        # «...модели принятия решения Наука ауд.221»
+                        teacher_text = last
+                        pre = _squish(" ".join(words[:-1]))
+                    if pre:
+                        roles.subject = pre
+                    tail = pos
+                # иначе «юридический корпус, 3 этаж ауд. 22» — целиком локация
+        if first >= 0 and not roles.subject and first > 0:
+            roles.subject = _squish(rest[:first])
+        if teacher_text:
+            roles.teacher, name_notes = _clean_name_parens(teacher_text)
+            roles.notes = roles.notes + tuple(name_notes)
+        room_part = _squish(rest[tail:])
+        if room_part:
+            roles.room, room_notes = _clean_room_parens(room_part)
+            roles.notes = roles.notes + tuple(room_notes)
+        return roles
+
+    initial_matches = list(_NAME_INITIALS_RE.finditer(line))
+    if initial_matches:
+        first = initial_matches[0].start()
+        if first > 0:
+            roles.subject = _squish(line[:first])
+        roles.teacher, notes = _clean_name_parens(line[first:])
+        roles.notes = tuple(notes)
+        return roles
+    full_m = _FULL_NAME_RE.match(line)
+    if full_m is not None:
+        roles.teacher, notes = _clean_name_parens(full_m.group(0))
+        if full_m.end() < len(line):
+            roles.subject = _squish(line[full_m.end() :])
+        roles.notes = tuple(notes)
+        return roles
+
+    if _TIME_RE.search(line):
+        frag = line.strip()
+        if frag.startswith("(") and frag.endswith(")") and frag.count("(") == 1:
+            frag = frag[1:-1].strip()
+        roles.notes = (frag,)
+        return roles
+
+    if _is_org_line(line):
+        roles.org = line
+        return roles
+
+    subject = _squish(line)
+    # «Методы сжатия КрасновМ.В.» — инициалы без пробела
+    if " " in subject:
+        m = re.search(r"^(\S.*\s+)([А-ЯЁ][А-ЯЁа-яё\-]*\s*[А-ЯЁ]\.\s*[А-ЯЁ]?\.*)[\s,]*$", subject)
+        if m:
+            roles.subject, roles.teacher = m.group(1).strip(), m.group(2).strip()
+            return roles
+        # «Предмет Денис Верховцев (Сигма)» — ФИО без отчества в конце строки
+        m = re.search(
+            r"^(.*\s)([А-ЯЁ][а-яё]{2,}\s+[А-ЯЁ][а-яё]{2,})(\s*\([^()]*\))?\s*$", subject
+        )
+        if m and len(subject.split()) >= 4:
+            teacher = _squish(m.group(2) + " " + (m.group(3) or ""))
+            roles.subject, roles.teacher = m.group(1).strip(), teacher
+            return roles
+    roles.subject = subject
+    return roles
+
+
+def _line_kind(line: str) -> str:
+    """Вид строки только для разбиения ячейки на блоки занятий."""
+    if _MARKER_LINE_RE.match(line) or _MARKER_PREFIX_RE.match(line):
+        return "marker"
+    if _line_is_room(line):
+        return "room"
+    if (
+        _FULL_NAME_RE.match(line)
+        or _NAME_INITIALS_RE.search(line)
+        or _TIME_RE.search(line)
+    ):
+        return "not-subject"
+    if _is_org_line(line):
+        return "org"
+    if line[:1].isupper():
+        return "subject"
+    return "other"
+
+
+def _starts_new_lesson(line: str) -> bool:
+    """Строка начинает новое занятие: с прописной, и не сама аудитория/ссылка/локация."""
+    if not line[:1].isupper():
+        return False
+    if re.match(r"(?i)^(?:ауд|каб)\.?", line):
+        return False
+    if _URL_RE.match(line) or re.match(r"(?i)^онлайн\b", line):
+        return False
+    if _ROOM_START_RE.match(line):
+        return False
+    return True
+
+
+def _split_blocks(lines: list[str]) -> list[list[str]]:
+    """Ячейка -> блоки занятий.
+
+    Новый блок начинается:
+      - после пустой строки;
+      - на строке с маркером «к.в.»;
+      - когда после аудитории или преподавателя строка начинается с названия
+        предмета (даже если она сама содержит аудиторию, «Методы сжатия ... ауд.231»).
+    Организация/локация («НПО Криста», «ИТ-11») новым занятием не считается.
+    """
+    blocks: list[list[str]] = []
+    current: list[str] = []
+    prev_kind = ""
+    for raw in lines:
+        line = raw.strip()
+        if not line:
+            if current:
+                blocks.append(current)
+                current = []
+            prev_kind = ""
+            continue
+        kind = _line_kind(line)
+        if current and (
+            kind == "marker"
+            or (
+                prev_kind in ("room", "not-subject")
+                and kind != "org"
+                and _starts_new_lesson(line)
+            )
+        ):
+            blocks.append(current)
+            current = []
+        current.append(line)
+        prev_kind = kind
+    if current:
+        blocks.append(current)
+    return blocks
+
+
+def _extract_marker(lines: list[str]) -> tuple[str, list[str]]:
+    first = lines[0]
+    m = _MARKER_LINE_RE.match(first)
+    if m:
+        return _normalize_marker(m.group(1)), lines[1:]
+    m = _MARKER_PREFIX_RE.match(first)
+    if m:
+        rest = first[m.end(1) :].strip()
+        lines = lines[1:]
+        if rest:
+            lines = [rest, *lines]
+        return _normalize_marker(m.group(2)), lines
+    return "", lines
+
+
+def _red_fragments(text: str) -> tuple[list[str], str]:
+    """Красные фрагменты -> примечания; текст остаётся на месте (пробелом)."""
+    frag_re = re.escape(RED_OPEN) + r"(.*?)" + re.escape(RED_CLOSE)
+    frags = []
+    for m in re.finditer(frag_re, text, re.S):
+        frag = _squish(m.group(1))
+        if frag.startswith("(") and frag.endswith(")"):
+            frag = frag[1:-1].strip()
+        if frag:
+            frags.append(frag)
+    return frags, re.sub(frag_re, " ", text, flags=re.S)
+
+
+def _balanced(text: str) -> str:
+    """Убирает осиротевшие скобки (в таблице их иногда не закрывают)."""
+    text = text.strip()
+    while text and (
+        (text[-1] == "(" and text.count("(") > text.count(")"))
+        or (text[-1] == ")" and text.count(")") > text.count("("))
+    ):
+        text = text[:-1].rstrip()
+    return text
+
+
+def _parse_block(block: list[str]) -> Optional[Lesson]:
+    text = "\n".join(block)
+    red_notes, text = _red_fragments(text)
+    lines = [ln.strip() for ln in text.split("\n") if ln.strip()]
+    if not lines:
+        if red_notes:
+            # в ячейке только примечание (например, «пары не будет»)
+            return Lesson(note="\n".join(dict.fromkeys(red_notes)))
+        return None
+
+    marker, lines = _extract_marker(lines)
+    if not lines:
+        if red_notes:
+            # в ячейке только примечание (например, «пары не будет»)
+            return Lesson(marker=marker, note="\n".join(dict.fromkeys(red_notes)))
+        return None  # в ячейке только маркер — занятия ещё нет
+
+    subjects: list[str] = []
+    teachers: list[str] = []
+    rooms: list[str] = []
+    notes: list[str] = list(red_notes)
+    person_seen = False
+
+    for line in lines:
+        roles = _classify_line(line)
+        notes.extend(roles.notes)
+        if roles.subject:
+            if not person_seen:
+                # однословная строка в позиции преподавателя — организация: «Хинт»
+                if (
+                    subjects
+                    and " " not in roles.subject
+                    and not re.search(r"\d", roles.subject)
+                    and 2 <= len(roles.subject) <= 12
+                ):
+                    teachers.append(roles.subject)
+                    person_seen = True
+                else:
+                    subjects.append(roles.subject)
+            elif not rooms:
+                rooms.append(roles.subject)  # локация без номера: «первый этаж, ...»
+            else:
+                notes.append(roles.subject)  # «ссылка в эл. университете»
+        if roles.teacher:
+            teachers.append(roles.teacher)
+            person_seen = True
+        if roles.room:
+            rooms.append(roles.room)
+            person_seen = True
+        if roles.org:
+            if not person_seen and not subjects:
+                subjects.append(roles.org)  # «МАИС», «БЖД» — предмет-аббревиатура
+            elif " " not in roles.org and re.search(r"\d", roles.org):
+                notes.append(roles.org)  # «ИТ-11» — метка параллельной группы
+            elif teachers:
+                rooms.append(roles.org)  # место проведения: «НПО Криста»
+            else:
+                teachers.append(roles.org)  # занятие ведёт организация: «ПравоТех»
+
+    return Lesson(
+        marker=marker,
+        subject=_squish(" ".join(subjects)),
+        teacher=_balanced(_squish(", ".join(dict.fromkeys(t for t in teachers if t)))),
+        room=_balanced(_squish(" / ".join(dict.fromkeys(r for r in rooms if r)))),
+        note=_balanced("\n".join(dict.fromkeys(n for n in notes if n))),
+    )
+
+
+def _normalize_marker_of(line: str) -> Optional[str]:
+    m = _MARKER_LINE_RE.match(line) or _MARKER_PREFIX_RE.match(line)
+    if not m:
+        return None
+    num = m.group(1) if m.re is _MARKER_LINE_RE else m.group(2)
+    return _normalize_marker(num or None)
+
+
+def parse_lesson_cell(cell_text: str) -> list[Lesson]:
+    """Текст ячейки -> список занятий."""
+    if not cell_text or not cell_text.strip():
+        return []
+    lines = cell_text.replace("\r\n", "\n").replace("\r", "\n").split("\n")
+    lessons: list[Lesson] = []
+    last_marker = ""
+    for block in _split_blocks(lines):
+        if len(block) == 1 and not _line_is_room(block[0]):
+            standalone = _normalize_marker_of(block[0])
+            if standalone:
+                last_marker = standalone
+                continue
+        lesson = _parse_block(block)
+        if lesson is None:
+            continue
+        if lesson.marker:
+            last_marker = lesson.marker
+        elif last_marker:
+            lesson = replace(lesson, marker=last_marker)
+        lessons.append(lesson)
+    return lessons
+
+
+# --- извлечение имён преподавателей (для индексов) -----------------------------
+
+def is_teacher_name(text: str) -> bool:
+    return bool(_NAME_INITIALS_RE.search(text) or _FULL_NAME_RE.match(text.strip()))
+
+
+def extract_teacher_names(teacher: str) -> list[str]:
+    """Строка преподавателя -> список коротких имён «Фамилия И.О.» (ключи индекса).
+
+    «Смирнов А.В., Петров П.П.» -> оба; «Лабеев Игорь Владимирович» -> «Лабеев И.В.»;
+    «ПравоТех» -> как есть.
+    """
+    if not teacher:
+        return []
+    names = [m.strip() for m in _NAME_INITIALS_RE.findall(teacher) if m.strip()]
+    if not names:
+        full = re.sub(r"\s*\([^()]*\)", "", teacher).strip()
+        full_m = _FULL_NAME_RE.match(full)
+        if full_m:
+            parts = full_m.group(0).split()
+            short = parts[0] + " " + parts[1][0].upper() + "."
+            if len(parts) > 2:
+                short += parts[2][0].upper() + "."
+            return [short]
+        if (
+            not re.search(r"\d|\s", teacher)
+            or (len(teacher) <= 30 and " " in teacher)
+        ) and not re.search(r"[а-яё][А-ЯЁ]", teacher):
+            return [teacher]  # организация одним словом или «НПО Криста»
+    return names
diff --git a/src/backend/schedule/parsing.py b/src/backend/schedule/parsing.py
new file mode 100644
index 0000000..e3ea942
--- /dev/null
+++ b/src/backend/schedule/parsing.py
@@ -0,0 +1,390 @@
+"""Разбор листов рабочей книги в структуру расписания.
+
+Основной лист «Бакалавры и магистры» имеет сетку:
+    столбец 0-1  — даты недели числителей («с»/«по»),
+    столбец 2-3  — dates недели знаменателей,
+    столбец 4    — день недели (в первой строке блока дня),
+    столбец 5    — номер пары и время (объединён на обе строки пары),
+    столбец 6+   — столбцы групп (скрытые столбцы игнорируются).
+
+Строки блока дня идут в хронологии семестра парами: первая строка пары —
+неделя числителей, вторая — знаменателей (даты в левой колонке каждой пары).
+Ячейки занятия разбирает lessons.parse_lesson_cell.
+"""
+
+from __future__ import annotations
+
+import logging
+import re
+from datetime import date
+
+from .errors import ScheduleError
+from .lessons import extract_teacher_names, parse_lesson_cell
+from .xlsx import RED_CLOSE, RED_OPEN, Worksheet, excel_serial_to_date
+
+log = logging.getLogger(__name__)
+
+MAIN_SHEET = "Бакалавры и магистры"
+ROOMS_SHEET = "аудитории"
+TEACHERS_SHEET = "Преподаватели"
+
+DAYS = ["понедельник", "вторник", "среда", "четверг", "пятница", "суббота", "воскресенье"]
+PARITIES = ("ч", "з")
+
+_COL_DAY = 4  # день недели
+_COL_PERIOD = 5  # пара и время
+_FIRST_GROUP_COL = 6
+
+_GROUP_RE = re.compile(r"^[А-ЯЁ]{2,4}-\d")
+_PERIOD_RE = re.compile(r"^\s*(\d{1,2})\s*(.*)$")
+_ROOM_RE = re.compile(r"ауд\.\s*([\w\-]+)", re.I)
+_SEMESTER_DATE_RE = re.compile(r"(\d{1,2}\.\d{1,2}\.\d{2})")
+_TIME_SPAN_RE = re.compile(r"\s*[-–—]\s*")
+
+
+def _strip_marks(text: str) -> str:
+    return text.replace(RED_OPEN, "").replace(RED_CLOSE, "").strip()
+
+
+def _normalize_header(text: str) -> str:
+    return _strip_marks(text).split("\n", 1)[0].strip()
+
+
+def _semester_of(header_cell: str) -> str | None:
+    """Дата окончания семестра из второй строки заголовка группы."""
+    parts = header_cell.split("\n", 1)
+    if len(parts) < 2:
+        return None
+    m = _SEMESTER_DATE_RE.search(_strip_marks(parts[1]))
+    return m.group(1) if m else None
+
+
+def _parse_period_cell(text: str) -> tuple[int | None, str]:
+    """'1|9:00-|10:35' / '3 13:20- 14:55' -> (номер пары, '13:20-14:55')."""
+    lines = [ln.strip() for ln in text.split("\n") if ln.strip()]
+    if not lines:
+        return None, ""
+    m = _PERIOD_RE.match(lines[0])
+    if not m:
+        return None, ""
+    parts = [m.group(2).strip(), *lines[1:]]
+    return int(m.group(1)), _TIME_SPAN_RE.sub("-", " ".join(p for p in parts if p))
+
+
+# --- недели и чётность ---------------------------------------------------------
+
+
+def extract_week_ranges(sheets: dict[str, Worksheet]) -> list[dict]:
+    """Все циклы семестра: [{'parity', 'start', 'end'}...] в хронологии."""
+    sheet = sheets.get(MAIN_SHEET)
+    if sheet is None:
+        return []
+    ranges: list[dict] = []
+    seen: set[tuple[str, date]] = set()
+    for row in sheet.rows[1:]:
+        if not any(row[i] for i in range(4)):
+            continue
+        for parity, start_col, end_col in (("ч", 0, 1), ("з", 2, 3)):
+            start = excel_serial_to_date(row[start_col])
+            end = excel_serial_to_date(row[end_col])
+            if start is None or end is None:
+                continue
+            key = (parity, start)
+            if key not in seen:
+                seen.add(key)
+                ranges.append({"parity": parity, "start": start, "end": end})
+    return sorted(ranges, key=lambda w: w["start"])
+
+
+def current_parity(week_ranges: list[dict], today: date | None = None) -> str | None:
+    today = today or date.today()
+    for week in week_ranges:
+        if week["start"] <= today <= week["end"]:
+            return week["parity"]
+    return None
+
+
+# --- главный лист -------------------------------------------------------------
+
+
+def _find_group_columns(header: list[str], hidden_cols: set[int]) -> dict[int, str]:
+    columns: dict[int, str] = {}
+    seen: set[str] = set()
+    for idx, cell in enumerate(header):
+        if idx in hidden_cols:
+            continue
+        name = _normalize_header(cell)
+        if name and _GROUP_RE.match(name) and name not in seen:
+            columns[idx] = name
+            seen.add(name)
+    return columns
+
+
+def parse_schedule(sheets: dict[str, Worksheet]) -> dict:
+    """Главный лист -> {группа: {'semester_until', 'days': {день: {пара: slot}}}}.
+
+    slot = {'time', 'ч': raw|None, 'з': raw|None, 'lessons': {'ч': [...], 'з': [...]}}
+    """
+    sheet = sheets.get(MAIN_SHEET)
+    if sheet is None:
+        raise ScheduleError(f"Лист «{MAIN_SHEET}» не найден в таблице")
+    rows = sheet.rows
+    header = rows[0]
+    group_columns = _find_group_columns(header, sheet.hidden_cols)
+    groups = {
+        name: {"semester_until": _semester_of(header[col]), "days": {}}
+        for col, name in group_columns.items()
+    }
+    day_times: dict[str, dict[int, str]] = {}
+
+    cur_day: str | None = None
+    cur_period: int | None = None
+    cur_time = ""
+    parity: str | None = None
+    rows_in_day = 0
+
+    for row in rows[1:]:
+        if not any(row[i] for i in range(4)):
+            continue
+        day = _normalize_header(row[_COL_DAY]).lower()
+        if day in DAYS and day != cur_day:
+            if cur_day is not None and rows_in_day % 2:
+                log.warning(
+                    "День «%s»: нечётное число строк (%d), недели могли сдвинуться",
+                    cur_day,
+                    rows_in_day,
+                )
+            cur_day = day
+            parity = None
+            rows_in_day = 0
+        if cur_day is None:
+            continue
+        rows_in_day += 1
+
+        period_cell = row[_COL_PERIOD]
+        if period_cell:
+            period, time = _parse_period_cell(period_cell)
+            if period is not None:
+                cur_period = period
+                cur_time = time
+                day_times.setdefault(cur_day, {}).setdefault(period, time)
+        if cur_period is None:
+            continue
+        parity = "з" if parity == "ч" else "ч"
+
+        for col, group_name in group_columns.items():
+            text = row[col]
+            if not text:
+                continue
+            days_map = groups[group_name]["days"].setdefault(cur_day, {})
+            slot = days_map.setdefault(
+                cur_period, {"time": cur_time, "ч": None, "з": None, "lessons": {}}
+            )
+            slot[parity] = text if slot[parity] is None else slot[parity]
+
+    # пары без занятий заполняем временем, как раньше
+    for group in groups.values():
+        for day, periods in day_times.items():
+            days_map = group["days"].setdefault(day, {})
+            for period, time in periods.items():
+                days_map.setdefault(
+                    period, {"time": time, "ч": None, "з": None, "lessons": {}}
+                )
+
+    for group in groups.values():
+        for day, periods in group["days"].items():
+            for slot in periods.values():
+                for par in PARITIES:
+                    raw = slot[par]
+                    slot["lessons"][par] = (
+                        [l.to_dict() for l in parse_lesson_cell(raw)] if raw else None
+                    )
+            group["days"][day] = dict(sorted(periods.items()))
+    return groups
+
+
+# --- представление для API -----------------------------------------------------
+
+
+def build_group_schedule(data: dict, group_name: str) -> dict | None:
+    group = data.get(group_name)
+    if group is None:
+        return None
+    out = {"group": group_name, "semester_until": group["semester_until"], "days": {}}
+    for day, periods in group["days"].items():
+        out["days"][day] = {}
+        for period, slot in sorted(periods.items()):
+            entry = {"time": slot["time"]}
+            for par in PARITIES:
+                raw = slot[par]
+                entry[par] = (
+                    None
+                    if not raw
+                    else {"raw": raw, "lessons": (slot["lessons"] or {}).get(par) or []}
+                )
+            out["days"][day][str(period)] = entry
+    return out
+
+
+def iter_lessons(schedule_data: dict):
+    """Все занятия: (group, day, period, time, parity, lesson_dict)."""
+    for group, gdata in schedule_data.items():
+        for day, periods in gdata["days"].items():
+            for period, slot in periods.items():
+                for par in PARITIES:
+                    if not slot[par]:
+                        continue
+                    for lesson in slot["lessons"].get(par) or []:
+                        yield group, day, period, slot["time"], par, lesson
+
+
+def _merge_entry(slot_list: list, entry_key: dict, extra: dict) -> dict:
+    for item in slot_list:
+        if all(item.get(k) == v for k, v in entry_key.items()):
+            return item
+    item = dict(entry_key)
+    item["groups"] = []
+    item.update(extra)
+    slot_list.append(item)
+    return item
+
+
+def build_teacher_room_index(schedule_data: dict) -> tuple[dict, dict]:
+    """Расписание -> (индекс преподавателей, индекс аудиторий)."""
+    teachers: dict = {}
+    rooms: dict = {}
+    for group, day, period, time, parity, lesson in iter_lessons(schedule_data):
+        subject = lesson["subject"]
+        room = lesson["room"].strip()
+
+        names = extract_teacher_names(lesson["teacher"])
+        if names:
+            # в ячейке может быть несколько преподавателей — заносим в каждый
+            for name in names:
+                slot = teachers.setdefault(name, {}).setdefault(day, {}).setdefault(
+                    str(period), {"time": time, "ч": [], "з": []}
+                )
+                item = _merge_entry(
+                    slot[parity],
+                    {"subject": subject, "room": room},
+                    {"marker": lesson["marker"]},
+                )
+                if group not in item["groups"]:
+                    item["groups"].append(group)
+
+        room_m = _ROOM_RE.match(room)
+        if room_m:
+            label = "ауд. " + room_m.group(1)
+            slot = rooms.setdefault(label, {}).setdefault(day, {}).setdefault(
+                str(period), {"time": time, "ч": [], "з": []}
+            )
+            display_teacher = ", ".join(names)
+            item = _merge_entry(
+                slot[parity],
+                {"subject": subject, "teacher": display_teacher},
+                {"marker": lesson["marker"]},
+            )
+            if group not in item["groups"]:
+                item["groups"].append(group)
+    return teachers, rooms
+
+
+def sort_rooms(room_names) -> list:
+    def key(name: str):
+        m = re.search(r"(\d+)", name)
+        return (0, int(m.group(1))) if m else (1, name)
+
+    return sorted(room_names, key=key)
+
+
+def build_day_times(schedule_data: dict) -> dict:
+    """Время пар по дням: {'понедельник': {'1': '9:00-10:35', ...}}."""
+    day_times: dict = {}
+    for gdata in schedule_data.values():
+        for day, periods in gdata["days"].items():
+            for period, slot in periods.items():
+                day_times.setdefault(day, {}).setdefault(
+                    str(period), slot.get("time", "")
+                )
+    return day_times
+
+
+def build_teacher_schedule(teachers: dict, name: str) -> dict | None:
+    if name not in teachers:
+        return None
+    return {"name": name, "days": teachers[name]}
+
+
+def build_room_schedule(rooms: dict, label: str, day_times: dict | None = None) -> dict | None:
+    if label not in rooms:
+        return None
+    data = rooms[label]
+    day_times = day_times or {}
+    out = {"room": label, "days": {}}
+    all_days = {*data.keys(), *day_times.keys()}
+    for day in sorted(all_days, key=lambda d: DAYS.index(d) if d in DAYS else 99):
+        times = day_times.get(day, {})
+        periods = {*data.get(day, {}).keys(), *times.keys()}
+        out["days"][day] = {}
+        for period in sorted(periods, key=int):
+            occupied = data.get(day, {}).get(period, {})
+            entry = {"time": occupied.get("time", times.get(period, ""))}
+            for par in PARITIES:
+                lessons = occupied.get(par) or []
+                entry[par] = lessons if lessons else None
+            out["days"][day][str(period)] = entry
+    return out
+
+
+# --- вспомогательные листы ------------------------------------------------------
+
+
+def parse_rooms_info(sheets: dict[str, Worksheet]) -> dict:
+    """Лист «аудитории»: 'ауд. N' -> {'room', 'info'} (оснащение, вместимость)."""
+    sheet = sheets.get(ROOMS_SHEET)
+    if sheet is None or len(sheet.rows) < 2:
+        return {}
+    header, desc = sheet.rows[0], sheet.rows[1]
+    info: dict = {}
+    for col in range(_FIRST_GROUP_COL, max(len(header), len(desc))):
+        m = re.search(r"(\d+)", str(header[col]))
+        if not m:
+            continue
+        number = m.group(1)
+        text = " ".join(
+            ln.strip() for ln in str(desc[col]).split("\n") if ln.strip()
+        )
+        label = f"ауд. {number}"
+        info[label] = {"room": label, "info": _strip_marks(text)}
+    return info
+
+
+def _initials_from_parts(first: str, patronymic: str) -> str:
+    initials = ""
+    if first:
+        initials += first[0].upper() + "."
+    if patronymic:
+        initials += patronymic[0].upper() + "."
+    return initials
+
+
+def parse_teachers_full(sheets: dict[str, Worksheet]) -> dict:
+    """Лист «Преподаватели»: 'Фамилия И.О.' -> полное ФИО (строка-заголовок)."""
+    sheet = sheets.get(TEACHERS_SHEET)
+    if sheet is None or len(sheet.rows) < 2:
+        return {}
+    header = sheet.rows[1]
+    result: dict = {}
+    for col in range(_FIRST_GROUP_COL, len(header)):
+        value = _strip_marks(str(header[col]))
+        parts = [p.strip() for p in re.split(r"[\s\n]+", value) if p.strip()]
+        if not parts:
+            continue
+        surname = parts[0]
+        first = parts[1] if len(parts) > 1 else ""
+        patronymic = parts[2] if len(parts) > 2 else ""
+        short = f"{surname} {_initials_from_parts(first, patronymic)}".strip()
+        full = " ".join(parts)
+        if short and full:
+            result.setdefault(short, full)
+    return result
diff --git a/src/backend/schedule/source.py b/src/backend/schedule/source.py
new file mode 100644
index 0000000..dc40451
--- /dev/null
+++ b/src/backend/schedule/source.py
@@ -0,0 +1,45 @@
+"""Загрузка файла расписания по публичной ссылке Яндекс.Диска."""
+
+from __future__ import annotations
+
+import logging
+
+import requests
+
+from .errors import ScheduleError
+
+log = logging.getLogger(__name__)
+
+CLOUD_API = "https://cloud-api.yandex.net/v1/disk/public/resources"
+
+
+def download_schedule(public_url: str, timeout: float = 60.0) -> bytes:
+    """Скачивает файл с диска; при любой ошибке бросает ScheduleError."""
+    try:
+        resp = requests.get(
+            f"{CLOUD_API}/download",
+            params={"public_key": public_url},
+            timeout=timeout,
+        )
+        resp.raise_for_status()
+        href = resp.json()["href"]
+        file_resp = requests.get(href, timeout=timeout)
+        file_resp.raise_for_status()
+        return file_resp.content
+    except (requests.RequestException, KeyError, ValueError) as exc:
+        raise ScheduleError(f"Не удалось скачать таблицу: {exc}") from exc
+
+
+def fetch_table_modified(public_url: str, timeout: float = 20.0) -> str | None:
+    """Время последнего изменения файла на диске или None, если не удалось узнать."""
+    try:
+        resp = requests.get(
+            CLOUD_API,
+            params={"public_key": public_url},
+            timeout=timeout,
+        )
+        resp.raise_for_status()
+        return resp.json().get("modified")
+    except (requests.RequestException, ValueError) as exc:
+        log.debug("Не удалось получить modified таблицы: %s", exc)
+        return None
diff --git a/src/backend/schedule/xlsx.py b/src/backend/schedule/xlsx.py
new file mode 100644
index 0000000..01ed260
--- /dev/null
+++ b/src/backend/schedule/xlsx.py
@@ -0,0 +1,235 @@
+"""Чтение xlsx-рабочей книги без сторонних библиотек.
+
+Извлекает только то, что нужно для расписания:
+- строки каждого листа как матрицу строк (объединённые ячейки раскатываются
+  до верхне-левого значения, пустые ячейки — ""),
+- номера скрытых столбцов (в таблице ими помечены служебные данные),
+- красные фрагменты текста, которые в таблице используются как примечания:
+  они оборачиваются служебными знаками RED_OPEN/RED_CLOSE.
+"""
+
+from __future__ import annotations
+
+import io
+import re
+import zipfile
+import xml.etree.ElementTree as ET
+from dataclasses import dataclass
+from datetime import date, datetime, timedelta
+
+from .errors import ScheduleError
+
+XLSX_NS = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
+REL_NS = "http://schemas.openxmlformats.org/officeDocument/2006/relationships"
+
+RED_OPEN = "\u27EA"  # ⟪ — начало красного фрагмента (примечание)
+RED_CLOSE = "\u27EB"  # ⟫ — конец красного фрагмента
+
+_REF_RE = re.compile(r"^([A-Z]+)(\d+)$")
+
+
+@dataclass
+class Worksheet:
+    rows: list[list[str]]
+    hidden_cols: set[int]
+
+    def cell(self, row_idx: int, col_idx: int) -> str:
+        """Значение ячейки, "" вне границ матрицы."""
+        if row_idx < 0 or row_idx >= len(self.rows):
+            return ""
+        row = self.rows[row_idx]
+        if col_idx < 0 or col_idx >= len(row):
+            return ""
+        return row[col_idx]
+
+
+def col_index(col_letter: str) -> int:
+    """'A' -> 0, 'Z' -> 25, 'AA' -> 26."""
+    idx = 0
+    for ch in col_letter:
+        idx = idx * 26 + (ord(ch) - ord("A") + 1)
+    return idx - 1
+
+
+def _parse_ref(ref: str) -> tuple[int, int]:
+    m = _REF_RE.match(ref)
+    if not m:
+        raise ScheduleError(f"Некорректная ссылка на ячейку: {ref!r}")
+    return col_index(m.group(1)), int(m.group(2)) - 1
+
+
+def excel_serial_to_date(serial: object) -> date | None:
+    """Серийная дата Excel (число или строка) в date; None, если не похоже на дату."""
+    try:
+        value = float(str(serial).replace(",", "."))
+    except (TypeError, ValueError):
+        return None
+    if value <= 0:
+        return None
+    # Excel считает 1.01.1900 = 1 и знает о несуществующем 29.02.1900 (серия 60).
+    if value <= 59:
+        value += 1
+    return (datetime(1899, 12, 30) + timedelta(days=value)).date()
+
+
+def _is_red_rgb(rgb: str | None) -> bool:
+    """Красный цвет ячейки вида FFRRGGBB."""
+    if not rgb or len(rgb) < 8 or not rgb.startswith("FF"):
+        return False
+    try:
+        r = int(rgb[2:4], 16)
+        g = int(rgb[4:6], 16)
+        b = int(rgb[6:8], 16)
+    except ValueError:
+        return False
+    return r > 0x90 and g < 0x70 and b < 0x70
+
+
+def _parse_shared_strings(xml_bytes: bytes) -> list[str]:
+    """sharedStrings.xml -> список значений.
+
+    Красные ранки оборачиваются RED_OPEN/RED_CLOSE, чтобы на этапе разбора
+    занятий примечания отделить от основного текста.
+    """
+    root = ET.fromstring(xml_bytes)
+    out: list[str] = []
+    for si in root.iter(f"{{{XLSX_NS}}}si"):
+        parts: list[tuple[str, bool]] = []
+        for child in si:
+            if child.tag == f"{{{XLSX_NS}}}t":
+                parts.append((child.text or "", False))
+                continue
+            if child.tag != f"{{{XLSX_NS}}}r":
+                continue
+            t = child.find(f"{{{XLSX_NS}}}t")
+            red = False
+            rpr = child.find(f"{{{XLSX_NS}}}rPr")
+            if rpr is not None:
+                color = rpr.find(f"{{{XLSX_NS}}}color")
+                if color is not None:
+                    red = _is_red_rgb(color.get("rgb"))
+            parts.append((t.text or "", red))
+        out.append(
+            "".join(
+                f"{RED_OPEN}{text}{RED_CLOSE}" if red else text for text, red in parts
+            )
+        )
+    return out
+
+
+def _parse_sheet(xml_bytes: bytes, shared: list[str]) -> Worksheet:
+    root = ET.fromstring(xml_bytes)
+    cells: dict[tuple[int, int], str] = {}
+    max_row = 0
+    max_col = 0
+
+    hidden_cols: set[int] = set()
+    cols_node = root.find(f".//{{{XLSX_NS}}}cols")
+    if cols_node is not None:
+        for col in cols_node.iter(f"{{{XLSX_NS}}}col"):
+            try:
+                c_min = int(col.get("min"))
+                c_max = int(col.get("max"))
+            except (TypeError, ValueError):
+                continue
+            if col.get("hidden") == "1":
+                hidden_cols.update(range(c_min - 1, c_max))
+
+    for row in root.iter(f"{{{XLSX_NS}}}row"):
+        row_num = row.get("r")
+        if not row_num:
+            continue
+        r = int(row_num) - 1
+        for cell in row.iter(f"{{{XLSX_NS}}}c"):
+            ref = cell.get("r")
+            if not ref:
+                continue
+            c = col_index("".join(ch for ch in ref if ch.isalpha()))
+            t = cell.get("t")
+            v = cell.find(f"{{{XLSX_NS}}}v")
+            if t == "s" and v is not None and v.text is not None:
+                try:
+                    idx = int(v.text)
+                except ValueError:
+                    continue
+                value = shared[idx] if idx < len(shared) else ""
+            elif v is not None and v.text is not None:
+                value = v.text
+            else:
+                is_node = cell.find(f"{{{XLSX_NS}}}is")
+                value = "".join(_iter_text(is_node)) if is_node is not None else ""
+            if value != "":
+                cells[(r, c)] = value
+            max_row = max(max_row, r)
+            max_col = max(max_col, c)
+
+    merge_node = root.find(f".//{{{XLSX_NS}}}mergeCells")
+    if merge_node is not None:
+        for mc in merge_node.iter(f"{{{XLSX_NS}}}mergeCell"):
+            ref = mc.get("ref")
+            if not ref or ":" not in ref:
+                continue
+            a, b = ref.split(":")
+            c1, r1 = _parse_ref(a)
+            c2, r2 = _parse_ref(b)
+            max_row = max(max_row, r2)
+            max_col = max(max_col, c2)
+            top = cells.get((r1, c1), "")
+            if not top:
+                continue
+            for rr in range(r1, r2 + 1):
+                for cc in range(c1, c2 + 1):
+                    if (rr, cc) not in cells:
+                        cells[(rr, cc)] = top
+
+    rows = [
+        [cells.get((r, c), "") for c in range(max_col + 1)]
+        for r in range(max_row + 1)
+    ]
+    return Worksheet(rows=rows, hidden_cols=hidden_cols)
+
+
+def _iter_text(node: ET.Element):
+    for el in node.iter(f"{{{XLSX_NS}}}t"):
+        if el.text:
+            yield el.text
+
+
+def parse_workbook(xlsx_bytes: bytes) -> dict[str, Worksheet]:
+    """xlsx -> {имя листа: Worksheet}."""
+    try:
+        zf = zipfile.ZipFile(io.BytesIO(xlsx_bytes))
+    except zipfile.BadZipFile as exc:
+        raise ScheduleError("Скачанный файл не является xlsx") from exc
+
+    try:
+        shared = _parse_shared_strings(zf.read("xl/sharedStrings.xml"))
+    except KeyError:
+        shared = []
+
+    rels_root = ET.fromstring(zf.read("xl/_rels/workbook.xml.rels"))
+    rel_map = {
+        rel.get("Id"): rel.get("Target")
+        for rel in rels_root
+        if rel.get("Id") and rel.get("Target")
+    }
+
+    sheets: dict[str, Worksheet] = {}
+    wb_root = ET.fromstring(zf.read("xl/workbook.xml"))
+    for sheet in wb_root.iter(f"{{{XLSX_NS}}}sheet"):
+        name = sheet.get("name")
+        rid = sheet.get(f"{{{REL_NS}}}id")
+        target = rel_map.get(rid or "")
+        if not (name and target):
+            continue
+        target = target.lstrip("/")
+        if target.startswith("xl/"):
+            target = target[3:]
+        if target.startswith("worksheets/"):
+            try:
+                sheets[name] = _parse_sheet(zf.read("xl/" + target), shared)
+            except ScheduleError:
+                raise
+            except ET.ParseError as exc:
+                raise ScheduleError(f"Не удалось разобрать лист «{name}»") from exc
+    return sheets
diff --git a/src/backend/schedule_parser.py b/src/backend/schedule_parser.py
deleted file mode 100644
index 0da8711..0000000
--- a/src/backend/schedule_parser.py
+++ /dev/null
@@ -1,799 +0,0 @@
-import io
-import re
-import zipfile
-import xml.etree.ElementTree as ET
-from datetime import date, datetime, timedelta
-
-import requests
-
-XLSX_NS = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
-REL_NS = "http://schemas.openxmlformats.org/officeDocument/2006/relationships"
-MAIN_SHEET = "Бакалавры и магистры"
-
-DAYS = ["понедельник", "вторник", "среда", "четверг", "пятница", "суббота", "воскресенье"]
-
-_PERIOD_RE = re.compile(r"^\s*(\d+)\s*(.*)$")
-_REF_RE = re.compile(r"^([A-Z]+)(\d+)$")
-
-
-class ScheduleError(Exception):
-    pass
-
-
-def _iter_text(node):
-    for el in node.iter(f"{{{XLSX_NS}}}t"):
-        if el.text:
-            yield el.text
-
-
-def _col_index(col_letter):
-    idx = 0
-    for ch in col_letter:
-        idx = idx * 26 + (ord(ch) - ord("A") + 1)
-    return idx - 1
-
-
-def _parse_ref(ref):
-    m = _REF_RE.match(ref)
-    if not m:
-        raise ValueError(f"Некорректная ссылка на ячейку: {ref}")
-    return _col_index(m.group(1)), int(m.group(2)) - 1
-
-
-RED_OPEN = "\u27EA"
-RED_CLOSE = "\u27EB"
-
-
-def _is_red_rgb(rgb):
-    try:
-        if not rgb or len(rgb) < 8 or not rgb.startswith("FF"):
-            return False
-        r = int(rgb[2:4], 16)
-        g = int(rgb[4:6], 16)
-        b = int(rgb[6:8], 16)
-    except (ValueError, TypeError):
-        return False
-    return r > 0x90 and g < 0x70 and b < 0x70
-
-
-def _parse_shared_strings(xml_bytes):
-    root = ET.fromstring(xml_bytes)
-    out = []
-    for si in root.iter(f"{{{XLSX_NS}}}si"):
-        parts = []
-        for child in si:
-            if child.tag == f"{{{XLSX_NS}}}t":
-                parts.append((child.text or "", False))
-                continue
-            if child.tag != f"{{{XLSX_NS}}}r":
-                continue
-            t = child.find(f"{{{XLSX_NS}}}t")
-            text = t.text if t is not None else ""
-            red = False
-            rpr = child.find(f"{{{XLSX_NS}}}rPr")
-            if rpr is not None:
-                color = rpr.find(f"{{{XLSX_NS}}}color")
-                if color is not None:
-                    red = _is_red_rgb(color.get("rgb"))
-            parts.append((text or "", red))
-        chunks = []
-        for text, red in parts:
-            if red:
-                chunks.append(RED_OPEN + text + RED_CLOSE)
-            else:
-                chunks.append(text)
-        out.append("".join(chunks))
-    return out
-
-
-def _parse_sheet(xml_bytes, shared):
-    root = ET.fromstring(xml_bytes)
-    cells = {}
-    max_row = 0
-    max_col = 0
-    hidden_cols = set()
-
-    cols_node = root.find(f".//{{{XLSX_NS}}}cols")
-    if cols_node is not None:
-        for col in cols_node.iter(f"{{{XLSX_NS}}}col"):
-            if col.get("hidden") == "1":
-                try:
-                    c_min = int(col.get("min"))
-                    c_max = int(col.get("max"))
-                except (TypeError, ValueError):
-                    continue
-                hidden_cols.update(range(c_min - 1, c_max))
-
-    for row in root.iter(f"{{{XLSX_NS}}}row"):
-        r = int(row.get("r")) - 1
-        for cell in row.iter(f"{{{XLSX_NS}}}c"):
-            ref = cell.get("r")
-            if not ref:
-                continue
-            c = _col_index("".join(ch for ch in ref if ch.isalpha()))
-            t = cell.get("t")
-            v = cell.find(f"{{{XLSX_NS}}}v")
-            if t == "s" and v is not None and v.text:
-                idx = int(v.text)
-                value = shared[idx] if idx < len(shared) else ""
-            elif v is not None and v.text is not None:
-                value = v.text
-            else:
-                is_node = cell.find(f"{{{XLSX_NS}}}is")
-                value = "".join(_iter_text(is_node)) if is_node is not None else ""
-            if value != "":
-                cells[(r, c)] = value
-            max_row = max(max_row, r)
-            max_col = max(max_col, c)
-
-    merge_node = root.find(f".//{{{XLSX_NS}}}mergeCells")
-    if merge_node is not None:
-        for mc in merge_node.iter(f"{{{XLSX_NS}}}mergeCell"):
-            ref = mc.get("ref")
-            if not ref or ":" not in ref:
-                continue
-            a, b = ref.split(":")
-            c1, r1 = _parse_ref(a)
-            c2, r2 = _parse_ref(b)
-            max_row = max(max_row, r2)
-            max_col = max(max_col, c2)
-            top = cells.get((r1, c1), "")
-            if not top:
-                continue
-            for rr in range(r1, r2 + 1):
-                for cc in range(c1, c2 + 1):
-                    if (rr, cc) not in cells:
-                        cells[(rr, cc)] = top
-
-    matrix = [
-        [cells.get((r, c), "") for c in range(max_col + 1)]
-        for r in range(max_row + 1)
-    ]
-    return matrix, hidden_cols
-
-
-def _read_cell(row, col_idx):
-    if col_idx < len(row):
-        return row[col_idx]
-    return ""
-
-
-def download_schedule(public_url):
-    try:
-        resp = requests.get(
-            "https://cloud-api.yandex.net/v1/disk/public/resources/download",
-            params={"public_key": public_url},
-            timeout=30,
-        )
-        resp.raise_for_status()
-        href = resp.json()["href"]
-        file_resp = requests.get(href, timeout=60)
-        file_resp.raise_for_status()
-        return file_resp.content
-    except Exception as exc:
-        raise ScheduleError(f"Не удалось скачать таблицу: {exc}") from exc
-
-
-def fetch_table_modified(public_url):
-    try:
-        resp = requests.get(
-            "https://cloud-api.yandex.net/v1/disk/public/resources",
-            params={"public_key": public_url},
-            timeout=30,
-        )
-        resp.raise_for_status()
-        return resp.json().get("modified")
-    except Exception:
-        return None
-
-
-def parse_workbook(xlsx_bytes):
-    try:
-        zf = zipfile.ZipFile(io.BytesIO(xlsx_bytes))
-    except zipfile.BadZipFile as exc:
-        raise ScheduleError("Скачанный файл не является xlsx") from exc
-
-    shared = []
-    try:
-        shared = _parse_shared_strings(zf.read("xl/sharedStrings.xml"))
-    except KeyError:
-        pass
-
-    rels_root = ET.fromstring(zf.read("xl/_rels/workbook.xml.rels"))
-    rel_map = {}
-    for rel in rels_root:
-        rid = rel.get("Id")
-        target = rel.get("Target")
-        if rid and target:
-            rel_map[rid] = target
-
-    wb_root = ET.fromstring(zf.read("xl/workbook.xml"))
-    sheets = {}
-    for sheet in wb_root.iter(f"{{{XLSX_NS}}}sheet"):
-        name = sheet.get("name")
-        rid = sheet.get(f"{{{REL_NS}}}id")
-        if name and rid and rid in rel_map:
-            target = rel_map[rid]
-            if target.startswith("worksheets/"):
-                matrix, hidden_cols = _parse_sheet(zf.read("xl/" + target), shared)
-                sheets[name] = {"rows": matrix, "hidden_cols": hidden_cols}
-
-    return sheets
-
-
-def _normalize_header(text):
-    return text.split("\n", 1)[0].strip()
-
-
-def _excel_serial_to_date(serial):
-    try:
-        value = float(str(serial).replace(",", "."))
-    except (TypeError, ValueError):
-        return None
-    if value <= 0:
-        return None
-    if value <= 60:
-        value -= 1
-    return (datetime(1899, 12, 30) + timedelta(days=value)).date()
-
-
-def extract_week_ranges(sheets):
-    if MAIN_SHEET not in sheets:
-        return []
-    matrix = sheets[MAIN_SHEET]["rows"]
-    ranges = []
-    seen = set()
-    for row in matrix[1:]:
-        if not any(_read_cell(row, i) for i in range(4)):
-            continue
-        for parity, start_col, end_col in (("ч", 0, 1), ("з", 2, 3)):
-            start = _excel_serial_to_date(_read_cell(row, start_col))
-            end = _excel_serial_to_date(_read_cell(row, end_col))
-            if start and end:
-                key = (parity, start)
-                if key not in seen:
-                    seen.add(key)
-                    ranges.append({"parity": parity, "start": start, "end": end})
-    return sorted(ranges, key=lambda w: w["start"])
-
-
-def current_parity(week_ranges, today=None):
-    today = today or date.today()
-    for week in week_ranges:
-        if week["start"] <= today <= week["end"]:
-            return week["parity"]
-    return None
-
-
-def parse_schedule(sheets):
-    if MAIN_SHEET not in sheets:
-        raise ScheduleError(f"Лист «{MAIN_SHEET}» не найден в таблице")
-    sheet = sheets[MAIN_SHEET]
-    matrix = sheet["rows"]
-    hidden_cols = sheet["hidden_cols"]
-
-    header = matrix[0]
-    group_columns = {}
-    seen_names = set()
-    group_re = re.compile(r"^[А-ЯЁ]{2,4}-\d")
-    for idx, cell in enumerate(header):
-        if idx in hidden_cols:
-            continue
-        name = _normalize_header(cell)
-        if name and group_re.match(name) and name not in seen_names:
-            group_columns[idx] = name
-            seen_names.add(name)
-
-    groups = {}
-    for col, name in group_columns.items():
-        header_text = _read_cell(header, col)
-        semester = None
-        if "\n" in header_text:
-            second = header_text.split("\n", 1)[1].strip()
-            m = re.search(r"(\d{1,2}\.\d{2}\.\d{2})", second)
-            if m:
-                semester = m.group(1)
-        groups[name] = {"semester_until": semester, "days": {}}
-
-    day_periods = {}
-    cur_day = None
-    period = None
-    cur_time = ""
-    parity = None
-
-    for row in matrix[1:]:
-        has_dates = any(_read_cell(row, i) for i in range(4))
-        if not has_dates:
-            continue
-
-        day = _read_cell(row, 4)
-        if day:
-            normalized = day.strip().lower()
-            if normalized in DAYS:
-                if normalized != cur_day:
-                    cur_day = normalized
-                    parity = None
-        if cur_day is None:
-            continue
-
-        period_cell = _read_cell(row, 5)
-        if period_cell:
-            lines = [ln.strip() for ln in period_cell.split("\n") if ln.strip()]
-            m = _PERIOD_RE.match(lines[0])
-            if m:
-                period = int(m.group(1))
-                time_parts = [m.group(2).strip()]
-                time_parts += lines[1:]
-                cur_time = " ".join(p for p in time_parts if p)
-                cur_time = re.sub(r"\s*[-–—]\s*", "-", cur_time)
-                day_periods.setdefault(cur_day, {}).setdefault(period, cur_time)
-
-        if period is None:
-            continue
-
-        parity = "з" if parity == "ч" else "ч"
-
-        for col, group_name in group_columns.items():
-            cell_text = _read_cell(row, col)
-            if cell_text:
-                days_map = groups[group_name]["days"].setdefault(cur_day, {})
-                slot = days_map.setdefault(period, {"time": cur_time, "ч": None, "з": None})
-                slot[parity] = cell_text
-
-    for group_name in groups:
-        for day, periods in day_periods.items():
-            days_map = groups[group_name]["days"]
-            for period, time in periods.items():
-                days_map.setdefault(day, {})[period] = days_map.get(day, {}).get(
-                    period, {"time": time, "ч": None, "з": None}
-                )
-            days_map[day] = dict(sorted(days_map[day].items()))
-
-    return groups
-
-
-_MARKER_RE = re.compile(r"к\.в\.?\s*-?\s*\d*\s*", re.IGNORECASE)
-
-
-_ROOM_LINE_RE = re.compile(r"ауд\.\s*[\w\-]+", re.IGNORECASE)
-_SUBJECT_START_RE = re.compile(r"^[А-ЯЁA-Z]")
-
-
-def _split_lesson_blocks(cell_text):
-    lines = cell_text.replace("\r\n", "\n").replace("\r", "\n").split("\n")
-    blocks = []
-    current = []
-    prev_blank = True
-    prev_room_line = False
-    for raw in lines:
-        line = raw.strip()
-        if not line:
-            prev_blank = True
-            continue
-        starts_marker = bool(_MARKER_RE.match(line))
-        room_line = bool(_ROOM_LINE_RE.search(line))
-        subject_start = bool(_SUBJECT_START_RE.match(line)) and not any(
-            w in line for w in ("не будет", "отменяется", "переносится")
-        )
-        if current and (prev_blank or starts_marker or (prev_room_line and subject_start)):
-            blocks.append(current)
-            current = []
-        current.append(line)
-        prev_blank = False
-        prev_room_line = room_line
-    if current:
-        blocks.append(current)
-    return blocks
-
-
-def _lesson(marker, subject, teacher, room):
-    room = re.sub(r"ауд\.?\s*", "ауд. ", room, flags=re.IGNORECASE)
-    room = re.sub(r"\s{2,}", " ", room).strip()
-    return {
-        "marker": marker,
-        "subject": subject,
-        "teacher": teacher,
-        "room": room,
-    }
-
-
-def _split_subject_teacher(head):
-    head = head.strip()
-    name_re = re.compile(
-        r"([А-ЯЁ][а-яё-]+(?:\s+[А-ЯЁ]\.[А-ЯЁ]\.?)+)(\s*\([^)]*\))*$"
-    )
-    name_m = name_re.search(head)
-    if name_m:
-        teacher = name_m.group(1).strip()
-        subject = (head[: name_m.start()] + (name_m.group(2) or "")).strip()
-        return subject, teacher
-    words = head.split()
-    if len(words) >= 2 and words[-1][:1].isupper():
-        return " ".join(words[:-1]), words[-1]
-    return head, ""
-
-
-def _parse_inline(text, marker):
-    text = text.strip()
-    m = None
-    for match in re.finditer(r"ауд\.?\s*[\d\-]+\w*", text, re.IGNORECASE):
-        m = match
-    if not m:
-        return _lesson(marker, text, "", "")
-    room = m.group(0).strip()
-    head = text[: m.start()].strip()
-    subject, teacher = _split_subject_teacher(head)
-    return _lesson(marker, subject, teacher, room)
-
-
-def _parse_lesson(lines):
-    lines = [
-        ln.replace(RED_OPEN, "").replace(RED_CLOSE, "").strip()
-        for ln in lines
-        if ln.strip()
-    ]
-    if not lines:
-        return None
-
-    marker = None
-    m = re.match(r"^(к\.в\.?\s*-?\s*\d*)\s*(.*)$", lines[0], re.IGNORECASE)
-    if m:
-        marker = m.group(1).strip()
-        rest_head = m.group(2).strip()
-        if rest_head:
-            lines[0] = rest_head
-        else:
-            lines = lines[1:]
-    if not lines:
-        return None
-
-    if len(lines) == 1:
-        return _parse_inline(lines[0], marker)
-
-    if len(lines) == 2:
-        second = lines[1]
-        if re.search(r"(ауд\.|http|зал|каб\.|онлайн)", second, re.IGNORECASE):
-            subject, teacher = _split_subject_teacher(lines[0])
-            return _lesson(marker, subject, teacher, second)
-        if re.search(r"\b[А-ЯЁ]\.[А-ЯЁ]\.?$", second):
-            return _lesson(marker, lines[0], second, "")
-        return _lesson(marker, lines[0], "", second)
-
-    # >=3 строк: ищем строку аудитории, преподаватель — строка перед ней;
-    # строки после аудитории (примечания) не ломают разбор
-    room_idx = None
-    for i in range(len(lines) - 1, -1, -1):
-        if _ROOM_LINE_RE.match(lines[i]):
-            room_idx = i
-            break
-    if room_idx is None:
-        room = lines[-1]
-        teacher = lines[-2]
-        subject = " ".join(lines[:-2])
-        return _lesson(marker, subject, teacher, room)
-
-    room = lines[room_idx]
-    before = lines[:room_idx]
-    teacher = ""
-    teacher_idx = None
-    for i in range(len(before) - 1, -1, -1):
-        cand = before[i]
-        if _looks_like_teacher_line(cand):
-            teacher_idx = i
-            teacher = cand
-            break
-    if teacher_idx is not None:
-        subject = " ".join(before[:teacher_idx])
-    else:
-        subject = " ".join(before)
-    return _lesson(marker, subject, teacher, room)
-
-
-def _unwrap_parens(text):
-    text = text.strip()
-    if text.startswith("(") and text.endswith(")"):
-        inner = text[1:-1].strip()
-        if inner:
-            return inner
-    return text
-
-
-def _collect_notes(text):
-    notes = []
-    for m in re.findall(r"⟪([^⟫]*)⟫", text):
-        frag = m.strip()
-        if frag:
-            notes.append((_unwrap_parens(frag), True))
-    plain = re.sub(r"⟪[^⟫]*⟫", "", text)
-    for m in re.finditer(r"\(([^()]*)\)", plain):
-        inner = m.group(1).strip()
-        if not inner:
-            continue
-        if re.search(r"[А-ЯЁ]\.[А-ЯЁ]\.?", inner):
-            continue
-        if not re.search(r"[а-яёА-ЯЁa-zA-Z]", inner):
-            continue
-        notes.append((_unwrap_parens(inner), False))
-    return notes
-
-
-def _strip_note_markers(value):
-    return value.replace(RED_OPEN, "").replace(RED_CLOSE, "")
-
-
-def _split_lessons(cell_text):
-    lessons = []
-    last_marker = None
-    for block in _split_lesson_blocks(cell_text):
-        block_text = "\n".join(block)
-        lesson = _parse_lesson(block)
-        if lesson is None:
-            continue
-        for key in ("marker", "subject", "teacher", "room"):
-            if lesson[key]:
-                lesson[key] = _strip_note_markers(lesson[key])
-        fields = " ".join(
-            x for x in (lesson["subject"], lesson["teacher"], lesson["room"]) if x
-        )
-        keep = []
-        seen_notes = set()
-        for note_text, is_red in _collect_notes(block_text):
-            if not note_text or note_text in seen_notes:
-                continue
-            if not is_red and note_text in fields:
-                continue
-            seen_notes.add(note_text)
-            keep.append(note_text)
-        lesson["note"] = "\n".join(keep)
-        if lesson["marker"]:
-            last_marker = lesson["marker"]
-        elif last_marker:
-            lesson["marker"] = last_marker
-        lessons.append(lesson)
-    return lessons
-
-
-def build_group_schedule(data, group_name):
-    group = data.get(group_name)
-    if group is None:
-        return None
-    out = {
-        "group": group_name,
-        "semester_until": group.get("semester_until"),
-        "days": {},
-    }
-    for day, periods in group["days"].items():
-        out["days"][day] = {}
-        for period, slot in periods.items():
-            entry = {"time": slot.get("time", "")}
-            for parity in ("ч", "з"):
-                raw = slot.get(parity)
-                if raw:
-                    entry[parity] = {"raw": raw, "lessons": _split_lessons(raw)}
-                else:
-                    entry[parity] = None
-            out["days"][day][str(period)] = entry
-    return out
-
-
-_ROOM_RE = re.compile(r"ауд\.\s*([\w\-]+)", re.IGNORECASE)
-
-
-def _iter_lessons(schedule_data):
-    for group, gdata in schedule_data.items():
-        for day, periods in gdata.get("days", {}).items():
-            for period, slot in periods.items():
-                time = slot.get("time", "")
-                for parity in ("ч", "з"):
-                    raw = slot.get(parity)
-                    if not raw:
-                        continue
-                    for lesson in _split_lessons(raw):
-                        yield group, day, period, time, parity, lesson
-
-
-def _is_name(text):
-    if not text:
-        return False
-    if text.startswith(("(", "—", "–", "-", "«", '"')):
-        return False
-    if any(w in text for w in ("не будет", "отменяется", "переносится", "пара будет")):
-        return False
-    if not re.search(r"[А-ЯЁа-яё]", text):
-        return False
-    if re.search(r"\d", text) and not re.search(r"[А-ЯЁ]\.[А-ЯЁ]", text):
-        return False
-    return True
-
-
-_NAME_RE = re.compile(r"[А-ЯЁ][а-яё-]+(?:\s+[А-ЯЁ]\.[А-ЯЁ]\.?)+")
-
-
-def _extract_teachers(text):
-    return [m.strip() for m in _NAME_RE.findall(text) if m.strip()]
-
-
-def _is_org(text):
-    if not _is_name(text):
-        return False
-    if any(ch in text for ch in "()"):
-        return False
-    if re.search(r"[А-ЯЁ]\.[А-ЯЁ]", text):
-        return False
-    return True
-
-
-_ORG_LINE_RE = re.compile(
-    r"[А-ЯЁ][A-Za-zА-ЯЁа-яё-]*(?:\s+[А-ЯЁ][A-Za-zА-ЯЁа-яё-]+)?"
-)
-
-
-def _looks_like_teacher_line(text):
-    if re.search(r"[А-ЯЁ]\.[А-ЯЁ]\.?", text):
-        return True
-    return bool(_ORG_LINE_RE.fullmatch(text)) and len(text) <= 40
-
-
-def _merge_entry(slot_list, entry_key, fields):
-    for item in slot_list:
-        if all(item.get(k) == v for k, v in entry_key.items()):
-            return item
-    item = dict(entry_key)
-    item["groups"] = []
-    item.update(fields)
-    slot_list.append(item)
-    return item
-
-
-def build_teacher_room_index(schedule_data):
-    teachers = {}
-    rooms = {}
-
-    for group, day, period, time, parity, lesson in _iter_lessons(schedule_data):
-        subject = lesson["subject"]
-        room = lesson["room"].strip()
-
-        if lesson["teacher"]:
-            teachers_found = _extract_teachers(lesson["teacher"])
-            if not teachers_found and _is_org(lesson["teacher"]):
-                teachers_found = [lesson["teacher"].strip()]
-
-            for teacher in teachers_found:
-                days_map = teachers.setdefault(teacher, {}).setdefault(day, {})
-                slot = days_map.setdefault(
-                    str(period), {"time": time, "ч": [], "з": []}
-                )
-                item = _merge_entry(
-                    slot[parity],
-                    {"subject": subject, "room": room},
-                    {"marker": lesson["marker"]},
-                )
-                if group not in item["groups"]:
-                    item["groups"].append(group)
-
-            display_teacher = ", ".join(teachers_found) if teachers_found else ""
-        else:
-            display_teacher = ""
-
-        room_m = _ROOM_RE.match(room)
-        if room_m:
-            label = "ауд. " + room_m.group(1)
-            days_map = rooms.setdefault(label, {}).setdefault(day, {})
-            slot = days_map.setdefault(
-                str(period), {"time": time, "ч": [], "з": []}
-            )
-            item = _merge_entry(
-                slot[parity],
-                {"subject": subject, "teacher": display_teacher},
-                {"marker": lesson["marker"]},
-            )
-            if group not in item["groups"]:
-                item["groups"].append(group)
-
-    return teachers, rooms
-
-
-def sort_rooms(room_names):
-    def key(name):
-        m = re.search(r"(\d+)", name)
-        return (0, int(m.group(1))) if m else (1, name)
-
-    return sorted(room_names, key=key)
-
-
-def parse_rooms_info(sheets):
-    """Аудитории: номер (заголовок) -> оснащение/вместимость (2-я строка)."""
-    name = "аудитории"
-    if name not in sheets:
-        return {}
-    rows = sheets[name]["rows"]
-    if len(rows) < 2:
-        return {}
-    header = rows[0]
-    desc = rows[1]
-    info = {}
-    for col in range(6, max(len(header), len(desc))):
-        raw = _read_cell(header, col)
-        m = re.search(r"(\d+)", str(raw))
-        if not m:
-            continue
-        number = int(m.group(1))
-        text = " ".join(
-            line.strip()
-            for line in _read_cell(desc, col).split("\n")
-            if line.strip()
-        )
-        label = f"ауд. {number}"
-        info[label] = {"room": label, "info": text}
-    return info
-
-
-def _initials_from_parts(first, patronymic):
-    initials = ""
-    if first:
-        initials += first[0].upper() + "."
-    if patronymic:
-        initials += patronymic[0].upper() + "."
-    return initials
-
-
-def parse_teachers_full(sheets):
-    """Преподаватели: короткое «Фамилия И.О.» -> полное ФИО (3-я строка-заголовок)."""
-    name = "Преподаватели"
-    if name not in sheets:
-        return {}
-    rows = sheets[name]["rows"]
-    if len(rows) < 2:
-        return {}
-    header = rows[1]
-    result = {}
-    for col in range(6, len(header)):
-        value = _read_cell(header, col)
-        parts = [p.strip() for p in re.split(r"[\s\n]+", value) if p.strip()]
-        if not parts:
-            continue
-        surname = parts[0]
-        first = parts[1] if len(parts) > 1 else ""
-        patronymic = parts[2] if len(parts) > 2 else ""
-        short = f"{surname} {_initials_from_parts(first, patronymic)}".strip()
-        full = " ".join(parts)
-        if short and full:
-            result.setdefault(short, full)
-    return result
-
-
-def build_teacher_schedule(teachers, name):
-    if name not in teachers:
-        return None
-    return {"name": name, "days": teachers[name]}
-
-
-def build_day_times(schedule_data):
-    day_times = {}
-    for gdata in schedule_data.values():
-        for day, periods in gdata.get("days", {}).items():
-            target = day_times.setdefault(day, {})
-            for period, slot in periods.items():
-                target.setdefault(str(period), slot.get("time", ""))
-    return day_times
-
-
-def build_room_schedule(rooms, label, day_times=None):
-    if label not in rooms:
-        return None
-    data = rooms[label]
-    out = {"room": label, "days": {}}
-    day_times = day_times or {}
-    all_days = {*data.keys(), *day_times.keys()}
-    for day in sorted(all_days, key=lambda d: DAYS.index(d) if d in DAYS else 99):
-        out["days"][day] = {}
-        times = day_times.get(day, {})
-        periods = {*data.get(day, {}).keys(), *times.keys()}
-        for period in sorted(periods, key=lambda p: int(p)):
-            entry = {"time": times.get(period, data.get(day, {}).get(period, {}).get("time", ""))}
-            occupied = data.get(day, {}).get(period, {})
-            for parity in ("ч", "з"):
-                lessons = occupied.get(parity) or []
-                entry[parity] = lessons if lessons else None
-            out["days"][day][str(period)] = entry
-    return out