Fix

backend/app/api/v1/marathons.py

@@ -1,5 +1,6 @@
 from datetime import timedelta
 import secrets
+import string
 from fastapi import APIRouter, HTTPException, status
 from sqlalchemy import select, func
 from sqlalchemy.orm import selectinload
@@ -10,7 +11,7 @@ from app.api.deps import (
     get_participant,
 )
 from app.models import (
-    Marathon, Participant, MarathonStatus, Game, GameStatus,
+    Marathon, Participant, MarathonStatus, Game, GameStatus, Challenge,
     Assignment, AssignmentStatus, Activity, ActivityType, ParticipantRole,
 )
 from app.schemas import (
@@ -40,7 +41,7 @@ async def get_marathon_by_code(invite_code: str, db: DbSession):
         select(Marathon, func.count(Participant.id).label("participants_count"))
         .outerjoin(Participant)
         .options(selectinload(Marathon.creator))
-        .where(Marathon.invite_code == invite_code)
+        .where(func.upper(Marathon.invite_code) == invite_code.upper())
         .group_by(Marathon.id)
     )
     row = result.first()
@@ -62,7 +63,9 @@ async def get_marathon_by_code(invite_code: str, db: DbSession):
 
 
 def generate_invite_code() -> str:
-    return secrets.token_urlsafe(8)
+    """Generate a clean 8-character uppercase alphanumeric code."""
+    alphabet = string.ascii_uppercase + string.digits
+    return ''.join(secrets.choice(alphabet) for _ in range(8))
 
 
 async def get_marathon_or_404(db, marathon_id: int) -> Marathon:
@@ -272,15 +275,33 @@ async def start_marathon(marathon_id: int, current_user: CurrentUser, db: DbSess
     if marathon.status != MarathonStatus.PREPARING.value:
         raise HTTPException(status_code=400, detail="Marathon is not in preparing state")
 
-    # Check if there are approved games with challenges
-    games_count = await db.scalar(
-        select(func.count()).select_from(Game).where(
+    # Check if there are approved games
+    games_result = await db.execute(
+        select(Game).where(
             Game.marathon_id == marathon_id,
             Game.status == GameStatus.APPROVED.value,
         )
     )
-    if games_count == 0:
-        raise HTTPException(status_code=400, detail="Add and approve at least one game before starting")
+    approved_games = games_result.scalars().all()
+
+    if len(approved_games) == 0:
+        raise HTTPException(status_code=400, detail="Добавьте и одобрите хотя бы одну игру")
+
+    # Check that all approved games have at least one challenge
+    games_without_challenges = []
+    for game in approved_games:
+        challenge_count = await db.scalar(
+            select(func.count()).select_from(Challenge).where(Challenge.game_id == game.id)
+        )
+        if challenge_count == 0:
+            games_without_challenges.append(game.title)
+
+    if games_without_challenges:
+        games_list = ", ".join(games_without_challenges)
+        raise HTTPException(
+            status_code=400,
+            detail=f"У следующих игр нет челленджей: {games_list}"
+        )
 
     marathon.status = MarathonStatus.ACTIVE.value
 
@@ -332,7 +353,7 @@ async def finish_marathon(marathon_id: int, current_user: CurrentUser, db: DbSes
 @router.post("/join", response_model=MarathonResponse)
 async def join_marathon(data: JoinMarathon, current_user: CurrentUser, db: DbSession):
     result = await db.execute(
-        select(Marathon).where(Marathon.invite_code == data.invite_code)
+        select(Marathon).where(func.upper(Marathon.invite_code) == data.invite_code.upper())
     )
     marathon = result.scalar_one_or_none()