Files
Hulumath-Web/backend/contest/services.py
T
2026-08-09 15:33:07 +08:00

563 lines
20 KiB
Python

import secrets
from datetime import timedelta
from decimal import Decimal
from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer
from django.db import transaction
from django.db.models import Q
from django.utils import timezone
from rest_framework.exceptions import ValidationError
from accounts.models import User
from .models import (
CheatFlag,
Contest,
ContestAnswer,
ContestAttempt,
RatingHistory,
RealtimeMatch,
)
CHALLENGE_CODE_ALPHABET = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"
WAITING_MATCH_TTL = timedelta(minutes=10)
def _broadcast_match(match_id, reason):
channel_layer = get_channel_layer()
if channel_layer is None:
return
async_to_sync(channel_layer.group_send)(
f"match_{match_id}",
{
"type": "match.state",
"reason": reason,
},
)
def notify_match_on_commit(match_id, reason):
transaction.on_commit(lambda: _broadcast_match(match_id, reason))
def _new_challenge_code():
for _ in range(20):
code = "".join(secrets.choice(CHALLENGE_CODE_ALPHABET) for _ in range(6))
if not RealtimeMatch.objects.filter(challenge_code=code).exists():
return code
raise ValidationError("暂时无法生成联机码,请稍后重试")
def _validate_realtime_contest(contest):
if contest.kind != Contest.Kind.REALTIME or contest.status != Contest.Status.PUBLISHED:
raise ValidationError("实时比赛不可用")
def _cancel_expired_waiting_matches():
RealtimeMatch.objects.filter(status=RealtimeMatch.Status.WAITING).filter(
Q(expires_at__isnull=True) | Q(expires_at__lte=timezone.now())
).update(status=RealtimeMatch.Status.CANCELLED)
def _active_match_for(user):
return (
RealtimeMatch.objects.filter(
Q(player_one=user) | Q(player_two=user),
status=RealtimeMatch.Status.ACTIVE,
)
.select_related("contest", "player_one", "player_two")
.first()
)
def _cancel_other_waiting_matches(user, match_type):
matches = list(
RealtimeMatch.objects.filter(
player_one=user,
status=RealtimeMatch.Status.WAITING,
)
.exclude(match_type=match_type)
.values_list("id", flat=True)
)
if matches:
RealtimeMatch.objects.filter(id__in=matches).update(
status=RealtimeMatch.Status.CANCELLED
)
for match_id in matches:
notify_match_on_commit(match_id, "cancelled")
def _activate_match(match, user):
now = timezone.now()
match.player_two = user
match.player_two_rating = user.rating
match.status = RealtimeMatch.Status.ACTIVE
match.started_at = now
match.save(
update_fields=["player_two", "player_two_rating", "status", "started_at"]
)
ContestAttempt.objects.bulk_create(
[
ContestAttempt(contest=match.contest, user=match.player_one, match=match),
ContestAttempt(contest=match.contest, user=user, match=match),
]
)
match.attempts.update(started_at=now)
notify_match_on_commit(match.id, "matched")
return match
def normalize_answer(value):
text = str(value).strip().lower().replace(" ", "")
try:
return str(Decimal(text).normalize())
except Exception:
return text
def attempt_payload(attempt, include_results=False):
questions = []
answers = {answer.contest_question_id: answer for answer in attempt.answers.all()}
for item in attempt.contest.contest_questions.select_related("question_version").all():
question = {
"order": item.order,
"prompt": item.question_version.prompt,
"metadata": item.question_version.metadata,
"points": item.points,
}
if include_results:
answer = answers.get(item.id)
question.update(
{
"submitted_answer": answer.submitted_answer if answer else "",
"is_correct": answer.is_correct if answer else False,
"correct_answer": item.question_version.answer,
"explanation": item.question_version.explanation,
}
)
questions.append(question)
return {
"attempt_id": attempt.id,
"match_id": attempt.match_id,
"contest": attempt.contest.title,
"kind": attempt.contest.kind,
"status": attempt.status,
"duration_seconds": attempt.contest.duration_seconds,
"server_started_at": attempt.started_at,
"score": attempt.score,
"correct_count": attempt.correct_count,
"answer_count": attempt.answer_count,
"duration_ms": attempt.duration_ms,
"questions": questions,
}
@transaction.atomic
def start_attempt(user, contest):
now = timezone.now()
if contest.status != Contest.Status.PUBLISHED:
raise ValidationError("比赛尚未发布")
if contest.starts_at and contest.starts_at > now:
raise ValidationError("比赛尚未开始")
if contest.ends_at and contest.ends_at <= now:
raise ValidationError("比赛已经结束")
if contest.kind == Contest.Kind.DAILY:
existing = ContestAttempt.objects.filter(user=user, contest=contest).first()
if existing:
return attempt_payload(
existing,
include_results=existing.status != ContestAttempt.Status.ACTIVE,
)
attempt = ContestAttempt.objects.create(contest=contest, user=user)
return attempt_payload(attempt)
@transaction.atomic
def submit_attempt(user, attempt_id, raw_answers, submission_key):
attempt = (
ContestAttempt.objects.select_for_update()
.select_related("contest")
.get(id=attempt_id, user=user)
)
if attempt.status != ContestAttempt.Status.ACTIVE:
if submission_key and attempt.submission_key == submission_key:
include_results = not attempt.match_id or (
attempt.match.status == RealtimeMatch.Status.COMPLETED
)
return attempt_payload(attempt, include_results=include_results)
raise ValidationError("该答题记录已经结算")
if not submission_key:
raise ValidationError({"Idempotency-Key": "正式提交必须提供幂等键"})
now = timezone.now()
duration_ms = max(0, int((now - attempt.started_at).total_seconds() * 1000))
limit_ms = attempt.contest.duration_seconds * 1000
items = list(
attempt.contest.contest_questions.select_related("question_version").all()
)
if not isinstance(raw_answers, list):
raise ValidationError({"answers": "答案必须是数组"})
by_order = {}
try:
for item in raw_answers:
order = int(item["order"])
if order <= 0 or order in by_order:
raise ValueError
by_order[order] = item.get("answer", "")
except (KeyError, TypeError, ValueError) as exc:
raise ValidationError({"answers": "答案题号无效或重复"}) from exc
score = 0
correct_count = 0
for contest_question in items:
submitted = str(by_order.get(contest_question.order, ""))[:200]
correct = normalize_answer(submitted) == normalize_answer(
contest_question.question_version.answer
)
if correct and duration_ms <= limit_ms:
score += contest_question.points
correct_count += 1
ContestAnswer.objects.create(
attempt=attempt,
contest_question=contest_question,
submitted_answer=submitted,
is_correct=correct and duration_ms <= limit_ms,
elapsed_ms=min(duration_ms, limit_ms + 60_000),
)
attempt.status = (
ContestAttempt.Status.SUBMITTED
if duration_ms <= limit_ms
else ContestAttempt.Status.EXPIRED
)
attempt.score = score
attempt.correct_count = correct_count
attempt.answer_count = len(raw_answers)
attempt.duration_ms = duration_ms
attempt.submission_key = submission_key
attempt.submitted_at = now
attempt.save()
if raw_answers and duration_ms / len(raw_answers) < 150:
CheatFlag.objects.create(
attempt=attempt,
reason="extreme_answer_speed",
evidence={
"duration_ms": duration_ms,
"answer_count": len(raw_answers),
},
)
if attempt.match_id:
match = finalize_match(attempt.match_id)
if match.status != RealtimeMatch.Status.COMPLETED:
notify_match_on_commit(attempt.match_id, "submitted")
attempt.match.refresh_from_db()
return attempt_payload(
attempt,
include_results=attempt.match.status == RealtimeMatch.Status.COMPLETED,
)
return attempt_payload(attempt, include_results=True)
@transaction.atomic
def find_match(user, contest):
_validate_realtime_contest(contest)
_cancel_expired_waiting_matches()
active = _active_match_for(user)
if active:
if active.contest_id == contest.id:
return active
raise ValidationError("你已有一场进行中的实时比赛")
_cancel_other_waiting_matches(user, RealtimeMatch.MatchType.RANDOM)
existing = (
RealtimeMatch.objects.filter(
Q(player_one=user) | Q(player_two=user),
contest=contest,
match_type=RealtimeMatch.MatchType.RANDOM,
status__in=[RealtimeMatch.Status.WAITING, RealtimeMatch.Status.ACTIVE],
).filter(Q(status=RealtimeMatch.Status.ACTIVE) | Q(expires_at__gt=timezone.now()))
.order_by("-created_at")
.first()
)
if existing:
return existing
waiting = (
RealtimeMatch.objects.select_for_update(skip_locked=True)
.filter(
contest=contest,
match_type=RealtimeMatch.MatchType.RANDOM,
status=RealtimeMatch.Status.WAITING,
expires_at__gt=timezone.now(),
player_one_rating__gte=max(0, user.rating - 300),
player_one_rating__lte=user.rating + 300,
)
.exclude(player_one=user)
.order_by("created_at")
.first()
)
if waiting is None:
return RealtimeMatch.objects.create(
contest=contest,
match_type=RealtimeMatch.MatchType.RANDOM,
player_one=user,
player_one_rating=user.rating,
expires_at=timezone.now() + WAITING_MATCH_TTL,
)
return _activate_match(waiting, user)
@transaction.atomic
def create_challenge(user, contest):
_validate_realtime_contest(contest)
_cancel_expired_waiting_matches()
active = _active_match_for(user)
if active:
raise ValidationError("你已有一场进行中的实时比赛")
_cancel_other_waiting_matches(user, RealtimeMatch.MatchType.CHALLENGE)
existing = (
RealtimeMatch.objects.filter(
player_one=user,
contest=contest,
match_type=RealtimeMatch.MatchType.CHALLENGE,
status=RealtimeMatch.Status.WAITING,
expires_at__gt=timezone.now(),
)
.order_by("-created_at")
.first()
)
if existing:
return existing
return RealtimeMatch.objects.create(
contest=contest,
match_type=RealtimeMatch.MatchType.CHALLENGE,
challenge_code=_new_challenge_code(),
player_one=user,
player_one_rating=user.rating,
expires_at=timezone.now() + WAITING_MATCH_TTL,
)
@transaction.atomic
def join_challenge(user, challenge_code):
_cancel_expired_waiting_matches()
code = str(challenge_code or "").strip().upper()
if len(code) != 6 or any(character not in CHALLENGE_CODE_ALPHABET for character in code):
raise ValidationError({"challenge_code": "联机码应为 6 位大写字母或数字"})
try:
match = (
RealtimeMatch.objects.select_for_update()
.select_related("contest", "player_one")
.get(
challenge_code=code,
match_type=RealtimeMatch.MatchType.CHALLENGE,
)
)
except RealtimeMatch.DoesNotExist as exc:
raise ValidationError({"challenge_code": "联机码不存在"}) from exc
if match.player_one_id == user.id:
raise ValidationError({"challenge_code": "不能加入自己创建的约战"})
if match.status != RealtimeMatch.Status.WAITING or (
match.expires_at and match.expires_at <= timezone.now()
):
raise ValidationError({"challenge_code": "联机码已失效或已被使用"})
active = _active_match_for(user)
if active and active.id != match.id:
raise ValidationError("你已有一场进行中的实时比赛")
own_waiting_ids = list(
RealtimeMatch.objects.filter(
player_one=user,
status=RealtimeMatch.Status.WAITING,
)
.exclude(id=match.id)
.values_list("id", flat=True)
)
if own_waiting_ids:
RealtimeMatch.objects.filter(id__in=own_waiting_ids).update(
status=RealtimeMatch.Status.CANCELLED
)
for match_id in own_waiting_ids:
notify_match_on_commit(match_id, "cancelled")
return _activate_match(match, user)
@transaction.atomic
def cancel_waiting_match(user, match_id):
match = RealtimeMatch.objects.select_for_update().get(id=match_id)
if match.player_one_id != user.id:
raise ValidationError("只有创建者可以取消等待")
if match.status != RealtimeMatch.Status.WAITING:
raise ValidationError("只能取消等待中的比赛")
match.status = RealtimeMatch.Status.CANCELLED
match.save(update_fields=["status"])
notify_match_on_commit(match.id, "cancelled")
return match
def match_payload(match, user):
reveal_results = match.status == RealtimeMatch.Status.COMPLETED
attempts = {
attempt.user_id: attempt
for attempt in match.attempts.select_related("user", "contest").all()
}
attempt = attempts.get(user.id)
opponent = match.player_two if match.player_one_id == user.id else match.player_one
opponent_attempt = attempts.get(opponent.id) if opponent else None
rating_change = (
match.rating_changes.filter(user=user).values("delta", "rating_after").first()
if reveal_results
else None
)
return {
"match_id": match.id,
"match_type": match.match_type,
"is_owner": match.player_one_id == user.id,
"challenge_code": (
match.challenge_code
if match.match_type == RealtimeMatch.MatchType.CHALLENGE
and match.status == RealtimeMatch.Status.WAITING
else None
),
"status": match.status,
"contest": match.contest.title,
"duration_seconds": match.contest.duration_seconds,
"expires_at": match.expires_at,
"started_at": match.started_at,
"opponent": (
{
"nickname": opponent.nickname,
"rating": opponent.rating,
"status": opponent_attempt.status if opponent_attempt else None,
"score": opponent_attempt.score if reveal_results and opponent_attempt else None,
"correct_count": (
opponent_attempt.correct_count
if reveal_results and opponent_attempt
else None
),
"duration_ms": (
opponent_attempt.duration_ms
if reveal_results and opponent_attempt
else None
),
}
if opponent
else None
),
"attempt": (
attempt_payload(attempt, include_results=reveal_results)
if attempt
else None
),
"result": (
{
"winner": (
"draw"
if match.winner_id is None
else "self"
if match.winner_id == user.id
else "opponent"
),
"rating_delta": rating_change["delta"] if rating_change else 0,
"rating_after": rating_change["rating_after"] if rating_change else user.rating,
}
if reveal_results
else None
),
"websocket_path": f"/ws/v1/contest/matches/{match.id}/",
}
@transaction.atomic
def refresh_match_state(match_id):
match = (
RealtimeMatch.objects.select_for_update()
.select_related("contest", "player_one", "player_two")
.get(id=match_id)
)
if (
match.status == RealtimeMatch.Status.WAITING
and match.expires_at
and match.expires_at <= timezone.now()
):
match.status = RealtimeMatch.Status.CANCELLED
match.save(update_fields=["status"])
notify_match_on_commit(match.id, "expired")
elif match.status == RealtimeMatch.Status.ACTIVE and match.started_at:
deadline = match.started_at + timedelta(seconds=match.contest.duration_seconds)
if timezone.now() >= deadline:
now = timezone.now()
for attempt in match.attempts.filter(status=ContestAttempt.Status.ACTIVE):
elapsed_ms = max(0, int((now - attempt.started_at).total_seconds() * 1000))
attempt.status = ContestAttempt.Status.EXPIRED
attempt.duration_ms = elapsed_ms
attempt.submitted_at = now
attempt.save(update_fields=["status", "duration_ms", "submitted_at"])
match = finalize_match(match.id)
return match
def _elo_delta(rating, opponent_rating, score, k=32):
expected = 1 / (1 + 10 ** ((opponent_rating - rating) / 400))
return round(k * (score - expected))
@transaction.atomic
def finalize_match(match_id):
match = RealtimeMatch.objects.select_for_update().get(id=match_id)
if match.status != RealtimeMatch.Status.ACTIVE:
return match
attempts = list(match.attempts.select_related("user").order_by("user_id"))
if len(attempts) != 2 or any(
attempt.status == ContestAttempt.Status.ACTIVE for attempt in attempts
):
return match
first = next(item for item in attempts if item.user_id == match.player_one_id)
second = next(item for item in attempts if item.user_id == match.player_two_id)
if first.score > second.score:
first_result, second_result = 1.0, 0.0
match.winner_id = first.user_id
elif second.score > first.score:
first_result, second_result = 0.0, 1.0
match.winner_id = second.user_id
else:
diff = first.duration_ms - second.duration_ms
if abs(diff) <= 100:
first_result = second_result = 0.5
elif diff < 0:
first_result, second_result = 1.0, 0.0
match.winner_id = first.user_id
else:
first_result, second_result = 0.0, 1.0
match.winner_id = second.user_id
users = {
user.id: user
for user in User.objects.select_for_update().filter(
id__in=[match.player_one_id, match.player_two_id]
)
}
player_one = users[match.player_one_id]
player_two = users[match.player_two_id]
deltas = (
_elo_delta(player_one.rating, player_two.rating, first_result),
_elo_delta(player_two.rating, player_one.rating, second_result),
)
for user, delta in zip((player_one, player_two), deltas):
before = user.rating
user.rating = max(0, before + delta)
user.save(update_fields=["rating"])
RatingHistory.objects.create(
user=user,
match=match,
rating_before=before,
rating_after=user.rating,
delta=delta,
)
match.status = RealtimeMatch.Status.COMPLETED
match.completed_at = timezone.now()
match.save(update_fields=["winner", "status", "completed_at"])
notify_match_on_commit(match.id, "completed")
return match