280 lines
9.5 KiB
Python
280 lines
9.5 KiB
Python
from decimal import Decimal
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from django.db import transaction
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from django.db.models import Q
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from django.utils import timezone
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from rest_framework.exceptions import ValidationError
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from accounts.models import User
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from .models import (
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CheatFlag,
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Contest,
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ContestAnswer,
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ContestAttempt,
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RatingHistory,
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RealtimeMatch,
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)
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def normalize_answer(value):
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text = str(value).strip().lower().replace(" ", "")
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try:
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return str(Decimal(text).normalize())
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except Exception:
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return text
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def attempt_payload(attempt, include_results=False):
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questions = []
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answers = {answer.contest_question_id: answer for answer in attempt.answers.all()}
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for item in attempt.contest.contest_questions.select_related("question_version").all():
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question = {
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"order": item.order,
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"prompt": item.question_version.prompt,
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"metadata": item.question_version.metadata,
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"points": item.points,
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}
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if include_results and item.id in answers:
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answer = answers[item.id]
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question.update(
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{
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"submitted_answer": answer.submitted_answer,
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"is_correct": answer.is_correct,
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"correct_answer": item.question_version.answer,
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"explanation": item.question_version.explanation,
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}
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)
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questions.append(question)
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return {
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"attempt_id": attempt.id,
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"contest": attempt.contest.title,
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"kind": attempt.contest.kind,
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"status": attempt.status,
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"duration_seconds": attempt.contest.duration_seconds,
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"server_started_at": attempt.started_at,
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"score": attempt.score,
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"correct_count": attempt.correct_count,
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"answer_count": attempt.answer_count,
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"duration_ms": attempt.duration_ms,
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"questions": questions,
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}
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@transaction.atomic
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def start_attempt(user, contest):
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now = timezone.now()
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if contest.status != Contest.Status.PUBLISHED:
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raise ValidationError("比赛尚未发布")
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if contest.starts_at and contest.starts_at > now:
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raise ValidationError("比赛尚未开始")
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if contest.ends_at and contest.ends_at <= now:
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raise ValidationError("比赛已经结束")
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if contest.kind == Contest.Kind.DAILY:
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existing = ContestAttempt.objects.filter(user=user, contest=contest).first()
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if existing:
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return attempt_payload(
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existing,
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include_results=existing.status != ContestAttempt.Status.ACTIVE,
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)
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attempt = ContestAttempt.objects.create(contest=contest, user=user)
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return attempt_payload(attempt)
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@transaction.atomic
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def submit_attempt(user, attempt_id, raw_answers, submission_key):
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attempt = (
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ContestAttempt.objects.select_for_update()
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.select_related("contest")
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.get(id=attempt_id, user=user)
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)
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if attempt.status != ContestAttempt.Status.ACTIVE:
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if submission_key and attempt.submission_key == submission_key:
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return attempt_payload(attempt, include_results=True)
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raise ValidationError("该答题记录已经结算")
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if not submission_key:
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raise ValidationError({"Idempotency-Key": "正式提交必须提供幂等键"})
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now = timezone.now()
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duration_ms = max(0, int((now - attempt.started_at).total_seconds() * 1000))
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limit_ms = attempt.contest.duration_seconds * 1000
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items = list(
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attempt.contest.contest_questions.select_related("question_version").all()
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)
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if not isinstance(raw_answers, list):
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raise ValidationError({"answers": "答案必须是数组"})
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by_order = {}
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try:
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for item in raw_answers:
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order = int(item["order"])
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if order <= 0 or order in by_order:
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raise ValueError
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by_order[order] = item.get("answer", "")
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except (KeyError, TypeError, ValueError) as exc:
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raise ValidationError({"answers": "答案题号无效或重复"}) from exc
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score = 0
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correct_count = 0
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for contest_question in items:
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submitted = str(by_order.get(contest_question.order, ""))[:200]
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correct = normalize_answer(submitted) == normalize_answer(
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contest_question.question_version.answer
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)
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if correct and duration_ms <= limit_ms:
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score += contest_question.points
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correct_count += 1
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ContestAnswer.objects.create(
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attempt=attempt,
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contest_question=contest_question,
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submitted_answer=submitted,
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is_correct=correct and duration_ms <= limit_ms,
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elapsed_ms=min(duration_ms, limit_ms + 60_000),
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)
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attempt.status = (
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ContestAttempt.Status.SUBMITTED
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if duration_ms <= limit_ms
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else ContestAttempt.Status.EXPIRED
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)
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attempt.score = score
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attempt.correct_count = correct_count
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attempt.answer_count = len(raw_answers)
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attempt.duration_ms = duration_ms
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attempt.submission_key = submission_key
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attempt.submitted_at = now
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attempt.save()
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if raw_answers and duration_ms / len(raw_answers) < 150:
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CheatFlag.objects.create(
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attempt=attempt,
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reason="extreme_answer_speed",
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evidence={
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"duration_ms": duration_ms,
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"answer_count": len(raw_answers),
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},
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)
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if attempt.match_id:
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finalize_match(attempt.match_id)
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return attempt_payload(attempt, include_results=True)
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@transaction.atomic
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def find_match(user, contest):
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if contest.kind != Contest.Kind.REALTIME or contest.status != Contest.Status.PUBLISHED:
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raise ValidationError("实时比赛不可用")
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existing = (
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RealtimeMatch.objects.filter(
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Q(player_one=user) | Q(player_two=user),
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contest=contest,
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status__in=[RealtimeMatch.Status.WAITING, RealtimeMatch.Status.ACTIVE],
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)
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.order_by("-created_at")
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.first()
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)
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if existing:
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return existing
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waiting = (
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RealtimeMatch.objects.select_for_update(skip_locked=True)
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.filter(
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contest=contest,
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status=RealtimeMatch.Status.WAITING,
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player_one_rating__gte=max(0, user.rating - 300),
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player_one_rating__lte=user.rating + 300,
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)
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.exclude(player_one=user)
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.order_by("created_at")
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.first()
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)
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if waiting is None:
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return RealtimeMatch.objects.create(
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contest=contest,
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player_one=user,
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player_one_rating=user.rating,
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)
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waiting.player_two = user
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waiting.player_two_rating = user.rating
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waiting.status = RealtimeMatch.Status.ACTIVE
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waiting.started_at = timezone.now()
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waiting.save(
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update_fields=["player_two", "player_two_rating", "status", "started_at"]
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)
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ContestAttempt.objects.bulk_create(
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[
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ContestAttempt(contest=contest, user=waiting.player_one, match=waiting),
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ContestAttempt(contest=contest, user=user, match=waiting),
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]
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)
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return waiting
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def match_payload(match, user):
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attempt = match.attempts.filter(user=user).first()
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opponent = match.player_two if match.player_one_id == user.id else match.player_one
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return {
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"match_id": match.id,
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"status": match.status,
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"opponent": (
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{"nickname": opponent.nickname, "rating": opponent.rating}
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if opponent
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else None
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),
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"attempt": attempt_payload(attempt) if attempt else None,
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"websocket_path": f"/ws/v1/contest/matches/{match.id}/",
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}
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def _elo_delta(rating, opponent_rating, score, k=32):
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expected = 1 / (1 + 10 ** ((opponent_rating - rating) / 400))
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return round(k * (score - expected))
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@transaction.atomic
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def finalize_match(match_id):
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match = RealtimeMatch.objects.select_for_update().get(id=match_id)
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if match.status != RealtimeMatch.Status.ACTIVE:
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return match
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attempts = list(match.attempts.select_related("user").order_by("user_id"))
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if len(attempts) != 2 or any(
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attempt.status == ContestAttempt.Status.ACTIVE for attempt in attempts
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):
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return match
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first = next(item for item in attempts if item.user_id == match.player_one_id)
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second = next(item for item in attempts if item.user_id == match.player_two_id)
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if first.score > second.score:
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first_result, second_result = 1.0, 0.0
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match.winner_id = first.user_id
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elif second.score > first.score:
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first_result, second_result = 0.0, 1.0
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match.winner_id = second.user_id
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else:
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first_result = second_result = 0.5
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users = {
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user.id: user
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for user in User.objects.select_for_update().filter(
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id__in=[match.player_one_id, match.player_two_id]
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)
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}
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player_one = users[match.player_one_id]
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player_two = users[match.player_two_id]
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deltas = (
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_elo_delta(player_one.rating, player_two.rating, first_result),
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_elo_delta(player_two.rating, player_one.rating, second_result),
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)
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for user, delta in zip((player_one, player_two), deltas):
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before = user.rating
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user.rating = max(0, before + delta)
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user.save(update_fields=["rating"])
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RatingHistory.objects.create(
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user=user,
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match=match,
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rating_before=before,
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rating_after=user.rating,
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delta=delta,
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)
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match.status = RealtimeMatch.Status.COMPLETED
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match.completed_at = timezone.now()
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match.save(update_fields=["winner", "status", "completed_at"])
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return match
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