Files
Hulumath-Web/backend/toolbox/board_services.py
T

148 lines
4.9 KiB
Python

import secrets
from datetime import timedelta
from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer
from django.db import transaction
from django.utils import timezone
from rest_framework.exceptions import ValidationError
from .models import BoardSession
BOARD_CODE_ALPHABET = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"
BOARD_TTL = timedelta(minutes=30)
DRAW_GUESS_TARGETS = (
"抛物线",
"三角形",
"勾股定理",
"质数",
"圆",
"正弦函数",
"分数",
"坐标系",
)
def _new_board_code():
for _ in range(20):
code = "".join(secrets.choice(BOARD_CODE_ALPHABET) for _ in range(6))
if not BoardSession.objects.filter(code=code).exists():
return code
raise ValidationError("暂时无法生成画板联机码,请稍后重试")
def broadcast_board(session_id, reason):
channel_layer = get_channel_layer()
if channel_layer is None:
return
async_to_sync(channel_layer.group_send)(
f"board_{session_id}",
{
"type": "board.state",
"reason": reason,
},
)
def board_payload(session, user):
is_host = session.host_id == user.id
reveal_target = (
session.mode == BoardSession.Mode.DRAW_GUESS
and (is_host or session.status == BoardSession.Status.COMPLETED)
)
return {
"session_id": session.id,
"code": session.code,
"mode": session.mode,
"mode_label": session.get_mode_display(),
"status": session.status,
"role": "host" if is_host else "guest",
"target": session.target if reveal_target else None,
"host": session.host.nickname,
"guest": session.guest.nickname if session.guest else None,
"host_score": session.host_score,
"guest_score": session.guest_score,
"expires_at": session.expires_at,
"websocket_path": f"/ws/v1/toolbox/boards/{session.id}/",
}
@transaction.atomic
def create_board(user, mode):
if mode not in BoardSession.Mode.values:
raise ValidationError({"mode": "不支持的画板联机模式"})
BoardSession.objects.filter(
host=user,
status=BoardSession.Status.WAITING,
).update(status=BoardSession.Status.CANCELLED)
return BoardSession.objects.create(
code=_new_board_code(),
mode=mode,
host=user,
target=(
secrets.choice(DRAW_GUESS_TARGETS)
if mode == BoardSession.Mode.DRAW_GUESS
else ""
),
expires_at=timezone.now() + BOARD_TTL,
)
@transaction.atomic
def join_board(user, code):
normalized = str(code or "").strip().upper()
if len(normalized) != 6 or any(
character not in BOARD_CODE_ALPHABET for character in normalized
):
raise ValidationError({"code": "画板联机码应为 6 位大写字母或数字"})
try:
session = (
BoardSession.objects.select_for_update()
.select_related("host", "guest")
.get(code=normalized)
)
except BoardSession.DoesNotExist as exc:
raise ValidationError({"code": "画板联机码不存在"}) from exc
if session.host_id == user.id:
raise ValidationError({"code": "不能加入自己创建的画板"})
if session.status != BoardSession.Status.WAITING:
raise ValidationError({"code": "画板联机码已失效或已被使用"})
if session.expires_at <= timezone.now():
session.status = BoardSession.Status.CANCELLED
session.save(update_fields=["status"])
raise ValidationError({"code": "画板联机码已经过期"})
session.guest = user
session.status = BoardSession.Status.ACTIVE
session.save(update_fields=["guest", "status"])
transaction.on_commit(lambda: broadcast_board(session.id, "joined"))
return session
@transaction.atomic
def submit_guess(user, session_id, raw_guess):
session = (
BoardSession.objects.select_for_update()
.select_related("host", "guest")
.get(id=session_id)
)
if session.guest_id != user.id:
raise ValidationError("只有猜题方可以提交答案")
if (
session.mode != BoardSession.Mode.DRAW_GUESS
or session.status != BoardSession.Status.ACTIVE
):
raise ValidationError("当前画板不接受猜题")
guess = str(raw_guess or "").strip()
if not guess or len(guess) > 40:
raise ValidationError({"guess": "请输入不超过 40 个字符的数学对象"})
correct = guess.replace(" ", "").lower() == session.target.replace(" ", "").lower()
if correct:
session.guest_score += 1
session.status = BoardSession.Status.COMPLETED
session.completed_at = timezone.now()
session.save(
update_fields=["guest_score", "status", "completed_at"]
)
transaction.on_commit(lambda: broadcast_board(session.id, "completed"))
return session, correct