102201601work2/Rollcall_applet/api/consumers.py

from channels.generic.websocket import AsyncWebsocketConsumer
import json
import random
from asgiref.sync import sync_to_async
from .models import Students


class ClassroomConsumer(AsyncWebsocketConsumer):
    async def connect(self):
        self.teacher_group = 'teacher_group'
        self.student_group = 'student_group'

        await self.channel_layer.group_add(self.teacher_group, self.channel_name)
        await self.channel_layer.group_add(self.student_group, self.channel_name)

        await self.accept()

    async def disconnect(self, close_code):
        await self.channel_layer.group_discard(self.teacher_group, self.channel_name)
        await self.channel_layer.group_discard(self.student_group, self.channel_name)

    async def receive(self, text_data):
        data = json.loads(text_data)

        if data['action'] == 'pick_student':
            selected_student = await self.pick_student()
            await self.send_student_message(selected_student)

        elif data['action'] == 'use_exemption_card':
            # 处理学生使用豁免卡的信息
            student_id = data['studentId']
            new_score = data['newScore']

            # 更新学生积分等逻辑，假设在数据库中保存
            await self.update_student_score(student_id, new_score)

            # 将豁免卡信息发送给教师组
            await self.channel_layer.group_send(
                self.teacher_group,
                {
                    'type': 'exemption_card_used',
                    'student_id': student_id,
                    'student_name': data['studentName'],
                    'new_score': new_score,
                }
            )

    # 处理教师端收到豁免卡使用信息
    async def exemption_card_used(self, event):
        student_id = event['student_id']
        student_name = event['student_name']
        new_score = event['new_score']

        # 在教师端显示学生使用豁免卡的信息
        await self.send(text_data=json.dumps({
            'action': 'exemption_card_used',
            'student_id': student_id,
            'student_name': student_name,
            'new_score': new_score,
        }))

    async def send_student_message(self, student):
        if student is None:
            return  # 如果没有选中学生，直接返回

        message = {
            'name': student.name,
            'student_id': student.sid,
        }

        # 将点名结果发送到学生组
        await self.channel_layer.group_send(
            self.student_group,
            {
                'type': 'student_message',
                'message': message,
            }
        )

    # 接收到点名结果后发送给学生端
    async def student_message(self, event):
        message = event['message']
        await self.send(text_data=json.dumps({
            'action': 'student_picked',
            'name': message['name'],
            'student_id': message['student_id'],
        }))

    async def pick_student(self):
        # 使用 sync_to_async 获取学生列表
        students = await sync_to_async(list)(Students.objects.all())

        if not students:
            return None

        # 计算权重
        weights = []
        for student in students:
            score = float(student.score)
            if score < 0:
                weights.append(-score)  # 负分数，绝对值越大权重越大
            elif score == 0:
                weights.append(0.2)  # 分数为0，设置为一个中等权重
            else:
                weights.append(1 / (score + 10))  # 正分数，分数越大权重越小

        # 防止所有权重为0的情况
        if sum(weights) == 0:
            return random.choice(students)  # 如果所有权重为0，随机选一个学生

        # 根据权重选择学生
        chosen_student = random.choices(students, weights=weights, k=1)[0]
        return chosen_student

    async def update_student_score(self, student_id, new_score):
        # 使用 Django ORM 更新学生积分
        student = await sync_to_async(Students.objects.get)(sid=student_id)
        student.score = new_score
        await sync_to_async(student.save)()