from rest_framework import serializers
from .models import Meeting, Participant, Message, MeetingMinutes
from django.contrib.auth import get_user_model

User = get_user_model()


class UserSerializer(serializers.ModelSerializer):
    """用户序列化器"""
    class Meta:
        model = User
        fields = ['id', 'username', 'email', 'created_at']


class MeetingSerializer(serializers.ModelSerializer):
    """会议室序列化器"""
    host_name = serializers.CharField(source='host.username', read_only=True)
    participant_count = serializers.SerializerMethodField()
    
    class Meta:
        model = Meeting
        fields = [
            'id', 'topic', 'host', 'host_name', 'status', 'invite_code',
            'created_at', 'started_at', 'ended_at', 'participant_count',
            'host_agent_id', 'host_instance_id', 'minutes_generated', 'minutes_uploaded_at'
        ]
        read_only_fields = ['host', 'invite_code', 'status']
    
    def get_participant_count(self, obj):
        return obj.participants.filter(left_at__isnull=True).count()
    
    def create(self, validated_data):
        # 使用第一个用户作为 host（临时方案）
        host = User.objects.first()
        validated_data['host'] = host
        return super().create(validated_data)


class ParticipantSerializer(serializers.ModelSerializer):
    """参会者序列化器"""
    class Meta:
        model = Participant
        fields = [
            'id', 'meeting', 'user', 'agent_type', 'agent_id',
            'agent_name', 'agent_emoji', 'nickname', 'is_host',
            'joined_at', 'api_key'
        ]
        read_only_fields = ['api_key', 'joined_at']


class MessageSerializer(serializers.ModelSerializer):
    """消息序列化器"""
    sender_name = serializers.CharField(source='sender.nickname', read_only=True)
    sender_emoji = serializers.CharField(source='sender.agent_emoji', read_only=True)
    
    class Meta:
        model = Message
        fields = [
            'id', 'meeting', 'sender', 'sender_name', 'sender_emoji',
            'content', 'created_at', 'is_broadcast', 'requires_response',
            'in_reply_to', 'read_by'
        ]
        read_only_fields = ['sender', 'created_at']


class InboxSerializer(serializers.Serializer):
    """信箱序列化器"""
    unread_count = serializers.IntegerField()
    messages = MessageSerializer(many=True)


class MeetingMinutesSerializer(serializers.ModelSerializer):
    """会议纪要序列化器"""
    class Meta:
        model = MeetingMinutes
        fields = ['meeting', 'content', 'generated_at', 'exported_at']
        read_only_fields = ['meeting', 'generated_at']