# apps/chat/models.py
from django.db import models
from django.utils import timezone
import uuid
from itertools import count
from apps.user.models import User
from apps.knowledge_base.models import KnowledgeBase
from apps.expertproducts.models import Negotiation
from apps.daren_detail.models import CreatorProfile  # 导入CreatorProfile模型
from apps.brands.models import Product  # 导入Product模型

class ChatHistory(models.Model):
    """聊天历史记录"""
    ROLE_CHOICES = [
        ('user', '用户'),
        ('assistant', 'AI助手'),
        ('system', '系统')
    ]

    user = models.ForeignKey(User, on_delete=models.CASCADE)
    # 保留与主知识库的关联
    knowledge_base = models.ForeignKey(KnowledgeBase, on_delete=models.CASCADE)
    # 用于标识知识库组合的对话
    conversation_id = models.CharField(max_length=100, db_index=True)
    # 对话标题
    title = models.CharField(max_length=100, null=True, blank=True, default='New chat', help_text="对话标题")
    parent_id = models.CharField(max_length=100, null=True, blank=True)
    role = models.CharField(max_length=20, choices=ROLE_CHOICES)
    content = models.TextField()
    tokens = models.IntegerField(default=0, help_text="消息token数")
    # 扩展metadata字段，用于存储知识库组合信息
    metadata = models.JSONField(default=dict, blank=True, help_text="""
    {
        'model_id': 'xxx',
        'dataset_id_list': ['id1', 'id2', ...],
        'dataset_external_id_list': ['ext1', 'ext2', ...],
        'primary_knowledge_base': 'id1'
    }
    """)
    created_at = models.DateTimeField(auto_now_add=True)
    is_deleted = models.BooleanField(default=False)

    class Meta:
        ordering = ['created_at']
        indexes = [
            models.Index(fields=['conversation_id', 'created_at']),
            models.Index(fields=['user', 'created_at']),
            # 添加新的索引以支持知识库组合查询
            models.Index(fields=['conversation_id', 'is_deleted']),
        ]

    def __str__(self):
        return f"{self.user.name} - {self.knowledge_base.name} - {self.created_at}"

    @classmethod
    def get_conversation(cls, conversation_id):
        """获取完整对话历史"""
        return cls.objects.filter(
            conversation_id=conversation_id,
            is_deleted=False
        ).order_by('created_at')

    @classmethod
    def get_conversations_by_knowledge_bases(cls, dataset_ids, user):
        """根据知识库组合获取对话历史"""
        # 对知识库ID列表排序以确保一致性
        sorted_kb_ids = sorted(dataset_ids)
        conversation_id = str(uuid.uuid5(
            uuid.NAMESPACE_DNS, 
            '-'.join(sorted_kb_ids)
        ))
        
        return cls.objects.filter(
            conversation_id=conversation_id,
            user=user,
            is_deleted=False
        ).order_by('created_at')

    @classmethod
    def get_knowledge_base_combinations(cls, user):
        """获取用户的所有知识库组合"""
        return cls.objects.filter(
            user=user,
            is_deleted=False
        ).values('conversation_id').annotate(
            last_message=max('created_at'),
            message_count=count('id')
        ).values(
            'conversation_id',
            'last_message',
            'message_count',
            'metadata'
        ).order_by('-last_message')

    def get_knowledge_bases(self):
        """获取此消息关联的所有知识库"""
        if self.metadata and 'dataset_id_list' in self.metadata:
            return KnowledgeBase.objects.filter(
                id__in=self.metadata['dataset_id_list']
            )
        return KnowledgeBase.objects.filter(id=self.knowledge_base.id)

    def soft_delete(self):
        """软删除消息"""
        self.is_deleted = True
        self.save()

    def to_dict(self):
        """转换为字典格式"""
        return {
            'id': str(self.id),
            'conversation_id': self.conversation_id,
            'role': self.role,
            'content': self.content,
            'created_at': self.created_at.strftime('%Y-%m-%d %H:%M:%S'),
            'metadata': self.metadata,
            'knowledge_bases': [
                {
                    'id': str(kb.id),
                    'name': kb.name,
                    'type': kb.type
                } for kb in self.get_knowledge_bases()
            ]
        }

class NegotiationChat(models.Model):
    """谈判对话关联表"""
    negotiation = models.ForeignKey(Negotiation, on_delete=models.CASCADE, related_name='chats')
    conversation_id = models.CharField(max_length=100, unique=True, db_index=True)
    creator = models.ForeignKey(CreatorProfile, on_delete=models.CASCADE)
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    class Meta:
        ordering = ['-updated_at']
        indexes = [
            models.Index(fields=['negotiation', 'updated_at']),
            models.Index(fields=['creator_id', 'product_id']),
        ]
    
    def __str__(self):
        return f"谈判 {self.negotiation.id} - 对话 {self.conversation_id}"