"""
Chat models: conversations and messages with status tracking.
"""
import uuid
from datetime import datetime
from app import db


class Conversation(db.Model):
    __tablename__ = "conversations"
    id = db.Column(db.String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    user_id = db.Column(db.String(36), db.ForeignKey("users.id"), nullable=False, index=True)
    title = db.Column(db.String(256), default="新对话")
    last_message_at = db.Column(db.DateTime, default=datetime.utcnow)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    messages = db.relationship("Message", backref="conversation", lazy="dynamic", order_by="Message.created_at")


class MessageStatus:
    SENT = "sent"
    DELIVERED = "delivered"
    READ = "read"
    RECALLED = "recalled"
    FAILED = "failed"


class Message(db.Model):
    __tablename__ = "messages"
    id = db.Column(db.String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    conversation_id = db.Column(db.String(36), db.ForeignKey("conversations.id"), nullable=False, index=True)
    sender_id = db.Column(db.String(36), db.ForeignKey("users.id"), nullable=False, index=True)
    content = db.Column(db.Text, nullable=False)
    content_type = db.Column(db.String(32), default="text")  # text, image, file
    attachment_url = db.Column(db.String(512))
    attachment_name = db.Column(db.String(256))
    status = db.Column(db.String(32), default=MessageStatus.SENT)
    is_recalled = db.Column(db.Boolean, default=False)
    recalled_at = db.Column(db.DateTime)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)

    def to_dict(self):
        return {
            "id": self.id,
            "conversation_id": self.conversation_id,
            "sender_id": self.sender_id,
            "content": self.content,
            "content_type": self.content_type,
            "attachment_url": self.attachment_url,
            "attachment_name": self.attachment_name,
            "status": self.status,
            "is_recalled": self.is_recalled,
            "created_at": self.created_at.isoformat() if self.created_at else None,
        }