"""
书影音收藏模型
"""
from datetime import datetime
from typing import Optional, TYPE_CHECKING
from sqlmodel import SQLModel, Field, Relationship
from .user import User

if TYPE_CHECKING:
    from .tag import Tag
else:
    Tag = "Tag"


class MediaTag(SQLModel, table=True):
    """媒体-标签关联表"""
    __tablename__ = "media_tags"
    
    media_id: int = Field(foreign_key="media.id", primary_key=True)
    tag_id: int = Field(foreign_key="tags.id", primary_key=True)


class Media(SQLModel, table=True):
    """书影音收藏表"""
    __tablename__ = "media"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    title: str = Field(max_length=200)
    media_type: str = Field(max_length=20)  # book / movie / music
    rating: Optional[float] = Field(default=None, ge=0.0, le=5.0)
    comment: Optional[str] = Field(default=None)
    external_id: Optional[str] = Field(default=None, max_length=100)  # ISBN、IMDb ID等
    cover_url: Optional[str] = Field(default=None, max_length=300)
    created_at: datetime = Field(default_factory=datetime.now)
    user_id: int = Field(foreign_key="users.id", index=True)
    
    # 关系
    user: Optional[User] = Relationship()
    tags: list["Tag"] = Relationship(back_populates="media", link_model="MediaTag")