from datetime import datetime, timezone
from typing import Optional

from sqlmodel import SQLModel, Field


def _now_utc() -> datetime:
    return datetime.now(timezone.utc)


class Novel(SQLModel, table=True):
    """小说主表"""

    id: Optional[int] = Field(default=None, primary_key=True)
    title: str = Field(max_length=200, index=True)
    description: str = Field(default="", max_length=2000)
    created_at: datetime = Field(default_factory=_now_utc)
    updated_at: datetime = Field(default_factory=_now_utc)


class AIConfig(SQLModel, table=True):
    """AI服务配置（单行表）"""

    id: Optional[int] = Field(default=None, primary_key=True)
    provider: str = Field(default="openai")  # "openai" | "anthropic"
    base_url: str = Field(default="https://api.openai.com/v1")
    api_key: str = Field(default="")
    model: str = Field(default="gpt-4o")
    updated_at: datetime = Field(default_factory=_now_utc)


class ChatMessage(SQLModel, table=True):
    """聊天消息"""

    id: Optional[int] = Field(default=None, primary_key=True)
    novel_id: Optional[int] = Field(default=None, foreign_key="novel.id", index=True)
    role: str = Field(max_length=20)  # "user" | "assistant"
    content: str = Field(default="")
    created_at: datetime = Field(default_factory=_now_utc)

class Outline(SQLModel, table=True):
    """大纲表，属于小说的子资源"""

    id: Optional[int] = Field(default=None, primary_key=True)
    novel_id: int = Field(foreign_key="novel.id", index=True)
    sort_order: int = Field(default=0)
    summary: str = Field(max_length=200)
    detail: str = Field(default="", max_length=1000)
    created_at: datetime = Field(default_factory=_now_utc)
    updated_at: datetime = Field(default_factory=_now_utc)