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，支持两级结构（父+子）"""

    id: Optional[int] = Field(default=None, primary_key=True)
    novel_id: int = Field(foreign_key="novel.id", index=True)
    parent_id: int | None = Field(default=None, foreign_key="outline.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)


class Character(SQLModel, table=True):
    """角色表，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)
    name: str = Field(max_length=100)
    description: str = Field(default="", max_length=1000)
    created_at: datetime = Field(default_factory=_now_utc)
    updated_at: datetime = Field(default_factory=_now_utc)


class Chapter(SQLModel, table=True):
    """章节表，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)
    title: str = Field(max_length=200)
    content: str = Field(default="", max_length=5000)
    created_at: datetime = Field(default_factory=_now_utc)
    updated_at: datetime = Field(default_factory=_now_utc)


class NovelFile(SQLModel, table=True):
    """小说关联文件"""

    id: Optional[int] = Field(default=None, primary_key=True)
    novel_id: int = Field(foreign_key="novel.id", index=True)
    filename: str = Field(max_length=255)         # 原始文件名
    stored_name: str = Field(max_length=255)      # 磁盘存储名（uuid + 扩展名）
    file_size: int = Field(default=0)             # 字节数
    mime_type: str = Field(default="", max_length=100)
    text_length: int = Field(default=0)           # 解析后纯文本字符数
    created_at: datetime = Field(default_factory=_now_utc)


class Skill(SQLModel, table=True):
    """Skill 插件：自定义系统提示词 + 工具白名单"""

    id: Optional[int] = Field(default=None, primary_key=True)
    name: str = Field(max_length=100, index=True)
    description: str = Field(default="", max_length=500)
    system_prompt: str = Field(default="")
    allowed_tools: str = Field(default="[]")  # JSON 数组字符串，"[]" 表示全部工具
    is_builtin: bool = Field(default=False)
    novel_id: int | None = Field(default=None, foreign_key="novel.id", index=True)
    created_at: datetime = Field(default_factory=_now_utc)
    updated_at: datetime = Field(default_factory=_now_utc)


class WorldSetting(SQLModel, table=True):
    """世界观设定，每部小说一条记录"""

    id: Optional[int] = Field(default=None, primary_key=True)
    novel_id: int = Field(foreign_key="novel.id", index=True, unique=True)
    content: str = Field(default="", max_length=5000)
    created_at: datetime = Field(default_factory=_now_utc)
    updated_at: datetime = Field(default_factory=_now_utc)