from pydantic import BaseModel, field_validator
from typing import List, Optional
from datetime import datetime


class AuthorBase(BaseModel):
    name: str
    biography: Optional[str] = None
    birthdate: Optional[datetime] = None


class AuthorCreate(AuthorBase):
    pass


class AuthorUpdate(BaseModel):
    name: Optional[str] = None
    biography: Optional[str] = None
    birthdate: Optional[datetime] = None


class Author(AuthorBase):
    id: int
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class CategoryBase(BaseModel):
    name: str
    description: Optional[str] = None


class CategoryCreate(CategoryBase):
    pass


class CategoryUpdate(BaseModel):
    name: Optional[str] = None
    description: Optional[str] = None


class Category(CategoryBase):
    id: int
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class BookBase(BaseModel):
    title: str
    isbn: str
    description: Optional[str] = None
    price: float
    cover_image_url: Optional[str] = None
    publication_date: Optional[datetime] = None
    publisher: Optional[str] = None
    language: Optional[str] = None
    page_count: Optional[int] = None
    stock_quantity: int = 0

    @field_validator("price")
    def price_must_be_positive(cls, v):
        if v <= 0:
            raise ValueError("Price must be greater than zero")
        return v

    @field_validator("stock_quantity")
    def stock_quantity_must_be_non_negative(cls, v):
        if v < 0:
            raise ValueError("Stock quantity must be non-negative")
        return v


class BookCreate(BookBase):
    author_ids: List[int]
    category_ids: List[int]


class BookUpdate(BaseModel):
    title: Optional[str] = None
    isbn: Optional[str] = None
    description: Optional[str] = None
    price: Optional[float] = None
    cover_image_url: Optional[str] = None
    publication_date: Optional[datetime] = None
    publisher: Optional[str] = None
    language: Optional[str] = None
    page_count: Optional[int] = None
    stock_quantity: Optional[int] = None
    author_ids: Optional[List[int]] = None
    category_ids: Optional[List[int]] = None

    @field_validator("price")
    def price_must_be_positive(cls, v):
        if v is not None and v <= 0:
            raise ValueError("Price must be greater than zero")
        return v

    @field_validator("stock_quantity")
    def stock_quantity_must_be_non_negative(cls, v):
        if v is not None and v < 0:
            raise ValueError("Stock quantity must be non-negative")
        return v


class Book(BookBase):
    id: int
    authors: List[Author]
    categories: List[Category]
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class BookList(BaseModel):
    total: int
    items: List[Book]