from pydantic import BaseModel, ConfigDict
from typing import Optional, List
from datetime import datetime
from decimal import Decimal


class ProductCreate(BaseModel):
    sku: str
    name: str
    description: Optional[str] = None
    category: Optional[str] = None
    unit: str = "件"
    item_type: str = "finished"
    cost_price: Decimal = Decimal("0")
    sale_price: Decimal = Decimal("0")
    min_stock: int = 0
    max_stock: int = 1000


class ProductResponse(BaseModel):
    id: int
    sku: str
    name: str
    description: Optional[str]
    category: Optional[str]
    unit: str
    item_type: str
    cost_price: Decimal
    sale_price: Decimal
    min_stock: int
    max_stock: int
    material_cost: Decimal = Decimal("0")
    is_active: bool
    created_at: datetime

    model_config = ConfigDict(from_attributes=True)


class ProductMaterialItemUpdate(BaseModel):
    material_id: int
    quantity: Decimal
    loss_rate: Decimal = Decimal("0")


class ProductBOMUpdate(BaseModel):
    items: List[ProductMaterialItemUpdate]


class ProductMaterialItemResponse(BaseModel):
    material_id: int
    material_sku: str
    material_name: str
    quantity: Decimal
    unit_cost: Decimal
    line_cost: Decimal


class ProductBOMResponse(BaseModel):
    product_id: int
    product_name: str
    total_material_cost: Decimal
    items: List[ProductMaterialItemResponse]