import json
from datetime import datetime
from typing import Any

from pydantic import BaseModel, Field, validator


class CartItemBase(BaseModel):
    product_id: str
    quantity: int = Field(..., gt=0)
    custom_properties: dict[str, Any] | None = None

class CartItemCreate(CartItemBase):
    pass

class CartItemUpdate(BaseModel):
    quantity: int | None = Field(None, gt=0)
    custom_properties: dict[str, Any] | None = None

class CartItemInDBBase(CartItemBase):
    id: str
    user_id: str
    price_at_addition: float
    created_at: datetime
    updated_at: datetime | None = None

    class Config:
        orm_mode = True

    @validator('custom_properties', pre=True)
    def parse_custom_properties(cls, v):
        if isinstance(v, str):
            try:
                return json.loads(v)
            except:
                return None
        return v

class CartItem(CartItemInDBBase):
    product_name: str
    product_image: str | None = None
    current_price: float
    subtotal: float

class CartSummary(BaseModel):
    items: list[CartItem]
    total_items: int
    subtotal: float
    total_weight: float | None = None