from pydantic import BaseModel, Field, EmailStr, validator
from typing import List, Optional
from datetime import datetime
from bson import ObjectId
from pydantic import ConfigDict
from typing import Any, ClassVar


class PyObjectId(ObjectId):
  @classmethod
  def __get_pydantic_core_schema__(
      cls, _source_type: Any, _handler: Any
  ) -> Any:
    from pydantic_core import core_schema
    return core_schema.json_or_python_schema(
        python_schema=core_schema.is_instance_schema(ObjectId),
        json_schema=core_schema.StringSchema(),
        serialization=core_schema.to_string_ser_schema(),
    )


class MongoBaseModel(BaseModel):
  id: PyObjectId = Field(default_factory=PyObjectId, alias="_id")

  model_config = ConfigDict(
      populate_by_name=True,
      arbitrary_types_allowed=True,
      json_encoders={ObjectId: str}
  )


class Item(MongoBaseModel):
  name: str
  price: float
  quantity: int
  unit: str
  related_items: List[str] = []


class OrderItem(BaseModel):
  item_id: PyObjectId
  quantity: int
  price_at_order: float


class Order(MongoBaseModel):
  user_id: PyObjectId
  items: List[OrderItem]
  total_amount: float
  payment_method: Optional[str] = None
  payment_status: str = "pending"
  order_status: str = "created"
  created_at: datetime = Field(default_factory=datetime.utcnow)
  updated_at: Optional[datetime] = None
  discount_applied: Optional[float] = None
  notes: Optional[str] = None

  @validator('order_status')
  def valid_order_status(cls, v):
    allowed_statuses = ["created", "processing",
                        "shipped", "delivered", "cancelled"]
    if v not in allowed_statuses:
      raise ValueError(f"Invalid order status. Must be one of: {
                       ', '.join(allowed_statuses)}")
    return v

  @validator('payment_status')
  def valid_payment_status(cls, v):
    allowed_statuses = ["pending", "paid", "refunded", "failed"]
    if v not in allowed_statuses:
      raise ValueError(f"Invalid payment status. Must be one of: {
                       ', '.join(allowed_statuses)}")
    return v


class UserBase(BaseModel):
  username: str
  email: EmailStr
  full_name: str
  is_active: bool = True
  is_superuser: bool = False


class UserCreate(UserBase):
  password: str


class UserInDB(UserBase, MongoBaseModel):
  hashed_password: str


class User(UserBase, MongoBaseModel):
  pass


class Token(BaseModel):
  access_token: str
  token_type: str


class TokenData(BaseModel):
  username: Optional[str] = None