from pydantic import BaseModel, Field, EmailStr, field_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.now(datetime.UTC))
  updated_at: Optional[datetime] = None
  discount_applied: Optional[float] = None
  notes: Optional[str] = None

  @field_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

  @field_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