from datetime import datetime
from typing import Optional, List
from pydantic import BaseModel, Field
from bson import ObjectId


class PyObjectId(ObjectId):
    """Custom ObjectId type for Pydantic"""
    @classmethod
    def __get_validators__(cls):
        yield cls.validate

    @classmethod
    def validate(cls, v):
        if not ObjectId.is_valid(v):
            raise ValueError("Invalid ObjectId")
        return ObjectId(v)

    @classmethod
    def __get_pydantic_json_schema__(cls, field_schema):
        field_schema.update(type="string")


class Application(BaseModel):
    """OAuth2 Application data model"""

    id: Optional[PyObjectId] = Field(default=None, alias="_id")
    name: str = Field(..., min_length=1, max_length=100)
    client_id: str = Field(..., description="OAuth2 Client ID (unique)")
    client_secret: str = Field(..., description="Hashed client secret")
    redirect_uris: List[str] = Field(default_factory=list)
    grant_types: List[str] = Field(
        default_factory=lambda: ["authorization_code", "refresh_token"]
    )
    scopes: List[str] = Field(
        default_factory=lambda: ["read", "write"]
    )
    owner_id: str = Field(..., description="User ID who owns this application")
    created_at: datetime = Field(default_factory=datetime.utcnow)
    updated_at: datetime = Field(default_factory=datetime.utcnow)

    class Config:
        populate_by_name = True
        arbitrary_types_allowed = True
        json_encoders = {ObjectId: str}
        json_schema_extra = {
            "example": {
                "name": "News Frontend App",
                "client_id": "news_app_12345",
                "redirect_uris": [
                    "http://localhost:3000/auth/callback",
                    "https://news.example.com/auth/callback"
                ],
                "grant_types": ["authorization_code", "refresh_token"],
                "scopes": ["read", "write"],
                "owner_id": "507f1f77bcf86cd799439011"
            }
        }