from datetime import datetime
from pydantic import BaseModel, Field, field_validator
import re


class UserBase(BaseModel):
    nickname: str = Field(..., min_length=2, max_length=50)


class UserRegister(UserBase):
    login: str = Field(..., min_length=3, max_length=50)
    password: str = Field(..., min_length=6, max_length=100)

    @field_validator("login")
    @classmethod
    def validate_login(cls, v: str) -> str:
        if not re.match(r"^[a-zA-Z0-9_]+$", v):
            raise ValueError("Login can only contain letters, numbers, and underscores")
        return v.lower()


class UserLogin(BaseModel):
    login: str
    password: str


class UserUpdate(BaseModel):
    nickname: str | None = Field(None, min_length=2, max_length=50)


class UserPublic(UserBase):
    id: int
    login: str
    avatar_url: str | None = None
    created_at: datetime

    class Config:
        from_attributes = True


class UserWithTelegram(UserPublic):
    telegram_id: int | None = None
    telegram_username: str | None = None


class TokenResponse(BaseModel):
    access_token: str
    token_type: str = "bearer"
    user: UserPublic


class TelegramLink(BaseModel):
    telegram_id: int
    telegram_username: str | None = None