import re
from typing import Optional

from pydantic import BaseModel, Field, field_validator

from app.core.dto.user import UserRole

EMAIL_PATTERN = re.compile(r"^[^@\s]+@[^@\s]+\.[^@\s]+$")


def _normalize_email(value: str) -> str:
    value = value.strip().lower()
    if not EMAIL_PATTERN.match(value) or len(value) > 254:
        raise ValueError("invalid email")
    return value


class UserCreate(BaseModel):
    email: str
    password: str = Field(min_length=8, max_length=128)
    first_name: str = Field(default="", max_length=100)
    last_name: str = Field(default="", max_length=100)
    role: UserRole = UserRole.trainee

    _email = field_validator("email")(_normalize_email)


class UserUpdate(BaseModel):
    """Partial update: only the fields that were sent are changed."""

    email: Optional[str] = None
    password: Optional[str] = Field(default=None, min_length=8, max_length=128)
    first_name: Optional[str] = Field(default=None, max_length=100)
    last_name: Optional[str] = Field(default=None, max_length=100)
    role: Optional[UserRole] = None
    is_active: Optional[bool] = None

    @field_validator("email")
    @classmethod
    def normalize_email(cls, value: Optional[str]) -> Optional[str]:
        return None if value is None else _normalize_email(value)