"""
MFAFactor model — stores TOTP/OTP configuration per user.

Maps to AGENT.md DBML: `mfa_factors` table (Lines 228-235).
"""
from django.conf import settings
from django.db import models

from core.models import BaseModel


class MFAFactor(BaseModel):
    """
    Multi-factor authentication factor for a user.

    Stores the encrypted TOTP secret. The `enabled` flag allows users
    to set up MFA before activating it (verify first, then enable).
    """

    class FactorType(models.TextChoices):
        TOTP = "totp", "Time-based OTP"
        SMS = "sms", "SMS OTP"
        EMAIL = "email", "Email OTP"

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="mfa_factors",
    )
    type = models.CharField(
        max_length=20,
        choices=FactorType.choices,
        default=FactorType.TOTP,
    )
    secret = models.TextField(
        help_text="Encrypted TOTP secret. Use core.services.encryption to encrypt/decrypt.",
    )
    enabled = models.BooleanField(default=False)

    class Meta:
        db_table = "mfa_factors"
        constraints = [
            models.UniqueConstraint(
                fields=["user", "type"],
                name="unique_mfa_factor_per_user_type",
            ),
        ]

    def __str__(self) -> str:
        status = "enabled" if self.enabled else "disabled"
        return f"MFA ({self.type}) for {self.user_id} [{status}]"