"""Map users-table unique constraint violations to auth error codes."""

from __future__ import annotations

from sqlalchemy.exc import IntegrityError

_PHONE_CONSTRAINT_MARKERS = frozenset({"phone", "ix_users_phone", "users_phone_key"})
_EMAIL_CONSTRAINT_MARKERS = frozenset({"email", "users_email_key", "ix_users_email"})


def _constraint_text(exc: IntegrityError) -> str:
    orig = exc.orig
    if orig is None:
        return str(exc).lower()
    diag = getattr(orig, "diag", None)
    if diag is not None:
        name = getattr(diag, "constraint_name", None)
        if name:
            return str(name).lower()
    return str(orig).lower()


def _matches(markers: frozenset[str], text: str) -> bool:
    return any(marker in text for marker in markers)


def user_integrity_auth_code(
    exc: IntegrityError,
    *,
    phone_conflict: str,
) -> str | None:
    """Return auth internal code for a users-table unique violation, or None."""
    text = _constraint_text(exc)
    if _matches(_PHONE_CONSTRAINT_MARKERS, text):
        return phone_conflict
    if _matches(_EMAIL_CONSTRAINT_MARKERS, text):
        return "EMAIL_EXISTS"
    return None


def is_user_phone_unique_violation(exc: IntegrityError) -> bool:
    return _matches(_PHONE_CONSTRAINT_MARKERS, _constraint_text(exc))