"""Local email/password authentication provider."""

import logging

from app.gateway.auth.models import User
from app.gateway.auth.password import hash_password_async, needs_rehash, verify_password_async
from app.gateway.auth.providers import AuthProvider
from app.gateway.auth.repositories.base import UserRepository

logger = logging.getLogger(__name__)


class LocalAuthProvider(AuthProvider):
    """Email/password authentication provider using local database."""

    def __init__(self, repository: UserRepository):
        """Initialize with a UserRepository.

        Args:
            repository: UserRepository implementation (SQLite)
        """
        self._repo = repository

    async def authenticate(self, credentials: dict) -> User | None:
        """Authenticate with email and password.

        Args:
            credentials: dict with 'email' and 'password' keys

        Returns:
            User if authentication succeeds, None otherwise
        """
        email = credentials.get("email")
        password = credentials.get("password")

        if not email or not password:
            return None

        user = await self._repo.get_user_by_email(email)
        if user is None:
            return None

        if user.password_hash is None:
            # OAuth user without local password
            return None

        if not await verify_password_async(password, user.password_hash):
            return None

        if needs_rehash(user.password_hash):
            try:
                user.password_hash = await hash_password_async(password)
                await self._repo.update_user(user)
            except Exception:
                # Rehash is an opportunistic upgrade; a transient DB error must not
                # prevent an otherwise-valid login from succeeding.
                logger.warning("Failed to rehash password for user %s; login will still succeed", user.email, exc_info=True)

        return user

    async def get_user(self, user_id: str) -> User | None:
        """Get user by ID."""
        return await self._repo.get_user_by_id(user_id)

    async def find_user_by_email_local_part(self, local_part: str) -> User | None:
        """Find a user whose email starts with ``local_part@`` regardless of domain.

        Used by the passwordless username-login flow to keep a single
        username mapped to the same account across legacy / canonical
        email-domain defaults.
        """
        return await self._repo.find_user_by_email_local_part(local_part)

    async def find_users_by_email_local_part_like(self, substring: str, *, limit: int = 500) -> list[User]:
        """Fuzzy-match users by a substring of their email local part.

        Backs the admin LLM-metrics username filter — returns every account
        whose username contains ``substring`` (case-insensitive).
        """
        return await self._repo.find_users_by_email_local_part_like(substring, limit=limit)

    async def create_user(self, email: str, password: str | None = None, system_role: str = "user", needs_setup: bool = False, approved: bool = True) -> User:
        """Create a new local user.

        Args:
            email: User email address
            password: Plain text password (will be hashed)
            system_role: Role to assign ("admin" or "user")
            needs_setup: If True, user must complete setup on first login
            approved: Login-whitelist 放行标记. **黑名单模式**:新账号默认 ``True``
                (从未登录过的用户首次登录即放行),管理员可在白名单管理页对个别
                用户「取消放行」(置 ``False``) 来封禁。仅当 ``login_whitelist.enabled``
                打开时 ``approved=False`` 才会被拦。

        Returns:
            Created User instance
        """
        password_hash = await hash_password_async(password) if password else None
        user = User(
            email=email,
            password_hash=password_hash,
            system_role=system_role,
            needs_setup=needs_setup,
            approved=approved,
        )
        return await self._repo.create_user(user)

    async def get_user_by_oauth(self, provider: str, oauth_id: str) -> User | None:
        """Get user by OAuth provider and ID."""
        return await self._repo.get_user_by_oauth(provider, oauth_id)

    async def count_users(self) -> int:
        """Return total number of registered users."""
        return await self._repo.count_users()

    async def count_admin_users(self) -> int:
        """Return number of admin users."""
        return await self._repo.count_admin_users()

    async def update_user(self, user: User) -> User:
        """Update an existing user."""
        return await self._repo.update_user(user)

    async def list_users(self) -> list[User]:
        """Return all registered users ordered by creation date."""
        return await self._repo.list_users()

    async def get_user_by_email(self, email: str) -> User | None:
        """Get user by email."""
        return await self._repo.get_user_by_email(email)