"""Authentication daemon handlers.

Handles login, logout, token refresh, session management, password change,
user CRUD, and WebAuthn operations.
"""

from __future__ import annotations

import logging
from typing import Any

from daemon.iface import (
    DELETE_AUTH_USER,
    DELETE_AUTH_WEBAUTHN_CREDENTIAL,
    GET_AUTH_SESSION,
    GET_AUTH_USERS,
    GET_AUTH_WEBAUTHN_CREDENTIAL_COUNTS,
    GET_AUTH_WEBAUTHN_CREDENTIALS,
    POST_AUTH_LOGIN,
    POST_AUTH_LOGOUT,
    POST_AUTH_PASSWORD,
    POST_AUTH_REFRESH,
    POST_AUTH_USER_CREATE,
    POST_AUTH_USER_UPDATE,
    POST_AUTH_WEBAUTHN_AUTHENTICATE_BEGIN,
    POST_AUTH_WEBAUTHN_AUTHENTICATE_FINISH,
    POST_AUTH_WEBAUTHN_REGISTER_BEGIN,
    POST_AUTH_WEBAUTHN_REGISTER_FINISH,
)
from daemon.server import ConflictError, NotFoundError, registry
from lib.auth import (
    blacklist_active_refresh_token,
    blacklist_token,
    check_login_rate,
    check_webauthn_rate,
    clear_active_refresh_token,
    generate_tokens,
    get_access_ttl,
    validate_token,
)
from lib.auth_users import (
    ALL_SUBSYSTEMS,
    create_user,
    delete_user,
    get_user,
    list_users,
    update_password,
    update_permissions,
    verify_user_password,
)
from lib.webauthn import (
    create_authentication_options,
    create_registration_options,
    get_all_credential_counts,
    list_credentials,
    remove_credential,
    verify_authentication,
    verify_registration,
)

logger = logging.getLogger(__name__)

_ALL_RW = {sub: "rw" for sub in ALL_SUBSYSTEMS}


def _clear_refresh_token_after_rotation(username: str) -> None:
    """Remove the user's entry from refresh_tokens after a successful refresh rotation."""
    clear_active_refresh_token(username)


@registry.register(POST_AUTH_LOGIN)
def auth_login(_request: Any, body: Any) -> dict[str, Any]:
    """Handle user login.

    Args:
        _request: Unused.
        body: Dict with ``username`` and ``password``.

    Returns:
        Dict with ``tokens``, ``user``, and ``permissions``.

    Raises:
        ValueError: If credentials are invalid.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    password = body.get("password")
    if not username or not password:
        raise ValueError("username and password are required")

    if not check_login_rate(username):
        raise ValueError("Too many login attempts. Please try again later.")

    user = verify_user_password(username, password)
    if user is None:
        raise ValueError("Invalid credentials")

    permissions = user["permissions"]
    tokens = generate_tokens(username, permissions)

    return {
        "tokens": tokens,
        "access_ttl": get_access_ttl(),
        "user": {
            "id": user["id"],
            "username": user["username"],
        },
        "permissions": permissions,
    }


@registry.register(POST_AUTH_LOGOUT)
def auth_logout(request: Any, body: Any) -> dict[str, Any]:
    """Handle user logout by blacklisting the access and refresh tokens.

    Args:
        request: The aiohttp request.
        body: Dict with ``jti``, ``username`` from Flask user context, and
            ``refresh_token`` from the client.

    Returns:
        Success response.
    """
    if not body:
        return {"ok": True}

    jti = body.get("jti")
    if jti:
        blacklist_token(jti)

    username = body.get("username")
    if username:
        blacklist_active_refresh_token(username)

    return {"ok": True}


@registry.register(POST_AUTH_REFRESH)
def auth_refresh(_request: Any, body: Any) -> dict[str, Any]:
    """Handle token refresh.

    Validates the refresh token, blacklists it, and issues a new access token.

    Args:
        _request: Unused.
        body: Dict with ``refresh_token``.

    Returns:
        Dict with new access token, refresh token, user, and permissions.

    Raises:
        ValueError: If refresh token is invalid.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    refresh_token = body.get("refresh_token")
    if not refresh_token:
        raise ValueError("refresh_token is required")

    payload = validate_token(refresh_token, token_type="refresh")
    if payload is None:
        raise ValueError("Invalid or expired refresh token")

    username = payload["sub"]
    user = get_user(username)
    if user is None:
        raise ValueError("User not found")

    jti = payload.get("jti")
    if jti:
        blacklist_token(jti, token_type="refresh")
    if username:
        _clear_refresh_token_after_rotation(username)
    permissions = user["permissions"]
    tokens = generate_tokens(username, permissions)

    return {
        "tokens": tokens,
        "access_ttl": get_access_ttl(),
        "user": {
            "id": user["id"],
            "username": user["username"],
        },
        "permissions": permissions,
    }


@registry.register(GET_AUTH_SESSION)
def auth_session(request: Any, body: Any) -> dict[str, Any]:
    """Return current user session info.

    Args:
        request: The aiohttp request.
        body: Dict with ``username`` from Flask user context.

    Returns:
        Dict with user info and permissions.
    """
    username = body.get("username") if body else None
    if username is None:
        raise ValueError("No active session")

    user = get_user(username)
    if user is None:
        raise ValueError("User not found")

    return {
        "user": {
            "id": user["id"],
            "username": user["username"],
        },
        "permissions": user["permissions"],
    }


@registry.register(POST_AUTH_PASSWORD)
def auth_change_password(_request: Any, body: Any) -> dict[str, Any]:
    """Change user password.

    Args:
        _request: Unused.
        body: Dict with ``username``, ``oldPassword``, ``newPassword``.

    Returns:
        Success response.

    Raises:
        ValueError: If password change fails.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    old_password = body.get("oldPassword")
    new_password = body.get("newPassword")

    if not username or not old_password or not new_password:
        raise ValueError("username, oldPassword, and newPassword are required")

    if len(new_password) < 8:
        raise ValueError("New password must be at least 8 characters")

    update_password(username, old_password, new_password)
    logger.info("Password changed for user %r", username)
    return {"ok": True}


@registry.register(GET_AUTH_USERS)
def auth_list_users(_request: Any, body: Any) -> list[dict[str, Any]]:
    """List all users.

    Args:
        _request: Unused.
        body: Unused.

    Returns:
        List of user summary dicts.
    """
    return list_users()


@registry.register(POST_AUTH_USER_CREATE)
def auth_create_user(_request: Any, body: Any) -> dict[str, Any]:
    """Create a new user.

    Args:
        _request: Unused.
        body: Dict with ``username``, ``password``, ``permissions``.

    Returns:
        Created user dict.

    Raises:
        ConflictError: If user already exists.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    password = body.get("password")
    permissions = body.get("permissions", {})

    if not username or not password:
        raise ValueError("username and password are required")

    if len(password) < 8:
        raise ValueError("Password must be at least 8 characters")

    try:
        user = create_user(username, password, permissions)
        return {
            "id": user["id"],
            "username": user["username"],
            "permissions": user["permissions"],
        }
    except ValueError as e:
        raise ConflictError(str(e)) from e


@registry.register(POST_AUTH_USER_UPDATE)
def auth_update_user(_request: Any, body: Any) -> dict[str, Any]:
    """Update a user's permissions.

    Args:
        _request: Unused.
        body: Dict with optional ``permissions``, ``password`` keys.
            Path param ``username`` is merged into body by the daemon.

    Returns:
        Updated user dict.

    Raises:
        NotFoundError: If user not found.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    if not username:
        raise ValueError("username is required")

    existing = get_user(username)
    if existing is None:
        raise NotFoundError(f"User {username!r} not found")

    if "permissions" in body:
        update_permissions(username, body["permissions"])

    user = get_user(username)
    if user is None:
        raise NotFoundError(f"User {username!r} not found")

    return {
        "id": user["id"],
        "username": user["username"],
        "permissions": user["permissions"],
    }


@registry.register(DELETE_AUTH_USER)
def auth_delete_user(_request: Any, body: Any) -> dict[str, Any]:
    """Delete a user.

    Self-deletion is blocked by Flask middleware (auth blueprint).

    Args:
        _request: Unused.
        body: Path param ``username`` merged by the daemon.

    Returns:
        Success response.

    Raises:
        NotFoundError: If user not found.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    if not username:
        raise ValueError("username is required")

    try:
        delete_user(username)
        logger.info("User %r deleted", username)
        return {"ok": True}
    except ValueError as e:
        if "not found" in str(e):
            raise NotFoundError(str(e)) from e
        raise


# ---------------------------------------------------------------------------
# WebAuthn handlers
# ---------------------------------------------------------------------------


@registry.register(POST_AUTH_WEBAUTHN_REGISTER_BEGIN)
def webauthn_register_begin(_request: Any, body: Any) -> dict[str, Any]:
    """Begin WebAuthn registration — return options for ``credentials.create()``."""
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    if not username:
        raise ValueError("username is required")

    options = create_registration_options(username)
    return options


@registry.register(POST_AUTH_WEBAUTHN_REGISTER_FINISH)
def webauthn_register_finish(_request: Any, body: Any) -> dict[str, Any]:
    """Finish WebAuthn registration — verify credential and persist."""
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    credential_response = body.get("credential_response")
    registration_options = body.get("registration_options")
    credential_name = body.get("name", "")

    if not username or not credential_response or not registration_options:
        raise ValueError(
            "username, credential_response, and registration_options are required"
        )

    try:
        cred = verify_registration(
            username, credential_response, registration_options, credential_name
        )
        return {"ok": True, "credential": cred}
    except ValueError:
        raise


@registry.register(POST_AUTH_WEBAUTHN_AUTHENTICATE_BEGIN)
def webauthn_authenticate_begin(_request: Any, body: Any) -> dict[str, Any]:
    """Begin WebAuthn authentication — return options for ``credentials.get()``.

    Public endpoint — no JWT required. Returns ``{"noWebAuthn": true}`` if the
    user has no registered credentials (so the frontend can fall back to password).
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    if not username:
        raise ValueError("username is required")

    options = create_authentication_options(username)
    if options is None:
        return {"no_webauthn": True}
    return options


@registry.register(POST_AUTH_WEBAUTHN_AUTHENTICATE_FINISH)
def webauthn_authenticate_finish(_request: Any, body: Any) -> dict[str, Any]:
    """Finish WebAuthn authentication — verify assertion, issue tokens.

    Public endpoint — no JWT required.
    """
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    assertion_response = body.get("assertion_response")
    auth_options = body.get("auth_options")

    if not username or not assertion_response or not auth_options:
        raise ValueError("username, assertion_response, and auth_options are required")

    if not check_webauthn_rate(username):
        raise ValueError("Too many WebAuthn attempts. Please try again later.")

    try:
        verify_authentication(username, assertion_response, auth_options)
    except ValueError:
        raise

    user = get_user(username)
    if user is None:
        raise ValueError("User not found")

    permissions = user["permissions"]
    tokens = generate_tokens(username, permissions)

    return {
        "tokens": tokens,
        "access_ttl": get_access_ttl(),
        "user": {
            "id": user["id"],
            "username": user["username"],
        },
        "permissions": permissions,
    }


@registry.register(GET_AUTH_WEBAUTHN_CREDENTIALS)
def webauthn_credentials(request: Any, body: Any) -> list[dict[str, Any]]:
    """List WebAuthn credentials for the authenticated user."""
    username = body.get("username") if body else None
    if not username:
        raise ValueError("No active session")

    return list_credentials(username)


@registry.register(DELETE_AUTH_WEBAUTHN_CREDENTIAL)
def webauthn_remove_credential(request: Any, body: Any) -> dict[str, Any]:
    """Remove a WebAuthn credential."""
    if not body or not isinstance(body, dict):
        raise ValueError("Request body is required")

    username = body.get("username")
    if not username:
        raise ValueError("No active session")

    credential_id = body.get("credential_id")
    if not credential_id:
        raise ValueError("credential_id is required")

    try:
        remove_credential(username, credential_id)
        logger.info("WebAuthn credential removed for %s", username)
        return {"ok": True}
    except ValueError as e:
        if "not found" in str(e):
            raise NotFoundError(str(e)) from e
        raise


@registry.register(GET_AUTH_WEBAUTHN_CREDENTIAL_COUNTS)
def webauthn_credential_counts(_request: Any, body: Any) -> dict[str, int]:
    """Return credential counts for all users (admin endpoint)."""
    return get_all_credential_counts()