"""Setup service.

Implements the one-time first-run configuration wizard.  Responsible for
hashing the master password, persisting all initial settings, and
enforcing the rule that setup can only run once.
"""

from __future__ import annotations

from typing import TYPE_CHECKING

import bcrypt
import structlog

if TYPE_CHECKING:
    import aiosqlite

from app.repositories import settings_repo

log: structlog.stdlib.BoundLogger = structlog.get_logger()

# Keys used in the settings table.
_KEY_PASSWORD_HASH = "master_password_hash"
_KEY_SETUP_DONE = "setup_completed"
_KEY_DATABASE_PATH = "database_path"
_KEY_FAIL2BAN_SOCKET = "fail2ban_socket"
_KEY_TIMEZONE = "timezone"
_KEY_SESSION_DURATION = "session_duration_minutes"


async def is_setup_complete(db: aiosqlite.Connection) -> bool:
    """Return ``True`` if initial setup has already been performed.

    Args:
        db: Active aiosqlite connection.

    Returns:
        ``True`` when the ``setup_completed`` key exists in settings.
    """
    value = await settings_repo.get_setting(db, _KEY_SETUP_DONE)
    return value == "1"


async def run_setup(
    db: aiosqlite.Connection,
    *,
    master_password: str,
    database_path: str,
    fail2ban_socket: str,
    timezone: str,
    session_duration_minutes: int,
) -> None:
    """Persist the initial configuration and mark setup as complete.

    Hashes *master_password* with bcrypt before storing.  Raises
    :class:`RuntimeError` if setup has already been completed.

    Args:
        db: Active aiosqlite connection.
        master_password: Plain-text master password chosen by the user.
        database_path: Filesystem path to the BanGUI SQLite database.
        fail2ban_socket: Unix socket path for the fail2ban daemon.
        timezone: IANA timezone identifier (e.g. ``"UTC"``).
        session_duration_minutes: Session validity period in minutes.

    Raises:
        RuntimeError: If setup has already been completed.
    """
    if await is_setup_complete(db):
        raise RuntimeError("Setup has already been completed.")

    log.info("bangui_setup_started")

    # Hash the master password — bcrypt automatically generates a salt.
    password_bytes = master_password.encode()
    hashed = bcrypt.hashpw(password_bytes, bcrypt.gensalt()).decode()

    await settings_repo.set_setting(db, _KEY_PASSWORD_HASH, hashed)
    await settings_repo.set_setting(db, _KEY_DATABASE_PATH, database_path)
    await settings_repo.set_setting(db, _KEY_FAIL2BAN_SOCKET, fail2ban_socket)
    await settings_repo.set_setting(db, _KEY_TIMEZONE, timezone)
    await settings_repo.set_setting(
        db, _KEY_SESSION_DURATION, str(session_duration_minutes)
    )
    # Mark setup as complete — must be last so a partial failure leaves
    # setup_completed unset and does not lock out the user.
    await settings_repo.set_setting(db, _KEY_SETUP_DONE, "1")

    log.info("bangui_setup_completed")


async def get_password_hash(db: aiosqlite.Connection) -> str | None:
    """Return the stored bcrypt password hash, or ``None`` if not set.

    Args:
        db: Active aiosqlite connection.

    Returns:
        The bcrypt hash string, or ``None``.
    """
    return await settings_repo.get_setting(db, _KEY_PASSWORD_HASH)


async def get_timezone(db: aiosqlite.Connection) -> str:
    """Return the configured IANA timezone string.

    Falls back to ``"UTC"`` when no timezone has been stored (e.g. before
    setup completes or for legacy databases).

    Args:
        db: Active aiosqlite connection.

    Returns:
        An IANA timezone identifier such as ``"Europe/Berlin"`` or ``"UTC"``.
    """
    tz = await settings_repo.get_setting(db, _KEY_TIMEZONE)
    return tz if tz else "UTC"