from pathlib import Path

from sqlalchemy import create_engine, inspect, text
from sqlalchemy.orm import declarative_base, sessionmaker

from app.core.config import settings
from app.core.security import get_password_hash


def _ensure_sqlite_parent(database_url: str) -> None:
    if not database_url.startswith('sqlite:///'):
        return
    relative_path = database_url.removeprefix('sqlite:///')
    if not relative_path or relative_path == ':memory:':
        return
    db_path = Path(relative_path)
    if not db_path.is_absolute():
        db_path = Path.cwd() / db_path
    db_path.parent.mkdir(parents=True, exist_ok=True)


_ensure_sqlite_parent(settings.database_url)

engine = create_engine(
    settings.database_url,
    connect_args={'check_same_thread': False} if settings.database_url.startswith('sqlite') else {},
)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()


def _ensure_column(table_name: str, column_name: str, ddl: str) -> None:
    inspector = inspect(engine)
    existing = {column['name'] for column in inspector.get_columns(table_name)}
    if column_name in existing:
        return
    with engine.begin() as connection:
        connection.execute(text(f'ALTER TABLE {table_name} ADD COLUMN {column_name} {ddl}'))


def _run_lightweight_migrations() -> None:
    tables = set(inspect(engine).get_table_names())
    if 'global_settings' in tables:
        _ensure_column('global_settings', 'connection_test_interval_minutes', 'INTEGER DEFAULT 0')
        _ensure_column('global_settings', 'default_switchos_username', 'VARCHAR(120)')
        _ensure_column('global_settings', 'default_switchos_password', 'VARCHAR(255)')
    if 'users' in tables:
        _ensure_column('users', 'preferred_language', "VARCHAR(8) DEFAULT 'pl' NOT NULL")
        _ensure_column('users', 'preferred_font', "VARCHAR(32) DEFAULT 'default' NOT NULL")
    if 'routers' in tables:
        _ensure_column('routers', 'device_type', "VARCHAR(32) DEFAULT 'routeros' NOT NULL")
        _ensure_column('routers', 'last_connection_status', 'BOOLEAN')
        _ensure_column('routers', 'last_connection_tested_at', 'DATETIME')
        _ensure_column('routers', 'last_connection_error', 'TEXT')
        _ensure_column('routers', 'last_connection_hostname', 'VARCHAR(255)')
        _ensure_column('routers', 'last_connection_model', 'VARCHAR(255)')
        _ensure_column('routers', 'last_connection_version', 'VARCHAR(255)')
        _ensure_column('routers', 'last_connection_uptime', 'VARCHAR(255)')
        _ensure_column('routers', 'last_connection_transport', 'VARCHAR(32)')
        _ensure_column('routers', 'last_connection_server', 'VARCHAR(255)')
        _ensure_column('routers', 'last_connection_auth_mode', 'VARCHAR(64)')
        _ensure_column('routers', 'last_connection_http_status', 'VARCHAR(32)')
        _ensure_column('routers', 'last_connection_backup_available', 'BOOLEAN')


def init_db():
    import app.db.base  # noqa: F401
    from app.models.settings import GlobalSettings
    from app.models.user import User

    Base.metadata.create_all(bind=engine)
    _run_lightweight_migrations()
    with SessionLocal() as db:
        if not db.query(User).first():
            db.add(
                User(
                    username=settings.default_admin_username,
                    password_hash=get_password_hash(settings.default_admin_password),
                )
            )
            db.commit()
        if not db.query(GlobalSettings).first():
            db.add(GlobalSettings())
            db.commit()