"""Connector factory keyed on `c2_type`.

Concrete connectors register themselves at import time via the
`@register_connector` decorator. Sprint 0 ships only the interface — no real
implementation registers in this codebase yet.
"""

from __future__ import annotations

from collections.abc import Callable
from typing import TypeVar

from mimic.connectors.base import C2Connector
from mimic.db.types import C2Type

ConnectorClass = type[C2Connector]
C = TypeVar("C", bound=C2Connector)

_REGISTRY: dict[C2Type, ConnectorClass] = {}


def register_connector(c2_type: C2Type) -> Callable[[type[C]], type[C]]:
    """Class decorator: register a concrete connector under its C2Type."""

    def _wrap(klass: type[C]) -> type[C]:
        if c2_type in _REGISTRY:
            raise RuntimeError(f"connector already registered for {c2_type.value}")
        _REGISTRY[c2_type] = klass
        klass.name = c2_type
        return klass

    return _wrap


class ConnectorFactory:
    """Resolves a connector instance for a given C2 type."""

    def __init__(self, config_resolver: Callable[[C2Type], dict[str, object]]):
        self._resolver = config_resolver

    @staticmethod
    def registered() -> dict[C2Type, ConnectorClass]:
        return dict(_REGISTRY)

    def build(self, c2_type: C2Type) -> C2Connector:
        try:
            klass = _REGISTRY[c2_type]
        except KeyError as exc:
            raise NotImplementedError(
                f"no connector registered for {c2_type.value}"
            ) from exc

        connector = klass()
        connector.authenticate(self._resolver(c2_type))
        return connector