"""Registry of the TTS backends the audiobook generator can talk to.

Each backend (audio.cpp, qwen, faster) lives in its own module and owns
its setup wizard, its status detection, and the launch command it prints
once configured. This package aggregates them into a single registry so
``audiobook.py``'s TUI hub and future tools can iterate backends without
hardcoding their names: ``backends.detect_all()`` reports which are set
up, and ``backends.REGISTRY`` drives the hub's setup/modify menus.

Adding a backend: create ``backends/<name>.py`` exposing
``detect() -> BackendStatus``, ``run_tui() -> int`` and
``modify_actions: list[ModifyAction]``, then append a ``BackendInfo`` in
``_build_registry`` below. ``audiobook.py`` and the hub pick it up
automatically.
"""

from dataclasses import dataclass, field
from typing import Callable, List, Optional


@dataclass
class BackendStatus:
    """How far a backend is set up, plus the command to start it.

    INSTALLED means the backend itself is present (a cloned + built
    checkout, or a pip package). CONFIGURED means the supporting files are
    in place (a server.json / voices.json and a converter/config.py that
    points at the right port). DETAILS are short status lines for the hub.
    LAUNCH_HINT is the exact command the user runs to start the server.
    """
    key: str
    label: str
    installed: bool
    configured: bool
    details: List[str] = field(default_factory=list)
    launch_hint: str = ""

    @property
    def ready(self) -> bool:
        """True when the backend is installed and configured for use."""
        return self.installed and self.configured


@dataclass
class ModifyAction:
    """A per-backend "modify" menu entry (e.g. "New server.json")."""
    label: str
    run: Callable[[], int]


@dataclass
class BackendInfo:
    """One registry entry: identity, detector, setup wizard, modify menu."""
    key: str
    label: str
    detect: Callable[[], BackendStatus]
    setup_tui: Callable[[], int]
    modify_actions: List[ModifyAction] = field(default_factory=list)


REGISTRY: List[BackendInfo] = []
_BY_KEY: dict = {}


def _build_registry() -> None:
    """Import the backend modules and wire up REGISTRY (once)."""
    if REGISTRY:
        return
    from . import audiocpp, faster, qwen

    REGISTRY.append(BackendInfo(
        key="audiocpp",
        label="audio.cpp",
        detect=audiocpp.detect,
        setup_tui=audiocpp.run_tui,
        modify_actions=audiocpp.modify_actions,
    ))
    REGISTRY.append(BackendInfo(
        key="qwen",
        label="Qwen3-TTS (demo server)",
        detect=qwen.detect,
        setup_tui=qwen.run_tui,
        modify_actions=qwen.modify_actions,
    ))
    REGISTRY.append(BackendInfo(
        key="faster",
        label="faster-qwen3-tts",
        detect=faster.detect,
        setup_tui=faster.run_tui,
        modify_actions=faster.modify_actions,
    ))
    for info in REGISTRY:
        _BY_KEY[info.key] = info


def get(key: str) -> Optional[BackendInfo]:
    """Return the registry entry for KEY, or None."""
    _build_registry()
    return _BY_KEY.get(key)


def detect_all() -> List[BackendStatus]:
    """Detect every registered backend's status, in registry order."""
    _build_registry()
    return [info.detect() for info in REGISTRY]


def detect(key: str) -> Optional[BackendStatus]:
    """Detect a single backend by key."""
    info = get(key)
    return info.detect() if info is not None else None


_build_registry()