"""Adapter registry — resolves the active TTS / LLM / Guardrail from env.

Centralizes the D-014 (TTS swap), D-020 (LLM swap), D-019 (guardrail plug) wiring
so the Pipecat pipeline never imports a concrete adapter directly.
"""

from __future__ import annotations

import os
from functools import lru_cache


def _require(key: str, *, default: str | None = None) -> str:
    val = os.environ.get(key, default or "").strip()
    if not val:
        raise RuntimeError(
            f"Required env var {key} is not set. See .env.example."
        )
    return val


@lru_cache(maxsize=1)
def get_tts() -> "TTSProvider":  # type: ignore[name-defined]
    """Return the active TTSProvider based on PRAXIS_TTS (D-014)."""
    # Imported lazily so importing the registry doesn't drag in Pipecat/TTS deps
    # for tools that only need the interfaces.
    choice = os.environ.get("PRAXIS_TTS", "cartesia").strip().lower()
    if choice == "piper":
        from server.tts.piper_tts import PiperTTS

        return PiperTTS()
    if choice == "cartesia":
        from server.tts.cartesia_tts import CartesiaTTS

        return CartesiaTTS()
    raise RuntimeError(
        f"Unknown PRAXIS_TTS={choice!r}; expected 'cartesia' or 'piper'."
    )


@lru_cache(maxsize=1)
def get_llm() -> "LLMProvider":  # type: ignore[name-defined]
    """Return the active LLMProvider (Ollama Cloud direct API, D-020)."""
    from server.llm.ollama_cloud import OllamaCloudLLM

    return OllamaCloudLLM()


@lru_cache(maxsize=1)
def get_guardrail() -> "Guardrail":  # type: ignore[name-defined]
    """Return the active Guardrail (D-019).

    v0.1 SLICE-02 returns NoOpGuardrail; SLICE-03 swaps in CustomerServiceGuardrail.
    Selection via PRAXIS_GUARDRAIL=none|customer_service (default: customer_service
    once implemented; falls back to none if the ruleset isn't importable yet).
    """
    choice = os.environ.get("PRAXIS_GUARDRAIL", "customer_service").strip().lower()
    if choice == "none":
        from server.guardrails.noop import NoOpGuardrail

        return NoOpGuardrail()
    if choice == "customer_service":
        try:
            from server.guardrails.customer_service import CustomerServiceGuardrail

            return CustomerServiceGuardrail()
        except ImportError:
            # SLICE-02 fallback — real ruleset arrives in SLICE-03.
            from server.guardrails.noop import NoOpGuardrail

            return NoOpGuardrail()
    raise RuntimeError(
        f"Unknown PRAXIS_GUARDRAIL={choice!r}; expected 'none' or 'customer_service'."
    )