from __future__ import annotations

import os
from typing import Any

from engine.config import AppConfig


def _provider(cfg: AppConfig, path: str, default: str) -> str:
    env_map = {
        "llm.provider": "ENGINE_LLM_PROVIDER",
        "image.provider": "ENGINE_IMAGE_PROVIDER",
        "image_fallback.provider": "ENGINE_IMAGE_FALLBACK_PROVIDER",
        "video.provider": "ENGINE_VIDEO_PROVIDER",
        "tts.provider": "ENGINE_TTS_PROVIDER",
    }
    env_key = env_map.get(path)
    if env_key:
        env_val = str(os.environ.get(env_key, "")).strip()
        if env_val:
            return env_val
    v = cfg.get(path, default)
    return str(v or default).strip() or default


def get_model(name: str, cfg: AppConfig) -> Any:
    if name == "llm":
        provider = _provider(cfg, "llm.provider", "openai")
        if provider == "mock":
            from engine.adapters.llm.mock_adapter import MockLLM

            return MockLLM()
        from engine.adapters.llm.openai_adapter import OpenAIAdapter

        return OpenAIAdapter(cfg)

    if name in ("image", "image_fallback"):
        section = "image" if name == "image" else "image_fallback"
        # Important: fallback must default to mock, not follow primary image provider.
        provider_default = "mock" if name == "image_fallback" else _provider(cfg, "image.provider", "mock")
        provider = _provider(cfg, f"{section}.provider", provider_default)
        if provider == "comfy":
            from engine.adapters.image.comfy_adapter import ComfyAdapter

            return ComfyAdapter(cfg)
        if provider == "replicate":
            from engine.adapters.image.replicate_adapter import ReplicateAdapter

            return ReplicateAdapter(cfg)
        if provider == "openai":
            from engine.adapters.image.openai_image_adapter import OpenAIImageAdapter

            return OpenAIImageAdapter(cfg)

        from engine.adapters.image.mock_adapter import MockImageGen

        return MockImageGen()

    if name == "video":
        provider = _provider(cfg, "video.provider", "moviepy")
        if provider == "ltx":
            from engine.adapters.video.ltx_adapter import LTXVideoGen

            return LTXVideoGen(cfg)
        from engine.adapters.video.moviepy_adapter import MoviePyVideoGen

        return MoviePyVideoGen(cfg)

    if name == "tts":
        provider = _provider(cfg, "tts.provider", "edge")
        if provider == "mock":
            from engine.adapters.tts.mock_adapter import MockTTS

            return MockTTS()
        from engine.adapters.tts.edge_adapter import EdgeTTS

        return EdgeTTS(cfg)

    raise ValueError(f"Unknown model adapter name: {name}")