from dataclasses import dataclass
from collections.abc import Mapping
from typing import Any

from app.config import Settings


def _configured(value: str) -> bool:
    return bool(value) and not value.startswith("replace_with_")


@dataclass(frozen=True)
class ProviderCapability:
    provider: str
    configured: bool
    strengths: tuple[str, ...]


class ModelRouter:
    def __init__(self, settings: Settings | Mapping[str, Any]) -> None:
        self.settings = settings

    def _value(self, key: str, default: str = "") -> str:
        if isinstance(self.settings, Mapping):
            return str(self.settings.get(key, default) or "")
        return str(getattr(self.settings, key, default) or "")

    def capabilities(self) -> list[ProviderCapability]:
        return [
            ProviderCapability(
                provider=self._value("ai_provider", "custom"),
                configured=_configured(self._value("ai_api_key"))
                and bool(self._value("ai_base_url"))
                and bool(self._value("image_model")),
                strengths=("统一模型网关", "空间理解", "图像生成与编辑"),
            ),
        ]

    def choose_image_provider(self, task: str) -> str:
        configured = [item.provider for item in self.capabilities() if item.configured]
        if configured:
            return configured[0]
        raise RuntimeError("No image provider is configured.")