"""Read-only client for the reversible SBOM Nexus compatibility facade."""
from __future__ import annotations

from typing import Any

import httpx

from api.config import settings


class SBOMNexusError(RuntimeError):
    """An SBOM Nexus request failed without a usable compatibility response."""

    def __init__(self, status_code: int, detail: str):
        super().__init__(detail)
        self.status_code = status_code
        self.detail = detail


def reads_from_nexus() -> bool:
    return settings.sbom_nexus_read_mode == "nexus"


async def get_json(
    path: str,
    *,
    params: dict[str, Any] | None = None,
) -> Any:
    """Fetch one Nexus resource; never fall back silently to legacy storage."""
    if not settings.sbom_nexus_url:
        raise SBOMNexusError(503, "SBOM Nexus read mode is enabled without SBOM_NEXUS_URL")

    try:
        async with httpx.AsyncClient(
            base_url=settings.sbom_nexus_url.rstrip("/"),
            timeout=settings.sbom_nexus_timeout_seconds,
        ) as client:
            response = await client.get(path, params=params)
    except httpx.RequestError as exc:
        raise SBOMNexusError(502, f"SBOM Nexus is unavailable: {exc.__class__.__name__}") from exc

    if response.status_code >= 400:
        detail = f"SBOM Nexus returned HTTP {response.status_code}"
        try:
            payload = response.json()
            if isinstance(payload, dict) and isinstance(payload.get("detail"), str):
                detail = payload["detail"]
        except ValueError:
            pass
        status_code = 404 if response.status_code == 404 else 502
        raise SBOMNexusError(status_code, detail)

    try:
        return response.json()
    except ValueError as exc:
        raise SBOMNexusError(502, "SBOM Nexus returned invalid JSON") from exc