import os
import time
from typing import Tuple

import httpx
from fastapi import APIRouter, HTTPException, Query

router = APIRouter(tags=["octopart"])

NEXAR_TOKEN_URL = "https://identity.nexar.com/connect/token"
NEXAR_API_URL   = "https://api.nexar.com/graphql"

_token_cache: dict = {"token": None, "expires_at": 0.0}

_SEARCH_GQL = """
query PartSearch($q: String!, $limit: Int!) {
  supSearchMpn(q: $q, limit: $limit) {
    results {
      part {
        mpn
        manufacturer { name }
        shortDescription
        bestDatasheet { url }
      }
    }
  }
}
"""


def _credentials() -> Tuple[str, str]:
    return (
        os.getenv("NEXAR_CLIENT_ID", ""),
        os.getenv("NEXAR_CLIENT_SECRET", ""),
    )


async def _get_token() -> str:
    client_id, client_secret = _credentials()
    if not client_id or not client_secret:
        raise HTTPException(
            status_code=503,
            detail="Nexar/Octopart credentials not configured — set NEXAR_CLIENT_ID and NEXAR_CLIENT_SECRET environment variables",
        )

    now = time.time()
    if _token_cache["token"] and now < _token_cache["expires_at"] - 60:
        return _token_cache["token"]  # type: ignore[return-value]

    async with httpx.AsyncClient() as client:
        resp = await client.post(
            NEXAR_TOKEN_URL,
            data={
                "grant_type": "client_credentials",
                "client_id": client_id,
                "client_secret": client_secret,
            },
            timeout=10,
        )
    if resp.status_code != 200:
        raise HTTPException(status_code=502, detail=f"Nexar auth failed: {resp.text[:200]}")

    body = resp.json()
    _token_cache["token"] = body["access_token"]
    _token_cache["expires_at"] = now + body.get("expires_in", 3600)
    return _token_cache["token"]  # type: ignore[return-value]


@router.get("/status")
async def octopart_status():
    client_id, client_secret = _credentials()
    return {"configured": bool(client_id and client_secret)}


@router.get("/search")
async def octopart_search(
    q: str = Query(..., min_length=1),
    limit: int = Query(8, ge=1, le=20),
):
    token = await _get_token()

    async with httpx.AsyncClient() as client:
        resp = await client.post(
            NEXAR_API_URL,
            headers={"Authorization": f"Bearer {token}", "Content-Type": "application/json"},
            json={"query": _SEARCH_GQL, "variables": {"q": q, "limit": limit}},
            timeout=12,
        )

    if resp.status_code != 200:
        raise HTTPException(status_code=502, detail=f"Nexar API error {resp.status_code}")

    body = resp.json()
    if "errors" in body:
        raise HTTPException(status_code=502, detail=str(body["errors"])[:300])

    results = body.get("data", {}).get("supSearchMpn", {}).get("results", [])
    out = []
    for r in results:
        part = r.get("part")
        if not part:
            continue
        out.append({
            "mpn":          part.get("mpn", ""),
            "manufacturer": (part.get("manufacturer") or {}).get("name", ""),
            "description":  part.get("shortDescription") or "",
            "datasheet_url": (part.get("bestDatasheet") or {}).get("url"),
        })
    return out