"""
Eingebauter Routing-Gateway (OpenAI-kompatibel) — EIN Endpunkt für Hermes + IDEs.

`model: auto` → Komplexitäts-Routing fast↔heavy; jeder andere Name geht als
llama-swap-Alias durch (das lädt das Modell bei Bedarf). Streaming wird
durchgereicht. Ersetzt LiteLLM (das auf Python 3.14 nicht baut) — gleicher
Vertrag, später austauschbar.
"""

import httpx
from fastapi import APIRouter, Request
from fastapi.responses import JSONResponse, StreamingResponse

from config import LLAMA_SWAP_URL
from services.router_logic import choose_model

router = APIRouter(prefix="/v1")


@router.get("/models")
async def models():
    async with httpx.AsyncClient(timeout=10) as c:
        r = await c.get(f"{LLAMA_SWAP_URL}/v1/models")
        return JSONResponse(r.json(), status_code=r.status_code)


async def _proxy(path: str, request: Request):
    body = await request.json()
    requested = str(body.get("model") or "auto")
    if requested == "auto":
        alias, reason = choose_model(body)
        body["model"] = alias
        routed = {"x-mc-routed-to": alias, "x-mc-route-reason": reason}
    else:
        routed = {"x-mc-routed-to": requested}
    url = f"{LLAMA_SWAP_URL}{path}"

    if body.get("stream"):
        async def gen():
            async with httpx.AsyncClient(timeout=None) as c:
                async with c.stream("POST", url, json=body) as r:
                    async for chunk in r.aiter_raw():
                        yield chunk
        return StreamingResponse(gen(), media_type="text/event-stream", headers=routed)

    async with httpx.AsyncClient(timeout=600) as c:
        r = await c.post(url, json=body)
        return JSONResponse(r.json(), status_code=r.status_code, headers=routed)


@router.post("/chat/completions")
async def chat_completions(request: Request):
    return await _proxy("/v1/chat/completions", request)


@router.post("/completions")
async def completions(request: Request):
    return await _proxy("/v1/completions", request)