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

from config import LLAMA_SWAP_URL
from services.router_logic import FAST, FAST_NO_THINK, choose_model
from services.token_stats import increment_tokens

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:
        alias = requested
        routed = {"x-mc-routed-to": requested}
    # fast-Spur: Thinking aus für flotte Antworten (sofern Client es nicht selbst setzt).
    if FAST_NO_THINK and alias == FAST and "chat_template_kwargs" not in body:
        body["chat_template_kwargs"] = {"enable_thinking": False}
    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():
                        try:
                            chunk_str = chunk.decode("utf-8", errors="ignore")
                            if '"usage":' in chunk_str:
                                for line in chunk_str.splitlines():
                                    if line.startswith("data:"):
                                        data_str = line[5:].strip()
                                        if data_str == "[DONE]":
                                            continue
                                        try:
                                            data_json = json.loads(data_str)
                                            usage = data_json.get("usage")
                                            if usage:
                                                prompt = usage.get("prompt_tokens", 0)
                                                completion = usage.get("completion_tokens", 0)
                                                if prompt or completion:
                                                    increment_tokens(prompt, completion)
                                        except Exception:
                                            pass
                        except Exception:
                            pass
                        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)
        resp_json = r.json()
        try:
            usage = resp_json.get("usage")
            if usage:
                prompt = usage.get("prompt_tokens", 0)
                completion = usage.get("completion_tokens", 0)
                if prompt or completion:
                    increment_tokens(prompt, completion)
        except Exception:
            pass
        return JSONResponse(resp_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)