"""Sense 路由（T-G1）：/sense 前缀组 + /v1 无前缀组（embeddings 透传）。

/v1/route（T-G5 grader）后续加入无前缀组；/sense/admin/*（T-G3+）加入前缀组。
"""
from __future__ import annotations

from typing import List

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

from gateway.sense.config import SenseConfig
from gateway.sense.embedder import embed
from gateway.sense.errors import EmbedderDown


def build_sense_routers(cfg: SenseConfig) -> List[APIRouter]:
    """组装 sense 路由组：[/sense 前缀组, /v1 无前缀组]。"""
    main = APIRouter(prefix="/sense")
    v1 = APIRouter()

    @main.get("/health", tags=["sense"])
    async def health():
        """sense 面健康检查（含灰度状态，供看板/运维）。"""
        return {"enabled": cfg.enabled, "mode": cfg.mode,
                "embedder": cfg.embedder.base_url}

    @v1.post("/v1/embeddings", tags=["sense"])
    async def embeddings(request: Request):
        """OpenAI 兼容透传 embedder（客户端/代理共用）。

        请求：{"model"?, "input": str}；响应：{"object":"list","data":[{"object":
        "embedding","index":0,"embedding":[int8...]}],"model":...}。
        embedder 不可用 -> 503（D-G4 fail-closed，客户端可感知降级）。
        """
        try:
            body = await request.json()
        except Exception:
            body = {}
        text = str((body or {}).get("input") or "").strip()
        if not text:
            return JSONResponse({"error": {"message": "input 必填"}}, status_code=400)
        model = str((body or {}).get("model") or cfg.embedder.model)
        try:
            vec = await embed(text, cfg.embedder)
        except EmbedderDown as e:
            return JSONResponse(
                {"error": {"message": str(e), "type": "embedder_down"}}, status_code=503)
        return {"object": "list", "model": model,
                "data": [{"object": "embedding", "index": 0, "embedding": vec}]}

    return [main, v1]