import crypto from "crypto";
import express from "express";
import config from "../config.js";
import { Patch } from "../db/models/index.js";
import { getConfiguredDevice } from "../services/devices.js";
import { normalizeProduceIcon } from "../services/patches.js";
import {
  NodeInputError,
  listNodes,
  setNodePatches,
  upsertNodes,
} from "../services/nodes.js";
import { getLogger } from "../logger.js";

const logger = getLogger("HubApi");

function keysMatch(given, expected) {
  const a = Buffer.from(given);
  const b = Buffer.from(expected);
  return a.length === b.length && crypto.timingSafeEqual(a, b);
}

function requireHubKey(req, res, next) {
  const expected = config.hub?.apiKey;
  if (!expected) {
    res.status(503).json({ status: "error", error: "Hub API not configured" });
    return;
  }
  const match = /^Bearer\s+(.+)$/i.exec(req.get("authorization") || "");
  if (!match || !keysMatch(match[1].trim(), expected)) {
    res.status(401).json({ status: "error", error: "Unauthorized" });
    return;
  }
  next();
}

function sendError(res, e, fallback) {
  if (e instanceof NodeInputError) {
    res.status(400).json({ status: "error", error: e.message });
    return;
  }
  logger.error(fallback, e);
  res.status(500).json({ status: "error", error: e.message || fallback });
}

/** HTTP API used by the hub firmware to relay BLE patch assignments (BLE_PROTOCOL.md Appendix A). */
export function createHubRouter() {
  const router = express.Router();
  router.use(requireHubKey);
  router.use(express.json());

  router.get("/patches", async (_req, res) => {
    try {
      const device = await getConfiguredDevice();
      const docs = device
        ? await Patch.find({ deviceId: device._id })
            .select("patchId name icon")
            .sort({ patchId: 1 })
            .lean()
        : [];
      const patches = docs.map((p) => ({
        id: p.patchId,
        name: p.name ?? "",
        icon: normalizeProduceIcon(p.icon),
      }));
      res.json({ status: "ok", data: { patches } });
    } catch (e) {
      sendError(res, e, "list patches failed");
    }
  });

  router.get("/nodes", async (_req, res) => {
    try {
      res.json({ status: "ok", data: { nodes: await listNodes() } });
    } catch (e) {
      sendError(res, e, "list nodes failed");
    }
  });

  router.post("/nodes", async (req, res) => {
    try {
      const nodes = await upsertNodes(req.body?.serials);
      res.json({ status: "ok", data: { nodes } });
    } catch (e) {
      sendError(res, e, "register nodes failed");
    }
  });

  router.put("/nodes/:serial", async (req, res) => {
    try {
      const node = await setNodePatches(req.params.serial, req.body?.patches);
      res.json({ status: "ok", data: { node } });
    } catch (e) {
      sendError(res, e, "set node patches failed");
    }
  });

  return router;
}