import { Router } from "express";
import type { Request, Response } from "express";
import {
  fetchSubscription,
  authorizeSession,
  closeSession,
  recordTraffic,
  VpnError,
} from "./vpn.service";
import { SUBSCRIPTION_UPDATE_INTERVAL_HOURS } from "./vpn.config";

function handleVpnError(res: Response, err: unknown): void {
  if (err instanceof VpnError) {
    res.status(403).type("text/plain").send(err.message);
    return;
  }
  console.error("[VPN API] error:", err);
  res.status(500).type("text/plain").send("Internal error");
}

export function registerVpnRoutes(router: Router): void {
  // Subscription endpoint used by olcbox clients
  router.get("/api/vpn/sub/:token", async (req: Request, res: Response) => {
    try {
      const token = req.params.token;
      const hwid = req.headers["x-hwid"] as string | undefined;
      const uri = await fetchSubscription(token, hwid);
      res.setHeader("profile-update-interval", String(SUBSCRIPTION_UPDATE_INTERVAL_HOURS));
      res.setHeader("Content-Type", "text/plain; charset=utf-8");
      res.send(uri);
    } catch (err) {
      handleVpnError(res, err);
    }
  });

  // olrtc srv AuthHook
  router.post("/api/vpn/olrtc/auth", async (req: Request, res: Response) => {
    try {
      const { device_id, room_url } = req.body || {};
      if (!device_id || !room_url) {
        res.status(400).json({ success: false, error: "missing device_id or room_url" });
        return;
      }
      const result = await authorizeSession(room_url, device_id);
      res.json({ success: true, session_id: result.sessionId });
    } catch (err) {
      if (err instanceof VpnError) {
        res.status(403).json({ success: false, error: err.message });
        return;
      }
      console.error("[VPN Auth] error:", err);
      res.status(500).json({ success: false, error: "internal error" });
    }
  });

  // olrtc srv OnSessionClose
  router.post("/api/vpn/olrtc/close", async (req: Request, res: Response) => {
    try {
      const { session_id, room_url } = req.body || {};
      if (!session_id || !room_url) {
        res.status(400).json({ success: false, error: "missing fields" });
        return;
      }
      await closeSession(room_url, session_id);
      res.json({ success: true });
    } catch (err) {
      console.error("[VPN Close] error:", err);
      res.status(500).json({ success: false, error: "internal error" });
    }
  });

  // olrtc srv OnTraffic
  router.post("/api/vpn/olrtc/traffic", async (req: Request, res: Response) => {
    try {
      const { session_id, room_url, bytes_in, bytes_out } = req.body || {};
      if (!session_id || !room_url || typeof bytes_in !== "number" || typeof bytes_out !== "number") {
        res.status(400).json({ success: false, error: "missing fields" });
        return;
      }
      await recordTraffic(room_url, session_id, bytes_in, bytes_out);
      res.json({ success: true });
    } catch (err) {
      console.error("[VPN Traffic] error:", err);
      res.status(500).json({ success: false, error: "internal error" });
    }
  });
}