/**
 * Embedded HTTP server for the OpenFinClaw dashboard.
 * Binds to 127.0.0.1 only (loopback) for local access.
 *
 * The server instance is stored on globalThis so that a plugin hot-reload
 * (register() called a second time after module cache is cleared) can close
 * the previous server before binding a new one — avoiding EADDRINUSE.
 */
import type { Server } from "node:http";
import { createServer } from "node:http";
import { getDb } from "../db/db.js";
import { handleRoute } from "./routes.js";

export interface DashboardLogger {
  info(msg: string): void;
}

/** globalThis key — survives module hot-reloads within the same process. */
const GLOBAL_SERVER_KEY = "__openfinclaw_http_server__" as const;

/**
 * Start the dashboard HTTP server.
 * If a previous server instance exists (from a prior register() call),
 * it is closed first so the port is released.
 */
export function startHttpServer(port: number, logger: DashboardLogger): void {
  const server = createServer((req, res) => {
    try {
      handleRoute(getDb(), req, res);
    } catch (err) {
      if (!res.headersSent) {
        res.writeHead(500, { "Content-Type": "text/plain" });
      }
      res.end(`Internal Server Error: ${String(err)}`);
    }
  });

  server.on("error", (err) => {
    logger.info(`[OpenFinClaw] Dashboard server error: ${String(err)}`);
  });

  /** Bind server after ensuring the port is free. */
  function listen() {
    (globalThis as Record<string, unknown>)[GLOBAL_SERVER_KEY] = server;
    server.listen(port, "127.0.0.1", () => {
      logger.info(`[OpenFinClaw] Dashboard available at http://127.0.0.1:${port}`);
    });
  }

  // Close previous server left over from a hot-reload, then bind
  const prev = (globalThis as Record<string, unknown>)[GLOBAL_SERVER_KEY] as Server | undefined;
  if (prev) {
    logger.info("[OpenFinClaw] Closing previous Dashboard server (hot-reload)");
    prev.close(listen);
  } else {
    listen();
  }
}