// Shows the pi session name in herdr's (or tmuxrdr's) Agent sidebar, in place of
// the "pi" label.
//
// herdr's own pi integration (herdr-agent-state.ts, which herdr installs and
// overwrites) reports lifecycle state only. This sits beside it and reports
// display-only pane metadata: `display_agent` replaces the `agent` token in
// sidebar rows. `agent: "pi"` guards it, so it stops applying once the pane no
// longer runs pi. With no session name, the label is cleared back to "pi".
//
// Reported on session start (including /resume, /new and reloads) and whenever
// the name changes (/name, --name, or an extension's pi.setSessionName()).
// TUI sessions only: print, JSON and RPC runs launched from inside a pane (a
// review panel, a subagent) inherit the pane's HERDR_* variables and would
// otherwise rename the pane after themselves.
//
// API: pane.report_metadata, herdr socket API (herdr 0.9.3).

import net from "node:net";

const socketPath = process.env.HERDR_SOCKET_PATH;
const paneId = process.env.HERDR_PANE_ID;
const source = "user:pi-session-name";

function enabled(): boolean {
  return process.env.HERDR_ENV === "1" && !!socketPath && !!paneId;
}

function send(request: unknown, timeoutMs = 1000): Promise<void> {
  return new Promise((resolve) => {
    const endpoint =
      process.platform === "win32" ? `\\\\.\\pipe\\${socketPath}` : socketPath!;
    const socket = net.createConnection(endpoint);
    const finish = () => {
      clearTimeout(timer);
      socket.destroy();
      resolve();
    };
    const timer = setTimeout(finish, timeoutMs);
    timer.unref?.();
    socket.on("error", finish);
    socket.on("end", finish);
    socket.on("data", finish);
    socket.on("connect", () => socket.write(`${JSON.stringify(request)}\n`));
  });
}

let seq = Date.now() * 1000;

function report(name: string | undefined): Promise<void> {
  const label = name?.trim();
  seq += 1;
  return send({
    id: `${source}:${seq}`,
    method: "pane.report_metadata",
    params: {
      pane_id: paneId,
      source,
      agent: "pi",
      seq,
      ...(label ? { display_agent: label } : { clear_display_agent: true }),
    },
  });
}

export default function (pi: any) {
  if (!enabled()) {
    return;
  }

  let active = false;

  pi.on("session_start", async (_event: unknown, ctx: any) => {
    active = ctx?.mode === "tui";
    if (active) {
      await report(pi.getSessionName());
    }
  });

  pi.on("session_info_changed", async (event: { name?: string }) => {
    if (active) {
      await report(event?.name);
    }
  });
}