export const createNotificationEmitterRuntime = (dependencies) => {
  const {
    process,
    getDesktopNotifyEnabled,
    desktopNotifyPrefix,
    getUiNotificationClients,
  } = dependencies;

  const writeSseEvent = (res, payload) => {
    res.write(`data: ${JSON.stringify(payload)}\n\n`);
  };

  const emitDesktopNotification = (payload) => {
    const desktopNotifyEnabled = getDesktopNotifyEnabled();
    if (!desktopNotifyEnabled) {
      return;
    }

    if (!payload || typeof payload !== 'object') {
      return;
    }

    try {
      // One-line protocol consumed by the Tauri shell.
      process.stdout.write(`${desktopNotifyPrefix}${JSON.stringify(payload)}\n`);
    } catch {
      // ignore
    }
  };

  const broadcastUiNotification = (payload) => {
    const desktopNotifyEnabled = getDesktopNotifyEnabled();
    if (!payload || typeof payload !== 'object') {
      return;
    }

    const clients = getUiNotificationClients();
    if (clients.size === 0) {
      return;
    }

    for (const res of clients) {
      try {
        writeSseEvent(res, {
          type: 'openchamber:notification',
          properties: {
            ...payload,
            // Tell the UI whether the sidecar stdout notification channel is active.
            // When true, the desktop UI should skip this SSE notification to avoid duplicates.
            // When false (e.g. tauri dev), the UI must handle this SSE notification itself.
            desktopStdoutActive: desktopNotifyEnabled,
          },
        });
      } catch {
        // ignore
      }
    }
  };

  return {
    writeSseEvent,
    emitDesktopNotification,
    broadcastUiNotification,
  };
};