import { createConnection } from 'node:net';
import { readFile } from 'node:fs/promises';

/** Same-user 0600 Unix channel. Never print the connect response or persist its token. */
export async function subscriptionOperation(operation: 'connect' | 'status' | 'limits' | 'stop') {
  const pointer = JSON.parse(
    await readFile('build/lekiwi-agent/subscription-session.json', 'utf8'),
  ) as { socket?: string; status: string };
  if (!pointer.socket || pointer.status === 'closed')
    throw new Error('隔离订阅会话已关闭，请重新发起官方登录');
  return new Promise<Record<string, unknown>>((resolve, reject) => {
    const channel = createConnection(pointer.socket!);
    let buffer = '';
    channel.setTimeout(20000);
    channel.once('connect', () => channel.write(JSON.stringify(operation) + '\n'));
    channel.on('data', (chunk) => {
      buffer += String(chunk);
      if (buffer.length > 16384) {
        channel.destroy();
        reject(new Error('订阅管理响应过大'));
        return;
      }
      if (buffer.includes('\n')) {
        try {
          const result = JSON.parse(buffer.split('\n')[0]) as Record<string, unknown>;
          if (result.error) reject(new Error('订阅管理请求失败'));
          else resolve(result);
        } catch {
          reject(new Error('订阅管理响应非法'));
        }
        channel.end();
      }
    });
    channel.once('timeout', () => {
      channel.destroy();
      reject(new Error('订阅管理请求超时'));
    });
    channel.once('error', () => reject(new Error('无法连接隔离订阅会话')));
    channel.once('end', () => {
      if (!buffer.includes('\n')) reject(new Error('订阅管理连接提前关闭'));
    });
  });
}