import * as plugins from './plugins.js';
import { SshClient } from './classes.sshclient.js';
import type { IMountRequest, TDapMountBackend } from './types.js';

export class MountManager {
  constructor(private sshClient = new SshClient()) {}

  public parseRemoteSpec(remoteSpec: string): { host: string; remotePath: string } {
    const separatorIndex = remoteSpec.indexOf(':');
    if (separatorIndex <= 0) {
      throw new Error('Remote mount spec must look like <host>:<remotePath>');
    }
    const host = remoteSpec.slice(0, separatorIndex);
    const remotePath = remoteSpec.slice(separatorIndex + 1) || '.';
    return { host, remotePath };
  }

  public buildSshfsArgs(request: IMountRequest): string[] {
    return [`${request.host}:${request.remotePath}`, request.localPath];
  }

  public buildRcloneArgs(request: IMountRequest): string[] {
    return [
      'mount',
      `:sftp:${request.remotePath}`,
      request.localPath,
      '--sftp-ssh',
      `ssh ${request.host}`,
      '--sftp-shell-type',
      'none',
      '--vfs-cache-mode',
      'writes',
    ];
  }

  public async mount(request: IMountRequest): Promise<number> {
    await plugins.fs.mkdir(request.localPath, { recursive: true });
    const backend = request.backend ?? (await this.detectBackend());
    if (backend === 'sshfs') {
      return this.sshClient.spawnInteractive('sshfs', this.buildSshfsArgs(request));
    }
    return this.sshClient.spawnInteractive('rclone', this.buildRcloneArgs(request));
  }

  public async mountDetached(request: IMountRequest): Promise<number> {
    await plugins.fs.mkdir(request.localPath, { recursive: true });
    const backend = request.backend ?? (await this.detectBackend());
    if (backend === 'sshfs') {
      return this.sshClient.spawnInteractive('sshfs', this.buildSshfsArgs(request));
    }
    return this.sshClient.spawnDetached('rclone', this.buildRcloneArgs(request));
  }

  public async unmount(localPath: string): Promise<number> {
    if (process.platform === 'darwin') {
      return this.sshClient.spawnInteractive('umount', [localPath]);
    }
    if (await this.sshClient.commandExists('fusermount3')) {
      return this.sshClient.spawnInteractive('fusermount3', ['-u', localPath]);
    }
    if (await this.sshClient.commandExists('fusermount')) {
      return this.sshClient.spawnInteractive('fusermount', ['-u', localPath]);
    }
    return this.sshClient.spawnInteractive('umount', [localPath]);
  }

  public async detectBackend(): Promise<TDapMountBackend> {
    if (await this.sshClient.commandExists('sshfs')) {
      return 'sshfs';
    }
    if (await this.sshClient.commandExists('rclone')) {
      return 'rclone';
    }
    throw new Error('No mount backend found. Install sshfs, or install rclone with FUSE/macFUSE support.');
  }
}