import { CanActivate, Injectable, NotFoundException } from '@nestjs/common';

import { InstanceSettingsService } from '../settings/instance-settings.service';

/**
 * Instance-wide plugin kill switch (issue #200, ADR 0025): while
 * `plugins.enabled` is false, every guarded plugin surface answers 404 —
 * existence stays hidden, the same semantics as `api.enabled` and
 * `mcp.enabled`. The fallback-metadata route is deliberately NOT guarded
 * (it serves no plugin code and existing blocks need it for their declared
 * fallback). The settings cache is in-process, so flipping the switch is
 * followed by an api restart like every other instance setting
 * (operations.md); the admin UI toggle documents that.
 */
@Injectable()
export class PluginsEnabledGuard implements CanActivate {
  constructor(private readonly settings: InstanceSettingsService) {}

  async canActivate(): Promise<boolean> {
    if (!(await this.settings.get('plugins.enabled'))) throw new NotFoundException();
    return true;
  }
}