import { ConsentError } from './_errors.ts';
import { logger } from './_logger.ts';

export type ToolConsentMode = 'never' | 'once-per-server' | 'always';

export class ConsentManager {
  private approvedServers = new Set<string>();
  private deniedServers = new Set<string>();
  private log = logger.child({ component: 'ConsentManager' });

  constructor(private mode: ToolConsentMode = 'once-per-server') {
    this.log.debug('Initialized', { mode });
  }

  requiresPrompt(serverName: string): boolean {
    if (this.mode === 'never') {
      return false;
    }

    if (this.deniedServers.has(serverName)) {
      return true;
    }

    if (this.mode === 'always') {
      return true;
    }

    return !this.approvedServers.has(serverName);
  }

  shouldCacheConsent(): boolean {
    return this.mode !== 'always';
  }

  registerDecision(serverName: string, approved: boolean): void {
    this.deniedServers.delete(serverName);
    this.approvedServers.delete(serverName);

    if (approved) {
      this.approvedServers.add(serverName);
      this.log.debug('Consent granted', { server: serverName });

      return;
    }

    this.deniedServers.add(serverName);
    this.log.debug('Consent denied', { server: serverName });
  }

  ensureApproved(serverName: string): void {
    if (this.mode === 'never') {
      return;
    }

    if (this.deniedServers.has(serverName)) {
      throw new ConsentError(serverName, { denied: true });
    }

    if (!this.approvedServers.has(serverName)) {
      throw new ConsentError(serverName, { requiresApproval: true });
    }

    if (this.mode === 'always') {
      this.approvedServers.delete(serverName);
    }
  }

  clear(serverName?: string): void {
    if (serverName) {
      this.approvedServers.delete(serverName);
      this.deniedServers.delete(serverName);
      this.log.debug('Cleared consent for server', { server: serverName });

      return;
    }

    this.approvedServers.clear();
    this.deniedServers.clear();
    this.log.debug('Cleared all consent records');
  }
}