import { Injectable, Logger } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';

import { verifyToken } from '@tria-plc/api-common/utils/token';
import { ESessionStatus } from '@tria-plc/api-common/utils/enums/user.enum';
import { Session } from '@tria-plc/iamapi-common/entities/iam/user/session.entity';

/**
 * Authenticates a WebSocket handshake by mirroring the HTTP JwtGuard: the access
 * token payload is only a *session* pointer (`{ id: <sessionId> }`), not the
 * user — so we verify the signature (`verifyToken`), then load the IAM session
 * and require it to be ACTIVE and unexpired, and read the real user id out of
 * `session.userInfo`. The `Session` entity is served by the app's default
 * TypeORM DataSource (the same one the shared JwtGuard queries for `iam.sessions`).
 *
 * Returns the IAM user id, or null for any invalid/expired/revoked/malformed token.
 */
@Injectable()
export class WsAuthService {
  private readonly logger = new Logger(WsAuthService.name);

  constructor(
    @InjectRepository(Session)
    private readonly sessions: Repository<Session>,
  ) {}

  async resolveUserId(token?: string): Promise<string | null> {
    if (!token) return null;
    try {
      const payload = verifyToken(token) as { id?: string };
      const sessionId = payload?.id;
      if (!sessionId) return null;

      const session = await this.sessions.findOne({ where: { id: sessionId } });
      if (!session) return null;
      if (session.status !== ESessionStatus.ACTIVE) return null;
      if (!session.expiryTime || new Date(session.expiryTime) <= new Date()) {
        return null;
      }

      return session.userInfo?.id ?? null;
    } catch (err) {
      this.logger.debug(`WS auth rejected: ${(err as Error).message}`);
      return null;
    }
  }
}