import { Injectable, CanActivate, ExecutionContext, UnauthorizedException } from '@nestjs/common';
import { Request } from 'express';
import { AuthHelper } from '../../utils/auth.helpers';

@Injectable()
export class AuthGuard implements CanActivate {
  constructor(private readonly authHelper: AuthHelper) {}

  async canActivate(ctx: ExecutionContext): Promise<boolean> {
    const request = ctx.switchToHttp().getRequest();
    const token = this.extractTokenFromHeader(request);
    if (!token) throw new UnauthorizedException();

    try {
      const payload = this.authHelper.verifyToken(token);
      if (!payload) throw new UnauthorizedException();
      request['user'] = payload;
    } catch {
      throw new UnauthorizedException();
    }
    return true;
  }
  private extractTokenFromHeader(request: Request): string | undefined {
    const [type, token] = request.headers.authorization?.split(' ') ?? [];
    return type === 'Bearer' ? token : undefined;
  }
}