text: /*
   * Copyright (C) 2019 The "MysteriumNetwork/node" Authors.
   *
   * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package auth
  
  import (
  	"time"
  
  	"github.com/dgrijalva/jwt-go"
  	"github.com/pkg/errors"
  )
  
  // JWTAuthenticator contains JWT handling methods
  type JWTAuthenticator struct {
  	encryptionKey []byte
  }
  
  // JWT contains token details
  type JWT struct {
  	Token          string
  	ExpirationTime time.Time
  }
  
  // JWTEncryptionKey contains the encryption key for JWT
  type JWTEncryptionKey []byte
  
  // JWTCookieName name of the cookie JWT token is stored in
  const JWTCookieName string = "token"
  
  type jwtClaims struct {
  	Username string `json:"username"`
  	jwt.StandardClaims
  }
  
  const expiresIn = 48 * time.Hour
  
  // NewJWTAuthenticator creates a new JWT authentication instance
  func NewJWTAuthenticator(encryptionKey JWTEncryptionKey) *JWTAuthenticator {
  	auth := &JWTAuthenticator{
  		encryptionKey,
  	}
  
  	return auth
  }
  
  // CreateToken creates a new JWT token
  func (jwtAuth *JWTAuthenticator) CreateToken(username string) (JWT, error) {
  	expirationTime := jwtAuth.getExpirationTime()
  	claims := &jwtClaims{
  		Username: username,
  		StandardClaims: jwt.StandardClaims{
  			ExpiresAt: expirationTime.Unix(),
  		},
  	}
  
  	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
  	tokenString, err := token.SignedString(jwtAuth.encryptionKey)
  	if err != nil {
  		return JWT{}, err
  	}
  
  	return JWT{Token: tokenString, ExpirationTime: expirationTime}, nil
  }
  
  // ValidateToken validates a JWT token
  func (jwtAuth *JWTAuthenticator) ValidateToken(token string) (bool, error) {
  	claims := &jwtClaims{}
  
  	tkn, err := jwt.ParseWithClaims(token, claims, func(token *jwt.Token) (interface{}, error) {
  		return jwtAuth.encryptionKey, nil
  	})
  	if err != nil {
  		return false, err
  	}
  
  	if tkn == nil || !tkn.Valid {
  		return false, errors.New("invalid JWT token")
  	}
  
  	return true, nil
  }
  
  func (jwtAuth *JWTAuthenticator) getExpirationTime() time.Time {
  	return time.Now().Add(expiresIn)
  }
  