chore: update session and challenge repo -- using Redis for caching session and challenge verifying -- added api handler docs

internal/usecase/auth_service.go

@@ -17,14 +17,15 @@ import (
 
 type AuthService interface {
 	GenerateChallenge(ctx context.Context, pubKey string) (*domain.Challenge, error)
-	Authenticate(ctx context.Context, pubKey string, signature string, challenge *domain.Challenge, chainID uint, ipAddress, userAgent string) (*UserToken, error)
+	Authenticate(ctx context.Context, pubKey string, signature string, chainID uint, ipAddress, userAgent string) (*UserToken, error)
 }
 
 type authService struct {
-	userRepo     domain.UserRepo
-	sessionRepo  domain.SessionRepo
-	challengeExp uint
-	cfg          config.JWT
+	userRepo      domain.UserRepo
+	sessionRepo   domain.SessionRepo
+	challengeRepo domain.ChallengeRepo
+	challengeExp  uint
+	cfg           config.JWT
 }
 
 type UserToken struct {
@@ -36,14 +37,16 @@ type UserToken struct {
 func NewAuthService(
 	userRepo domain.UserRepo,
 	sessionRepo domain.SessionRepo,
+	challengeRepo domain.ChallengeRepo,
 	challengeExp uint,
 	cfg config.JWT,
 ) AuthService {
 	return &authService{
-		userRepo:     userRepo,
-		sessionRepo:  sessionRepo,
-		challengeExp: challengeExp,
-		cfg:          cfg,
+		userRepo:      userRepo,
+		sessionRepo:   sessionRepo,
+		challengeRepo: challengeRepo,
+		challengeExp:  challengeExp,
+		cfg:           cfg,
 	}
 }
 
@@ -54,19 +57,32 @@ func (s *authService) GenerateChallenge(ctx context.Context, pubKey string) (*do
 	}
 
 	challenge := &domain.Challenge{
-		Message:   uuid.New(),
+		Message:   uuid.New().String(),
 		TimeStamp: time.Now().UTC(),
 		ExpiresAt: time.Now().Add(time.Duration(s.challengeExp) * time.Minute),
 	}
+
+	// Save challenge to Redis
+	err = s.challengeRepo.Create(ctx, pubKey, challenge)
+	if err != nil {
+		return nil, fmt.Errorf("failed to save challenge: %w", err)
+	}
+
 	return challenge, nil
 }
 
-func (s *authService) Authenticate(ctx context.Context, pubKey string, signature string, challenge *domain.Challenge, chainID uint, ipAddress, userAgent string) (*UserToken, error) {
+func (s *authService) Authenticate(ctx context.Context, pubKey string, signature string, chainID uint, ipAddress, userAgent string) (*UserToken, error) {
 	_, err := common.IsValidPublicKey(pubKey)
 	if err != nil {
 		return nil, fmt.Errorf("invalid public key: %w", err)
 	}
 
+	// Retrieve challenge from Redis
+	challenge, err := s.challengeRepo.GetByPubKey(ctx, pubKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve challenge: %w", err)
+	}
+
 	isValid, err := challenge.Verify(pubKey, signature)
 	if err != nil {
 		return nil, fmt.Errorf("signature verification failed: %w", err)
@@ -75,6 +91,13 @@ func (s *authService) Authenticate(ctx context.Context, pubKey string, signature
 	if !isValid {
 		return nil, errors.New("invalid signature")
 	}
+
+	// Delete the challenge after successful verification to prevent replay attacks
+	err = s.challengeRepo.Delete(ctx, pubKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to delete challenge: %w", err)
+	}
+
 	user, err := s.userRepo.GetByPubKey(ctx, pubKey)
 	if err != nil {
 		return nil, err