ADD: added initial page with login

backend/internal/auth/jwt.go

@@ -0,0 +1,47 @@
+package auth
+
+import (
+	"errors"
+	"time"
+
+	"github.com/golang-jwt/jwt/v4"
+)
+
+var jwtSecret = []byte("supersecret")
+
+type Claims struct {
+	UserID string
+	Email  string
+	Role   string
+}
+
+func CreateJWT(userID, email, role string, duration time.Duration) (string, error) {
+	claims := jwt.MapClaims{
+		"userId": userID,
+		"email":  email,
+		"role":   role,
+		"exp":    time.Now().Add(duration).Unix(),
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString(jwtSecret)
+}
+
+func ParseJWT(tokenStr string) (*Claims, error) {
+	token, err := jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
+		return jwtSecret, nil
+	})
+	if err != nil || !token.Valid {
+		return nil, errors.New("invalid token")
+	}
+	claims, ok := token.Claims.(jwt.MapClaims)
+	if !ok {
+		return nil, errors.New("invalid claims")
+	}
+
+	return &Claims{
+		UserID: claims["userId"].(string),
+		Email:  claims["email"].(string),
+		Role:   claims["role"].(string),
+	}, nil
+}