first commit

backend/internal/auth/tokens.go

@@ -0,0 +1,70 @@
+package auth
+
+import (
+	"errors"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type Claims struct {
+	UserID string `json:"user_id"`
+	Email  string `json:"email"`
+	Role   string `json:"role"`
+	jwt.RegisteredClaims
+}
+
+type TokenService struct {
+	secret    []byte
+	accessTTL time.Duration
+}
+
+func NewTokenService(secret string, accessTTL time.Duration) TokenService {
+	return TokenService{
+		secret:    []byte(secret),
+		accessTTL: accessTTL,
+	}
+}
+
+func (s TokenService) IssueAccessToken(userID string, email string, role string) (string, error) {
+	if len(s.secret) == 0 {
+		return "", errors.New("jwt secret is not configured")
+	}
+
+	now := time.Now()
+	claims := Claims{
+		UserID: userID,
+		Email:  email,
+		Role:   role,
+		RegisteredClaims: jwt.RegisteredClaims{
+			Subject:   userID,
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(s.accessTTL)),
+		},
+	}
+
+	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString(s.secret)
+}
+
+func (s TokenService) ParseAccessToken(tokenValue string) (Claims, error) {
+	if len(s.secret) == 0 {
+		return Claims{}, errors.New("jwt secret is not configured")
+	}
+
+	token, err := jwt.ParseWithClaims(tokenValue, &Claims{}, func(token *jwt.Token) (interface{}, error) {
+		if token.Method != jwt.SigningMethodHS256 {
+			return nil, errors.New("unexpected signing method")
+		}
+		return s.secret, nil
+	})
+	if err != nil {
+		return Claims{}, err
+	}
+
+	claims, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return Claims{}, errors.New("invalid token")
+	}
+
+	return *claims, nil
+}