middleware/auth.go

package middleware

import (
	"net/http"
	"patbin/config"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
)

type Claims struct {
	UserID   uint   `json:"user_id"`
	Username string `json:"username"`
	jwt.RegisteredClaims
}

// AuthMiddleware validates JWT token and sets user info in context
func AuthMiddleware(cfg *config.Config) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Try to get token from cookie first
		tokenString, err := c.Cookie(cfg.CookieName)
		if err != nil {
			// Try Authorization header
			authHeader := c.GetHeader("Authorization")
			if authHeader != "" && strings.HasPrefix(authHeader, "Bearer ") {
				tokenString = strings.TrimPrefix(authHeader, "Bearer ")
			}
		}

		if tokenString == "" {
			c.Next()
			return
		}

		// Parse and validate token
		claims := &Claims{}
		token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
			return []byte(cfg.JWTSecret), nil
		})

		if err != nil || !token.Valid {
			c.Next()
			return
		}

		// Set user info in context
		c.Set("user_id", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("authenticated", true)

		c.Next()
	}
}

// RequireAuth ensures user is authenticated
func RequireAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		authenticated, exists := c.Get("authenticated")
		if !exists || !authenticated.(bool) {
			// Check if API request or web request
			if strings.HasPrefix(c.Request.URL.Path, "/api/") {
				c.JSON(http.StatusUnauthorized, gin.H{"error": "Authentication required"})
			} else {
				c.Redirect(http.StatusFound, "/login")
			}
			c.Abort()
			return
		}
		c.Next()
	}
}

// GetUserID returns the authenticated user ID from context
func GetUserID(c *gin.Context) (uint, bool) {
	userID, exists := c.Get("user_id")
	if !exists {
		return 0, false
	}
	return userID.(uint), true
}

// GetUsername returns the authenticated username from context
func GetUsername(c *gin.Context) (string, bool) {
	username, exists := c.Get("username")
	if !exists {
		return "", false
	}
	return username.(string), true
}