Potion/internal/app/server/middleware.go

package server

import (
	"fmt"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	domain "github.com/haydenhargreaves/Potion/internal/domain/server"
)

// DepedencyInjectionMiddleware injects the dependencies into the context set. This is a middleware
// that is used to apply the required services.
func DepedencyInjectionMiddleware(deps *domain.InjectedDependencies) gin.HandlerFunc {
	return func(ctx *gin.Context) {
		ctx.Set("deps", deps)
		ctx.Next()
	}
}

// JwtAuthMiddleWare handles collection the JWT from the browser's cookies and setting the
// appropriate data. If the data is not found, this middleware will do effectively nothing, by not
// setting any values. Protected routes can use this lack of a value as a sign that the user is not
// logged in and direct the user to login.
func JwtAuthMiddleWare(jwtSecretKey []byte) gin.HandlerFunc {
	return func(ctx *gin.Context) {
		// JWT cookie not found
		tokenString, err := ctx.Cookie("jwt_token")
		if err != nil {
			ctx.Next()
			return
		}

		claims := &domain.JwtClaims{}

		token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
			if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
				return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
			}
			return jwtSecretKey, nil
		})

		// Error occurred when parsing
		if err != nil {
			ctx.Next()
			return
		}

		// NOTE: If we need deeper error handling
		// if err != nil {
		// 	if errors.Is(err, jwt.ErrSignatureInvalid) {
		// 		ctx.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token signature"})
		// 	} else if errors.Is(err, jwt.ErrTokenExpired) || errors.Is(err, jwt.ErrTokenNotValidYet) {
		// 		ctx.JSON(http.StatusUnauthorized, gin.H{"error": "Token expired or not yet valid"})
		// 	} else {
		// 		log.Printf("JWT parsing error: %v", err)
		// 		ctx.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
		// 	}
		// 	ctx.Abort()
		// 	return
		// }

		// Token is invalid
		if !token.Valid {
			ctx.Next()
			return
		}

		// Found: Set the values
		ctx.Set("userId", claims.UserId)
		ctx.Set("userEmail", claims.Email)
		ctx.Next()
	}
}