package jwt

import (
	"net/http"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"github.com/google/uuid"
	"github.com/spf13/viper"
)

type Claims struct {
	UserID uuid.UUID `json:"user_id"`
	jwt.RegisteredClaims
}

func JWTAuth() gin.HandlerFunc {
	var JwtSecret = []byte(viper.GetString("secrets.jwt_secret"))
	return func(c *gin.Context) {
		auth := c.GetHeader("Authorization")
		if auth == "" {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
				"error": "missing Authorization header",
			})
			return
		}

		parts := strings.SplitN(auth, " ", 2)
		if len(parts) != 2 || parts[0] != "Bearer" {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
				"error": "invalid Authorization header format",
			})
			return
		}

		tokenStr := parts[1]

		token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(token *jwt.Token) (interface{}, error) {
			return JwtSecret, nil
		})

		if err != nil || !token.Valid {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
				"error": "invalid or expired token",
			})
			return
		}

		claims, ok := token.Claims.(*Claims)
		if !ok {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
				"error": "invalid token claims",
			})
			return
		}

		c.Set("user_id", claims.UserID)
		c.Next()
	}
}

func GenerateToken(userID uuid.UUID, application string) (string, error) {
	var JwtSecret = []byte(viper.GetString("server.jwt_secret"))
	claims := Claims{
		UserID: userID,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(viper.GetDuration("ttl.jwt_ttl"))),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			Issuer:    application,
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(JwtSecret)
}