package auth

import (
	"fmt"
	"os"
	"strings"

	"gitea.d3m0k1d.ru/d3m0k1d/d3m0k1d.ru/backend/internal/storage"
	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
)

var jwtSecret = []byte(os.Getenv("JWT_SECRET"))

func GenerateJWT(user storage.User) (string, error) {
	token := jwt.NewWithClaims(jwt.SigningMethodHS512, jwt.MapClaims{
		"id":        user.ID,
		"email":     user.Email,
		"github_id": user.GithubID,
	})
	tokenString, err := token.SignedString(jwtSecret)
	if err != nil {
		return "", err
	}
	return tokenString, nil
}

func JWTMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		auth := c.GetHeader("Authorization")
		if !strings.HasPrefix(auth, "Bearer ") {
			c.AbortWithStatusJSON(401, gin.H{"error": "Bearer required"})
			return
		}

		tokenString := strings.TrimPrefix(auth, "Bearer ")
		token, err := jwt.Parse(tokenString, 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 jwtSecret, nil
		})

		if err != nil || !token.Valid {
			c.AbortWithStatusJSON(401, gin.H{"error": "invalid token"})
			return
		}

		claims, ok := token.Claims.(jwt.MapClaims)
		if !ok {
			c.AbortWithStatusJSON(401, gin.H{"error": "invalid claims"})
			return
		}

		c.Set("user_id", int(claims["id"].(float64)))
		c.Set("login", claims["login"].(string))
		c.Next()
	}
}