package middleware

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

	"sql-platform/config"
	"sql-platform/internal/model"

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

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

func GenerateToken(user *model.User) (string, error) {
	claims := Claims{
		UserID:   user.ID,
		Username: user.Username,
		Role:     user.Role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(config.C.JWTExpire) * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(config.C.JWTSecret))
}

func AuthMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"detail": "Not authenticated"})
			c.Abort()
			return
		}

		tokenStr := strings.TrimPrefix(authHeader, "Bearer ")
		if tokenStr == authHeader {
			c.JSON(http.StatusUnauthorized, gin.H{"detail": "Invalid token format"})
			c.Abort()
			return
		}

		claims := &Claims{}
		token, err := jwt.ParseWithClaims(tokenStr, claims, func(token *jwt.Token) (interface{}, error) {
			return []byte(config.C.JWTSecret), nil
		})

		if err != nil || !token.Valid {
			c.JSON(http.StatusUnauthorized, gin.H{"detail": "Invalid or expired token"})
			c.Abort()
			return
		}

		c.Set("user_id", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("role", claims.Role)
		c.Next()
	}
}

func GetCurrentUser(c *gin.Context) (int, string, string) {
	return c.GetInt("user_id"), c.GetString("username"), c.GetString("role")
}

// RBAC middleware — allow specified roles (superadmin is treated as admin)
func RequireRole(roles ...string) gin.HandlerFunc {
	roleSet := make(map[string]bool)
	for _, r := range roles {
		roleSet[r] = true
	}
	// superadmin inherits all admin privileges
	roleSet["superadmin"] = true
	return func(c *gin.Context) {
		role := c.GetString("role")
		if !roleSet[role] {
			c.JSON(http.StatusForbidden, gin.H{"detail": "Permission denied"})
			c.Abort()
			return
		}
		c.Next()
	}
}