package middleware

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"github.com/wangjia/jiu/backend/config"
)

type Claims struct {
	UserID uint64 `json:"user_id"`
	ShopID uint64 `json:"shop_id"`
	Role   string `json:"role"`
	jwt.RegisteredClaims
}

const (
	CtxUserID = "user_id"
	CtxShopID = "shop_id"
	CtxRole   = "role"
)

func JWT() gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" || !strings.HasPrefix(authHeader, "Bearer ") {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "missing token"})
			return
		}

		tokenStr := strings.TrimPrefix(authHeader, "Bearer ")
		claims := &Claims{}
		token, err := jwt.ParseWithClaims(tokenStr, claims, func(t *jwt.Token) (interface{}, error) {
			return []byte(config.C.JWT.Secret), nil
		})
		if err != nil || !token.Valid {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "invalid token"})
			return
		}

		c.Set(CtxUserID, claims.UserID)
		c.Set(CtxShopID, claims.ShopID)
		c.Set(CtxRole, claims.Role)
		c.Next()
	}
}

// AdminOnly 仅管理员可访问
func AdminOnly() gin.HandlerFunc {
	return func(c *gin.Context) {
		role, _ := c.Get(CtxRole)
		if role != "admin" && role != "superadmin" {
			c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"error": "admin only"})
			return
		}
		c.Next()
	}
}

// ReadOnly 只读用户禁止写操作
func ReadOnly() gin.HandlerFunc {
	return func(c *gin.Context) {
		role, _ := c.Get(CtxRole)
		if role == "readonly" && c.Request.Method != "GET" {
			c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"error": "readonly user"})
			return
		}
		c.Next()
	}
}

// GetShopID 从 context 中安全获取 shop_id
func GetShopID(c *gin.Context) uint64 {
	v, _ := c.Get(CtxShopID)
	id, _ := v.(uint64)
	return id
}

// GetUserID 从 context 中安全获取 user_id
func GetUserID(c *gin.Context) uint64 {
	v, _ := c.Get(CtxUserID)
	id, _ := v.(uint64)
	return id
}

// SuperAdminOnly 仅超级管理员可访问
func SuperAdminOnly() gin.HandlerFunc {
	return func(c *gin.Context) {
		role, _ := c.Get(CtxRole)
		if role != "superadmin" {
			c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"error": "superadmin only"})
			return
		}
		c.Next()
	}
}