package middleware

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

	"ezops/internal/config"
	"ezops/internal/models"

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

// JWTClaims JWT声明
type JWTClaims struct {
	UserID   uint   `json:"user_id"`
	Username string `json:"username"`
	IsAdmin  bool   `json:"is_admin"`
	jwt.RegisteredClaims
}

// GenerateToken 生成JWT令牌
func GenerateToken(user *models.User, cfg *config.JWTConfig) (string, error) {
	claims := JWTClaims{
		UserID:   user.ID,
		Username: user.Username,
		IsAdmin:  user.IsAdmin,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(cfg.ExpireHour) * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			Issuer:    "ezops",
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(cfg.Secret))
}

// JWTAuth JWT认证中间件
func JWTAuth(cfg *config.JWTConfig) gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, models.Response{
				Code:    401,
				Message: "未提供认证令牌",
			})
			c.Abort()
			return
		}

		parts := strings.SplitN(authHeader, " ", 2)
		if !(len(parts) == 2 && parts[0] == "Bearer") {
			c.JSON(http.StatusUnauthorized, models.Response{
				Code:    401,
				Message: "认证令牌格式错误",
			})
			c.Abort()
			return
		}

		tokenString := parts[1]
		token, err := jwt.ParseWithClaims(tokenString, &JWTClaims{}, func(token *jwt.Token) (interface{}, error) {
			return []byte(cfg.Secret), nil
		})

		if err != nil {
			c.JSON(http.StatusUnauthorized, models.Response{
				Code:    401,
				Message: "无效的认证令牌: " + err.Error(),
			})
			c.Abort()
			return
		}

		if claims, ok := token.Claims.(*JWTClaims); ok && token.Valid {
			c.Set("userID", claims.UserID)
			c.Set("username", claims.Username)
			c.Set("isAdmin", claims.IsAdmin)
			c.Next()
		} else {
			c.JSON(http.StatusUnauthorized, models.Response{
				Code:    401,
				Message: "无效的认证令牌",
			})
			c.Abort()
		}
	}
}

// AdminAuth 管理员认证中间件
func AdminAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		isAdmin, exists := c.Get("isAdmin")
		if !exists || !isAdmin.(bool) {
			c.JSON(http.StatusForbidden, models.Response{
				Code:    403,
				Message: "需要管理员权限",
			})
			c.Abort()
			return
		}
		c.Next()
	}
}

// GetUserID 获取当前用户ID
func GetUserID(c *gin.Context) uint {
	userID, exists := c.Get("userID")
	if !exists {
		return 0
	}
	return userID.(uint)
}

// GetUsername 获取当前用户名
func GetUsername(c *gin.Context) string {
	username, exists := c.Get("username")
	if !exists {
		return ""
	}
	return username.(string)
}

// GetIsAdmin 获取是否为管理员
func GetIsAdmin(c *gin.Context) bool {
	isAdmin, exists := c.Get("isAdmin")
	if !exists {
		return false
	}
	return isAdmin.(bool)
}