package middleware

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

	"ezops/config"
	"ezops/model"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

// 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 *model.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 / API AccessKey 双模式认证中间件 // Logan.Li
func JWTAuth(cfg *config.JWTConfig, db *gorm.DB) gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			if token := c.Query("token"); token != "" {
				authHeader = "Bearer " + token
			}
		}
		// 兼容 CI/CD 脚本直接传 AccessKey 头 // Logan.Li
		if authHeader == "" {
			if key := c.GetHeader("X-AIOps-Access-Key"); key != "" {
				authHeader = "Bearer " + key
			}
		}
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, model.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, model.Response{Code: 401, Message: "认证令牌格式错误"})
			c.Abort()
			return
		}

		tokenString := parts[1]
		if tryJWTAuth(c, cfg, tokenString) || tryAPIKeyAuth(c, db, tokenString) {
			c.Next()
			return
		}

		c.JSON(http.StatusUnauthorized, model.Response{Code: 401, Message: "无效或过期的认证令牌"})
		c.Abort()
	}
}

// tryJWTAuth 尝试 JWT 认证 // Logan.Li
func tryJWTAuth(c *gin.Context, cfg *config.JWTConfig, tokenString string) bool {
	token, err := jwt.ParseWithClaims(tokenString, &JWTClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(cfg.Secret), nil
	})
	if err != nil {
		return false
	}
	claims, ok := token.Claims.(*JWTClaims)
	if !ok || !token.Valid {
		return false
	}
	c.Set("userID", claims.UserID)
	c.Set("username", claims.Username)
	c.Set("isAdmin", claims.IsAdmin)
	c.Set("authType", "jwt")
	return true
}

// tryAPIKeyAuth 尝试长期 API 访问密钥（prefix.secret 格式）// Logan.Li
func tryAPIKeyAuth(c *gin.Context, db *gorm.DB, tokenString string) bool {
	if db == nil {
		return false
	}
	segs := strings.Split(tokenString, ".")
	if len(segs) != 2 || segs[0] == "" || segs[1] == "" {
		return false
	}
	prefix := segs[0]
	var user model.User
	if err := db.Where("api_access_key_prefix = ? AND status = 1", prefix).First(&user).Error; err != nil {
		return false
	}
	if user.ApiAccessKeyHash == "" {
		return false
	}
	if err := bcrypt.CompareHashAndPassword([]byte(user.ApiAccessKeyHash), []byte(tokenString)); err != nil {
		return false
	}
	// 密钥已过期则拒绝 // Logan.Li
	if user.ApiAccessKeyExpiresAt != nil && user.ApiAccessKeyExpiresAt.Before(time.Now()) {
		return false
	}
	now := time.Now()
	_ = db.Model(&model.User{}).Where("id = ?", user.ID).Update("api_access_key_last_used_at", now).Error
	c.Set("userID", user.ID)
	c.Set("username", user.Username)
	c.Set("isAdmin", user.IsAdmin)
	c.Set("authType", "api_key")
	return true
}

// 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, model.Response{
				Code:    403,
				Message: "需要管理员权限",
			})
			c.Abort()
			return
		}
		c.Next()
	}
}

// PermissionAuth 校验当前用户是否拥有指定权限码，管理员直接放行。 // Logan.Li
func PermissionAuth(db *gorm.DB, permissionCode string) gin.HandlerFunc {
	return func(c *gin.Context) {
		if GetIsAdmin(c) {
			c.Next()
			return
		}
		var count int64
		err := db.Table("iam_user_roles ur").
			Joins("JOIN iam_roles r ON r.id = ur.role_id AND r.status = 1").
			Joins("JOIN iam_role_permissions rp ON rp.role_id = r.id").
			Joins("JOIN iam_permissions p ON p.id = rp.permission_id AND p.status = 1").
			Where("ur.user_id = ? AND p.code = ?", GetUserID(c), permissionCode).
			Count(&count).Error
		if err != nil || count == 0 {
			c.JSON(http.StatusForbidden, model.Response{Code: 403, Message: "无此功能权限"})
			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)
}