// Package middleware 提供HTTP中间件功能
// 包含鉴权、日志、恢复等中间件实现
package middleware

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

	"git.huangwc.com/pig/pig-farm-controller/internal/logs"
	"git.huangwc.com/pig/pig-farm-controller/internal/storage/repository"
	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"gorm.io/gorm"
)

// AuthMiddleware 鉴权中间件结构
type AuthMiddleware struct {
	userRepo repository.UserRepo
	logger   *logs.Logger
}

// AuthUser 用于在上下文中存储的用户信息
type AuthUser struct {
	ID       uint   `json:"id"`
	Username string `json:"username"`
}

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

// NewAuthMiddleware 创建鉴权中间件实例
func NewAuthMiddleware(userRepo repository.UserRepo) *AuthMiddleware {
	return &AuthMiddleware{
		userRepo: userRepo,
		logger:   logs.NewLogger(),
	}
}

// getJWTSecret 获取JWT密钥
func (m *AuthMiddleware) getJWTSecret() []byte {
	// 在实际项目中，应该从配置文件或环境变量中读取
	secret := os.Getenv("JWT_SECRET")
	if secret == "" {
		secret = "pig-farm-controller-secret-key" // 默认密钥
	}
	return []byte(secret)
}

// GenerateToken 为用户生成JWT token
func (m *AuthMiddleware) GenerateToken(userID uint, username string) (string, error) {
	claims := JWTClaims{
		UserID:   userID,
		Username: username,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(24 * time.Hour)), // 24小时过期
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			NotBefore: jwt.NewNumericDate(time.Now()),
			Issuer:    "pig-farm-controller",
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(m.getJWTSecret())
}

// Handle 鉴权中间件处理函数
func (m *AuthMiddleware) Handle() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 从请求头中获取认证信息
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "缺少认证信息"})
			c.Abort()
			return
		}

		// 检查Bearer token格式
		if !strings.HasPrefix(authHeader, "Bearer ") {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "认证信息格式错误"})
			c.Abort()
			return
		}

		// 解析token
		tokenString := strings.TrimPrefix(authHeader, "Bearer ")

		// 验证token并获取用户信息
		user, err := m.getUserFromJWT(tokenString)
		if err != nil {
			if err == gorm.ErrRecordNotFound {
				c.JSON(http.StatusUnauthorized, gin.H{"error": "用户不存在"})
			} else {
				m.logger.Error("Token验证失败: " + err.Error())
				c.JSON(http.StatusUnauthorized, gin.H{"error": "无效的认证令牌"})
			}
			c.Abort()
			return
		}

		// 将用户信息保存到上下文中，供后续处理函数使用
		c.Set("user", user)

		// 继续处理请求
		c.Next()
	}
}

// getUserFromJWT 从JWT token中获取用户信息
func (m *AuthMiddleware) getUserFromJWT(tokenString string) (*AuthUser, error) {
	// 解析token
	token, err := jwt.ParseWithClaims(tokenString, &JWTClaims{}, func(token *jwt.Token) (interface{}, error) {
		return m.getJWTSecret(), nil
	})

	if err != nil {
		return nil, err
	}

	// 验证token
	if !token.Valid {
		return nil, gorm.ErrRecordNotFound
	}

	// 获取声明
	claims, ok := token.Claims.(*JWTClaims)
	if !ok {
		return nil, gorm.ErrRecordNotFound
	}

	// 根据用户ID查找用户
	userModel, err := m.userRepo.FindByID(claims.UserID)
	if err != nil {
		return nil, err
	}

	user := &AuthUser{
		ID:       userModel.ID,
		Username: userModel.Username,
	}

	return user, nil
}