// Copyright © 2023 OpenIM open source community. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package cache

import (
	"context"
	"time"

	"github.com/openimsdk/tools/errs"
	"github.com/redis/go-redis/v9"
)

const (
	userLoginIPPrefix = "CHAT:USER_LOGIN_IP:"
	// 缓存过期时间：7天（用户登录IP变化不频繁，可以设置较长的过期时间）
	userLoginIPExpire = 7 * 24 * time.Hour
)

func getUserLoginIPKey(userID string) string {
	return userLoginIPPrefix + userID
}

type UserLoginIPInterface interface {
	// GetLatestLoginIP 获取用户最新登录IP（从缓存）
	// 返回值：(ip, found, error)
	// - ip: 缓存的IP值（如果found为false，则ip为空字符串）
	// - found: 是否在缓存中找到（true表示缓存命中，false表示缓存未命中）
	// - error: 错误信息
	GetLatestLoginIP(ctx context.Context, userID string) (string, bool, error)
	// SetLatestLoginIP 设置用户最新登录IP到缓存
	SetLatestLoginIP(ctx context.Context, userID, ip string) error
	// DeleteLatestLoginIP 删除用户最新登录IP缓存（用于保证缓存一致性）
	DeleteLatestLoginIP(ctx context.Context, userID string) error
}

type userLoginIPCacheRedis struct {
	rdb redis.UniversalClient
}

func NewUserLoginIPInterface(rdb redis.UniversalClient) UserLoginIPInterface {
	return &userLoginIPCacheRedis{rdb: rdb}
}

func (u *userLoginIPCacheRedis) GetLatestLoginIP(ctx context.Context, userID string) (string, bool, error) {
	key := getUserLoginIPKey(userID)
	ip, err := u.rdb.Get(ctx, key).Result()
	if err != nil {
		if err == redis.Nil {
			// 缓存不存在，返回 false 表示缓存未命中
			return "", false, nil
		}
		return "", false, errs.Wrap(err)
	}
	// 缓存命中，返回 true
	return ip, true, nil
}

func (u *userLoginIPCacheRedis) SetLatestLoginIP(ctx context.Context, userID, ip string) error {
	key := getUserLoginIPKey(userID)
	err := u.rdb.Set(ctx, key, ip, userLoginIPExpire).Err()
	if err != nil {
		return errs.Wrap(err)
	}
	return nil
}

func (u *userLoginIPCacheRedis) DeleteLatestLoginIP(ctx context.Context, userID string) error {
	key := getUserLoginIPKey(userID)
	err := u.rdb.Del(ctx, key).Err()
	if err != nil {
		return errs.Wrap(err)
	}
	return nil
}