package main

import (
	"encoding/json"
	"fmt"
	"time"

	"github.com/redis/go-redis/v9"
	"golang.org/x/net/context"
)

var ctx = context.Background()

type UserBenefits struct {
	client *redis.Client
}

// NewUserBenefits 初始化 UserBenefits 实例
func NewUserBenefits(redisClient *redis.Client) *UserBenefits {
	return &UserBenefits{
		client: redisClient,
	}
}

// CheckAndDecrement 检查用户是否可以访问并递减剩余次数，0表示可用，其他值表示异常
func (ub *UserBenefits) CheckAndDecrement(ID int, timeZone string, secondsFromGMT int) (int, error) {
	loc, err := time.LoadLocation(timeZone)
	if err != nil {
		// 使用 secondsFromGMT 计算时区
		loc = time.FixedZone("Custom", secondsFromGMT)
	}
	currentTime := time.Now().In(loc)
	dateKey := currentTime.Format("20060102")

	key := fmt.Sprintf("%d_%s", ID, dateKey)

	// 获取当前计数
	val, err := ub.client.Get(ctx, key).Int()
	if err == redis.Nil {
		// 如果没有设置，初始化为3
		ub.client.Set(ctx, key, DAILY_FREE_COUNT, 24*time.Hour)
		val = DAILY_FREE_COUNT
	} else if err != nil {
		return -1, err
	}

	// 检查次数是否已用完
	if val <= 0 {
		return 1, nil
	}

	// 递减次数
	ub.client.Decr(ctx, key)

	return 0, nil
}

// QueryUserBenefits 查询用户使用情况
func (ub *UserBenefits) QueryUserBenefits(ID int) (string, error) {
	keys, err := ub.client.Keys(ctx, fmt.Sprintf("%d_*", ID)).Result()
	if err != nil {
		return "", err
	}

	result := make(map[string]int)
	for _, key := range keys {
		val, err := ub.client.Get(ctx, key).Int()
		if err != nil {
			return "", err
		}
		result[key] = val
	}

	// 将结果编码为 JSON 格式
	jsonData, err := json.Marshal(result)
	if err != nil {
		return "", err
	}

	return string(jsonData), nil
}

// ResetUserBenefits 删除指定日期或所有日期的用户权益，只限于内部调用
func (ub *UserBenefits) ResetUserBenefits(ID int, dateStr string) error {
	var pattern string
	if dateStr == "" {
		// 删除该用户的所有权益
		pattern = fmt.Sprintf("%d_*", ID)
	} else {
		// 删除特定日期的权益
		pattern = fmt.Sprintf("%d_%s", ID, dateStr)
	}

	keys, err := ub.client.Keys(ctx, pattern).Result()
	if err != nil {
		return err
	}

	if len(keys) == 0 {
		fmt.Println("No keys to delete.")
		return nil
	}

	_, err = ub.client.Del(ctx, keys...).Result()
	if err != nil {
		return err
	}

	fmt.Printf("Deleted keys for pattern %s\n", pattern)
	return nil
}

func test_smain() {
	// Redis 客户端使用连接池初始化
	rdb := redis.NewClient(&redis.Options{
		Addr:     "172.18.0.4:6379",
		Password: "", // no password set
		DB:       0,  // use default DB
		PoolSize: 10, // 连接池大小
	})

	ub := NewUserBenefits(rdb)

	// 示例使用
	status, err := ub.CheckAndDecrement(10001, "Europe/Berlin", 0)
	if err != nil {
		fmt.Println("Error:", err)
	} else {
		fmt.Println("Status Code:", status)
	}

	// 查询用户使用情况
	userData, err := ub.QueryUserBenefits(10001)
	if err != nil {
		fmt.Println("Error:", err)
	} else {
		fmt.Println("User Data:", userData)
	}
}