// go-redis 外部 Redis 服务器实现
// 用于 Docker Compose / 生产环境部署 // Logan.Li
package redis

import (
	"context"
	"fmt"
	"time"

	goredis "github.com/redis/go-redis/v9"
)

// goRedisCache 基于 go-redis 的缓存实现 // Logan.Li
type goRedisCache struct {
	client *goredis.Client
}

func newGoRedis(cfg Config) (Cache, error) {
	client := goredis.NewClient(&goredis.Options{
		Addr:     fmt.Sprintf("%s:%d", cfg.Host, cfg.Port),
		Password: cfg.Password,
		DB:       cfg.DB,
	})

	// 连接测试
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := client.Ping(ctx).Err(); err != nil {
		return nil, fmt.Errorf("redis: 连接失败 %s:%d: %w", cfg.Host, cfg.Port, err)
	}

	return &goRedisCache{client: client}, nil
}

func (r *goRedisCache) Capabilities() Capabilities {
	return Capabilities{SortedSet: true, PubSub: true}
}

func (r *goRedisCache) Get(ctx context.Context, key string) (string, error) {
	val, err := r.client.Get(ctx, key).Result()
	if err == goredis.Nil {
		return "", nil
	}
	return val, err
}

func (r *goRedisCache) Set(ctx context.Context, key string, value string, expiration time.Duration) error {
	return r.client.Set(ctx, key, value, expiration).Err()
}

// SetNX 原子 SET if Not eXists — go-redis 原生支持，用于分布式锁
func (r *goRedisCache) SetNX(ctx context.Context, key string, value string, expiration time.Duration) (bool, error) {
	return r.client.SetNX(ctx, key, value, expiration).Result()
}

func (r *goRedisCache) Del(ctx context.Context, keys ...string) error {
	return r.client.Del(ctx, keys...).Err()
}

func (r *goRedisCache) Exists(ctx context.Context, keys ...string) (int64, error) {
	return r.client.Exists(ctx, keys...).Result()
}

func (r *goRedisCache) Expire(ctx context.Context, key string, expiration time.Duration) error {
	return r.client.Expire(ctx, key, expiration).Err()
}

func (r *goRedisCache) Ping(ctx context.Context) error {
	return r.client.Ping(ctx).Err()
}

func (r *goRedisCache) Close() error {
	return r.client.Close()
}

func (r *goRedisCache) ZAdd(ctx context.Context, key string, member SortedSetMember) error {
	return r.client.ZAdd(ctx, key, goredis.Z{
		Score:  member.Score,
		Member: member.Member,
	}).Err()
}

func (r *goRedisCache) ZRangeByScore(ctx context.Context, key string, min, max string) ([]SortedSetMember, error) {
	zs, err := r.client.ZRangeByScoreWithScores(ctx, key, &goredis.ZRangeBy{
		Min: min,
		Max: max,
	}).Result()
	if err != nil {
		return nil, err
	}
	members := make([]SortedSetMember, len(zs))
	for i, z := range zs {
		members[i] = SortedSetMember{
			Score:  z.Score,
			Member: z.Member.(string),
		}
	}
	return members, nil
}

func (r *goRedisCache) ZRemRangeByScore(ctx context.Context, key string, min, max string) error {
	return r.client.ZRemRangeByScore(ctx, key, min, max).Err()
}

func (r *goRedisCache) Publish(ctx context.Context, channel string, message string) error {
	return r.client.Publish(ctx, channel, message).Err()
}