backend/internal/cache/redis_cache.go

package cache

import (
	"context"
	"encoding/json"
	"time"

	redislib "github.com/redis/go-redis/v9"
	"go.uber.org/zap"

	redisPkg "carrot_bbs/internal/pkg/redis"
)

// RedisCache Redis缓存实现
type RedisCache struct {
	client *redisPkg.Client
	ctx    context.Context
}

// NewRedisCache 创建Redis缓存
func NewRedisCache(client *redisPkg.Client) *RedisCache {
	return &RedisCache{
		client: client,
		ctx:    context.Background(),
	}
}

// Set 设置缓存值
func (c *RedisCache) Set(key string, value interface{}, ttl time.Duration) {
	key = normalizeKey(key)
	// 将值序列化为JSON
	data, err := json.Marshal(value)
	if err != nil {
		recordSetError()
		zap.L().Error("Failed to marshal value for key",
			zap.String("key", key),
			zap.Error(err),
		)
		return
	}

	if err := c.client.Set(c.ctx, key, data, ttl); err != nil {
		recordSetError()
		zap.L().Error("Failed to set key",
			zap.String("key", key),
			zap.Error(err),
		)
	}
}

// Get 获取缓存值
func (c *RedisCache) Get(key string) (interface{}, bool) {
	key = normalizeKey(key)
	data, err := c.client.Get(c.ctx, key)
	if err != nil {
		if err == redislib.Nil {
			return nil, false
		}
		zap.L().Error("Failed to get key",
			zap.String("key", key),
			zap.Error(err),
		)
		return nil, false
	}

	// 返回原始字符串，由调用侧决定如何解码为目标类型
	return data, true
}

// Delete 删除缓存
func (c *RedisCache) Delete(key string) {
	key = normalizeKey(key)
	recordInvalidate()
	if err := c.client.Del(c.ctx, key); err != nil {
		zap.L().Error("Failed to delete key",
			zap.String("key", key),
			zap.Error(err),
		)
	}
}

// DeleteByPrefix 根据前缀删除缓存
func (c *RedisCache) DeleteByPrefix(prefix string) {
	prefix = normalizePrefix(prefix)
	// 使用原生客户端执行SCAN命令
	rdb := c.client.GetClient()
	var cursor uint64
	for {
		keys, nextCursor, err := rdb.Scan(c.ctx, cursor, prefix+"*", 100).Result()
		if err != nil {
			zap.L().Error("Failed to scan keys with prefix",
				zap.String("prefix", prefix),
				zap.Error(err),
			)
			return
		}

		if len(keys) > 0 {
			recordInvalidateMultiple(int64(len(keys)))
			if err := c.client.Del(c.ctx, keys...); err != nil {
				zap.L().Error("Failed to delete keys with prefix",
					zap.String("prefix", prefix),
					zap.Error(err),
				)
			}
		}

		cursor = nextCursor
		if cursor == 0 {
			break
		}
	}
}

// Clear 清空所有缓存
func (c *RedisCache) Clear() {
	if settings.DisableFlushDB {
		zap.L().Debug("Skip FlushDB because cache.disable_flushdb=true")
		return
	}
	recordInvalidate()
	rdb := c.client.GetClient()
	if err := rdb.FlushDB(c.ctx).Err(); err != nil {
		zap.L().Error("Failed to clear cache",
			zap.Error(err),
		)
	}
}

// Exists 检查键是否存在
func (c *RedisCache) Exists(key string) bool {
	key = normalizeKey(key)
	n, err := c.client.Exists(c.ctx, key)
	if err != nil {
		zap.L().Error("Failed to check existence of key",
			zap.String("key", key),
			zap.Error(err),
		)
		return false
	}
	return n > 0
}

// Increment 增加计数器的值
func (c *RedisCache) Increment(key string) int64 {
	return c.IncrementBy(key, 1)
}

// IncrementBy 增加指定值
func (c *RedisCache) IncrementBy(key string, value int64) int64 {
	key = normalizeKey(key)
	rdb := c.client.GetClient()
	result, err := rdb.IncrBy(c.ctx, key, value).Result()
	if err != nil {
		zap.L().Error("Failed to increment key",
			zap.String("key", key),
			zap.Error(err),
		)
		return 0
	}
	return result
}

// ==================== RedisCache Hash 操作 ====================

// HSet 设置 Hash 字段
func (c *RedisCache) HSet(ctx context.Context, key string, field string, value interface{}) error {
	key = normalizeKey(key)
	return c.client.HSet(ctx, key, field, value)
}

// HMSet 批量设置 Hash 字段
func (c *RedisCache) HMSet(ctx context.Context, key string, values map[string]interface{}) error {
	key = normalizeKey(key)
	return c.client.HMSet(ctx, key, values)
}

// HGet 获取 Hash 字段值
func (c *RedisCache) HGet(ctx context.Context, key string, field string) (string, error) {
	key = normalizeKey(key)
	return c.client.HGet(ctx, key, field)
}

// HMGet 批量获取 Hash 字段值
func (c *RedisCache) HMGet(ctx context.Context, key string, fields ...string) ([]interface{}, error) {
	key = normalizeKey(key)
	return c.client.HMGet(ctx, key, fields...)
}

// HGetAll 获取 Hash 所有字段
func (c *RedisCache) HGetAll(ctx context.Context, key string) (map[string]string, error) {
	key = normalizeKey(key)
	return c.client.HGetAll(ctx, key)
}

// HDel 删除 Hash 字段
func (c *RedisCache) HDel(ctx context.Context, key string, fields ...string) error {
	key = normalizeKey(key)
	return c.client.HDel(ctx, key, fields...)
}

// ==================== RedisCache Sorted Set 操作 ====================

// ZAdd 添加 Sorted Set 成员
func (c *RedisCache) ZAdd(ctx context.Context, key string, score float64, member string) error {
	key = normalizeKey(key)
	return c.client.ZAdd(ctx, key, score, member)
}

// ZRangeByScore 按分数范围获取成员（升序）
func (c *RedisCache) ZRangeByScore(ctx context.Context, key string, min, max string, offset, count int64) ([]string, error) {
	key = normalizeKey(key)
	return c.client.ZRangeByScore(ctx, key, min, max, offset, count)
}

// ZRevRangeByScore 按分数范围获取成员（降序）
func (c *RedisCache) ZRevRangeByScore(ctx context.Context, key string, max, min string, offset, count int64) ([]string, error) {
	key = normalizeKey(key)
	return c.client.ZRevRangeByScore(ctx, key, max, min, offset, count)
}

// ZRevRange 按排名倒序获取成员
func (c *RedisCache) ZRevRange(ctx context.Context, key string, start, stop int64) ([]string, error) {
	key = normalizeKey(key)
	return c.client.ZRevRange(ctx, key, start, stop)
}

// ZReplaceSortedSet 删除后整表重写 ZSET
func (c *RedisCache) ZReplaceSortedSet(ctx context.Context, key string, members []redislib.Z) error {
	key = normalizeKey(key)
	rdb := c.client.GetClient()
	if err := rdb.Del(ctx, key).Err(); err != nil {
		return err
	}
	if len(members) == 0 {
		return nil
	}
	return c.client.ZAddArgs(ctx, key, members...)
}

// ZRem 删除 Sorted Set 成员
func (c *RedisCache) ZRem(ctx context.Context, key string, members ...interface{}) error {
	key = normalizeKey(key)
	return c.client.ZRem(ctx, key, members...)
}

// ZCard 获取 Sorted Set 成员数量
func (c *RedisCache) ZCard(ctx context.Context, key string) (int64, error) {
	key = normalizeKey(key)
	return c.client.ZCard(ctx, key)
}

// ==================== RedisCache 计数器操作 ====================

// Incr 原子递增（返回新值）
func (c *RedisCache) Incr(ctx context.Context, key string) (int64, error) {
	key = normalizeKey(key)
	return c.client.Incr(ctx, key)
}

// Expire 设置过期时间
func (c *RedisCache) Expire(ctx context.Context, key string, ttl time.Duration) error {
	key = normalizeKey(key)
	_, err := c.client.Expire(ctx, key, ttl)
	return err
}

// GetRedisClient 获取Redis客户端
func (c *RedisCache) GetRedisClient() *redisPkg.Client {
	return c.client
}