package cache

import (
	"context"
	"errors"
	"time"

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

type redisCache struct {
	client *goredis.Client
}

func newRedisCache(client *goredis.Client) Cache {
	return &redisCache{client: client}
}

func (c *redisCache) Get(ctx context.Context, key string) ([]byte, error) {
	val, err := c.client.Get(ctx, key).Bytes()
	if errors.Is(err, goredis.Nil) {
		return nil, ErrNotFound
	}
	return val, err
}

func (c *redisCache) Set(ctx context.Context, key string, value []byte, ttl time.Duration) error {
	return c.client.Set(ctx, key, value, ttl).Err()
}

func (c *redisCache) Delete(ctx context.Context, key string) error {
	return c.client.Del(ctx, key).Err()
}

func (c *redisCache) DeletePrefix(ctx context.Context, prefix string) error {
	if prefix == "" {
		return nil
	}

	pattern := prefix + "*"
	var cursor uint64
	for {
		keys, nextCursor, err := c.client.Scan(ctx, cursor, pattern, 100).Result()
		if err != nil {
			return err
		}
		if len(keys) > 0 {
			if err := c.client.Del(ctx, keys...).Err(); err != nil {
				return err
			}
		}
		cursor = nextCursor
		if cursor == 0 {
			return nil
		}
	}
}