package services

import (
	"context"
	"errors"
	"fmt"
	"log"
	"time"

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

var CacheClient Cache

var ErrCacheMiss = errors.New("cache: miss")

type Cache interface {
	Get(ctx context.Context, key string) ([]byte, error)
	Set(ctx context.Context, key string, value []byte, ttl time.Duration) error
}

type RedisConcrete struct {
	Redis *redis.Client
}

const cacheOperationTimeout = 100 * time.Millisecond

func (svc RedisConcrete) Get(ctx context.Context, key string) ([]byte, error) {
	ctx, cancel := context.WithTimeout(ctx, cacheOperationTimeout)
	defer cancel()

	value, err := svc.Redis.Get(ctx, key).Bytes()
	if errors.Is(err, redis.Nil) {
		return nil, ErrCacheMiss
	}
	if err != nil {
		return nil, err
	}
	return value, nil
}

func (svc RedisConcrete) Set(ctx context.Context, key string, value []byte, ttl time.Duration) error {
	ctx, cancel := context.WithTimeout(ctx, cacheOperationTimeout)
	defer cancel()

	return svc.Redis.Set(ctx, key, value, ttl).Err()
}

func (svc RedisConcrete) Close() error {
	return svc.Redis.Close()
}

func (svc RedisConcrete) AssertSuccessfulConnection(ctx context.Context) {
	if err := svc.Redis.Ping(ctx).Err(); err != nil {
		log.Printf("WARNING: %s", fmt.Errorf("redis: cannot reach cache at %q, searches will be served from the database: %w",
			svc.Redis.Options().Addr, err))
	}
}