<!-- Spring Cache -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>

<!-- Redis 缓存提供商 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

<!-- Caffeine 本地缓存（可选） -->
<dependency>
    <groupId>com.github.ben-manes.caffeine</groupId>
    <artifactId>caffeine</artifactId>
</dependency>

@Configuration
@EnableCaching
public class CacheConfig {
    
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory connectionFactory) {
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
            .entryTtl(Duration.ofMinutes(10))
            .serializeKeysWith(
                RedisSerializationContext.SerializationPair
                    .fromSerializer(new StringRedisSerializer()))
            .serializeValuesWith(
                RedisSerializationContext.SerializationPair
                    .fromSerializer(new GenericJackson2JsonRedisSerializer()));
        
        return RedisCacheManager.builder(connectionFactory)
            .cacheDefaults(config)
            .withCacheConfiguration("products",
                config.entryTtl(Duration.ofHours(1)))
            .withCacheConfiguration("users",
                config.entryTtl(Duration.ofMinutes(30)))
            .build();
    }
}

@Service
@RequiredArgsConstructor
public class ProductService {
    
    private final ProductRepository productRepository;
    
    @Cacheable(value = "products", key = "#id")
    public Product findById(Long id) {
        return productRepository.findById(id)
            .orElseThrow(() -> new ProductNotFoundException(id));
    }
    
    @CachePut(value = "products", key = "#result.id")
    public Product update(Long id, UpdateProductRequest request) {
        Product product = findById(id);
        product.update(request);
        return productRepository.save(product);
    }
    
    @CacheEvict(value = "products", key = "#id")
    public void delete(Long id) {
        productRepository.deleteById(id);
    }
    
    @CacheEvict(value = "products", allEntries = true)
    public void clearCache() {
        // 清除所有缓存
    }
}

@Cacheable(
    value = "users", 
    key = "#email",
    condition = "#email != null",
    unless = "#result == null"
)
public User findByEmail(String email) {
    return userRepository.findByEmail(email).orElse(null);
}

@Cacheable(value = {"l1Cache", "l2Cache"}, key = "#id")
public Product findById(Long id) {
    // 先查 L1（本地缓存），再查 L2（Redis），最后查数据库
    return productRepository.findById(id)
        .orElseThrow(() -> new ProductNotFoundException(id));
}