package cn.netkiller.service;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import org.springframework.stereotype.Service;

import javax.xml.bind.DatatypeConverter;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.time.Duration;
import java.util.function.Supplier;

@Service
@Slf4j
public class CacheService {
    @Autowired
    private RedisTemplate redisTemplate;

    private final String prefix = "service";

    @SneakyThrows
    public static String md5Key(String key) {
        String digest = DatatypeConverter
                .printHexBinary(MessageDigest.getInstance("MD5").digest(key.getBytes(StandardCharsets.UTF_8)));
        return digest;
    }


    public <T> T cache(String cacheKey, Duration duration, Supplier<T> supplier) {
//        RedisTemplate redisTemplate = new RedisTemplate();
        String key = String.format("%s:%s", prefix, cacheKey);

        T value;
        if (redisTemplate == null) {
            value = supplier.get();
            log.info("Cache Skip Key: " + key + " Value: " + value);
        } else {
            if (redisTemplate.hasKey(key)) {
                value = (T) redisTemplate.opsForValue().get(key);
                log.info("Cache Hit Key: " + key + " Value: " + value);
            } else {
                value = supplier.get();
                if (value != null) {
                    redisTemplate.setKeySerializer(new StringRedisSerializer());
                    redisTemplate.opsForValue().set(key, value);
                    redisTemplate.expire(key, duration);

                    log.info("Cache Set Key: " + key + " Value: " + value);
                } else {
                    log.info("Cache Set Key: " + key + " Error: " + value);
                }
            }
        }
        return value;
    }

}