/*
 *  Copyright 2019-2020 Zheng Jie
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package me.zhengjie.config;

import cn.hutool.core.lang.Assert;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.parser.ParserConfig;
import com.alibaba.fastjson.serializer.SerializerFeature;
import lombok.extern.slf4j.Slf4j;
import me.zhengjie.utils.StringUtils;
import org.apache.commons.codec.digest.DigestUtils;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.data.redis.RedisProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cache.Cache;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.CacheErrorHandler;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;

/**
 * @author Zheng Jie
 * @date 2018-11-24
 */
@Slf4j
@Configuration
@EnableCaching
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
public class RedisConfig extends CachingConfigurerSupport {

    /**
     *  设置 redis 数据默认过期时间,默认2小时
     *  设置@cacheable 序列化方式
     */
    @Bean
    public RedisCacheConfiguration redisCacheConfiguration(){
        FastJsonRedisSerializer<Object> fastJsonRedisSerializer = new FastJsonRedisSerializer<>(Object.class);
        RedisCacheConfiguration configuration = RedisCacheConfiguration.defaultCacheConfig();
        configuration = configuration.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(fastJsonRedisSerializer)).entryTtl(Duration.ofHours(2));
        return configuration;
    }

    @SuppressWarnings("all")
    @Bean(name = "redisTemplate")
    @ConditionalOnMissingBean(name = "redisTemplate")
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        //序列化
        FastJsonRedisSerializer<Object> fastJsonRedisSerializer = new FastJsonRedisSerializer<>(Object.class);
        // value值的序列化采用fastJsonRedisSerializer
        template.setValueSerializer(fastJsonRedisSerializer);
        template.setHashValueSerializer(fastJsonRedisSerializer);
        // 全局开启AutoType,这里方便开发,使用全局的方式
        ParserConfig.getGlobalInstance().setAutoTypeSupport(true);
        // 建议使用这种方式,小范围指定白名单
        // ParserConfig.getGlobalInstance().addAccept("me.zhengjie.domain");
        // key的序列化采用StringRedisSerializer
        template.setKeySerializer(new StringRedisSerializer());
        template.setHashKeySerializer(new StringRedisSerializer());
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

    /**
     * 自定义缓存key生成策略,默认将使用该策略
     */
    @Bean
    @Override
    public KeyGenerator keyGenerator() {
        return (target, method, params) -> {
            Map<String,Object> container = new HashMap<>(3);
            Class<?> targetClassClass = target.getClass();
            // 类地址
            container.put("class",targetClassClass.toGenericString());
            // 方法名称
            container.put("methodName",method.getName());
            // 包名称
            container.put("package",targetClassClass.getPackage());
            // 参数列表
            for (int i = 0; i < params.length; i++) {
                container.put(String.valueOf(i),params[i]);
            }
            // 转为JSON字符串
            String jsonString = JSON.toJSONString(container);
            // 做SHA256 Hash计算,得到一个SHA256摘要作为Key
            return DigestUtils.sha256Hex(jsonString);
        };
    }

    @Bean
    @Override
    public CacheErrorHandler errorHandler() {
        // 异常处理,当Redis发生异常时,打印日志,但是程序正常走
        log.info("初始化 -> [{}]", "Redis CacheErrorHandler");
        return new CacheErrorHandler() {
            @Override
            public void handleCacheGetError(RuntimeException e, Cache cache, Object key) {
                log.error("Redis occur handleCacheGetError:key -> [{}]", key, e);
            }

            @Override
            public void handleCachePutError(RuntimeException e, Cache cache, Object key, Object value) {
                log.error("Redis occur handleCachePutError:key -> [{}];value -> [{}]", key, value, e);
            }

            @Override
            public void handleCacheEvictError(RuntimeException e, Cache cache, Object key) {
                log.error("Redis occur handleCacheEvictError:key -> [{}]", key, e);
            }

            @Override
            public void handleCacheClearError(RuntimeException e, Cache cache) {
                log.error("Redis occur handleCacheClearError:", e);
            }
        };
    }

}

/**
 * Value 序列化
 *
 * @author /
 * @param <T>
 */
 class FastJsonRedisSerializer<T> implements RedisSerializer<T> {

    private final Class<T> clazz;

    FastJsonRedisSerializer(Class<T> clazz) {
        super();
        this.clazz = clazz;
    }

    @Override
    public byte[] serialize(T t) {
        if (t == null) {
            return new byte[0];
        }
        return JSON.toJSONString(t, SerializerFeature.WriteClassName).getBytes(StandardCharsets.UTF_8);
    }

    @Override
    public T deserialize(byte[] bytes) {
        if (bytes == null || bytes.length <= 0) {
            return null;
        }
        String str = new String(bytes, StandardCharsets.UTF_8);
        return JSON.parseObject(str, clazz);
    }

}

/**
 * 重写序列化器
 *
 * @author /
 */
class StringRedisSerializer implements RedisSerializer<Object> {

    private final Charset charset;

    StringRedisSerializer() {
        this(StandardCharsets.UTF_8);
    }

    private StringRedisSerializer(Charset charset) {
        Assert.notNull(charset, "Charset must not be null!");
        this.charset = charset;
    }

    @Override
    public String deserialize(byte[] bytes) {
        return (bytes == null ? null : new String(bytes, charset));
    }

    @Override
    public byte[] serialize(Object object) {
        String string = JSON.toJSONString(object);
        if (StringUtils.isBlank(string)) {
            return null;
        }
        string = string.replace("\"", "");
        return string.getBytes(charset);
    }
}