/**
 * Copyright (c) 2013-2024 Nikita Koksharov
 *
 * 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 org.redisson.eviction;

import org.redisson.RedissonObject;
import org.redisson.api.RFuture;
import org.redisson.client.codec.IntegerCodec;
import org.redisson.client.codec.LongCodec;
import org.redisson.client.protocol.RedisCommands;
import org.redisson.command.CommandAsyncExecutor;
import org.redisson.misc.CompletableFutureWrapper;

import java.util.Arrays;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;

/**
 *
 * @author Nikita Koksharov
 *
 */
public class MapCacheEvictionTask extends EvictionTask {

    private final String name;
    private final String timeoutSetName;
    private final String maxIdleSetName;
    private final String expiredChannelName;
    private final String lastAccessTimeSetName;
    private final String executeTaskOnceLatchName;
    private boolean removeEmpty;

    private EvictionScheduler evictionScheduler;

    private String publishCommand;

    public MapCacheEvictionTask(String name, String timeoutSetName, String maxIdleSetName,
                                String expiredChannelName, String lastAccessTimeSetName, CommandAsyncExecutor executor,
                                boolean removeEmpty, EvictionScheduler evictionScheduler, String publishCommand) {
        super(executor);
        this.name = name;
        this.timeoutSetName = timeoutSetName;
        this.maxIdleSetName = maxIdleSetName;
        this.expiredChannelName = expiredChannelName;
        this.lastAccessTimeSetName = lastAccessTimeSetName;
        this.executeTaskOnceLatchName = RedissonObject.prefixName("redisson__execute_task_once_latch", name);
        this.removeEmpty = removeEmpty;
        this.evictionScheduler = evictionScheduler;
        this.publishCommand = publishCommand;
    }

    @Override
    String getName() {
        return name;
    }

    @Override
    RFuture<Integer> execute() {
        int latchExpireTime = Math.min(delay, 30);
        RFuture<Integer> expiredFuture = executor.evalWriteNoRetryAsync(name, LongCodec.INSTANCE, RedisCommands.EVAL_INTEGER,
                "if redis.call('setnx', KEYS[6], ARGV[4]) == 0 then "
                 + "return -1;"
              + "end;"
              + "redis.call('expire', KEYS[6], ARGV[3]); "
               +"local expiredKeys1 = redis.call('zrangebyscore', KEYS[2], 0, ARGV[1], 'limit', 0, ARGV[2]); "
                + "for i, key in ipairs(expiredKeys1) do "
                    + "local v = redis.call('hget', KEYS[1], key); "
                    + "if v ~= false then "
                        + "local t, val = struct.unpack('dLc0', v); "
                        + "local msg = struct.pack('Lc0Lc0', string.len(key), key, string.len(val), val); "
                        + "local listeners = redis.call(ARGV[5], KEYS[4], msg); "
                        + "if (listeners == 0) then "
                            + "break;"
                        + "end; "
                    + "end;"
                + "end;"
                + "for i=1, #expiredKeys1, 5000 do "
                    + "redis.call('zrem', KEYS[5], unpack(expiredKeys1, i, math.min(i+4999, table.getn(expiredKeys1)))); "
                    + "redis.call('zrem', KEYS[3], unpack(expiredKeys1, i, math.min(i+4999, table.getn(expiredKeys1)))); "
                    + "redis.call('zrem', KEYS[2], unpack(expiredKeys1, i, math.min(i+4999, table.getn(expiredKeys1)))); "
                    + "redis.call('hdel', KEYS[1], unpack(expiredKeys1, i, math.min(i+4999, table.getn(expiredKeys1)))); "
                + "end; "
              + "local expiredKeys2 = redis.call('zrangebyscore', KEYS[3], 0, ARGV[1], 'limit', 0, ARGV[2]); "
              + "for i, key in ipairs(expiredKeys2) do "
                  + "local v = redis.call('hget', KEYS[1], key); "
                  + "if v ~= false then "
                      + "local t, val = struct.unpack('dLc0', v); "
                      + "local msg = struct.pack('Lc0Lc0', string.len(key), key, string.len(val), val); "
                      + "local listeners = redis.call(ARGV[5], KEYS[4], msg); "
                      + "if (listeners == 0) then "
                          + "break;"
                      + "end; "
                  + "end;"
              + "end;"
              + "for i=1, #expiredKeys2, 5000 do "
                  + "redis.call('zrem', KEYS[5], unpack(expiredKeys2, i, math.min(i+4999, table.getn(expiredKeys2)))); "
                  + "redis.call('zrem', KEYS[3], unpack(expiredKeys2, i, math.min(i+4999, table.getn(expiredKeys2)))); "
                  + "redis.call('zrem', KEYS[2], unpack(expiredKeys2, i, math.min(i+4999, table.getn(expiredKeys2)))); "
                  + "redis.call('hdel', KEYS[1], unpack(expiredKeys2, i, math.min(i+4999, table.getn(expiredKeys2)))); "
              + "end; "
              + "return #expiredKeys1 + #expiredKeys2;",
              Arrays.asList(name, timeoutSetName, maxIdleSetName, expiredChannelName, lastAccessTimeSetName, executeTaskOnceLatchName),
              System.currentTimeMillis(), keysLimit, latchExpireTime, 1, publishCommand);

        if (removeEmpty) {
            CompletionStage<Integer> r = expiredFuture.thenCompose(removed -> {
                RFuture<Integer> s = executor.readAsync(name, IntegerCodec.INSTANCE, RedisCommands.HLEN, name);
                return s.thenCompose(size -> {
                    if (size == 0) {
                        evictionScheduler.remove(name);
                        RFuture<Long> f = executor.writeAsync(name, LongCodec.INSTANCE, RedisCommands.DEL, name);
                        return f.thenApply(res -> {
                            return removed;
                        });
                    }
                    return CompletableFuture.completedFuture(removed);
                });
            });
            return new CompletableFutureWrapper<>(r);
        }
        return expiredFuture;
    }

}
