/*
 * Copyright 2004-2022 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (https://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.test.store;

import java.util.Random;

import org.h2.mvstore.MVMap;
import org.h2.mvstore.MVStore;
import org.h2.store.fs.FileUtils;
import org.h2.test.TestBase;

/**
 * Test that the MVStore eventually stops optimizing (does not excessively opti
 */
public class TestMVStoreStopCompact extends TestBase {

    /**
     * Run just this test.
     *
     * @param a ignored
     */
    public static void main(String... a) throws Exception {
        TestBase test = TestBase.createCaller().init();
        test.config.big = true;
        test.test();
    }

    @Override
    public void test() throws Exception {
        for(int retentionTime = 10; retentionTime < 1000; retentionTime *= 10) {
            for(int timeout = 100; timeout <= 1000; timeout *= 10) {
                testStopCompact(retentionTime, timeout);
            }
        }
    }

    private void testStopCompact(int retentionTime, int timeout) throws InterruptedException {
        String fileName = getBaseDir() + "/testStopCompact.h3";
        FileUtils.createDirectories(getBaseDir());
        FileUtils.delete(fileName);
        // store with a very small page size, to make sure
        // there are many leaf pages
        MVStore.Builder builder = new MVStore.Builder().fileName(fileName);
        try (MVStore s = builder.open()) {
            s.setRetentionTime(retentionTime);
            s.setVersionsToKeep(0);
            MVMap<Integer, String> map = s.openMap("data");
            long start = System.currentTimeMillis();
            Random r = new Random(1);
            for (int i = 0; i < 4_000_000; i++) {
                long time = System.currentTimeMillis() - start;
                if (time > timeout) {
                    break;
                }
                int x = r.nextInt(10_000_000);
                map.put(x, "Hello World " + i * 10);
            }
            s.setAutoCommitDelay(100);
            long oldWriteCount = s.getFileStore().getWriteCount();
            long totalWrites = 0;
            // expect background write to stop after a few seconds
            for (int i = 0; i < 50; i++) {
                Thread.sleep(200);
                long newWriteCount = s.getFileStore().getWriteCount();
                long delta = newWriteCount - oldWriteCount;
                if (delta == 0) {
                    break;
                }
                totalWrites += delta;
                oldWriteCount = newWriteCount;
            }
            // expect that compaction didn't cause many writes
            assertTrue("writeCount diff: " + retentionTime + "/" + timeout + " " + totalWrites,
                    totalWrites < 90);
        }
    }
}
