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package org.apache.cassandra.db.compaction;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

import org.junit.Test;
import static junit.framework.Assert.assertEquals;

import org.apache.cassandra.CleanupHelper;
import org.apache.cassandra.Util;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.compaction.OperationType;
import org.apache.cassandra.db.filter.QueryFilter;
import org.apache.cassandra.db.filter.QueryPath;
import org.apache.cassandra.io.sstable.*;
import org.apache.cassandra.utils.ByteBufferUtil;

public class CompactionsTest extends CleanupHelper
{
    public static final String TABLE1 = "Keyspace1";

    @Test
    public void testStandardColumnCompactions() throws IOException, ExecutionException, InterruptedException
    {
        // this test does enough rows to force multiple block indexes to be used
        Table table = Table.open(TABLE1);
        ColumnFamilyStore store = table.getColumnFamilyStore("Standard1");

        final int ROWS_PER_SSTABLE = 10;
        final int SSTABLES = DatabaseDescriptor.getIndexInterval() * 3 / ROWS_PER_SSTABLE;

        // disable compaction while flushing
        store.disableAutoCompaction();

        long maxTimestampExpected = Long.MIN_VALUE;
        Set<DecoratedKey> inserted = new HashSet<DecoratedKey>();
        for (int j = 0; j < SSTABLES; j++) {
            for (int i = 0; i < ROWS_PER_SSTABLE; i++) {
                DecoratedKey key = Util.dk(String.valueOf(i % 2));
                RowMutation rm = new RowMutation(TABLE1, key.key);
                long timestamp = j * ROWS_PER_SSTABLE + i;
                rm.add(new QueryPath("Standard1", null, ByteBufferUtil.bytes(String.valueOf(i / 2))),
                       ByteBufferUtil.EMPTY_BYTE_BUFFER,
                       timestamp);
                maxTimestampExpected = Math.max(timestamp, maxTimestampExpected);
                rm.apply();
                inserted.add(key);
            }
            store.forceBlockingFlush();
            assertMaxTimestamp(store, maxTimestampExpected);
            assertEquals(inserted.toString(), inserted.size(), Util.getRangeSlice(store).size());
        }

        forceCompactions(store);

        assertEquals(inserted.size(), Util.getRangeSlice(store).size());

        // make sure max timestamp of compacted sstables is recorded properly after compaction.
        assertMaxTimestamp(store, maxTimestampExpected);
    }


    @Test
    public void testSuperColumnCompactions() throws IOException, ExecutionException, InterruptedException
    {
        Table table = Table.open(TABLE1);
        ColumnFamilyStore store = table.getColumnFamilyStore("Super1");

        final int ROWS_PER_SSTABLE = 10;
        final int SSTABLES = DatabaseDescriptor.getIndexInterval() * 3 / ROWS_PER_SSTABLE;

        //disable compaction while flushing
        store.disableAutoCompaction();

        long maxTimestampExpected = Long.MIN_VALUE;
        Set<DecoratedKey> inserted = new HashSet<DecoratedKey>();
        ByteBuffer superColumn = ByteBufferUtil.bytes("TestSuperColumn");
        for (int j = 0; j < SSTABLES; j++)
        {
            for (int i = 0; i < ROWS_PER_SSTABLE; i++)
            {
                DecoratedKey key = Util.dk(String.valueOf(i % 2));
                RowMutation rm = new RowMutation(TABLE1, key.key);
                long timestamp = j * ROWS_PER_SSTABLE + i;
                rm.add(new QueryPath("Super1", superColumn, ByteBufferUtil.bytes((long)(i / 2))),
                       ByteBufferUtil.EMPTY_BYTE_BUFFER,
                       timestamp);
                maxTimestampExpected = Math.max(timestamp, maxTimestampExpected);
                rm.apply();
                inserted.add(key);
            }
            store.forceBlockingFlush();
            assertMaxTimestamp(store, maxTimestampExpected);
            assertEquals(inserted.toString(), inserted.size(), Util.getRangeSlice(store, superColumn).size());
        }

        forceCompactions(store);

        assertEquals(inserted.size(), Util.getRangeSlice(store, superColumn).size());

        // make sure max timestamp of compacted sstables is recorded properly after compaction.
        assertMaxTimestamp(store, maxTimestampExpected);
    }

    public void assertMaxTimestamp(ColumnFamilyStore store, long maxTimestampExpected)
    {
        long maxTimestampObserved = Long.MIN_VALUE;
        for (SSTableReader sstable : store.getSSTables())
            maxTimestampObserved = Math.max(sstable.getMaxTimestamp(), maxTimestampObserved);
        assertEquals(maxTimestampExpected, maxTimestampObserved);
    }

    private void forceCompactions(ColumnFamilyStore store) throws ExecutionException, InterruptedException
    {
        // re-enable compaction with thresholds low enough to force a few rounds
        store.setMinimumCompactionThreshold(2);
        store.setMaximumCompactionThreshold(4);

        // loop submitting parallel compactions until they all return 0
        while (true)
        {
            ArrayList<Future<Integer>> compactions = new ArrayList<Future<Integer>>();
            for (int i = 0; i < 10; i++)
                compactions.add(CompactionManager.instance.submitBackground(store));
            // another compaction attempt will be launched in the background by
            // each completing compaction: not much we can do to control them here
            boolean progress = false;
            for (Future<Integer> compaction : compactions)
               if (compaction.get() > 0)
                   progress = true;
            if (!progress)
                break;
        }
        if (store.getSSTables().size() > 1)
        {
            CompactionManager.instance.performMaximal(store);
        }
    }

    @Test
    public void testEchoedRow() throws IOException, ExecutionException, InterruptedException
    {
        // This test check that EchoedRow doesn't skipp rows: see CASSANDRA-2653

        Table table = Table.open(TABLE1);
        ColumnFamilyStore store = table.getColumnFamilyStore("Standard2");

        // disable compaction while flushing
        store.disableAutoCompaction();

        // Insert 4 keys in two sstables. We need the sstables to have 2 rows
        // at least to trigger what was causing CASSANDRA-2653
        for (int i=1; i < 5; i++)
        {
            DecoratedKey key = Util.dk(String.valueOf(i));
            RowMutation rm = new RowMutation(TABLE1, key.key);
            rm.add(new QueryPath("Standard2", null, ByteBufferUtil.bytes(String.valueOf(i))), ByteBufferUtil.EMPTY_BYTE_BUFFER, i);
            rm.apply();

            if (i % 2 == 0)
                store.forceBlockingFlush();
        }
        Collection<SSTableReader> toCompact = store.getSSTables();
        assert toCompact.size() == 2;

        // Reinserting the same keys. We will compact only the previous sstable, but we need those new ones
        // to make sure we use EchoedRow, otherwise it won't be used because purge can be done.
        for (int i=1; i < 5; i++)
        {
            DecoratedKey key = Util.dk(String.valueOf(i));
            RowMutation rm = new RowMutation(TABLE1, key.key);
            rm.add(new QueryPath("Standard2", null, ByteBufferUtil.bytes(String.valueOf(i))), ByteBufferUtil.EMPTY_BYTE_BUFFER, i);
            rm.apply();
        }
        store.forceBlockingFlush();
        SSTableReader tmpSSTable = null;
        for (SSTableReader sstable : store.getSSTables())
            if (!toCompact.contains(sstable))
                tmpSSTable = sstable;
        assert tmpSSTable != null;

        // Force compaction on first sstables. Since each row is in only one sstable, we will be using EchoedRow.
        Util.compact(store, toCompact, false);
        assertEquals(2, store.getSSTables().size());

        // Now, we remove the sstable that was just created to force the use of EchoedRow (so that it doesn't hide the problem)
        store.markCompacted(Collections.singleton(tmpSSTable), OperationType.UNKNOWN);
        assertEquals(1, store.getSSTables().size());

        // Now assert we do have the 4 keys
        assertEquals(4, Util.getRangeSlice(store).size());
    }

    @Test
    public void testDontPurgeAccidentaly() throws IOException, ExecutionException, InterruptedException
    {
        // Testing with and without forcing deserialization. Without deserialization, EchoedRow will be used.
        testDontPurgeAccidentaly("test1", "Super5", false);
        testDontPurgeAccidentaly("test2", "Super5", true);

        // Use CF with gc_grace=0, see last bug of CASSANDRA-2786
        testDontPurgeAccidentaly("test1", "SuperDirectGC", false);
        testDontPurgeAccidentaly("test2", "SuperDirectGC", true);
    }

    private void testDontPurgeAccidentaly(String k, String cfname, boolean forceDeserialize) throws IOException, ExecutionException, InterruptedException
    {
        // This test catches the regression of CASSANDRA-2786
        Table table = Table.open(TABLE1);
        ColumnFamilyStore store = table.getColumnFamilyStore(cfname);

        // disable compaction while flushing
        store.clearUnsafe();
        store.disableAutoCompaction();

        // Add test row
        DecoratedKey key = Util.dk(k);
        RowMutation rm = new RowMutation(TABLE1, key.key);
        rm.add(new QueryPath(cfname, ByteBufferUtil.bytes("sc"), ByteBufferUtil.bytes("c")), ByteBufferUtil.EMPTY_BYTE_BUFFER, 0);
        rm.apply();

        store.forceBlockingFlush();

        Collection<SSTableReader> sstablesBefore = store.getSSTables();

        QueryFilter filter = QueryFilter.getIdentityFilter(key, new QueryPath(cfname, null, null));
        assert !store.getColumnFamily(filter).isEmpty();

        // Remove key
        rm = new RowMutation(TABLE1, key.key);
        rm.delete(new QueryPath(cfname, null, null), 2);
        rm.apply();

        ColumnFamily cf = store.getColumnFamily(filter);
        assert cf == null || cf.isEmpty() : "should be empty: " + cf;

        store.forceBlockingFlush();

        Collection<SSTableReader> sstablesAfter = store.getSSTables();
        Collection<SSTableReader> toCompact = new ArrayList<SSTableReader>();
        for (SSTableReader sstable : sstablesAfter)
            if (!sstablesBefore.contains(sstable))
                toCompact.add(sstable);

        Util.compact(store, toCompact, forceDeserialize);

        cf = store.getColumnFamily(filter);
        assert cf == null || cf.isEmpty() : "should be empty: " + cf;
    }
}
