/**
 * Copyright 2011 Steve Coughlan.
 *
 * 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 com.google.bitcoin.core;

import com.google.bitcoin.params.MainNetParams;
import com.google.bitcoin.params.UnitTestParams;
import com.google.bitcoin.store.BlockStore;
import com.google.bitcoin.store.MemoryBlockStore;
import org.junit.Before;
import org.junit.Test;
import org.spongycastle.util.encoders.Hex;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Arrays;

import static com.google.bitcoin.core.TestUtils.createFakeBlock;
import static com.google.bitcoin.core.TestUtils.createFakeTx;
import static org.junit.Assert.*;

public class LazyParseByteCacheTest {

    private final byte[] txMessage = Hex.decode(
            "F9 BE B4 D9 74 78 00 00  00 00 00 00 00 00 00 00" +
            "02 01 00 00 E2 93 CD BE  01 00 00 00 01 6D BD DB" +
            "08 5B 1D 8A F7 51 84 F0  BC 01 FA D5 8D 12 66 E9" +
            "B6 3B 50 88 19 90 E4 B4  0D 6A EE 36 29 00 00 00" +
            "00 8B 48 30 45 02 21 00  F3 58 1E 19 72 AE 8A C7" +
            "C7 36 7A 7A 25 3B C1 13  52 23 AD B9 A4 68 BB 3A" +
            "59 23 3F 45 BC 57 83 80  02 20 59 AF 01 CA 17 D0" +
            "0E 41 83 7A 1D 58 E9 7A  A3 1B AE 58 4E DE C2 8D" +
            "35 BD 96 92 36 90 91 3B  AE 9A 01 41 04 9C 02 BF" +
            "C9 7E F2 36 CE 6D 8F E5  D9 40 13 C7 21 E9 15 98" +
            "2A CD 2B 12 B6 5D 9B 7D  59 E2 0A 84 20 05 F8 FC" +
            "4E 02 53 2E 87 3D 37 B9  6F 09 D6 D4 51 1A DA 8F" +
            "14 04 2F 46 61 4A 4C 70  C0 F1 4B EF F5 FF FF FF" +
            "FF 02 40 4B 4C 00 00 00  00 00 19 76 A9 14 1A A0" +
            "CD 1C BE A6 E7 45 8A 7A  BA D5 12 A9 D9 EA 1A FB" +
            "22 5E 88 AC 80 FA E9 C7  00 00 00 00 19 76 A9 14" +
            "0E AB 5B EA 43 6A 04 84  CF AB 12 48 5E FD A0 B7" +
            "8B 4E CC 52 88 AC 00 00  00 00");
    
    private final byte[] txMessagePart = Hex.decode(
            "08 5B 1D 8A F7 51 84 F0  BC 01 FA D5 8D 12 66 E9" +
            "B6 3B 50 88 19 90 E4 B4  0D 6A EE 36 29 00 00 00" +
            "00 8B 48 30 45 02 21 00  F3 58 1E 19 72 AE 8A C7" +
            "C7 36 7A 7A 25 3B C1 13  52 23 AD B9 A4 68 BB 3A");
    
    private Wallet wallet;
    private BlockStore blockStore;
    private NetworkParameters unitTestParams;
    
    private byte[] b1Bytes;
    private byte[] b1BytesWithHeader;
    
    private byte[] tx1Bytes;
    private byte[] tx1BytesWithHeader;
    
    private byte[] tx2Bytes;
    private byte[] tx2BytesWithHeader;
    
    private void resetBlockStore() {
        blockStore = new MemoryBlockStore(unitTestParams);
    }
    
    @Before
    public void setUp() throws Exception {
        unitTestParams = UnitTestParams.get();
        wallet = new Wallet(unitTestParams);
        wallet.addKey(new ECKey());

        resetBlockStore();
        
        Transaction tx1 = createFakeTx(unitTestParams,
        		Utils.toNanoCoins(2, 0),
        		wallet.getKeys().get(0).toAddress(unitTestParams));
        
        //add a second input so can test granularity of byte cache.
        Transaction prevTx = new Transaction(unitTestParams);
        TransactionOutput prevOut = new TransactionOutput(unitTestParams, prevTx, Utils.toNanoCoins(1, 0), wallet.getKeys().get(0).toAddress(unitTestParams));
        prevTx.addOutput(prevOut);
        // Connect it.
        tx1.addInput(prevOut);
        
        Transaction tx2 = createFakeTx(unitTestParams, Utils.toNanoCoins(1, 0),
                new ECKey().toAddress(unitTestParams));

        Block b1 = createFakeBlock(blockStore, tx1, tx2).block;

        BitcoinSerializer bs = new BitcoinSerializer(unitTestParams);
        
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        bs.serialize(tx1, bos);
        tx1BytesWithHeader = bos.toByteArray();
        tx1Bytes = tx1.bitcoinSerialize();
        
        bos.reset();
        bs.serialize(tx2, bos);
        tx2BytesWithHeader = bos.toByteArray();
        tx2Bytes = tx2.bitcoinSerialize();
        
        bos.reset();
        bs.serialize(b1, bos);
        b1BytesWithHeader = bos.toByteArray();
        b1Bytes = b1.bitcoinSerialize();
    }
    
    @Test
    public void validateSetup() {
    	byte[] b1 = new byte[] {1, 1, 1, 2, 3, 4, 5, 6, 7};
    	byte[] b2 = new byte[] {1, 2, 3};
    	assertTrue(arrayContains(b1, b2));
    	assertTrue(arrayContains(txMessage, txMessagePart));
    	assertTrue(arrayContains(tx1BytesWithHeader, tx1Bytes));
    	assertTrue(arrayContains(tx2BytesWithHeader, tx2Bytes));
    	assertTrue(arrayContains(b1BytesWithHeader, b1Bytes));
    	assertTrue(arrayContains(b1BytesWithHeader, tx1Bytes));
    	assertTrue(arrayContains(b1BytesWithHeader, tx2Bytes));
    	assertFalse(arrayContains(tx1BytesWithHeader, b1Bytes));
    }
    
    @Test
    public void testTransactionsLazyRetain() throws Exception {
    	testTransaction(MainNetParams.get(), txMessage, false, true, true);
    	testTransaction(unitTestParams, tx1BytesWithHeader, false, true, true);
    	testTransaction(unitTestParams, tx2BytesWithHeader, false, true, true);
    }
    
    @Test
    public void testTransactionsLazyNoRetain() throws Exception {
    	testTransaction(MainNetParams.get(), txMessage, false, true, false);
    	testTransaction(unitTestParams, tx1BytesWithHeader, false, true, false);
    	testTransaction(unitTestParams, tx2BytesWithHeader, false, true, false);
    }
    
    @Test
    public void testTransactionsNoLazyNoRetain() throws Exception {
    	testTransaction(MainNetParams.get(), txMessage, false, false, false);
    	testTransaction(unitTestParams, tx1BytesWithHeader, false, false, false);
    	testTransaction(unitTestParams, tx2BytesWithHeader, false, false, false);
    }
    
    @Test
    public void testTransactionsNoLazyRetain() throws Exception {
    	testTransaction(MainNetParams.get(), txMessage, false, false, true);
    	testTransaction(unitTestParams, tx1BytesWithHeader, false, false, true);
    	testTransaction(unitTestParams, tx2BytesWithHeader, false, false, true);
    }
    
    @Test
    public void testBlockAll() throws Exception {
    	testBlock(b1BytesWithHeader, false, false, false);
    	testBlock(b1BytesWithHeader, false, true, true);
    	testBlock(b1BytesWithHeader, false, true, false);
    	testBlock(b1BytesWithHeader, false, false, true);
    }
    
    
    public void testBlock(byte[] blockBytes, boolean isChild, boolean lazy, boolean retain) throws Exception {
    	//reference serializer to produce comparison serialization output after changes to
    	//message structure.
    	BitcoinSerializer bsRef = new BitcoinSerializer(unitTestParams, false, false);
    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
    	
    	BitcoinSerializer bs = new BitcoinSerializer(unitTestParams, lazy, retain);
    	Block b1;
    	Block bRef;
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//verify our reference BitcoinSerializer produces matching byte array.
    	bos.reset();
    	bsRef.serialize(bRef, bos);
    	assertTrue(Arrays.equals(bos.toByteArray(), blockBytes));
    	
    	//check lazy and retain status survive both before and after a serialization
    	assertEquals(!lazy, b1.isParsedTransactions());
    	assertEquals(!lazy, b1.isParsedHeader());
    	if (b1.isParsedHeader())
    		assertEquals(retain, b1.isHeaderBytesValid());
    	if (b1.isParsedTransactions())
    		assertEquals(retain, b1.isTransactionBytesValid());
    	
    	serDeser(bs, b1, blockBytes, null, null);
    	
    	assertEquals(!lazy, b1.isParsedTransactions());
    	assertEquals(!lazy, b1.isParsedHeader());
    	if (b1.isParsedHeader())
    		assertEquals(retain, b1.isHeaderBytesValid());
    	if (b1.isParsedTransactions())
    		assertEquals(retain, b1.isTransactionBytesValid());
    	
    	//compare to ref block
    	bos.reset();
		bsRef.serialize(bRef, bos);
		serDeser(bs, b1, bos.toByteArray(), null, null);
		
    	//retrieve a value from a child
		b1.getTransactions();
    	assertTrue(b1.isParsedTransactions());
    	if (b1.getTransactions().size() > 0) {
    		assertTrue(b1.isParsedTransactions());
    		Transaction tx1 = b1.getTransactions().get(0);
    		
    		//this will always be true for all children of a block once they are retrieved.
    		//the tx child inputs/outputs may not be parsed however.
    		
    		//no longer forced to parse if length not provided.
    		//assertEquals(true, tx1.isParsed());
        	if (tx1.isParsed())
        		assertEquals(retain, tx1.isCached());
        	else
        		assertTrue(tx1.isCached());
        	
        	//does it still match ref block?
        	serDeser(bs, b1, bos.toByteArray(), null, null);
        }
    	
    	//refresh block
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//retrieve a value from header
    	b1.getDifficultyTarget();
		assertTrue(b1.isParsedHeader());
		assertEquals(lazy, !b1.isParsedTransactions());
    	
		//does it still match ref block?
		serDeser(bs, b1, bos.toByteArray(), null, null);

    	
		//refresh block
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//retrieve a value from a child and header
    	b1.getDifficultyTarget();
    	assertTrue(b1.isParsedHeader());
    	assertEquals(lazy, !b1.isParsedTransactions());
    	
    	b1.getTransactions();
    	assertTrue(b1.isParsedTransactions());
    	if (b1.getTransactions().size() > 0) {
    		assertTrue(b1.isParsedTransactions());
    		Transaction tx1 = b1.getTransactions().get(0);
    		
    		//no longer forced to parse if length not provided.
    		//assertEquals(true, tx1.isParsed());
        	
        	if (tx1.isParsed())
        		assertEquals(retain, tx1.isCached());
        	else
        		assertTrue(tx1.isCached());	
        }
    	//does it still match ref block?
    	serDeser(bs, b1, bos.toByteArray(), null, null);
    	
    	//refresh block
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//change a value in header
    	b1.setNonce(23);
    	bRef.setNonce(23);
    	assertTrue(b1.isParsedHeader());
    	assertEquals(lazy, !b1.isParsedTransactions());
    	assertFalse(b1.isHeaderBytesValid());
    	if (b1.isParsedTransactions())
    		assertEquals(retain , b1.isTransactionBytesValid());
    	else
    		assertEquals(true, b1.isTransactionBytesValid());
    	//does it still match ref block?
    	bos.reset();
		bsRef.serialize(bRef, bos);
		serDeser(bs, b1, bos.toByteArray(), null, null);
    	
    	//refresh block
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//retrieve a value from a child of a child
		b1.getTransactions();
    	if (b1.getTransactions().size() > 0) {
    		Transaction tx1 = b1.getTransactions().get(0);
    		
    		TransactionInput tin = tx1.getInputs().get(0);
    		
    		assertTrue(tx1.isParsed());
    		assertTrue(b1.isParsedTransactions());
    		assertEquals(!lazy, b1.isParsedHeader());
    		
    		assertEquals(!lazy, tin.isParsed());
        	assertEquals(tin.isParsed() ? retain : true, tin.isCached());	
        	
        	//does it still match ref tx?
        	bos.reset();
        	bsRef.serialize(bRef, bos);
        	serDeser(bs, b1, bos.toByteArray(), null, null);
        }
    	
    	//refresh block
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//add an input
		b1.getTransactions();
    	if (b1.getTransactions().size() > 0) {
    		Transaction tx1 = b1.getTransactions().get(0);
    		
        	if (tx1.getInputs().size() > 0) {
        		tx1.addInput(tx1.getInputs().get(0));
        		//replicate on reference tx
        		bRef.getTransactions().get(0).addInput(bRef.getTransactions().get(0).getInputs().get(0));
        		
        		assertFalse(tx1.isCached());
        		assertTrue(tx1.isParsed());
        		assertFalse(b1.isTransactionBytesValid());
        		assertTrue(b1.isParsedHeader());
        		
        		//confirm sibling cache status was unaffected
        		if (tx1.getInputs().size() > 1) {
        			boolean parsed = tx1.getInputs().get(1).isParsed();
        			assertEquals(parsed ? retain : true, tx1.getInputs().get(1).isCached());
        			assertEquals(!lazy, parsed);
        		}
        		
        		//this has to be false. Altering a tx invalidates the merkle root.
        		//when we have seperate merkle caching then the entire header won't need to be
        		//invalidated.
        		assertFalse(b1.isHeaderBytesValid());
        		
        		bos.reset();
        		bsRef.serialize(bRef, bos);
        		byte[] source = bos.toByteArray();
        		//confirm we still match the reference tx.
        		serDeser(bs, b1, source, null, null);
        	}
    		
    		//does it still match ref tx?
        	bos.reset();
        	bsRef.serialize(bRef, bos);
        	serDeser(bs, b1, bos.toByteArray(), null, null);
        }
    	
    	//refresh block
    	b1 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	Block b2 = (Block) bs.deserialize(new ByteArrayInputStream(blockBytes));
    	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	Block bRef2 = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
    	
    	//reparent an input
		b1.getTransactions();
    	if (b1.getTransactions().size() > 0) {
    		Transaction tx1 = b1.getTransactions().get(0);
    		Transaction tx2 = b2.getTransactions().get(0);
    		
        	if (tx1.getInputs().size() > 0) {
        		TransactionInput fromTx1 = tx1.getInputs().get(0);
        		tx2.addInput(fromTx1);
        		
        		//replicate on reference tx
        		TransactionInput fromTxRef = bRef.getTransactions().get(0).getInputs().get(0);
        		bRef2.getTransactions().get(0).addInput(fromTxRef);
        		
        		//b1 hasn't changed but it's no longer in the parent
        		//chain of fromTx1 so has to have been uncached since it won't be
        		//notified of changes throught the parent chain anymore.
        		assertFalse(b1.isTransactionBytesValid());
        		
        		//b2 should have it's cache invalidated because it has changed.
        		assertFalse(b2.isTransactionBytesValid());
        		
        		bos.reset();
        		bsRef.serialize(bRef2, bos);
        		byte[] source = bos.toByteArray();
        		//confirm altered block matches altered ref block.
        		serDeser(bs, b2, source, null, null);
        	}
    		
    		//does unaltered block still match ref block?
        	bos.reset();
        	bsRef.serialize(bRef, bos);
        	serDeser(bs, b1, bos.toByteArray(), null, null);
        	
    		//how about if we refresh it?
        	bRef = (Block) bsRef.deserialize(new ByteArrayInputStream(blockBytes));
        	bos.reset();
        	bsRef.serialize(bRef, bos);
        	serDeser(bs, b1, bos.toByteArray(), null, null);
        }
    	
    }
    
    public void testTransaction(NetworkParameters params, byte[] txBytes, boolean isChild, boolean lazy, boolean retain) throws Exception {
        	
    	//reference serializer to produce comparison serialization output after changes to
    	//message structure.
    	BitcoinSerializer bsRef = new BitcoinSerializer(params, false, false);
    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
    	
    	BitcoinSerializer bs = new BitcoinSerializer(params, lazy, retain);
    	Transaction t1;
    	Transaction tRef;
    	t1 = (Transaction) bs.deserialize(new ByteArrayInputStream(txBytes));
    	tRef = (Transaction) bsRef.deserialize(new ByteArrayInputStream(txBytes));
    	
    	//verify our reference BitcoinSerializer produces matching byte array.
    	bos.reset();
    	bsRef.serialize(tRef, bos);
    	assertTrue(Arrays.equals(bos.toByteArray(), txBytes));
    	
    	//check lazy and retain status survive both before and after a serialization
    	assertEquals(!lazy, t1.isParsed());
    	if (t1.isParsed())
    		assertEquals(retain, t1.isCached());
    	
    	serDeser(bs, t1, txBytes, null, null);
    	
    	assertEquals(lazy, !t1.isParsed());
    	if (t1.isParsed())
    		assertEquals(retain, t1.isCached());
    	
    	//compare to ref tx
    	bos.reset();
		bsRef.serialize(tRef, bos);
		serDeser(bs, t1, bos.toByteArray(), null, null);
    	
    	//retrieve a value from a child
    	t1.getInputs();
    	assertTrue(t1.isParsed());
    	if (t1.getInputs().size() > 0) {
    		assertTrue(t1.isParsed());
    		TransactionInput tin = t1.getInputs().get(0);
    		assertEquals(!lazy, tin.isParsed());
    		if (tin.isParsed())
    			assertEquals(retain, tin.isCached());	
        	
        	//does it still match ref tx?
        	serDeser(bs, t1, bos.toByteArray(), null, null);
    	}
    	
    	//refresh tx
    	t1 = (Transaction) bs.deserialize(new ByteArrayInputStream(txBytes));
    	tRef = (Transaction) bsRef.deserialize(new ByteArrayInputStream(txBytes));
    	
    	//add an input
    	if (t1.getInputs().size() > 0) {
    		
    		t1.addInput(t1.getInputs().get(0));
    		
    		//replicate on reference tx
    		tRef.addInput(tRef.getInputs().get(0));
    		
    		assertFalse(t1.isCached());
    		assertTrue(t1.isParsed());
    		
    		bos.reset();
    		bsRef.serialize(tRef, bos);
    		byte[] source = bos.toByteArray();
    		//confirm we still match the reference tx.
    		serDeser(bs, t1, source, null, null);
    	}
    	
    }
    
    private void serDeser(BitcoinSerializer bs, Message message, byte[] sourceBytes, byte[] containedBytes, byte[] containingBytes) throws Exception {
    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
    	bs.serialize(message, bos);
    	byte[] b1 = bos.toByteArray();
    	
    	Message m2 = bs.deserialize(new ByteArrayInputStream(b1));

		assertEquals(message, m2);
 
    	bos.reset();
    	bs.serialize(m2, bos);
    	byte[] b2 = bos.toByteArray(); 
    	assertTrue(Arrays.equals(b1, b2));
    	
    	if (sourceBytes != null) {
    		assertTrue(arrayContains(sourceBytes, b1));
    		
    		assertTrue(arrayContains(sourceBytes, b2));
    	}
    	
    	if (containedBytes != null) {
    		assertTrue(arrayContains(b1, containedBytes));
    	}
    	if (containingBytes != null) {
    		assertTrue(arrayContains(containingBytes, b1));
    	}
    }
    
    public static boolean arrayContains(byte[] sup, byte[] sub) {
    	if (sup.length < sub.length)
    		return false;   	
    	
    	String superstring = Utils.bytesToHexString(sup);
    	String substring = Utils.bytesToHexString(sub);
    	
    	int ind = superstring.indexOf(substring);
    	
    	StringBuilder sb = new StringBuilder();
    	for (int i = 0; i < superstring.indexOf(substring); i++)
        	sb.append(" ");
    	
    	//System.out.println(superstring);
    	//System.out.println(sb.append(substring).toString());
    	//System.out.println();
    	return ind > -1;
    	
    }
}
