thehub/libs/server/rpcblockchain.cpp

/*
 * This file is part of the Flowee project
 * Copyright (C) 2010 Satoshi Nakamoto
 * Copyright (C) 2009-2015 The Bitcoin Core developers
 * Copyright (C) 2018-2020 Tom Zander <tomz@freedommail.ch>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "amount.h"
#include "SettingsDefaults.h"
#include "chain.h"
#include "chainparams.h"
#include "checkpoints.h"
#include "consensus/validation.h"
#include "main.h"
#include "policy/policy.h"
#include "primitives/transaction.h"
#include "primitives/FastBlock.h"
#include "rpcserver.h"
#include "streaming/streams.h"
#include "sync.h"
#include "txmempool.h"
#include "BlocksDB.h"
#include "timedata.h"
#include "util.h"
#include "utilstrencodings.h"
#include "UnspentOutputData.h"
#include "primitives/block.h"
#include <Application.h>
#include <validation/Engine.h>
#include <validation/VerifyDB.h>

#include <boost/foreach.hpp>

extern void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry);
void ScriptPubKeyToJSON(const CScript& scriptPubKey, UniValue& out, bool fIncludeHex);

double GetDifficulty(const CBlockIndex* blockindex)
{
    // Floating point number that is a multiple of the minimum difficulty,
    // minimum difficulty = 1.0.
    if (blockindex == NULL)
    {
        if (chainActive.Tip() == NULL)
            return 1.0;
        else
            blockindex = chainActive.Tip();
    }

    int nShift = (blockindex->nBits >> 24) & 0xff;

    double dDiff =
        (double)0x0000ffff / (double)(blockindex->nBits & 0x00ffffff);

    while (nShift < 29)
    {
        dDiff *= 256.0;
        nShift++;
    }
    while (nShift > 29)
    {
        dDiff /= 256.0;
        nShift--;
    }

    return dDiff;
}

UniValue blockheaderToJSON(const CBlockIndex* blockindex)
{
    UniValue result(UniValue::VOBJ);
    result.push_back(Pair("hash", blockindex->GetBlockHash().GetHex()));
    int confirmations = -1;
    // Only report confirmations if the block is on the main chain
    if (chainActive.Contains(blockindex))
        confirmations = chainActive.Height() - blockindex->nHeight + 1;
    result.push_back(Pair("confirmations", confirmations));
    result.push_back(Pair("height", blockindex->nHeight));
    result.push_back(Pair("version", blockindex->nVersion));
    result.push_back(Pair("merkleroot", blockindex->hashMerkleRoot.GetHex()));
    result.push_back(Pair("time", (int64_t)blockindex->nTime));
    result.push_back(Pair("mediantime", (int64_t)blockindex->GetMedianTimePast()));
    result.push_back(Pair("nonce", (uint64_t)blockindex->nNonce));
    result.push_back(Pair("bits", strprintf("%08x", blockindex->nBits)));
    result.push_back(Pair("difficulty", GetDifficulty(blockindex)));
    result.push_back(Pair("chainwork", blockindex->nChainWork.GetHex()));

    if (blockindex->pprev)
        result.push_back(Pair("previousblockhash", blockindex->pprev->GetBlockHash().GetHex()));
    CBlockIndex *pnext = chainActive.Next(blockindex);
    if (pnext)
        result.push_back(Pair("nextblockhash", pnext->GetBlockHash().GetHex()));
    return result;
}

UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails = false)
{
    UniValue result(UniValue::VOBJ);
    result.push_back(Pair("hash", block.GetHash().GetHex()));
    int confirmations = -1;
    // Only report confirmations if the block is on the main chain
    if (chainActive.Contains(blockindex))
        confirmations = chainActive.Height() - blockindex->nHeight + 1;
    result.push_back(Pair("confirmations", confirmations));
    result.push_back(Pair("size", (int)::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION)));
    result.push_back(Pair("height", blockindex->nHeight));
    result.push_back(Pair("version", block.nVersion));
    result.push_back(Pair("merkleroot", block.hashMerkleRoot.GetHex()));
    UniValue txs(UniValue::VARR);
    BOOST_FOREACH(const CTransaction&tx, block.vtx)
    {
        if(txDetails)
        {
            UniValue objTx(UniValue::VOBJ);
            TxToJSON(tx, uint256(), objTx);
            txs.push_back(objTx);
        }
        else
            txs.push_back(tx.GetHash().GetHex());
    }
    result.push_back(Pair("tx", txs));
    result.push_back(Pair("time", block.GetBlockTime()));
    result.push_back(Pair("mediantime", (int64_t)blockindex->GetMedianTimePast()));
    result.push_back(Pair("nonce", (uint64_t)block.nNonce));
    result.push_back(Pair("bits", strprintf("%08x", block.nBits)));
    result.push_back(Pair("difficulty", GetDifficulty(blockindex)));
    result.push_back(Pair("chainwork", blockindex->nChainWork.GetHex()));

    if (blockindex->pprev)
        result.push_back(Pair("previousblockhash", blockindex->pprev->GetBlockHash().GetHex()));
    CBlockIndex *pnext = chainActive.Next(blockindex);
    if (pnext)
        result.push_back(Pair("nextblockhash", pnext->GetBlockHash().GetHex()));
    return result;
}

UniValue getblockcount(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "getblockcount\n"
            "\nReturns the number of blocks in the longest block chain.\n"
            "\nResult:\n"
            "n    (numeric) The current block count\n"
            "\nExamples:\n"
            + HelpExampleCli("getblockcount", "")
            + HelpExampleRpc("getblockcount", "")
        );

    LOCK(cs_main);
    return chainActive.Height();
}

UniValue getbestblockhash(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "getbestblockhash\n"
            "\nReturns the hash of the best (tip) block in the longest block chain.\n"
            "\nResult\n"
            "\"hex\"      (string) the block hash hex encoded\n"
            "\nExamples\n"
            + HelpExampleCli("getbestblockhash", "")
            + HelpExampleRpc("getbestblockhash", "")
        );

    LOCK(cs_main);
    return chainActive.Tip()->GetBlockHash().GetHex();
}

UniValue getdifficulty(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "getdifficulty\n"
            "\nReturns the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
            "\nResult:\n"
            "n.nnn       (numeric) the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
            "\nExamples:\n"
            + HelpExampleCli("getdifficulty", "")
            + HelpExampleRpc("getdifficulty", "")
        );

    LOCK(cs_main);
    return GetDifficulty();
}

UniValue mempoolToJSON(bool fVerbose = false)
{
    if (fVerbose)
    {
        LOCK(mempool.cs);
        UniValue o(UniValue::VOBJ);
        BOOST_FOREACH(const CTxMemPoolEntry& e, mempool.mapTx)
        {
            const uint256& hash = e.GetTx().GetHash();
            UniValue info(UniValue::VOBJ);
            info.push_back(Pair("size", (int)e.GetTxSize()));
            info.push_back(Pair("fee", ValueFromAmount(e.GetFee())));
            info.push_back(Pair("modifiedfee", ValueFromAmount(e.GetModifiedFee())));
            info.push_back(Pair("time", e.GetTime()));
            info.push_back(Pair("height", (int)e.GetHeight()));
            info.push_back(Pair("startingpriority", e.GetPriority(e.GetHeight())));
            info.push_back(Pair("currentpriority", e.GetPriority(chainActive.Height())));
            info.push_back(Pair("descendantcount", e.GetCountWithDescendants()));
            info.push_back(Pair("descendantsize", e.GetSizeWithDescendants()));
            info.push_back(Pair("descendantfees", e.GetModFeesWithDescendants()));
            const CTransaction& tx = e.GetTx();
            std::set<std::string> setDepends;
            BOOST_FOREACH(const CTxIn& txin, tx.vin)
            {
                if (mempool.exists(txin.prevout.hash))
                    setDepends.insert(txin.prevout.hash.ToString());
            }

            UniValue depends(UniValue::VARR);
            BOOST_FOREACH(const std::string& dep, setDepends)
            {
                depends.push_back(dep);
            }

            info.push_back(Pair("depends", depends));
            o.push_back(Pair(hash.ToString(), info));
        }
        return o;
    }
    else
    {
        std::vector<uint256> vtxid;
        mempool.queryHashes(vtxid);

        UniValue a(UniValue::VARR);
        BOOST_FOREACH(const uint256& hash, vtxid)
            a.push_back(hash.ToString());

        return a;
    }
}

UniValue getrawmempool(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() > 1)
        throw std::runtime_error(
            "getrawmempool ( verbose )\n"
            "\nReturns all transaction ids in memory pool as a json array of string transaction ids.\n"
            "\nArguments:\n"
            "1. verbose           (boolean, optional, default=false) true for a json object, false for array of transaction ids\n"
            "\nResult: (for verbose = false):\n"
            "[                     (json array of string)\n"
            "  \"transactionid\"     (string) The transaction id\n"
            "  ,...\n"
            "]\n"
            "\nResult: (for verbose = true):\n"
            "{                           (json object)\n"
            "  \"transactionid\" : {       (json object)\n"
            "    \"size\" : n,             (numeric) transaction size in bytes\n"
            "    \"fee\" : n,              (numeric) transaction fee in " + CURRENCY_UNIT + "\n"
            "    \"modifiedfee\" : n,      (numeric) transaction fee with fee deltas used for mining priority\n"
            "    \"time\" : n,             (numeric) local time transaction entered pool in seconds since 1 Jan 1970 GMT\n"
            "    \"height\" : n,           (numeric) block height when transaction entered pool\n"
            "    \"startingpriority\" : n, (numeric) priority when transaction entered pool\n"
            "    \"currentpriority\" : n,  (numeric) transaction priority now\n"
            "    \"descendantcount\" : n,  (numeric) number of in-mempool descendant transactions (including this one)\n"
            "    \"descendantsize\" : n,   (numeric) size of in-mempool descendants (including this one)\n"
            "    \"descendantfees\" : n,   (numeric) modified fees (see above) of in-mempool descendants (including this one)\n"
            "    \"depends\" : [           (array) unconfirmed transactions used as inputs for this transaction\n"
            "        \"transactionid\",    (string) parent transaction id\n"
            "       ... ]\n"
            "  }, ...\n"
            "}\n"
            "\nExamples\n"
            + HelpExampleCli("getrawmempool", "true")
            + HelpExampleRpc("getrawmempool", "true")
        );

    LOCK(cs_main);

    bool fVerbose = false;
    if (params.size() > 0)
        fVerbose = params[0].get_bool();

    return mempoolToJSON(fVerbose);
}

UniValue getblockhash(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 1)
        throw std::runtime_error(
            "getblockhash index\n"
            "\nReturns hash of block in best-block-chain at index provided.\n"
            "\nArguments:\n"
            "1. index         (numeric, required) The block index\n"
            "\nResult:\n"
            "\"hash\"         (string) The block hash\n"
            "\nExamples:\n"
            + HelpExampleCli("getblockhash", "1000")
            + HelpExampleRpc("getblockhash", "1000")
        );

    LOCK(cs_main);

    int nHeight = params[0].get_int();
    if (nHeight < 0 || nHeight > chainActive.Height())
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Block height out of range");

    CBlockIndex* pblockindex = chainActive[nHeight];
    return pblockindex->GetBlockHash().GetHex();
}

UniValue getblockheader(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() < 1 || params.size() > 2)
        throw std::runtime_error(
            "getblockheader \"hash\" ( verbose )\n"
            "\nIf verbose is false, returns a string that is serialized, hex-encoded data for blockheader 'hash'.\n"
            "If verbose is true, returns an Object with information about blockheader <hash>.\n"
            "\nArguments:\n"
            "1. \"hash\"          (string, required) The block hash\n"
            "2. verbose           (boolean, optional, default=true) true for a json object, false for the hex encoded data\n"
            "\nResult (for verbose = true):\n"
            "{\n"
            "  \"hash\" : \"hash\",     (string) the block hash (same as provided)\n"
            "  \"confirmations\" : n,   (numeric) The number of confirmations, or -1 if the block is not on the main chain\n"
            "  \"height\" : n,          (numeric) The block height or index\n"
            "  \"version\" : n,         (numeric) The block version\n"
            "  \"merkleroot\" : \"xxxx\", (string) The merkle root\n"
            "  \"time\" : ttt,          (numeric) The block time in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"mediantime\" : ttt,    (numeric) The median block time in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"nonce\" : n,           (numeric) The nonce\n"
            "  \"bits\" : \"1d00ffff\", (string) The bits\n"
            "  \"difficulty\" : x.xxx,  (numeric) The difficulty\n"
            "  \"previousblockhash\" : \"hash\",  (string) The hash of the previous block\n"
            "  \"nextblockhash\" : \"hash\",      (string) The hash of the next block\n"
            "  \"chainwork\" : \"0000...1f3\"     (string) Expected number of hashes required to produce the current chain (in hex)\n"
            "}\n"
            "\nResult (for verbose=false):\n"
            "\"data\"             (string) A string that is serialized, hex-encoded data for block 'hash'.\n"
            "\nExamples:\n"
            + HelpExampleCli("getblockheader", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
            + HelpExampleRpc("getblockheader", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
        );

    LOCK(cs_main);

    std::string strHash = params[0].get_str();
    uint256 hash(uint256S(strHash));

    bool fVerbose = true;
    if (params.size() > 1)
        fVerbose = params[1].get_bool();

    CBlockIndex* pblockindex = Blocks::Index::get(hash);
    if (!pblockindex)
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");

    if (!fVerbose)
    {
        CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION);
        ssBlock << pblockindex->GetBlockHeader();
        std::string strHex = HexStr(ssBlock.begin(), ssBlock.end());
        return strHex;
    }

    return blockheaderToJSON(pblockindex);
}

UniValue getblock(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() < 1 || params.size() > 2)
        throw std::runtime_error(
            "getblock \"hash\" ( verbose )\n"
            "\nIf verbose is false, returns a string that is serialized, hex-encoded data for block 'hash'.\n"
            "If verbose is true, returns an Object with information about block <hash>.\n"
            "\nArguments:\n"
            "1. \"hash\"          (string, required) The block hash\n"
            "2. verbose           (boolean, optional, default=true) true for a json object, false for the hex encoded data\n"
            "\nResult (for verbose = true):\n"
            "{\n"
            "  \"hash\" : \"hash\",     (string) the block hash (same as provided)\n"
            "  \"confirmations\" : n,   (numeric) The number of confirmations, or -1 if the block is not on the main chain\n"
            "  \"size\" : n,            (numeric) The block size\n"
            "  \"height\" : n,          (numeric) The block height or index\n"
            "  \"version\" : n,         (numeric) The block version\n"
            "  \"merkleroot\" : \"xxxx\", (string) The merkle root\n"
            "  \"tx\" : [               (array of string) The transaction ids\n"
            "     \"transactionid\"     (string) The transaction id\n"
            "     ,...\n"
            "  ],\n"
            "  \"time\" : ttt,          (numeric) The block time in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"mediantime\" : ttt,    (numeric) The median block time in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"nonce\" : n,           (numeric) The nonce\n"
            "  \"bits\" : \"1d00ffff\", (string) The bits\n"
            "  \"difficulty\" : x.xxx,  (numeric) The difficulty\n"
            "  \"chainwork\" : \"xxxx\",  (string) Expected number of hashes required to produce the chain up to this block (in hex)\n"
            "  \"previousblockhash\" : \"hash\",  (string) The hash of the previous block\n"
            "  \"nextblockhash\" : \"hash\"       (string) The hash of the next block\n"
            "}\n"
            "\nResult (for verbose=false):\n"
            "\"data\"             (string) A string that is serialized, hex-encoded data for block 'hash'.\n"
            "\nExamples:\n"
            + HelpExampleCli("getblock", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
            + HelpExampleRpc("getblock", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
        );

    LOCK(cs_main);

    std::string strHash = params[0].get_str();
    uint256 hash(uint256S(strHash));

    bool fVerbose = true;
    if (params.size() > 1)
        fVerbose = params[1].get_bool();

    CBlockIndex* pblockindex = Blocks::Index::get(hash);
    if (!pblockindex)
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");

    CBlock block;
    if(!ReadBlockFromDisk(block, pblockindex, Params().GetConsensus()))
        throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");

    if (!fVerbose)
    {
        CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION);
        ssBlock << block;
        std::string strHex = HexStr(ssBlock.begin(), ssBlock.end());
        return strHex;
    }

    return blockToJSON(block, pblockindex);
}

UniValue gettxout(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() < 2 || params.size() > 3)
        throw std::runtime_error(
            "gettxout \"txid\" n ( includemempool )\n"
            "\nReturns details about an unspent transaction output.\n"
            "\nArguments:\n"
            "1. \"txid\"       (string, required) The transaction id\n"
            "2. n              (numeric, required) vout value\n"
            "3. includemempool  (boolean, optional) Whether to included the mem pool\n"
            "\nResult:\n"
            "{\n"
            "  \"bestblock\" : \"hash\",    (string) the block hash\n"
            "  \"confirmations\" : n,       (numeric) The number of confirmations\n"
            "  \"value\" : x.xxx,           (numeric) The transaction value in " + CURRENCY_UNIT + "\n"
            "  \"scriptPubKey\" : {         (json object)\n"
            "     \"asm\" : \"code\",       (string) \n"
            "     \"hex\" : \"hex\",        (string) \n"
            "     \"reqSigs\" : n,          (numeric) Number of required signatures\n"
            "     \"type\" : \"pubkeyhash\", (string) The type, eg pubkeyhash\n"
            "     \"addresses\" : [          (array of string) array of bitcoin addresses\n"
            "        \"bitcoinaddress\"     (string) bitcoin address\n"
            "        ,...\n"
            "     ]\n"
            "  },\n"
            "  \"version\" : n,            (numeric) The version\n"
            "  \"coinbase\" : true|false   (boolean) Coinbase or not\n"
            "}\n"

            "\nExamples:\n"
            "\nGet unspent transactions\n"
            + HelpExampleCli("listunspent", "") +
            "\nView the details\n"
            + HelpExampleCli("gettxout", "\"txid\" 1") +
            "\nAs a json rpc call\n"
            + HelpExampleRpc("gettxout", "\"txid\", 1")
        );

    LOCK(cs_main);

    UniValue ret(UniValue::VOBJ);

    std::string strHash = params[0].get_str();
    uint256 hash(uint256S(strHash));
    int n = params[1].get_int();
    bool fMempool = true;
    if (params.size() > 2)
        fMempool = params[2].get_bool();

    int confirmedHeight;
    std::uint64_t value = -1;
    CScript outScript;
    int version;
    bool isCoinbase;
    bool found = false;
    if (fMempool) {
        LOCK(mempool.cs);
        CTransaction tx;
        if (mempool.lookup(hash, tx) && tx.vout.size() > n) { // found it!
            confirmedHeight = MEMPOOL_HEIGHT;
            value = tx.vout[n].nValue;
            outScript = tx.vout[n].scriptPubKey;
            version = tx.nVersion;
            isCoinbase = n == 0;
            found = true;
        }
    }
    if (!found) {
        auto result = g_utxo->find(hash, n);
        if (result.isValid()) {
            UnspentOutputData data(result);
            confirmedHeight = data.blockHeight();
            value = data.outputValue();
            outScript = data.outputScript();
            version = data.prevTxVersion();
            isCoinbase = data.isCoinbase();
            found = true;
        }
    }

    if (!found)
        return NullUniValue;
    CBlockIndex *pindex = Blocks::Index::get(g_utxo->blockId());
    assert(pindex);
    ret.push_back(Pair("bestblock", pindex->GetBlockHash().GetHex()));
    if ((unsigned int)confirmedHeight == MEMPOOL_HEIGHT)
        ret.push_back(Pair("confirmations", 0));
    else
        ret.push_back(Pair("confirmations", pindex->nHeight - confirmedHeight + 1));
    ret.push_back(Pair("value", ValueFromAmount(value)));
    UniValue o(UniValue::VOBJ);
    ScriptPubKeyToJSON(outScript, o, true);
    ret.push_back(Pair("scriptPubKey", o));
    ret.push_back(Pair("version", version));
    ret.push_back(Pair("coinbase", isCoinbase));

    return ret;
}

UniValue verifychain(const UniValue& params, bool fHelp)
{
    int nCheckLevel = GetArg("-checklevel", Settings::DefaultCheckLevel);
    int nCheckDepth = GetArg("-checkblocks", Settings::DefaultCheckBlocks);
    if (fHelp || params.size() > 2)
        throw std::runtime_error(
            "verifychain ( checklevel numblocks )\n"
            "\nVerifies blockchain database.\n"
            "\nArguments:\n"
            "1. checklevel   (numeric, optional, 0-4, default=" + strprintf("%d", nCheckLevel) + ") How thorough the block verification is.\n"
            "2. numblocks    (numeric, optional, default=" + strprintf("%d", nCheckDepth) + ", 0=all) The number of blocks to check.\n"
            "\nResult:\n"
            "true|false       (boolean) Verified or not\n"
            "\nExamples:\n"
            + HelpExampleCli("verifychain", "")
            + HelpExampleRpc("verifychain", "")
        );

    if (params.size() > 0)
        nCheckLevel = params[0].get_int();
    if (params.size() > 1)
        nCheckDepth = params[1].get_int();

    return VerifyDB().verifyDB(nCheckLevel, nCheckDepth);
}

UniValue getblockchaininfo(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "getblockchaininfo\n"
            "Returns an object containing various state info regarding block chain processing.\n"
            "\nResult:\n"
            "{\n"
            "  \"chain\": \"xxxx\",        (string) current network name as defined in BIP70 (main, test, regtest)\n"
            "  \"blocks\": xxxxxx,         (numeric) the current number of blocks processed in the server\n"
            "  \"headers\": xxxxxx,        (numeric) the current number of headers we have validated\n"
            "  \"bestblockhash\": \"...\", (string) the hash of the currently best block\n"
            "  \"difficulty\": xxxxxx,     (numeric) the current difficulty\n"
            "  \"mediantime\": xxxxxx,     (numeric) median time for the current best block\n"
            "  \"verificationprogress\": xxxx, (numeric) estimate of verification progress [0..1]\n"
            "  \"chainwork\": \"xxxx\"     (string) total amount of work in active chain, in hexadecimal\n"
            "  \"pruned\": xx,             (boolean) if the blocks are subject to pruning\n"
            "  \"pruneheight\": xxxxxx,    (numeric) heighest block available\n"
            "  \"softforks\": [            (array) status of softforks in progress\n"
            "     {\n"
            "        \"id\": \"xxxx\",        (string) name of softfork\n"
            "        \"version\": xx,         (numeric) block version\n"
            "        \"enforce\": {           (object) progress toward enforcing the softfork rules for new-version blocks\n"
            "           \"status\": xx,       (boolean) true if threshold reached\n"
            "           \"found\": xx,        (numeric) number of blocks with the new version found\n"
            "           \"required\": xx,     (numeric) number of blocks required to trigger\n"
            "           \"window\": xx,       (numeric) maximum size of examined window of recent blocks\n"
            "        },\n"
            "        \"reject\": { ... }      (object) progress toward rejecting pre-softfork blocks (same fields as \"enforce\")\n"
            "     }, ...\n"
            "  ],\n"
            "  \"bip9_softforks\": [       (array) status of BIP9 softforks in progress\n"
            "     {\n"
            "        \"id\": \"xxxx\",        (string) name of the softfork\n"
            "        \"status\": \"xxxx\",    (string) one of \"defined\", \"started\", \"lockedin\", \"active\", \"failed\"\n"
            "     }\n"
            "  ]\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("getblockchaininfo", "")
            + HelpExampleRpc("getblockchaininfo", "")
        );

    LOCK(cs_main);

    UniValue obj(UniValue::VOBJ);
    obj.push_back(Pair("chain",                 Params().NetworkIDString()));
    obj.push_back(Pair("blocks",                (int)chainActive.Height()));
    obj.push_back(Pair("headers",               pindexBestHeader ? pindexBestHeader->nHeight : -1));
    obj.push_back(Pair("bestblockhash",         chainActive.Tip()->GetBlockHash().GetHex()));
    obj.push_back(Pair("difficulty",            (double)GetDifficulty()));
    obj.push_back(Pair("mediantime",            (int64_t)chainActive.Tip()->GetMedianTimePast()));
    obj.push_back(Pair("verificationprogress",  Checkpoints::GuessVerificationProgress(Params().Checkpoints(), chainActive.Tip())));
    obj.push_back(Pair("chainwork",             chainActive.Tip()->nChainWork.GetHex()));
    obj.push_back(Pair("initialblockdownload",
        (Blocks::DB::instance()->headerChain().Height() - chainActive.Height() > 1000)));
    obj.push_back(Pair("pruned",                false));
    return obj;
}

/** Comparison function for sorting the getchaintips heads.  */
struct CompareBlocksByHeight
{
    bool operator()(const CBlockIndex* a, const CBlockIndex* b) const
    {
        /* Make sure that unequal blocks with the same height do not compare
           equal. Use the pointers themselves to make a distinction. */

        if (a->nHeight != b->nHeight)
          return (a->nHeight > b->nHeight);

        return a < b;
    }
};

UniValue getchaintips(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "getchaintips\n"
            "Return information about all known tips in the block tree,"
            " including the main chain as well as orphaned branches.\n"
            "\nResult:\n"
            "[\n"
            "  {\n"
            "    \"height\": xxxx,         (numeric) height of the chain tip\n"
            "    \"hash\": \"xxxx\",         (string) block hash of the tip\n"
            "    \"branchlen\": 0          (numeric) zero for main chain\n"
            "    \"status\": \"active\"      (string) \"active\" for the main chain\n"
            "  },\n"
            "  {\n"
            "    \"height\": xxxx,\n"
            "    \"hash\": \"xxxx\",\n"
            "    \"branchlen\": 1          (numeric) length of branch connecting the tip to the main chain\n"
            "    \"status\": \"xxxx\"        (string) status of the chain (active, valid-fork, valid-headers, headers-only, invalid)\n"
            "  }\n"
            "]\n"
            "Possible values for status:\n"
            "1.  \"invalid\"               This branch contains at least one invalid block\n"
            "2.  \"headers-only\"          Not all blocks for this branch are available, but the headers are valid\n"
            "3.  \"valid-headers\"         All blocks are available for this branch, but they were never fully validated\n"
            "4.  \"valid-fork\"            This branch is not part of the active chain, but is fully validated\n"
            "5.  \"active\"                This is the tip of the active main chain, which is certainly valid\n"
            "\nExamples:\n"
            + HelpExampleCli("getchaintips", "")
            + HelpExampleRpc("getchaintips", "")
        );

    LOCK(cs_main);

    /* Build up a list of chain tips.  We start with the list of all
       known blocks, and successively remove blocks that appear as pprev
       of another block.  */
    std::set<const CBlockIndex*, CompareBlocksByHeight> setTips;
    for (auto index : Blocks::DB::instance()->headerChainTips()) {
        setTips.insert(index);
    }

    /* Construct the output array.  */
    UniValue res(UniValue::VARR);
    BOOST_FOREACH(const CBlockIndex* block, setTips)
    {
        UniValue obj(UniValue::VOBJ);
        obj.push_back(Pair("height", block->nHeight));
        obj.push_back(Pair("hash", block->phashBlock->GetHex()));

        const int branchLen = block->nHeight - chainActive.FindFork(block)->nHeight;
        obj.push_back(Pair("branchlen", branchLen));

        std::string status;
        if (chainActive.Contains(block)) {
            // This block is part of the currently active chain.
            status = "active";
        } else if (block->nStatus & BLOCK_FAILED_MASK) {
            // This block or one of its ancestors is invalid.
            status = "invalid";
        } else if (block->nChainTx == 0) {
            // This block cannot be connected because full block data for it or one of its parents is missing.
            status = "headers-only";
        } else if (block->IsValid(BLOCK_VALID_SCRIPTS)) {
            // This block is fully validated, but no longer part of the active chain. It was probably the active block once, but was reorganized.
            status = "valid-fork";
        } else if (block->IsValid(BLOCK_VALID_TREE)) {
            // The headers for this block are valid, but it has not been validated. It was probably never part of the most-work chain.
            status = "valid-headers";
        } else {
            // No clue.
            status = "unknown";
        }
        obj.push_back(Pair("status", status));

        res.push_back(obj);
    }

    return res;
}

UniValue mempoolInfoToJSON()
{
    UniValue ret(UniValue::VOBJ);
    ret.push_back(Pair("size", (int64_t) mempool.size()));
    ret.push_back(Pair("bytes", (int64_t) mempool.GetTotalTxSize()));
    ret.push_back(Pair("usage", (int64_t) mempool.DynamicMemoryUsage()));
    size_t maxmempool = GetArg("-maxmempool", Settings::DefaultMaxMempoolSize) * 1000000;
    ret.push_back(Pair("maxmempool", (int64_t) maxmempool));
    ret.push_back(Pair("mempoolminfee", ValueFromAmount(mempool.GetMinFee().GetFeePerK())));

    return ret;
}

UniValue getmempoolinfo(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "getmempoolinfo\n"
            "\nReturns details on the active state of the TX memory pool.\n"
            "\nResult:\n"
            "{\n"
            "  \"size\": xxxxx,               (numeric) Current tx count\n"
            "  \"bytes\": xxxxx,              (numeric) Sum of all tx sizes\n"
            "  \"usage\": xxxxx,              (numeric) Total memory usage for the mempool\n"
            "  \"maxmempool\": xxxxx,         (numeric) Maximum memory usage for the mempool\n"
            "  \"mempoolminfee\": xxxxx       (numeric) Minimum fee for tx to be accepted\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("getmempoolinfo", "")
            + HelpExampleRpc("getmempoolinfo", "")
        );

    return mempoolInfoToJSON();
}

UniValue invalidateblock(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 1)
        throw std::runtime_error(
            "invalidateblock \"hash\"\n"
            "\nPermanently marks a block as invalid, as if it violated a consensus rule.\n"
            "\nArguments:\n"
            "1. hash   (string, required) the hash of the block to mark as invalid\n"
            "\nResult:\n"
            "\nExamples:\n"
            + HelpExampleCli("invalidateblock", "\"blockhash\"")
            + HelpExampleRpc("invalidateblock", "\"blockhash\"")
        );

    std::string strHash = params[0].get_str();
    uint256 hash(uint256S(strHash));

    CBlockIndex* pblockindex = nullptr;
    {
        pblockindex = Blocks::Index::get(hash);
        if (!pblockindex)
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
    }
    Application::instance()->validation()->invalidateBlock(pblockindex);

    return NullUniValue;
}

UniValue reconsiderblock(const UniValue& params, bool fHelp)
{
    if (fHelp || params.size() != 1)
        throw std::runtime_error(
            "reconsiderblock \"hash\"\n"
            "\nRemoves invalidity status of a block and its descendants, reconsider them for activation.\n"
            "This can be used to undo the effects of invalidateblock.\n"
            "\nArguments:\n"
            "1. hash   (string, required) the hash of the block to reconsider\n"
            "\nResult:\n"
            "\nExamples:\n"
            + HelpExampleCli("reconsiderblock", "\"blockhash\"")
            + HelpExampleRpc("reconsiderblock", "\"blockhash\"")
        );

    std::string strHash = params[0].get_str();
    uint256 hash(uint256S(strHash));

    auto validator = Application::instance()->validation();
    CBlockIndex* pblockindex = Blocks::Index::get(hash);
    if (!pblockindex)
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
    Blocks::Index::reconsiderBlock(pblockindex, validator->mempool()->utxo());

    // try to actually validate the block again.
    Validation::Settings future;
    if (pblockindex->nStatus & BLOCK_HAVE_DATA) {
        future = validator->addBlock(pblockindex->GetBlockPos()).start();
    } else {
        future = validator->addBlock(FastBlock::fromOldBlock(pblockindex->GetBlockHeader()), 0).start();
    }
    future.waitUntilFinished();

    auto acceptedBlock = Blocks::DB::instance()->headerChain()[pblockindex->nHeight];
    if (acceptedBlock && acceptedBlock != pblockindex)
        logCritical(Log::RPC) << "Reconsider block done on block and alternate chain still wins. Consider invalidating block:"
            << acceptedBlock->GetBlockHash();

    if (!future.error().empty())
        throw JSONRPCError(RPC_DATABASE_ERROR, future.error());
    return NullUniValue;
}