// Copyright (c) 2019-2022 The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <test/util/mining.h>

#include <chainparams.h>

#include <consensus/merkle.h>

#include <consensus/validation.h>

#include <key_io.h>

#include <node/context.h>

#include <pow.h>

#include <primitives/transaction.h>

#include <test/util/script.h>

#include <util/check.h>

#include <validation.h>

#include <validationinterface.h>

#include <versionbits.h>

#include <algorithm>

#include <memory>

using node::BlockAssembler;

using node::NodeContext;

COutPoint generatetoaddress(const NodeContext& node, const std::string& address)

{

    const auto dest = DecodeDestination(address);

    assert(IsValidDestination(dest));

    BlockAssembler::Options assembler_options;

    assembler_options.coinbase_output_script = GetScriptForDestination(dest);

    return MineBlock(node, assembler_options);

}

std::vector<std::shared_ptr<CBlock>> CreateBlockChain(size_t total_height, const CChainParams& params)

{

    std::vector<std::shared_ptr<CBlock>> ret{total_height};

    auto time{params.GenesisBlock().nTime};

    // NOTE: here `height` does not correspond to the block height but the block height - 1.

    for (size_t height{0}; height < total_height; ++height) {

        CBlock& block{*(ret.at(height) = std::make_shared<CBlock>())};

        CMutableTransaction coinbase_tx;

        coinbase_tx.nLockTime = static_cast<uint32_t>(height);

        coinbase_tx.vin.resize(1);

        coinbase_tx.vin[0].prevout.SetNull();

        coinbase_tx.vin[0].nSequence = CTxIn::MAX_SEQUENCE_NONFINAL; // Make sure timelock is enforced.

        coinbase_tx.vout.resize(1);

        coinbase_tx.vout[0].scriptPubKey = P2WSH_OP_TRUE;

        coinbase_tx.vout[0].nValue = GetBlockSubsidy(height + 1, params.GetConsensus());

        coinbase_tx.vin[0].scriptSig = CScript() << (height + 1) << OP_0;

        block.vtx = {MakeTransactionRef(std::move(coinbase_tx))};

        block.nVersion = VERSIONBITS_LAST_OLD_BLOCK_VERSION;

        block.hashPrevBlock = (height >= 1 ? *ret.at(height - 1) : params.GenesisBlock()).GetHash();

        block.hashMerkleRoot = BlockMerkleRoot(block);

        block.nTime = ++time;

        block.nBits = params.GenesisBlock().nBits;

        block.nNonce = 0;

        while (!CheckProofOfWork(block.GetHash(), block.nBits, params.GetConsensus())) {

            ++block.nNonce;

            assert(block.nNonce);

        }

    }

    return ret;

}

COutPoint MineBlock(const NodeContext& node, const node::BlockAssembler::Options& assembler_options)

{

    auto block = PrepareBlock(node, assembler_options);

    auto valid = MineBlock(node, block);

    assert(!valid.IsNull());

    return valid;

}

struct BlockValidationStateCatcher : public CValidationInterface {

    const uint256 m_hash;

    std::optional<BlockValidationState> m_state;

    BlockValidationStateCatcher(const uint256& hash)

        : m_hash{hash},

          m_state{} {}

protected:

    void BlockChecked(const std::shared_ptr<const CBlock>& block, const BlockValidationState& state) override

    {

        if (block->GetHash() != m_hash) return;

        m_state = state;

    }

};

COutPoint MineBlock(const NodeContext& node, std::shared_ptr<CBlock>& block)

{

    while (!CheckProofOfWork(block->GetHash(), block->nBits, Params().GetConsensus())) {

        ++block->nNonce;

        assert(block->nNonce);

    }

    return ProcessBlock(node, block);

}

COutPoint ProcessBlock(const NodeContext& node, const std::shared_ptr<CBlock>& block)

{

    auto& chainman{*Assert(node.chainman)};

    const auto old_height = WITH_LOCK(chainman.GetMutex(), return chainman.ActiveHeight());

    bool new_block;

    BlockValidationStateCatcher bvsc{block->GetHash()};

    node.validation_signals->RegisterValidationInterface(&bvsc);

    const bool processed{chainman.ProcessNewBlock(block, true, true, &new_block)};

    const bool duplicate{!new_block && processed};

    assert(!duplicate);

    node.validation_signals->UnregisterValidationInterface(&bvsc);

    node.validation_signals->SyncWithValidationInterfaceQueue();

    const bool was_valid{bvsc.m_state && bvsc.m_state->IsValid()};

    assert(old_height + was_valid == WITH_LOCK(chainman.GetMutex(), return chainman.ActiveHeight()));

    if (was_valid) return {block->vtx[0]->GetHash(), 0};

    return {};

}

std::shared_ptr<CBlock> PrepareBlock(const NodeContext& node,

                                     const BlockAssembler::Options& assembler_options)

{

    auto block = std::make_shared<CBlock>(

        BlockAssembler{Assert(node.chainman)->ActiveChainstate(), Assert(node.mempool.get()), assembler_options}

            .CreateNewBlock()

            ->block);

    LOCK(cs_main);

    block->nTime = Assert(node.chainman)->ActiveChain().Tip()->GetMedianTimePast() + 1;

    block->hashMerkleRoot = BlockMerkleRoot(*block);

    return block;

}

std::shared_ptr<CBlock> PrepareBlock(const NodeContext& node, const CScript& coinbase_scriptPubKey)

{

    BlockAssembler::Options assembler_options;

    assembler_options.coinbase_output_script = coinbase_scriptPubKey;

    ApplyArgsManOptions(*node.args, assembler_options);

    return PrepareBlock(node, assembler_options);

}