// Copyright (c) 2021-present 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 <addresstype.h>

#include <consensus/amount.h>

#include <interfaces/chain.h>

#include <kernel/chain.h>

#include <outputtype.h>

#include <policy/feerate.h>

#include <policy/policy.h>

#include <primitives/block.h>

#include <primitives/transaction.h>

#include <script/descriptor.h>

#include <script/script.h>

#include <script/signingprovider.h>

#include <sync.h>

#include <test/fuzz/FuzzedDataProvider.h>

#include <test/fuzz/fuzz.h>

#include <test/fuzz/util.h>

#include <test/util/setup_common.h>

#include <tinyformat.h>

#include <uint256.h>

#include <util/check.h>

#include <util/result.h>

#include <util/translation.h>

#include <wallet/coincontrol.h>

#include <wallet/context.h>

#include <wallet/fees.h>

#include <wallet/receive.h>

#include <wallet/spend.h>

#include <wallet/test/util.h>

#include <wallet/wallet.h>

#include <wallet/walletutil.h>

#include <cstddef>

#include <cstdint>

#include <limits>

#include <numeric>

#include <set>

#include <string>

#include <tuple>

#include <utility>

#include <vector>

namespace wallet {

namespace {

const TestingSetup* g_setup;

void initialize_setup()

{

    static const auto testing_setup = MakeNoLogFileContext<const TestingSetup>();

    g_setup = testing_setup.get();

}

void ImportDescriptors(CWallet& wallet, const std::string& seed_insecure)

{

    const std::vector<std::string> DESCS{

        "pkh(%s/%s/*)",

        "sh(wpkh(%s/%s/*))",

        "tr(%s/%s/*)",

        "wpkh(%s/%s/*)",

    };

    for (const std::string& desc_fmt : DESCS) {

        for (bool internal : {true, false}) {

            const auto descriptor{(strprintf)(desc_fmt, "[5aa9973a/66h/4h/2h]" + seed_insecure, int{internal})};

            FlatSigningProvider keys;

            std::string error;

            auto parsed_desc = std::move(Parse(descriptor, keys, error, /*require_checksum=*/false).at(0));

            assert(parsed_desc);

            assert(error.empty());

            assert(parsed_desc->IsRange());

            assert(parsed_desc->IsSingleType());

            assert(!keys.keys.empty());

            WalletDescriptor w_desc{std::move(parsed_desc), /*creation_time=*/0, /*range_start=*/0, /*range_end=*/1, /*next_index=*/0};

            assert(!wallet.GetDescriptorScriptPubKeyMan(w_desc));

            LOCK(wallet.cs_wallet);

            auto spk_manager{wallet.AddWalletDescriptor(w_desc, keys, /*label=*/"", internal)};

            assert(spk_manager);

            wallet.AddActiveScriptPubKeyMan(spk_manager->GetID(), *Assert(w_desc.descriptor->GetOutputType()), internal);

        }

    }

}

/**

 * Wraps a descriptor wallet for fuzzing.

 */

struct FuzzedWallet {

    std::shared_ptr<CWallet> wallet;

    FuzzedWallet(const std::string& name, const std::string& seed_insecure)

    {

        auto& chain{*Assert(g_setup->m_node.chain)};

        wallet = std::make_shared<CWallet>(&chain, name, CreateMockableWalletDatabase());

        {

            LOCK(wallet->cs_wallet);

            wallet->SetWalletFlag(WALLET_FLAG_DESCRIPTORS);

            auto height{*Assert(chain.getHeight())};

            wallet->SetLastBlockProcessed(height, chain.getBlockHash(height));

        }

        wallet->m_keypool_size = 1; // Avoid timeout in TopUp()

        assert(wallet->IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));

        ImportDescriptors(*wallet, seed_insecure);

    }

    CTxDestination GetDestination(FuzzedDataProvider& fuzzed_data_provider)

    {

        auto type{fuzzed_data_provider.PickValueInArray(OUTPUT_TYPES)};

        if (fuzzed_data_provider.ConsumeBool()) {

            return *Assert(wallet->GetNewDestination(type, ""));

        } else {

            return *Assert(wallet->GetNewChangeDestination(type));

        }

    }

    CScript GetScriptPubKey(FuzzedDataProvider& fuzzed_data_provider) { return GetScriptForDestination(GetDestination(fuzzed_data_provider)); }

    void FundTx(FuzzedDataProvider& fuzzed_data_provider, CMutableTransaction tx)

    {

        // The fee of "tx" is 0, so this is the total input and output amount

        const CAmount total_amt{

            std::accumulate(tx.vout.begin(), tx.vout.end(), CAmount{}, [](CAmount t, const CTxOut& out) { return t + out.nValue; })};

        const uint32_t tx_size(GetVirtualTransactionSize(CTransaction{tx}));

        std::set<int> subtract_fee_from_outputs;

        if (fuzzed_data_provider.ConsumeBool()) {

            for (size_t i{}; i < tx.vout.size(); ++i) {

                if (fuzzed_data_provider.ConsumeBool()) {

                    subtract_fee_from_outputs.insert(i);

                }

            }

        }

        std::vector<CRecipient> recipients;

        for (size_t idx = 0; idx < tx.vout.size(); idx++) {

            const CTxOut& tx_out = tx.vout[idx];

            CTxDestination dest;

            ExtractDestination(tx_out.scriptPubKey, dest);

            CRecipient recipient = {dest, tx_out.nValue, subtract_fee_from_outputs.count(idx) == 1};

            recipients.push_back(recipient);

        }

        CCoinControl coin_control;

        coin_control.m_allow_other_inputs = fuzzed_data_provider.ConsumeBool();

        CallOneOf(

            fuzzed_data_provider, [&] { coin_control.destChange = GetDestination(fuzzed_data_provider); },

            [&] { coin_control.m_change_type.emplace(fuzzed_data_provider.PickValueInArray(OUTPUT_TYPES)); },

            [&] { /* no op (leave uninitialized) */ });

        coin_control.fAllowWatchOnly = fuzzed_data_provider.ConsumeBool();

        coin_control.m_include_unsafe_inputs = fuzzed_data_provider.ConsumeBool();

        {

            auto& r{coin_control.m_signal_bip125_rbf};

            CallOneOf(

                fuzzed_data_provider, [&] { r = true; }, [&] { r = false; }, [&] { r = std::nullopt; });

        }

        coin_control.m_feerate = CFeeRate{

            // A fee of this range should cover all cases

            fuzzed_data_provider.ConsumeIntegralInRange<CAmount>(0, 2 * total_amt),

            tx_size,

        };

        if (fuzzed_data_provider.ConsumeBool()) {

            *coin_control.m_feerate += GetMinimumFeeRate(*wallet, coin_control, nullptr);

        }

        coin_control.fOverrideFeeRate = fuzzed_data_provider.ConsumeBool();

        // Add solving data (m_external_provider and SelectExternal)?

        int change_position{fuzzed_data_provider.ConsumeIntegralInRange<int>(-1, tx.vout.size() - 1)};

        bilingual_str error;

        // Clear tx.vout since it is not meant to be used now that we are passing outputs directly.

        // This sets us up for a future PR to completely remove tx from the function signature in favor of passing inputs directly

        tx.vout.clear();

        (void)FundTransaction(*wallet, tx, recipients, change_position, /*lockUnspents=*/false, coin_control);

    }

};

FUZZ_TARGET(wallet_notifications, .init = initialize_setup)

{

    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};

    // The total amount, to be distributed to the wallets a and b in txs

    // without fee. Thus, the balance of the wallets should always equal the

    // total amount.

    const auto total_amount{ConsumeMoney(fuzzed_data_provider, /*max=*/MAX_MONEY / 100000)};

    FuzzedWallet a{

        "fuzzed_wallet_a",

        "tprv8ZgxMBicQKsPd1QwsGgzfu2pcPYbBosZhJknqreRHgsWx32nNEhMjGQX2cgFL8n6wz9xdDYwLcs78N4nsCo32cxEX8RBtwGsEGgybLiQJfk",

    };

    FuzzedWallet b{

        "fuzzed_wallet_b",

        "tprv8ZgxMBicQKsPfCunYTF18sEmEyjz8TfhGnZ3BoVAhkqLv7PLkQgmoG2Ecsp4JuqciWnkopuEwShit7st743fdmB9cMD4tznUkcs33vK51K9",

    };

    // Keep track of all coins in this test.

    // Each tuple in the chain represents the coins and the block created with

    // those coins. Once the block is mined, the next tuple will have an empty

    // block and the freshly mined coins.

    using Coins = std::set<std::tuple<CAmount, COutPoint>>;

    std::vector<std::tuple<Coins, CBlock>> chain;

    {

        // Add the initial entry

        chain.emplace_back();

        auto& [coins, block]{chain.back()};

        coins.emplace(total_amount, COutPoint{Txid::FromUint256(uint256::ONE), 1});

    }

    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 200)

    {

        CallOneOf(

            fuzzed_data_provider,

            [&] {

                auto& [coins_orig, block]{chain.back()};

                // Copy the coins for this block and consume all of them

                Coins coins = coins_orig;

                while (!coins.empty()) {

                    // Create a new tx

                    CMutableTransaction tx{};

                    // Add some coins as inputs to it

                    auto num_inputs{fuzzed_data_provider.ConsumeIntegralInRange<int>(1, coins.size())};

                    CAmount in{0};

                    while (num_inputs-- > 0) {

                        const auto& [coin_amt, coin_outpoint]{*coins.begin()};

                        in += coin_amt;

                        tx.vin.emplace_back(coin_outpoint);

                        coins.erase(coins.begin());

                    }

                    // Create some outputs spending all inputs, without fee

                    LIMITED_WHILE(in > 0 && fuzzed_data_provider.ConsumeBool(), 10)

                    {

                        const auto out_value{ConsumeMoney(fuzzed_data_provider, in)};

                        in -= out_value;

                        auto& wallet{fuzzed_data_provider.ConsumeBool() ? a : b};

                        tx.vout.emplace_back(out_value, wallet.GetScriptPubKey(fuzzed_data_provider));

                    }

                    // Spend the remaining input value, if any

                    auto& wallet{fuzzed_data_provider.ConsumeBool() ? a : b};

                    tx.vout.emplace_back(in, wallet.GetScriptPubKey(fuzzed_data_provider));

                    // Add tx to block

                    block.vtx.emplace_back(MakeTransactionRef(tx));

                    // Check that funding the tx doesn't crash the wallet

                    a.FundTx(fuzzed_data_provider, tx);

                    b.FundTx(fuzzed_data_provider, tx);

                }

                // Mine block

                const uint256& hash = block.GetHash();

                interfaces::BlockInfo info{hash};

                info.prev_hash = &block.hashPrevBlock;

                info.height = chain.size();

                info.data = █

                // Ensure that no blocks are skipped by the wallet by setting the chain's accumulated

                // time to the maximum value. This ensures that the wallet's birth time is always

                // earlier than this maximum time.

                info.chain_time_max = std::numeric_limits<unsigned int>::max();

                a.wallet->blockConnected(ChainstateRole::NORMAL, info);

                b.wallet->blockConnected(ChainstateRole::NORMAL, info);

                // Store the coins for the next block

                Coins coins_new;

                for (const auto& tx : block.vtx) {

                    uint32_t i{0};

                    for (const auto& out : tx->vout) {

                        coins_new.emplace(out.nValue, COutPoint{tx->GetHash(), i++});

                    }

                }

                chain.emplace_back(coins_new, CBlock{});

            },

            [&] {

                if (chain.size() <= 1) return; // The first entry can't be removed

                auto& [coins, block]{chain.back()};

                if (block.vtx.empty()) return; // Can only disconnect if the block was submitted first

                // Disconnect block

                const uint256& hash = block.GetHash();

                interfaces::BlockInfo info{hash};

                info.prev_hash = &block.hashPrevBlock;

                info.height = chain.size() - 1;

                info.data = █

                a.wallet->blockDisconnected(info);

                b.wallet->blockDisconnected(info);

                chain.pop_back();

            });

        auto& [coins, first_block]{chain.front()};

        if (!first_block.vtx.empty()) {

            // Only check balance when at least one block was submitted

            const auto bal_a{GetBalance(*a.wallet).m_mine_trusted};

            const auto bal_b{GetBalance(*b.wallet).m_mine_trusted};

            assert(total_amount == bal_a + bal_b);

        }

    }

}

} // namespace

} // namespace wallet