// Copyright (c) 2020-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 <chainparams.h>

#include <common/args.h>

#include <common/system.h>

#include <external_signer.h>

#include <node/types.h>

#include <wallet/external_signer_scriptpubkeyman.h>

#include <iostream>

#include <key_io.h>

#include <memory>

#include <stdexcept>

#include <string>

#include <univalue.h>

#include <utility>

#include <vector>

using common::PSBTError;

namespace wallet {

std::unique_ptr<ExternalSignerScriptPubKeyMan> ExternalSignerScriptPubKeyMan::LoadFromStorage(WalletStorage& storage, WalletDescriptor& descriptor, int64_t keypool_size, const KeyMap& keys, const CryptedKeyMap& ckeys)

{

    return std::unique_ptr<ExternalSignerScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(storage, descriptor, keypool_size, keys, ckeys));

}

std::unique_ptr<ExternalSignerScriptPubKeyMan> ExternalSignerScriptPubKeyMan::CreateNew(WalletStorage& storage, WalletBatch& batch, int64_t keypool_size, std::unique_ptr<Descriptor> desc)

{

    auto spkm = std::unique_ptr<ExternalSignerScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(storage, keypool_size));

    LOCK(spkm->cs_desc_man);

    assert(storage.IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));

    assert(storage.IsWalletFlagSet(WALLET_FLAG_EXTERNAL_SIGNER));

    int64_t creation_time = GetTime();

    // Make the descriptor

    WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);

    spkm->m_wallet_descriptor = w_desc;

    // Store the descriptor

    if (!batch.WriteDescriptor(spkm->GetID(), spkm->m_wallet_descriptor)) {

        throw std::runtime_error(std::string(__func__) + ": writing descriptor failed");

    }

    // TopUp

    spkm->TopUpWithDB(batch);

    storage.UnsetBlankWalletFlag(batch);

    return spkm;

}

 util::Result<ExternalSigner> ExternalSignerScriptPubKeyMan::GetExternalSigner() {

    const std::string command = gArgs.GetArg("-signer", "");

    if (command == "") return util::Error{Untranslated("restart bitcoind with -signer=<cmd>")};

    std::vector<ExternalSigner> signers;

    ExternalSigner::Enumerate(command, signers, Params().GetChainTypeString());

    if (signers.empty()) return util::Error{Untranslated("No external signers found")};

    // TODO: add fingerprint argument instead of failing in case of multiple signers.

    if (signers.size() > 1) return util::Error{Untranslated("More than one external signer found. Please connect only one at a time.")};

    return signers[0];

}

util::Result<void> ExternalSignerScriptPubKeyMan::DisplayAddress(const CTxDestination& dest, const ExternalSigner &signer) const

{

    // TODO: avoid the need to infer a descriptor from inside a descriptor wallet

    const CScript& scriptPubKey = GetScriptForDestination(dest);

    auto provider = GetSolvingProvider(scriptPubKey);

    auto descriptor = InferDescriptor(scriptPubKey, *provider);

    const UniValue& result = signer.DisplayAddress(descriptor->ToString());

    const UniValue& error = result.find_value("error");

    if (error.isStr()) return util::Error{strprintf(_("Signer returned error: %s"), error.getValStr())};

    const UniValue& ret_address = result.find_value("address");

    if (!ret_address.isStr()) return util::Error{_("Signer did not echo address")};

    if (ret_address.getValStr() != EncodeDestination(dest)) {

        return util::Error{strprintf(_("Signer echoed unexpected address %s"), ret_address.getValStr())};

    }

    return util::Result<void>();

}

// If sign is true, transaction must previously have been filled

std::optional<PSBTError> ExternalSignerScriptPubKeyMan::FillPSBT(PartiallySignedTransaction& psbt, const PrecomputedTransactionData& txdata, const common::PSBTFillOptions& options, int* n_signed) const

{

    if (!options.sign) {

        return DescriptorScriptPubKeyMan::FillPSBT(psbt, txdata, options, n_signed);

    }

    // Already complete if every input is now signed

    bool complete = true;

    for (const auto& input : psbt.inputs) {

        complete &= PSBTInputSigned(input);

    }

    if (complete) return {};

    auto signer{GetExternalSigner()};

    if (!signer) {

        LogWarning("%s", util::ErrorString(signer).original);

        return PSBTError::EXTERNAL_SIGNER_NOT_FOUND;

    }

    std::string failure_reason;

    if(!signer->SignTransaction(psbt, failure_reason)) {

        LogWarning("Failed to sign: %s\n", failure_reason);

        return PSBTError::EXTERNAL_SIGNER_FAILED;

    }

    if (options.finalize) FinalizePSBT(psbt); // This won't work in a multisig setup

    return {};

}

} // namespace wallet