// Copyright (c) 2018-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 <external_signer.h>

#include <chainparams.h>

#include <common/run_command.h>

#include <core_io.h>

#include <psbt.h>

#include <util/strencodings.h>

#include <util/subprocess.h>

#include <algorithm>

#include <stdexcept>

#include <string>

#include <vector>

ExternalSigner::ExternalSigner(std::vector<std::string> command, std::string chain, std::string fingerprint, std::string name)

    : m_command{std::move(command)}, m_chain{std::move(chain)}, m_fingerprint{std::move(fingerprint)}, m_name{std::move(name)} {}

std::vector<std::string> ExternalSigner::NetworkArg() const

{

    return {"--chain", m_chain};

}

bool ExternalSigner::Enumerate(const std::string& command, std::vector<ExternalSigner>& signers, const std::string& chain)

{

    // Call <command> enumerate

    std::vector<std::string> cmd_args = Cat(subprocess::util::split(command), {"enumerate"});

    const UniValue result = RunCommandParseJSON(cmd_args, "");

    if (!result.isArray()) {

        throw std::runtime_error(strprintf("'%s' received invalid response, expected array of signers", command));

    }

    for (const UniValue& signer : result.getValues()) {

        // Check for error

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

        if (!error.isNull()) {

            if (!error.isStr()) {

                throw std::runtime_error(strprintf("'%s' error", command));

            }

            throw std::runtime_error(strprintf("'%s' error: %s", command, error.getValStr()));

        }

        // Check if fingerprint is present

        const UniValue& fingerprint = signer.find_value("fingerprint");

        if (fingerprint.isNull()) {

            throw std::runtime_error(strprintf("'%s' received invalid response, missing signer fingerprint", command));

        }

        const std::string& fingerprintStr{fingerprint.get_str()};

        if (fingerprintStr.size() != 8 || !IsHex(fingerprintStr)) {

            throw std::runtime_error(strprintf("'%s' received invalid fingerprint, must be 8 hex characters", command));

        }

        // Skip duplicate signer

        bool duplicate = false;

        for (const ExternalSigner& signer : signers) {

            if (signer.m_fingerprint.compare(fingerprintStr) == 0) duplicate = true;

        }

        if (duplicate) continue;

        std::string name;

        const UniValue& model_field = signer.find_value("model");

        if (model_field.isStr() && model_field.getValStr() != "") {

            name += model_field.getValStr();

        }

        signers.emplace_back(subprocess::util::split(command), chain, fingerprintStr, name);

    }

    return true;

}

UniValue ExternalSigner::DisplayAddress(const std::string& descriptor) const

{

    return RunCommandParseJSON(Cat(m_command, Cat(Cat({"--fingerprint", m_fingerprint}, NetworkArg()), {"displayaddress", "--desc", descriptor})), "");

}

UniValue ExternalSigner::GetDescriptors(const int account)

{

    return RunCommandParseJSON(Cat(m_command, Cat(Cat({"--fingerprint", m_fingerprint}, NetworkArg()), {"getdescriptors", "--account", strprintf("%d", account)})), "");

}

bool ExternalSigner::SignTransaction(PartiallySignedTransaction& psbtx, std::string& error)

{

    // Serialize the PSBT

    DataStream ssTx{};

    ssTx << psbtx;

    // parse ExternalSigner master fingerprint

    std::vector<unsigned char> parsed_m_fingerprint = ParseHex(m_fingerprint);

    // Check if signer fingerprint matches any input master key fingerprint

    auto matches_signer_fingerprint = [&](const PSBTInput& input) {

        for (const auto& entry : input.hd_keypaths) {

            if (std::ranges::equal(parsed_m_fingerprint, entry.second.fingerprint)) return true;

        }

        for (const auto& entry : input.m_tap_bip32_paths) {

            if (std::ranges::equal(parsed_m_fingerprint, entry.second.second.fingerprint)) return true;

        }

        return false;

    };

    if (!std::any_of(psbtx.inputs.begin(), psbtx.inputs.end(), matches_signer_fingerprint)) {

        error = "Signer fingerprint " + m_fingerprint + " does not match any of the inputs:\n" + EncodeBase64(ssTx.str());

        return false;

    }

    const std::vector<std::string> command = Cat(m_command, Cat({"--stdin", "--fingerprint", m_fingerprint}, NetworkArg()));

    const std::string stdinStr = "signtx " + EncodeBase64(ssTx.str());

    const UniValue signer_result = RunCommandParseJSON(command, stdinStr);

    if (signer_result.find_value("error").isStr()) {

        error = signer_result.find_value("error").get_str();

        return false;

    }

    if (!signer_result.find_value("psbt").isStr()) {

        error = "Unexpected result from signer";

        return false;

    }

    util::Result<PartiallySignedTransaction> signer_psbtx = DecodeBase64PSBT(signer_result.find_value("psbt").get_str());

    if (!signer_psbtx) {

        error = strprintf("TX decode failed %s", util::ErrorString(signer_psbtx).original);

        return false;

    }

    psbtx = *signer_psbtx;

    return true;

}