// Copyright (c) 2010 Satoshi Nakamoto

// Copyright (c) 2009-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 <key_io.h>

#include <outputtype.h>

#include <pubkey.h>

#include <rpc/protocol.h>

#include <rpc/request.h>

#include <rpc/server.h>

#include <rpc/util.h>

#include <script/descriptor.h>

#include <script/script.h>

#include <script/signingprovider.h>

#include <tinyformat.h>

#include <univalue.h>

#include <util/check.h>

#include <util/strencodings.h>

#include <cstdint>

#include <memory>

#include <optional>

#include <string>

#include <string_view>

#include <tuple>

#include <vector>

static RPCMethod validateaddress()

{

    return RPCMethod{

        "validateaddress",

        "Return information about the given bitcoin address.\n",

        {

            {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address to validate"},

        },

        RPCResult{

            RPCResult::Type::OBJ, "", "",

            {

                {RPCResult::Type::BOOL, "isvalid", "If the address is valid or not"},

                {RPCResult::Type::STR, "address", /*optional=*/true, "The bitcoin address validated"},

                {RPCResult::Type::STR_HEX, "scriptPubKey", /*optional=*/true, "The hex-encoded output script generated by the address"},

                {RPCResult::Type::BOOL, "isscript", /*optional=*/true, "If the key is a script"},

                {RPCResult::Type::BOOL, "iswitness", /*optional=*/true, "If the address is a witness address"},

                {RPCResult::Type::NUM, "witness_version", /*optional=*/true, "The version number of the witness program"},

                {RPCResult::Type::STR_HEX, "witness_program", /*optional=*/true, "The hex value of the witness program"},

                {RPCResult::Type::STR, "error", /*optional=*/true, "Error message, if any"},

                {RPCResult::Type::ARR, "error_locations", /*optional=*/true, "Indices of likely error locations in address, if known (e.g. Bech32 errors)",

                    {

                        {RPCResult::Type::NUM, "index", "index of a potential error"},

                    }},

            }

        },

        RPCExamples{

            HelpExampleCli("validateaddress", "\"" + EXAMPLE_ADDRESS[0] + "\"") +

            HelpExampleRpc("validateaddress", "\"" + EXAMPLE_ADDRESS[0] + "\"")

        },

        [](const RPCMethod& self, const JSONRPCRequest& request) -> UniValue

        {

            std::string error_msg;

            std::vector<int> error_locations;

            CTxDestination dest = DecodeDestination(request.params[0].get_str(), error_msg, &error_locations);

            const bool isValid = IsValidDestination(dest);

            CHECK_NONFATAL(isValid == error_msg.empty());

            UniValue ret(UniValue::VOBJ);

            ret.pushKV("isvalid", isValid);

            if (isValid) {

                std::string currentAddress = EncodeDestination(dest);

                ret.pushKV("address", currentAddress);

                CScript scriptPubKey = GetScriptForDestination(dest);

                ret.pushKV("scriptPubKey", HexStr(scriptPubKey));

                UniValue detail = DescribeAddress(dest);

                ret.pushKVs(std::move(detail));

            } else {

                UniValue error_indices(UniValue::VARR);

                for (int i : error_locations) error_indices.push_back(i);

                ret.pushKV("error_locations", std::move(error_indices));

                ret.pushKV("error", error_msg);

            }

            return ret;

        },

    };

}

static RPCMethod createmultisig()

{

    return RPCMethod{

        "createmultisig",

        "Creates a multi-signature address with n signatures of m keys required.\n"

        "It returns a json object with the address and redeemScript.\n",

        {

            {"nrequired", RPCArg::Type::NUM, RPCArg::Optional::NO, "The number of required signatures out of the m keys."},

            {"keys", RPCArg::Type::ARR, RPCArg::Optional::NO, "The hex-encoded public keys.",

                {

                    {"key", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "The hex-encoded public key"},

                }},

            {"address_type", RPCArg::Type::STR, RPCArg::Default{"legacy"}, "The address type to use. Options are \"legacy\", \"p2sh-segwit\", and \"bech32\"."},

        },

        RPCResult{

            RPCResult::Type::OBJ, "", "",

            {

                {RPCResult::Type::STR, "address", "The value of the new multisig address."},

                {RPCResult::Type::STR_HEX, "redeemScript", "The string value of the hex-encoded redemption script."},

                {RPCResult::Type::STR, "descriptor", "The descriptor for this multisig"},

                {RPCResult::Type::ARR, "warnings", /*optional=*/true, "Any warnings resulting from the creation of this multisig",

                {

                    {RPCResult::Type::STR, "", ""},

                }},

            }

        },

        RPCExamples{

            "\nCreate a multisig address from 2 public keys\n"

            + HelpExampleCli("createmultisig", "2 \"[\\\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\\\",\\\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\\\"]\"") +

            "\nAs a JSON-RPC call\n"

            + HelpExampleRpc("createmultisig", "2, [\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\",\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\"]")

                },

        [](const RPCMethod& self, const JSONRPCRequest& request) -> UniValue

        {

            int required = request.params[0].getInt<int>();

            // Get the public keys

            const UniValue& keys = request.params[1].get_array();

            std::vector<CPubKey> pubkeys;

            pubkeys.reserve(keys.size());

            for (unsigned int i = 0; i < keys.size(); ++i) {

                pubkeys.push_back(HexToPubKey(keys[i].get_str()));

            }

            // Get the output type

            auto address_type{self.Arg<std::string_view>("address_type")};

            auto output_type{ParseOutputType(address_type)};

            if (!output_type) {

                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, tfm::format("Unknown address type '%s'", address_type));

            } else if (output_type.value() == OutputType::BECH32M) {

                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "createmultisig cannot create bech32m multisig addresses");

            }

            FlatSigningProvider keystore;

            CScript inner;

            const CTxDestination dest = AddAndGetMultisigDestination(required, pubkeys, output_type.value(), keystore, inner);

            // Make the descriptor

            std::unique_ptr<Descriptor> descriptor = InferDescriptor(GetScriptForDestination(dest), keystore);

            UniValue result(UniValue::VOBJ);

            result.pushKV("address", EncodeDestination(dest));

            result.pushKV("redeemScript", HexStr(inner));

            result.pushKV("descriptor", descriptor->ToString());

            UniValue warnings(UniValue::VARR);

            if (descriptor->GetOutputType() != output_type.value()) {

                // Only warns if the user has explicitly chosen an address type we cannot generate

                warnings.push_back("Unable to make chosen address type, please ensure no uncompressed public keys are present.");

            }

            PushWarnings(warnings, result);

            return result;

        },

    };

}

static RPCMethod getdescriptorinfo()

{

    const std::string EXAMPLE_DESCRIPTOR = "wpkh([d34db33f/84h/0h/0h]0279be667ef9dcbbac55a06295Ce870b07029Bfcdb2dce28d959f2815b16f81798)";

    return RPCMethod{

        "getdescriptorinfo",

        "Analyses a descriptor.\n",

        {

            {"descriptor", RPCArg::Type::STR, RPCArg::Optional::NO, "The descriptor."},

        },

        RPCResult{

            RPCResult::Type::OBJ, "", "",

            {

                {RPCResult::Type::STR, "descriptor", "The descriptor in canonical form, without private keys. For a multipath descriptor, only the first will be returned."},

                {RPCResult::Type::ARR, "multipath_expansion", /*optional=*/true, "All descriptors produced by expanding multipath derivation elements. Only if the provided descriptor specifies multipath derivation elements.",

                {

                    {RPCResult::Type::STR, "", ""},

                }},

                {RPCResult::Type::STR, "checksum", "The checksum for the input descriptor"},

                {RPCResult::Type::BOOL, "isrange", "Whether the descriptor is ranged"},

                {RPCResult::Type::BOOL, "issolvable", "Whether the descriptor is solvable"},

                {RPCResult::Type::BOOL, "hasprivatekeys", "Whether the input descriptor contained at least one private key"},

            }

        },

        RPCExamples{

            "Analyse a descriptor\n" +

            HelpExampleCli("getdescriptorinfo", "\"" + EXAMPLE_DESCRIPTOR + "\"") +

            HelpExampleRpc("getdescriptorinfo", "\"" + EXAMPLE_DESCRIPTOR + "\"")

        },

        [](const RPCMethod& self, const JSONRPCRequest& request) -> UniValue

        {

            FlatSigningProvider provider;

            std::string error;

            auto descs = Parse(self.Arg<std::string_view>("descriptor"), provider, error);

            if (descs.empty()) {

                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);

            }

            UniValue result(UniValue::VOBJ);

            result.pushKV("descriptor", descs.at(0)->ToString());

            if (descs.size() > 1) {

                UniValue multipath_descs(UniValue::VARR);

                for (const auto& d : descs) {

                    multipath_descs.push_back(d->ToString());

                }

                result.pushKV("multipath_expansion", multipath_descs);

            }

            result.pushKV("checksum", GetDescriptorChecksum(request.params[0].get_str()));

            result.pushKV("isrange", descs.at(0)->IsRange());

            result.pushKV("issolvable", descs.at(0)->IsSolvable());

            result.pushKV("hasprivatekeys", provider.keys.size() > 0);

            return result;

        },

    };

}

static UniValue DeriveAddresses(const Descriptor* desc, int64_t range_begin, int64_t range_end, FlatSigningProvider& key_provider)

{

    UniValue addresses(UniValue::VARR);

    for (int64_t i = range_begin; i <= range_end; ++i) {

        FlatSigningProvider provider;

        std::vector<CScript> scripts;

        if (!desc->Expand(i, key_provider, scripts, provider)) {

            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Cannot derive script without private keys");

        }

        for (const CScript& script : scripts) {

            CTxDestination dest;

            if (!ExtractDestination(script, dest)) {

                // ExtractDestination no longer returns true for P2PK since it doesn't have a corresponding address

                // However combo will output P2PK and should just ignore that script

                if (scripts.size() > 1 && std::get_if<PubKeyDestination>(&dest)) {

                    continue;

                }

                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Descriptor does not have a corresponding address");

            }

            addresses.push_back(EncodeDestination(dest));

        }

    }

    // This should not be possible, but an assert seems overkill:

    if (addresses.empty()) {

        throw JSONRPCError(RPC_MISC_ERROR, "Unexpected empty result");

    }

    return addresses;

}

static RPCMethod deriveaddresses()

{

    const std::string EXAMPLE_DESCRIPTOR = "wpkh([d34db33f/84h/0h/0h]xpub6DJ2dNUysrn5Vt36jH2KLBT2i1auw1tTSSomg8PhqNiUtx8QX2SvC9nrHu81fT41fvDUnhMjEzQgXnQjKEu3oaqMSzhSrHMxyyoEAmUHQbY/0/*)#cjjspncu";

    return RPCMethod{

        "deriveaddresses",

        "Derives one or more addresses corresponding to an output descriptor.\n"

         "Examples of output descriptors are:\n"

         "    pkh(<pubkey>)                                     P2PKH outputs for the given pubkey\n"

         "    wpkh(<pubkey>)                                    Native segwit P2PKH outputs for the given pubkey\n"

         "    sh(multi(<n>,<pubkey>,<pubkey>,...))              P2SH-multisig outputs for the given threshold and pubkeys\n"

         "    raw(<hex script>)                                 Outputs whose output script equals the specified hex-encoded bytes\n"

         "    tr(<pubkey>,multi_a(<n>,<pubkey>,<pubkey>,...))   P2TR-multisig outputs for the given threshold and pubkeys\n"

         "\nIn the above, <pubkey> either refers to a fixed public key in hexadecimal notation, or to an xpub/xprv optionally followed by one\n"

         "or more path elements separated by \"/\", where \"h\" represents a hardened child key.\n"

        "For more information on output descriptors, see the documentation in the doc/descriptors.md file.\n",

        {

            {"descriptor", RPCArg::Type::STR, RPCArg::Optional::NO, "The descriptor."},

            {"range", RPCArg::Type::RANGE, RPCArg::Optional::OMITTED, "If a ranged descriptor is used, this specifies the end or the range (in [begin,end] notation) to derive."},

        },

        {

            RPCResult{"for single derivation descriptors",

                RPCResult::Type::ARR, "", "",

                {

                    {RPCResult::Type::STR, "address", "the derived addresses"},

                }

            },

            RPCResult{"for multipath descriptors",

                RPCResult::Type::ARR, "", "The derived addresses for each of the multipath expansions of the descriptor, in multipath specifier order",

                {

                    {

                        RPCResult::Type::ARR, "", "The derived addresses for a multipath descriptor expansion",

                        {

                            {RPCResult::Type::STR, "address", "the derived address"},

                        },

                    },

                },

            },

        },

        RPCExamples{

            "First three native segwit receive addresses\n" +

            HelpExampleCli("deriveaddresses", "\"" + EXAMPLE_DESCRIPTOR + "\" \"[0,2]\"") +

            HelpExampleRpc("deriveaddresses", "\"" + EXAMPLE_DESCRIPTOR + "\", \"[0,2]\"")

        },

        [](const RPCMethod& self, const JSONRPCRequest& request) -> UniValue

        {

            auto desc_str{self.Arg<std::string_view>("descriptor")};

            int64_t range_begin = 0;

            int64_t range_end = 0;

            if (request.params.size() >= 2 && !request.params[1].isNull()) {

                std::tie(range_begin, range_end) = ParseDescriptorRange(request.params[1]);

            }

            FlatSigningProvider key_provider;

            std::string error;

            auto descs = Parse(desc_str, key_provider, error, /* require_checksum = */ true);

            if (descs.empty()) {

                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);

            }

            auto& desc = descs.at(0);

            if (!desc->IsRange() && request.params.size() > 1) {

                throw JSONRPCError(RPC_INVALID_PARAMETER, "Range should not be specified for an un-ranged descriptor");

            }

            if (desc->IsRange() && request.params.size() == 1) {

                throw JSONRPCError(RPC_INVALID_PARAMETER, "Range must be specified for a ranged descriptor");

            }

            UniValue addresses = DeriveAddresses(desc.get(), range_begin, range_end, key_provider);

            if (descs.size() == 1) {

                return addresses;

            }

            UniValue ret(UniValue::VARR);

            ret.push_back(addresses);

            for (size_t i = 1; i < descs.size(); ++i) {

                ret.push_back(DeriveAddresses(descs.at(i).get(), range_begin, range_end, key_provider));

            }

            return ret;

        },

    };

}

void RegisterOutputScriptRPCCommands(CRPCTable& t)

{

    static const CRPCCommand commands[]{

        {"util", &validateaddress},

        {"util", &createmultisig},

        {"util", &deriveaddresses},

        {"util", &getdescriptorinfo},

    };

    for (const auto& c : commands) {

        t.appendCommand(c.name, &c);

    }

}