// Copyright (c) 2009-2021 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 <core_io.h>

#include <primitives/block.h>
#include <primitives/transaction.h>
#include <script/script.h>
#include <script/sign.h>
#include <serialize.h>
#include <streams.h>
#include <univalue.h>
#include <util/string.h>
#include <util/strencodings.h>
#include <version.h>

#include <algorithm>
#include <string>

namespace {
class OpCodeParser
{
private:
    std::map<std::string, opcodetype> mapOpNames;

public:
    OpCodeParser()
    {
        for (unsigned int op = 0; op <= MAX_OPCODE; ++op) {
            // Allow OP_RESERVED to get into mapOpNames
            if (op < OP_NOP && op != OP_RESERVED) {
                continue;
            }

            std::string strName = GetOpName(static_cast<opcodetype>(op));
            if (strName == "OP_UNKNOWN") {
                continue;
            }
            mapOpNames[strName] = static_cast<opcodetype>(op);
            // Convenience: OP_ADD and just ADD are both recognized:
            if (strName.starts_with("OP_")) {
                mapOpNames[strName.substr(3)] = static_cast<opcodetype>(op);
            }
        }
    }
    opcodetype Parse(const std::string& s) const
    {
        auto it = mapOpNames.find(s);
        if (it == mapOpNames.end()) throw std::runtime_error("script parse error: unknown opcode");
        return it->second;
    }
};

opcodetype ParseOpCode(const std::string& s)
{
    static const OpCodeParser ocp;
    return ocp.Parse(s);
}

} // namespace

CScript ParseScript(const std::string& s)
{
    CScript result;


    std::vector<std::string> words = SplitString(s, " \t\n");

    for (const std::string& w : words) {
        if (w.empty()) {
            // Empty string, ignore. (SplitString doesn't combine multiple separators)
        } else if (std::all_of(w.begin(), w.end(), ::IsDigit) ||
                   (w.front() == '-' && w.size() > 1 && std::all_of(w.begin() + 1, w.end(), ::IsDigit)))
        {
            // Number
            const auto num{ToIntegral<int64_t>(w)};

            // limit the range of numbers ParseScript accepts in decimal
            // since numbers outside -0xFFFFFFFF...0xFFFFFFFF are illegal in scripts
            if (!num.has_value() || num > int64_t{0xffffffff} || num < -1 * int64_t{0xffffffff}) {
                throw std::runtime_error("script parse error: decimal numeric value only allowed in the "
                                         "range -0xFFFFFFFF...0xFFFFFFFF");
            }

            result << num.value();
        } else if (w.substr(0, 2) == "0x" && w.size() > 2 && IsHex(std::string(w.begin() + 2, w.end()))) {
            // Raw hex data, inserted NOT pushed onto stack:
            std::vector<unsigned char> raw = ParseHex(std::string(w.begin() + 2, w.end()));
            result.insert(result.end(), raw.begin(), raw.end());
        } else if (w.size() >= 2 && w.front() == '\'' && w.back() == '\'') {
            // Single-quoted string, pushed as data. NOTE: this is poor-man's
            // parsing, spaces/tabs/newlines in single-quoted strings won't work.
            std::vector<unsigned char> value(w.begin() + 1, w.end() - 1);
            result << value;
        } else {
            // opcode, e.g. OP_ADD or ADD:
            result << ParseOpCode(w);
        }
    }

    return result;
}

static bool DecodeTx(CMutableTransaction& tx, const std::vector<unsigned char>& tx_data)
{
    CDataStream ssData(tx_data, SER_NETWORK, PROTOCOL_VERSION);
    try {
        ssData >> tx;
        if (!ssData.empty()) {
            return false;
        }
    } catch (const std::exception&) {
        return false;
    }

    return true;
}

bool DecodeHexTx(CMutableTransaction& tx, const std::string& hex_tx)
{
    if (!IsHex(hex_tx)) {
        return false;
    }

    std::vector<unsigned char> txData(ParseHex(hex_tx));
    return DecodeTx(tx, txData);
}

bool DecodeHexBlockHeader(CBlockHeader& header, const std::string& hex_header)
{
    if (!IsHex(hex_header)) return false;

    const std::vector<unsigned char> header_data{ParseHex(hex_header)};
    CDataStream ser_header(header_data, SER_NETWORK, PROTOCOL_VERSION);
    try {
        ser_header >> header;
    } catch (const std::exception&) {
        return false;
    }
    return true;
}

bool DecodeHexBlk(CBlock& block, const std::string& strHexBlk)
{
    if (!IsHex(strHexBlk))
        return false;

    std::vector<unsigned char> blockData(ParseHex(strHexBlk));
    CDataStream ssBlock(blockData, SER_NETWORK, PROTOCOL_VERSION);
    try {
        ssBlock >> block;
    }
    catch (const std::exception&) {
        return false;
    }

    return true;
}

bool ParseHashStr(const std::string& strHex, uint256& result)
{
    if ((strHex.size() != 64) || !IsHex(strHex))
        return false;

    result.SetHex(strHex);
    return true;
}

std::vector<unsigned char> ParseHexUV(const UniValue& v, const std::string& strName)
{
    std::string strHex;
    if (v.isStr())
        strHex = v.getValStr();
    if (!IsHex(strHex))
        throw std::runtime_error(strName + " must be hexadecimal string (not '" + strHex + "')");
    return ParseHex(strHex);
}

int ParseSighashString(const UniValue& sighash)
{
    int hash_type = SIGHASH_ALL;
    if (!sighash.isNull()) {
        static std::map<std::string, int> map_sighash_values = {
            {std::string("ALL"), int(SIGHASH_ALL)},
            {std::string("ALL|ANYONECANPAY"), int(SIGHASH_ALL|SIGHASH_ANYONECANPAY)},
            {std::string("NONE"), int(SIGHASH_NONE)},
            {std::string("NONE|ANYONECANPAY"), int(SIGHASH_NONE|SIGHASH_ANYONECANPAY)},
            {std::string("SINGLE"), int(SIGHASH_SINGLE)},
            {std::string("SINGLE|ANYONECANPAY"), int(SIGHASH_SINGLE|SIGHASH_ANYONECANPAY)},
        };
        const std::string& strHashType = sighash.get_str();
        const auto& it = map_sighash_values.find(strHashType);
        if (it != map_sighash_values.end()) {
            hash_type = it->second;
        } else {
            throw std::runtime_error(strHashType + " is not a valid sighash parameter.");
        }
    }
    return hash_type;
}
