#pragma once

#include <yql/essentials/public/udf/udf_helpers.h>

#include <library/cpp/ipv6_address/ipv6_address.h>
#include <library/cpp/ipmath/ipmath.h>
#include <util/generic/buffer.h>

namespace {
    using TAutoMapString = NKikimr::NUdf::TAutoMap<char*>;
    using TOptionalString = NKikimr::NUdf::TOptional<char*>;
    using TOptionalByte = NKikimr::NUdf::TOptional<ui8>;
    using TStringRef = NKikimr::NUdf::TStringRef;
    using TUnboxedValue = NKikimr::NUdf::TUnboxedValue;
    using TUnboxedValuePod = NKikimr::NUdf::TUnboxedValuePod;

    ui8 GetAddressRangePrefix(const TIpAddressRange& range) {
        if (range.Contains(TIpv6Address(ui128(0), TIpv6Address::Ipv6)) && range.Contains(TIpv6Address(ui128(-1), TIpv6Address::Ipv6))) {
            return 0;
        }
        if (range.Size() == 0) {
            return range.Type() == TIpv6Address::Ipv4 ? 32 : 128;
        }
        ui128 size = range.Size();
        size_t sizeLog = MostSignificantBit(size);
        return ui8((range.Type() == TIpv6Address::Ipv4 ? 32 : 128) - sizeLog);
    }

    struct TRawIp4 {
        ui8 a, b, c, d;

        static TRawIp4 FromIpAddress(const TIpv6Address& addr) {
            ui128 x = addr;
            return {
                ui8(x >> 24 & 0xff),
                ui8(x >> 16 & 0xff),
                ui8(x >> 8  & 0xff),
                ui8(x & 0xff)
           };
        }

        static TRawIp4 MaskFromPrefix(ui8 prefix) {
            ui128 x = ui128(-1) << int(32 - prefix);
            x &= ui128(ui32(-1));
            return FromIpAddress({x, TIpv6Address::Ipv4});
        }

        TIpv6Address ToIpAddress() const {
            return {a, b, c, d};
        }

        std::pair<TRawIp4, TRawIp4> ApplyMask(const TRawIp4& mask) const {
            return {{
                    ui8(a & mask.a),
                    ui8(b & mask.b),
                    ui8(c & mask.c),
                    ui8(d & mask.d)
                },{
                    ui8(a | ~mask.a),
                    ui8(b | ~mask.b),
                    ui8(c | ~mask.c),
                    ui8(d | ~mask.d)
            }};
        }
    };

    struct TRawIp4Subnet {
        TRawIp4 base, mask;

        static TRawIp4Subnet FromIpRange(const TIpAddressRange& range) {
            return {TRawIp4::FromIpAddress(*range.Begin()), TRawIp4::MaskFromPrefix(GetAddressRangePrefix(range))};
        }

        TIpAddressRange ToIpRange() const {
            auto range = base.ApplyMask(mask);
            return {range.first.ToIpAddress(), range.second.ToIpAddress()};
        }
    };

    struct TRawIp6 {
        ui8 a1, a0, b1, b0, c1, c0, d1, d0, e1, e0, f1, f0, g1, g0, h1, h0;

        static TRawIp6 FromIpAddress(const TIpv6Address& addr) {
            ui128 x = addr;
            return {
                ui8(x >> 120 & 0xff), ui8(x >> 112 & 0xff),
                ui8(x >> 104 & 0xff), ui8(x >> 96 & 0xff),
                ui8(x >> 88 & 0xff), ui8(x >> 80 & 0xff),
                ui8(x >> 72 & 0xff), ui8(x >> 64 & 0xff),
                ui8(x >> 56 & 0xff), ui8(x >> 48 & 0xff),
                ui8(x >> 40 & 0xff), ui8(x >> 32 & 0xff),
                ui8(x >> 24 & 0xff), ui8(x >> 16 & 0xff),
                ui8(x >> 8 & 0xff), ui8(x & 0xff)
            };
        }

        static TRawIp6 MaskFromPrefix(ui8 prefix) {
            ui128 x = prefix == 0 ? ui128(0) : ui128(-1) << int(128 - prefix);
            return FromIpAddress({x, TIpv6Address::Ipv6});
        }

        TIpv6Address ToIpAddress() const {
            return {ui16(ui32(a1) << ui32(8) | ui32(a0)),
               ui16(ui32(b1) << ui32(8) | ui32(b0)),
               ui16(ui32(c1) << ui32(8) | ui32(c0)),
               ui16(ui32(d1) << ui32(8) | ui32(d0)),
               ui16(ui32(e1) << ui32(8) | ui32(e0)),
               ui16(ui32(f1) << ui32(8) | ui32(f0)),
               ui16(ui32(g1) << ui32(8) | ui32(g0)),
               ui16(ui32(h1) << ui32(8) | ui32(h0)),
            };
        }

        std::pair<TRawIp6, TRawIp6> ApplyMask(const TRawIp6& mask) const {
            return { {
                    ui8(a1 & mask.a1),
                    ui8(a0 & mask.a0),
                    ui8(b1 & mask.b1),
                    ui8(b0 & mask.b0),
                    ui8(c1 & mask.c1),
                    ui8(c0 & mask.c0),
                    ui8(d1 & mask.d1),
                    ui8(d0 & mask.d0),
                    ui8(e1 & mask.e1),
                    ui8(e0 & mask.e0),
                    ui8(f1 & mask.f1),
                    ui8(f0 & mask.f0),
                    ui8(g1 & mask.g1),
                    ui8(g0 & mask.g0),
                    ui8(h1 & mask.h1),
                    ui8(h0 & mask.h0)
                }, {
                    ui8(a1 | ~mask.a1),
                    ui8(a0 | ~mask.a0),
                    ui8(b1 | ~mask.b1),
                    ui8(b0 | ~mask.b0),
                    ui8(c1 | ~mask.c1),
                    ui8(c0 | ~mask.c0),
                    ui8(d1 | ~mask.d1),
                    ui8(d0 | ~mask.d0),
                    ui8(e1 | ~mask.e1),
                    ui8(e0 | ~mask.e0),
                    ui8(f1 | ~mask.f1),
                    ui8(f0 | ~mask.f0),
                    ui8(g1 | ~mask.g1),
                    ui8(g0 | ~mask.g0),
                    ui8(h1 | ~mask.h1),
                    ui8(h0 | ~mask.h0)
            }};
        }
    };

    struct TRawIp6Subnet {
        TRawIp6 base, mask;

        static TRawIp6Subnet FromIpRange(const TIpAddressRange& range) {
            return {TRawIp6::FromIpAddress(*range.Begin()), TRawIp6::MaskFromPrefix(GetAddressRangePrefix(range))};
        }

        TIpAddressRange ToIpRange() const {
            auto range = base.ApplyMask(mask);
            return {range.first.ToIpAddress(), range.second.ToIpAddress()};
        }
    };

    TIpv6Address DeserializeAddress(const TStringRef& str) {
        TIpv6Address addr;
        if (str.Size() == 4) {
            TRawIp4 addr4;
            memcpy(&addr4, str.Data(), sizeof addr4);
            addr = addr4.ToIpAddress();
        } else if (str.Size() == 16) {
            TRawIp6 addr6;
            memcpy(&addr6, str.Data(), sizeof addr6);
            addr = addr6.ToIpAddress();
        } else {
            ythrow yexception() << "Incorrect size of input, expected "
            << "4 or 16, got " << str.Size();
        }
        return addr;
    }

    TIpAddressRange DeserializeSubnet(const TStringRef& str) {
        TIpAddressRange range;
        if (str.Size() == sizeof(TRawIp4Subnet)) {
            TRawIp4Subnet subnet4;
            memcpy(&subnet4, str.Data(), sizeof subnet4);
            range = subnet4.ToIpRange();
        } else if (str.Size() == sizeof(TRawIp6Subnet)) {
            TRawIp6Subnet subnet6;
            memcpy(&subnet6, str.Data(), sizeof subnet6);
            range = subnet6.ToIpRange();
        } else {
            ythrow yexception() << "Invalid binary representation";
        }
        return range;
    }

    TString SerializeAddress(const TIpv6Address& addr) {
        Y_ENSURE(addr.Type() == TIpv6Address::Ipv4 || addr.Type() == TIpv6Address::Ipv6);
        TString res;
        if (addr.Type() == TIpv6Address::Ipv4) {
            auto addr4 = TRawIp4::FromIpAddress(addr);
            res = TString(reinterpret_cast<const char *>(&addr4), sizeof addr4);
        } else if (addr.Type() == TIpv6Address::Ipv6) {
            auto addr6 = TRawIp6::FromIpAddress(addr);
            res = TString(reinterpret_cast<const char *>(&addr6), sizeof addr6);
        }
        return res;
    }

    TString SerializeSubnet(const TIpAddressRange& range) {
        TString res;
        if (range.Type() == TIpv6Address::Ipv4) {
            auto subnet4 = TRawIp4Subnet::FromIpRange(range);
            res = TString(reinterpret_cast<const char *>(&subnet4), sizeof subnet4);
        } else if (range.Type() == TIpv6Address::Ipv6) {
            auto subnet6 = TRawIp6Subnet::FromIpRange(range);
            res = TString(reinterpret_cast<const char *>(&subnet6), sizeof subnet6);
        }
        return res;
    }

    SIMPLE_STRICT_UDF(TFromString, TOptionalString(TAutoMapString)) {
        TIpv6Address addr = TIpv6Address::FromString(args[0].AsStringRef());
        if (addr.Type() != TIpv6Address::Ipv4 && addr.Type() != TIpv6Address::Ipv6) {
            return TUnboxedValue();
        }
        return valueBuilder->NewString(SerializeAddress(addr));
    }

    SIMPLE_STRICT_UDF(TSubnetFromString, TOptionalString(TAutoMapString)) {
        TIpAddressRange range = TIpAddressRange::FromCompactString(args[0].AsStringRef());
        auto res = SerializeSubnet(range);
        return res ? valueBuilder->NewString(res) : TUnboxedValue(TUnboxedValuePod());
    }

    SIMPLE_UDF(TToString, char*(TAutoMapString)) {
        return valueBuilder->NewString(DeserializeAddress(args[0].AsStringRef()).ToString(false));
    }

    SIMPLE_UDF(TSubnetToString, char*(TAutoMapString)) {
        TStringBuilder result;
        auto range = DeserializeSubnet(args[0].AsStringRef());
        result << (*range.Begin()).ToString(false);
        result << '/';
        result << ToString(GetAddressRangePrefix(range));
        return valueBuilder->NewString(result);
    }

    SIMPLE_UDF(TSubnetMatch, bool(TAutoMapString, TAutoMapString)) {
        Y_UNUSED(valueBuilder);
        auto range1 = DeserializeSubnet(args[0].AsStringRef());
        if (args[1].AsStringRef().Size() == sizeof(TRawIp4) || args[1].AsStringRef().Size() == sizeof(TRawIp6)) {
            auto addr2 = DeserializeAddress(args[1].AsStringRef());
            return TUnboxedValuePod(range1.Contains(addr2));
        } else { // second argument is a whole subnet, not a single address
            auto range2 = DeserializeSubnet(args[1].AsStringRef());
            return TUnboxedValuePod(range1.Contains(range2));
        }
    }

    SIMPLE_STRICT_UDF(TIsIPv4, bool(TOptionalString)) {
        Y_UNUSED(valueBuilder);
        bool result = false;
        if (args[0]) {
            const auto ref = args[0].AsStringRef();
            result = ref.Size() == 4;
        }
        return TUnboxedValuePod(result);
    }

    SIMPLE_STRICT_UDF(TIsIPv6, bool(TOptionalString)) {
        Y_UNUSED(valueBuilder);
        bool result = false;
        if (args[0]) {
            const auto ref = args[0].AsStringRef();
            result = ref.Size() == 16;
        }
        return TUnboxedValuePod(result);
    }

    SIMPLE_STRICT_UDF(TIsEmbeddedIPv4, bool(TOptionalString)) {
        Y_UNUSED(valueBuilder);
        bool result = false;
        if (args[0]) {
            const auto ref = args[0].AsStringRef();
            if (ref.Size() == 16) {
                result = DeserializeAddress(ref).Isv4MappedTov6();
            }
        }
        return TUnboxedValuePod(result);
    }

    SIMPLE_UDF(TConvertToIPv6, char*(TAutoMapString)) {
        const auto& ref = args[0].AsStringRef();
        if (ref.Size() == 16) {
            return valueBuilder->NewString(ref);
        } else if (ref.Size() == 4) {
            TIpv6Address addr4 = DeserializeAddress(ref);
            auto addr6 = TIpv6Address(ui128(addr4) | ui128(0xFFFF) << 32, TIpv6Address::Ipv6);
            return valueBuilder->NewString(SerializeAddress(addr6));
        } else {
            ythrow yexception() << "Incorrect size of input, expected "
            << "4 or 16, got " << ref.Size();
        }
    }

    SIMPLE_UDF_WITH_OPTIONAL_ARGS(TGetSubnet, char*(TAutoMapString, TOptionalByte), 1) {
        const auto ref = args[0].AsStringRef();
        ui8 subnetSize = args[1].GetOrDefault<ui8>(0);
        TIpv6Address addr = DeserializeAddress(ref);
        if (ref.Size() == 4) {
            if (!subnetSize) {
                subnetSize = 24;
            }
            if (subnetSize > 32) {
                subnetSize = 32;
            }
        } else if (ref.Size() == 16) {
            if (!subnetSize) {
                subnetSize = 64;
            }
            if (subnetSize > 128) {
                subnetSize = 128;
            }
        } else {
            ythrow yexception() << "Incorrect size of input, expected "
            << "4 or 16, got " << ref.Size();
        }
        TIpv6Address beg = LowerBoundForPrefix(addr, subnetSize);
        return valueBuilder->NewString(SerializeAddress(beg));
    }

    SIMPLE_UDF(TGetSubnetByMask, char*(TAutoMapString, TAutoMapString)) {
        const auto refBase = args[0].AsStringRef();
        const auto refMask = args[1].AsStringRef();
        TIpv6Address addrBase = DeserializeAddress(refBase);
        TIpv6Address addrMask = DeserializeAddress(refMask);
        if (addrBase.Type() != addrMask.Type()) {
            ythrow yexception() << "Base and mask differ in length";
        }
        return valueBuilder->NewString(SerializeAddress(TIpv6Address(ui128(addrBase) & ui128(addrMask), addrBase.Type())));
    }

#define EXPORTED_IP_BASE_UDF \
    TFromString, \
    TSubnetFromString, \
    TToString, \
    TSubnetToString, \
    TIsIPv4, \
    TIsIPv6, \
    TIsEmbeddedIPv4, \
    TConvertToIPv6, \
    TGetSubnet, \
    TSubnetMatch, \
    TGetSubnetByMask
}