#include "MetaCoreRuntimeData/MetaCoreRuntimeDataSource.h"

#include <algorithm>
#include <array>
#include <cctype>
#include <cmath>
#include <filesystem>
#include <fstream>
#include <memory>
#include <sstream>

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#ifndef NOMINMAX
#define NOMINMAX
#endif
#include <winsock2.h>
#include <ws2tcpip.h>

namespace MetaCore {

namespace {

constexpr SOCKET MetaCoreInvalidSocket = INVALID_SOCKET;

[[nodiscard]] std::string MetaCoreTrim(std::string value) {
    const auto isSpace = [](unsigned char ch) {
        return std::isspace(ch) != 0;
    };

    value.erase(value.begin(), std::find_if(value.begin(), value.end(), [&](unsigned char ch) {
        return !isSpace(ch);
    }));
    value.erase(std::find_if(value.rbegin(), value.rend(), [&](unsigned char ch) {
        return !isSpace(ch);
    }).base(), value.end());
    return value;
}

[[nodiscard]] const std::string* MetaCoreFindSetting(
    const MetaCoreDataSourceDefinition& sourceDefinition,
    const std::string& key
) {
    const auto iterator = std::find_if(
        sourceDefinition.ConnectionSettings.begin(),
        sourceDefinition.ConnectionSettings.end(),
        [&](const MetaCoreDataSourceSetting& setting) {
            return setting.Key == key;
        }
    );
    if (iterator == sourceDefinition.ConnectionSettings.end()) {
        return nullptr;
    }
    return &iterator->Value;
}

[[nodiscard]] bool MetaCoreParseValuePayload(
    std::istringstream& parser,
    const std::string& valueType,
    MetaCoreRuntimeDataValue& value,
    std::string& errorMessage
) {
    value.Quality = MetaCoreRuntimeDataQuality::Good;

    if (valueType == "bool") {
        std::string token;
        if (!(parser >> token)) {
            errorMessage = "bool value missing";
            return false;
        }
        value.Type = MetaCoreRuntimeValueType::Bool;
        value.BoolValue = (token == "true" || token == "1");
        return true;
    }
    if (valueType == "int64") {
        std::int64_t parsedValue = 0;
        if (!(parser >> parsedValue)) {
            errorMessage = "int64 value missing";
            return false;
        }
        value.Type = MetaCoreRuntimeValueType::Int64;
        value.Int64Value = parsedValue;
        return true;
    }
    if (valueType == "double") {
        double parsedValue = 0.0;
        if (!(parser >> parsedValue)) {
            errorMessage = "double value missing";
            return false;
        }
        value.Type = MetaCoreRuntimeValueType::Double;
        value.DoubleValue = parsedValue;
        return true;
    }
    if (valueType == "string") {
        std::string parsedValue;
        std::getline(parser >> std::ws, parsedValue);
        value.Type = MetaCoreRuntimeValueType::String;
        value.StringValue = MetaCoreTrim(parsedValue);
        return true;
    }
    if (valueType == "vec3") {
        float x = 0.0F;
        float y = 0.0F;
        float z = 0.0F;
        if (!(parser >> x >> y >> z)) {
            errorMessage = "vec3 value missing";
            return false;
        }
        value.Type = MetaCoreRuntimeValueType::Vec3;
        value.Vec3Value = glm::vec3(x, y, z);
        return true;
    }

    errorMessage = "value type not supported";
    return false;
}

[[nodiscard]] std::string MetaCoreResolveReplayFilePath(const std::string& replayFilePath) {
    const std::filesystem::path inputPath(replayFilePath);
    const std::vector<std::filesystem::path> candidates{
        std::filesystem::current_path() / inputPath,
        std::filesystem::current_path() / ".." / ".." / ".." / inputPath,
        std::filesystem::current_path() / ".." / ".." / ".." / "TestProject" / "Runtime" / inputPath.filename()
    };

    for (const auto& candidate : candidates) {
        std::error_code errorCode;
        if (std::filesystem::exists(candidate, errorCode)) {
            return std::filesystem::weakly_canonical(candidate, errorCode).string();
        }
    }
    return (std::filesystem::current_path() / inputPath).string();
}

}  // namespace

std::string MetaCoreMockRuntimeDataSourceAdapter::GetAdapterType() const {
    return "mock";
}

bool MetaCoreMockRuntimeDataSourceAdapter::Configure(const MetaCoreDataSourceDefinition& sourceDefinition) {
    SourceDefinition_ = sourceDefinition;
    Status_.SourceId = sourceDefinition.Id;
    Status_.State = MetaCoreRuntimeDataSourceState::Disconnected;
    Status_.LastConnectedAt = 0;
    Status_.LastUpdateAt = 0;
    Status_.LastError.clear();
    ElapsedSeconds_ = 0.0;
    Sequence_ = 0;
    return true;
}

bool MetaCoreMockRuntimeDataSourceAdapter::Connect() {
    Status_.State = MetaCoreRuntimeDataSourceState::Connected;
    Status_.LastConnectedAt = 1;
    Status_.LastError.clear();
    return true;
}

void MetaCoreMockRuntimeDataSourceAdapter::Disconnect() {
    Status_.State = MetaCoreRuntimeDataSourceState::Disconnected;
    Status_.LastError.clear();
}

void MetaCoreMockRuntimeDataSourceAdapter::Tick(double deltaSeconds) {
    if (Status_.State != MetaCoreRuntimeDataSourceState::Connected) {
        return;
    }
    ElapsedSeconds_ += std::max(0.0, deltaSeconds);
    if (!EmitUpdates_) {
        Status_.State = MetaCoreRuntimeDataSourceState::Degraded;
        Status_.LastError = "Mock adapter update emission disabled";
    } else {
        Status_.State = MetaCoreRuntimeDataSourceState::Connected;
        Status_.LastError.clear();
    }
}

std::vector<MetaCoreRuntimeDataUpdate> MetaCoreMockRuntimeDataSourceAdapter::PollUpdates() {
    if (Status_.State == MetaCoreRuntimeDataSourceState::Disconnected || !EmitUpdates_) {
        return {};
    }

    const std::uint64_t timestamp = static_cast<std::uint64_t>(ElapsedSeconds_ * 1000.0);
    Status_.LastUpdateAt = timestamp;

    std::vector<MetaCoreRuntimeDataUpdate> updates;
    updates.push_back(MetaCoreRuntimeDataUpdate{
        "cube.position",
        MetaCoreRuntimeDataValue{
            MetaCoreRuntimeValueType::Vec3,
            false,
            0,
            0.0,
            {},
            glm::vec3(static_cast<float>(std::sin(ElapsedSeconds_)) * 2.0F, 0.5F, 0.0F),
            timestamp,
            MetaCoreRuntimeDataQuality::Good
        },
        ++Sequence_
    });
    updates.push_back(MetaCoreRuntimeDataUpdate{
        "cube.visible",
        MetaCoreRuntimeDataValue{
            MetaCoreRuntimeValueType::Bool,
            std::fmod(ElapsedSeconds_, 2.0) < 1.0,
            0,
            0.0,
            {},
            glm::vec3(0.0F, 0.0F, 0.0F),
            timestamp,
            MetaCoreRuntimeDataQuality::Good
        },
        ++Sequence_
    });
    updates.push_back(MetaCoreRuntimeDataUpdate{
        "cube.base_color",
        MetaCoreRuntimeDataValue{
            MetaCoreRuntimeValueType::Vec3,
            false,
            0,
            0.0,
            {},
            glm::vec3(
                0.5F + static_cast<float>(std::sin(ElapsedSeconds_)) * 0.5F,
                0.6F,
                0.9F - static_cast<float>(std::sin(ElapsedSeconds_)) * 0.3F
            ),
            timestamp,
            MetaCoreRuntimeDataQuality::Good
        },
        ++Sequence_
    });
    return updates;
}

const MetaCoreRuntimeDataSourceStatus& MetaCoreMockRuntimeDataSourceAdapter::GetStatus() const {
    return Status_;
}

void MetaCoreMockRuntimeDataSourceAdapter::SetEmitUpdates(bool emitUpdates) {
    EmitUpdates_ = emitUpdates;
}

std::string MetaCoreFileReplayRuntimeDataSourceAdapter::GetAdapterType() const {
    return "file_replay";
}

bool MetaCoreFileReplayRuntimeDataSourceAdapter::Configure(const MetaCoreDataSourceDefinition& sourceDefinition) {
    SourceDefinition_ = sourceDefinition;
    Status_.SourceId = sourceDefinition.Id;
    Status_.State = MetaCoreRuntimeDataSourceState::Disconnected;
    Status_.LastConnectedAt = 0;
    Status_.LastUpdateAt = 0;
    Status_.LastError.clear();
    Frames_.clear();
    ReplayFilePath_.clear();
    NextFrameIndex_ = 0;
    ElapsedSeconds_ = 0.0;
    Sequence_ = 0;

    const std::string* replayFilePath = MetaCoreFindSetting(sourceDefinition, "file_path");
    if (replayFilePath == nullptr || replayFilePath->empty()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "Missing file_path connection setting";
        return false;
    }

    ReplayFilePath_ = MetaCoreResolveReplayFilePath(*replayFilePath);
    return true;
}

bool MetaCoreFileReplayRuntimeDataSourceAdapter::Connect() {
    Status_.State = MetaCoreRuntimeDataSourceState::Connecting;
    if (!LoadReplayFile()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        if (Status_.LastError.empty()) {
            Status_.LastError = "Failed to load replay file";
        }
        return false;
    }

    Status_.State = MetaCoreRuntimeDataSourceState::Connected;
    Status_.LastConnectedAt = 1;
    Status_.LastError.clear();
    return true;
}

void MetaCoreFileReplayRuntimeDataSourceAdapter::Disconnect() {
    Status_.State = MetaCoreRuntimeDataSourceState::Disconnected;
    Status_.LastError.clear();
    NextFrameIndex_ = 0;
    ElapsedSeconds_ = 0.0;
}

void MetaCoreFileReplayRuntimeDataSourceAdapter::Tick(double deltaSeconds) {
    if (Status_.State != MetaCoreRuntimeDataSourceState::Connected &&
        Status_.State != MetaCoreRuntimeDataSourceState::Degraded) {
        return;
    }

    ElapsedSeconds_ += std::max(0.0, deltaSeconds);
    if (Frames_.empty()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Degraded;
        Status_.LastError = "Replay file has no frames";
        return;
    }

    if (NextFrameIndex_ >= Frames_.size()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Degraded;
        Status_.LastError = "Replay stream exhausted";
    } else {
        Status_.State = MetaCoreRuntimeDataSourceState::Connected;
        Status_.LastError.clear();
    }
}

std::vector<MetaCoreRuntimeDataUpdate> MetaCoreFileReplayRuntimeDataSourceAdapter::PollUpdates() {
    if (Status_.State == MetaCoreRuntimeDataSourceState::Disconnected ||
        Status_.State == MetaCoreRuntimeDataSourceState::Faulted ||
        Frames_.empty()) {
        return {};
    }

    std::vector<MetaCoreRuntimeDataUpdate> updates;
    while (NextFrameIndex_ < Frames_.size() &&
           Frames_[NextFrameIndex_].EmitAfterSeconds <= ElapsedSeconds_) {
        MetaCoreRuntimeDataUpdate update = Frames_[NextFrameIndex_].Update;
        update.Sequence = ++Sequence_;
        update.Value.SourceTimestamp = static_cast<std::uint64_t>(Frames_[NextFrameIndex_].EmitAfterSeconds * 1000.0);
        Status_.LastUpdateAt = update.Value.SourceTimestamp;
        updates.push_back(update);
        ++NextFrameIndex_;
    }

    if (NextFrameIndex_ >= Frames_.size() && updates.empty()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Degraded;
        Status_.LastError = "Replay stream exhausted";
    }

    return updates;
}

const MetaCoreRuntimeDataSourceStatus& MetaCoreFileReplayRuntimeDataSourceAdapter::GetStatus() const {
    return Status_;
}

bool MetaCoreFileReplayRuntimeDataSourceAdapter::LoadReplayFile() {
    Frames_.clear();
    std::ifstream input(ReplayFilePath_);
    if (!input) {
        Status_.LastError = "Unable to open replay file: " + ReplayFilePath_;
        return false;
    }

    std::string line;
    std::size_t lineNumber = 0;
    while (std::getline(input, line)) {
        ++lineNumber;
        line = MetaCoreTrim(line);
        if (line.empty() || line.front() == '#') {
            continue;
        }

        std::istringstream parser(line);
        double emitAfterSeconds = 0.0;
        std::string dataPointId;
        std::string valueType;
        if (!(parser >> emitAfterSeconds >> dataPointId >> valueType)) {
            Status_.LastError = "Replay parse error at line " + std::to_string(lineNumber);
            return false;
        }

        MetaCoreRuntimeDataUpdate update;
        update.DataPointId = dataPointId;
        update.Sequence = 0;
        std::string parseError;
        if (!MetaCoreParseValuePayload(parser, valueType, update.Value, parseError)) {
            Status_.LastError = "Replay " + parseError + " at line " + std::to_string(lineNumber);
            return false;
        }

        Frames_.push_back(ReplayFrame{
            emitAfterSeconds,
            update
        });
    }

    std::sort(Frames_.begin(), Frames_.end(), [](const ReplayFrame& lhs, const ReplayFrame& rhs) {
        return lhs.EmitAfterSeconds < rhs.EmitAfterSeconds;
    });
    return true;
}

std::string MetaCoreTcpRuntimeDataSourceAdapter::GetAdapterType() const {
    return "tcp";
}

bool MetaCoreTcpRuntimeDataSourceAdapter::Configure(const MetaCoreDataSourceDefinition& sourceDefinition) {
    SourceDefinition_ = sourceDefinition;
    Status_.SourceId = sourceDefinition.Id;
    Status_.State = MetaCoreRuntimeDataSourceState::Disconnected;
    Status_.LastConnectedAt = 0;
    Status_.LastUpdateAt = 0;
    Status_.LastError.clear();
    Host_ = "127.0.0.1";
    Port_ = 0;
    Sequence_ = 0;
    ElapsedSeconds_ = 0.0;
    ReceiveBuffer_.clear();
    PendingUpdates_.clear();

    if (const std::string* host = MetaCoreFindSetting(sourceDefinition, "host"); host != nullptr && !host->empty()) {
        Host_ = *host;
    }
    const std::string* portValue = MetaCoreFindSetting(sourceDefinition, "port");
    if (portValue == nullptr || portValue->empty()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "Missing port connection setting";
        return false;
    }

    try {
        Port_ = static_cast<std::uint16_t>(std::stoul(*portValue));
    } catch (...) {
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "Invalid port connection setting";
        return false;
    }

    return true;
}

bool MetaCoreTcpRuntimeDataSourceAdapter::EnsureWinsockInitialized() {
    static bool initialized = false;
    if (initialized) {
        return true;
    }

    WSADATA wsaData{};
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        Status_.LastError = "WSAStartup failed";
        return false;
    }
    initialized = true;
    return true;
}

bool MetaCoreTcpRuntimeDataSourceAdapter::Connect() {
    Status_.State = MetaCoreRuntimeDataSourceState::Connecting;
    if (!EnsureWinsockInitialized()) {
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        return false;
    }

    addrinfo hints{};
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    addrinfo* result = nullptr;
    const std::string portString = std::to_string(Port_);
    if (getaddrinfo(Host_.c_str(), portString.c_str(), &hints, &result) != 0 || result == nullptr) {
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "getaddrinfo failed";
        return false;
    }

    SOCKET socketHandle = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (socketHandle == MetaCoreInvalidSocket) {
        freeaddrinfo(result);
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "socket creation failed";
        return false;
    }

    if (connect(socketHandle, result->ai_addr, static_cast<int>(result->ai_addrlen)) == SOCKET_ERROR) {
        closesocket(socketHandle);
        freeaddrinfo(result);
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "tcp connect failed";
        return false;
    }
    freeaddrinfo(result);

    u_long nonBlocking = 1;
    ioctlsocket(socketHandle, FIONBIO, &nonBlocking);
    SocketHandle_ = reinterpret_cast<void*>(socketHandle);
    Status_.State = MetaCoreRuntimeDataSourceState::Connected;
    Status_.LastConnectedAt = 1;
    Status_.LastError.clear();
    return true;
}

void MetaCoreTcpRuntimeDataSourceAdapter::Disconnect() {
    if (SocketHandle_ != nullptr) {
        closesocket(reinterpret_cast<SOCKET>(SocketHandle_));
        SocketHandle_ = nullptr;
    }
    Status_.State = MetaCoreRuntimeDataSourceState::Disconnected;
    Status_.LastError.clear();
    ReceiveBuffer_.clear();
    PendingUpdates_.clear();
}

void MetaCoreTcpRuntimeDataSourceAdapter::Tick(double deltaSeconds) {
    ElapsedSeconds_ += std::max(0.0, deltaSeconds);
    if (SocketHandle_ == nullptr || Status_.State == MetaCoreRuntimeDataSourceState::Faulted) {
        return;
    }

    SOCKET socketHandle = reinterpret_cast<SOCKET>(SocketHandle_);
    std::array<char, 1024> buffer{};
    for (;;) {
        const int received = recv(socketHandle, buffer.data(), static_cast<int>(buffer.size()), 0);
        if (received > 0) {
            ReceiveBuffer_.append(buffer.data(), static_cast<std::size_t>(received));
            Status_.State = MetaCoreRuntimeDataSourceState::Connected;
            Status_.LastError.clear();
            continue;
        }
        if (received == 0) {
            Status_.State = MetaCoreRuntimeDataSourceState::Degraded;
            Status_.LastError = "tcp stream closed by peer";
            break;
        }

        const int socketError = WSAGetLastError();
        if (socketError == WSAEWOULDBLOCK) {
            break;
        }
        Status_.State = MetaCoreRuntimeDataSourceState::Faulted;
        Status_.LastError = "tcp recv failed";
        break;
    }

    for (;;) {
        const std::size_t newlineIndex = ReceiveBuffer_.find('\n');
        if (newlineIndex == std::string::npos) {
            break;
        }

        std::string line = MetaCoreTrim(ReceiveBuffer_.substr(0, newlineIndex));
        ReceiveBuffer_.erase(0, newlineIndex + 1);
        if (line.empty() || line.front() == '#') {
            continue;
        }

        MetaCoreRuntimeDataUpdate update;
        if (!ParseSocketLine(line, update)) {
            Status_.State = MetaCoreRuntimeDataSourceState::Degraded;
            if (Status_.LastError.empty()) {
                Status_.LastError = "tcp line parse failed";
            }
            continue;
        }
        PendingUpdates_.push_back(std::move(update));
    }
}

std::vector<MetaCoreRuntimeDataUpdate> MetaCoreTcpRuntimeDataSourceAdapter::PollUpdates() {
    if (PendingUpdates_.empty()) {
        return {};
    }

    const std::uint64_t timestamp = static_cast<std::uint64_t>(ElapsedSeconds_ * 1000.0);
    for (auto& update : PendingUpdates_) {
        update.Sequence = ++Sequence_;
        update.Value.SourceTimestamp = timestamp;
    }
    Status_.LastUpdateAt = timestamp;

    std::vector<MetaCoreRuntimeDataUpdate> updates = std::move(PendingUpdates_);
    PendingUpdates_.clear();
    return updates;
}

const MetaCoreRuntimeDataSourceStatus& MetaCoreTcpRuntimeDataSourceAdapter::GetStatus() const {
    return Status_;
}

bool MetaCoreTcpRuntimeDataSourceAdapter::ParseSocketLine(const std::string& line, MetaCoreRuntimeDataUpdate& update) {
    std::istringstream parser(line);
    std::string dataPointId;
    std::string valueType;
    if (!(parser >> dataPointId >> valueType)) {
        Status_.LastError = "tcp line missing header fields";
        return false;
    }

    update = MetaCoreRuntimeDataUpdate{};
    update.DataPointId = dataPointId;
    std::string parseError;
    if (!MetaCoreParseValuePayload(parser, valueType, update.Value, parseError)) {
        Status_.LastError = "tcp " + parseError;
        return false;
    }
    return true;
}

std::unique_ptr<MetaCoreIRuntimeDataSourceAdapter> MetaCoreCreateRuntimeDataSourceAdapter(
    const std::string& adapterType
) {
    if (adapterType == "mock") {
        return std::make_unique<MetaCoreMockRuntimeDataSourceAdapter>();
    }
    if (adapterType == "file_replay") {
        return std::make_unique<MetaCoreFileReplayRuntimeDataSourceAdapter>();
    }
    if (adapterType == "tcp") {
        return std::make_unique<MetaCoreTcpRuntimeDataSourceAdapter>();
    }
    return nullptr;
}

}  // namespace MetaCore