#include "WeldSeamTCPProtocol.h"

#include "IYTCPServer.h"
#include "VrLog.h"

#include <QByteArray>
#include <QMetaObject>
#include <QThread>
#include <atomic>
#include <map>
#include <mutex>
#include <set>
#include <vector>

namespace {

bool ParseIndexedCommand(const QString& command, const QString& name, int& cameraIndex)
{
    const QString prefix = name + QLatin1Char('_');
    if (!command.startsWith(prefix)) {
        return false;
    }

    bool valid = false;
    cameraIndex = command.mid(prefix.size()).toInt(&valid);
    return valid && cameraIndex > 0;
}

} // namespace

class WeldSeamTCPProtocol::Impl
{
public:
    explicit Impl(WeldSeamTCPProtocol* owner) : q(owner) {}

    bool Start(uint16_t port)
    {
        if (!VrCreatYTCPServer(&server) || !server) return false;
        if (!server->Init(port)) {
            delete server;
            server = nullptr;
            return false;
        }
        server->SetEventCallback([this](const TCPClient* client, TCPServerEventType type) {
            OnEvent(client, type);
        });
        if (!server->Start([this](const TCPClient* client, const char* data, unsigned int size) {
                OnData(client, data, size);
            })) {
            server->Close();
            delete server;
            server = nullptr;
            return false;
        }
        running = true;
        LOG_INFO("WeldSeam TCP server listening on %u\n", port);
        return true;
    }

    void Stop()
    {
        running = false;
        connected = false;
        if (server) {
            server->Stop();
            server->Close();
            delete server;
            server = nullptr;
        }
        std::lock_guard<std::mutex> lock(clientMutex);
        clients.clear();
        buffers.clear();
    }

    void Send(const QString& message)
    {
        if (!running || !server) return;
        QByteArray packet = message.toUtf8();
        if (!packet.endsWith("\r\n")) packet.append("\r\n");
        server->SendAllData(packet.constData(), static_cast<unsigned int>(packet.size()));
    }

private:
    void OnEvent(const TCPClient* client, TCPServerEventType type)
    {
        bool notify = false;
        bool isConnected = connected.load();
        if (type == TCP_EVENT_CLIENT_CONNECTED) {
            std::lock_guard<std::mutex> lock(clientMutex);
            clients.insert(client);
            const bool wasConnected = connected.exchange(true);
            isConnected = true;
            notify = !wasConnected;
        } else if (type == TCP_EVENT_CLIENT_DISCONNECTED || type == TCP_EVENT_CLIENT_EXCEPTION) {
            std::lock_guard<std::mutex> lock(clientMutex);
            buffers.erase(client);
            clients.erase(client);
            isConnected = !clients.empty();
            const bool wasConnected = connected.exchange(isConnected);
            notify = wasConnected != isConnected;
        }
        if (notify) {
            QMetaObject::invokeMethod(q, [this, isConnected]() {
                emit q->ConnectionChanged(isConnected);
            }, Qt::QueuedConnection);
        }
    }

    void OnData(const TCPClient* client, const char* data, unsigned int size)
    {
        if (!data || size == 0) return;
        std::vector<QString> commands;
        {
            std::lock_guard<std::mutex> lock(clientMutex);
            QByteArray& buffer = buffers[client];
            buffer.append(data, static_cast<int>(size));
            while (true) {
                const int end = buffer.indexOf("\r\n");
                if (end < 0) break;
                const QString command = QString::fromUtf8(buffer.left(end)).trimmed();
                buffer.remove(0, end + 2);
                if (!command.isEmpty()) commands.push_back(command);
            }
        }
        for (const auto& command : commands) Process(command);
    }

    void Process(const QString& command)
    {
        const QString normalized = command.trimmed().toUpper();
        QMetaObject::invokeMethod(q, [this, command]() { emit q->DataReceived(command); },
                                  Qt::QueuedConnection);
        int cameraIndex = 0;
        if (ParseIndexedCommand(normalized, QStringLiteral("START_SCAN"), cameraIndex)) {
            QMetaObject::invokeMethod(q, [this, cameraIndex]()
            {
                emit q->StartScanRequested(cameraIndex);
            }, Qt::QueuedConnection);
        } else if (normalized == QStringLiteral("STOP_SCAN")) {
            QMetaObject::invokeMethod(q, [this]() { emit q->StopScanRequested(); },
                                      Qt::QueuedConnection);
        } else if (ParseIndexedCommand(normalized, QStringLiteral("GET_RET"), cameraIndex)) {
            QMetaObject::invokeMethod(q, [this, cameraIndex]()
            {
                emit q->GetResultRequested(cameraIndex);
            }, Qt::QueuedConnection);
        } else if (normalized.startsWith(QStringLiteral("START_SCAN")) ||
                   normalized.startsWith(QStringLiteral("STOP_SCAN")) ||
                   normalized.startsWith(QStringLiteral("GET_RET"))) {
            q->SendMessage(QStringLiteral("ERROR_INVALID_FORMAT"));
        } else {
            q->SendMessage(QStringLiteral("ERROR_UNKNOWN_COMMAND"));
        }
    }

public:
    WeldSeamTCPProtocol* q = nullptr;
    IYTCPServer* server = nullptr;
    std::atomic<bool> running{false};
    std::atomic<bool> connected{false};
    std::set<const TCPClient*> clients;
    std::map<const TCPClient*, QByteArray> buffers;
    std::mutex clientMutex;
};

WeldSeamTCPProtocol::WeldSeamTCPProtocol(QObject* parent)
    : QObject(parent), m_impl(std::make_unique<Impl>(this))
{
}

WeldSeamTCPProtocol::~WeldSeamTCPProtocol()
{
    StopServer();
}

bool WeldSeamTCPProtocol::StartServer(uint16_t port) { return m_impl->Start(port); }
void WeldSeamTCPProtocol::StopServer() { m_impl->Stop(); }
bool WeldSeamTCPProtocol::IsConnected() const { return m_impl->connected.load(); }
void WeldSeamTCPProtocol::SendMessage(const QString& message)
{
    if (QThread::currentThread() != thread()) {
        QMetaObject::invokeMethod(this, [this, message]() { m_impl->Send(message); },
                                  Qt::QueuedConnection);
        return;
    }
    m_impl->Send(message);
}