/****************************************************************************
** Copyright (c) 2025 Evgeny Teterin (nayk) <nayk@nxt.ru>
** All right reserved.
**
** Permission is hereby granted, free of charge, to any person obtaining
** a copy of this software and associated documentation files (the
** "Software"), to deal in the Software without restriction, including
** without limitation the rights to use, copy, modify, merge, publish,
** distribute, sublicense, and/or sell copies of the Software, and to
** permit persons to whom the Software is furnished to do so, subject to
** the following conditions:
**
** The above copyright notice and this permission notice shall be
** included in all copies or substantial portions of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
** NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
** LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
** OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
** WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
**
****************************************************************************/
#include "main_window.h"
#include "./ui_main_window.h"

#include <QtWidgets/QApplication>
#include <QtGui/QRegularExpressionValidator>
#include <QtNetwork/QHostAddress>
#include <QtCore/QDateTime>
#include <QtCore/QElapsedTimer>

#include "application_config.h"

namespace server { //===========================================================

//==============================================================================
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    initialize();
    updateControls();
}
//==============================================================================
MainWindow::~MainWindow()
{
    disconnectClients();
    server.close();

    delete ui;
}
//==============================================================================
void MainWindow::initialize()
{
    setWindowTitle( QApplication::applicationName() );
    Application::initializeLog(ui->textEditLog);

    connect(ui->pushButtonConnect, &QPushButton::clicked, this, &MainWindow::btnConnect);
    connect(&server, &QTcpServer::newConnection, this, &MainWindow::newConnection);
}
//==============================================================================
void MainWindow::updateControls()
{
    bool connect {server.isListening()};

    ui->spinBoxPort->setEnabled(!connect);
    ui->pushButtonConnect->setText(connect ? tr("Закрыть") : tr("Открыть"));
}
//==============================================================================
void MainWindow::disconnectClients()
{
    while (!clients.isEmpty()) {

        QTcpSocket *socket = clients.takeLast();

        if (socket) {

            socket->close();

            if (socket->state() != QAbstractSocket::UnconnectedState)
                socket->waitForDisconnected(2000);
        }
    }
}
//==============================================================================
void MainWindow::btnConnect()
{
    ui->pushButtonConnect->setEnabled(false);
    ui->spinBoxPort->setEnabled(false);

    QApplication::processEvents(QEventLoop::ExcludeUserInputEvents);

    if (server.isListening()) {

        disconnectClients();
        server.close();

        Application::addToLog(
            ui->textEditLog,
            tr("Сервер закрыт"),
            Application::LogTypeWarning);

        ui->textEditLog->append("");
    }
    else {

        if (server.listen(
                QHostAddress::Any,
                static_cast<quint16>(ui->spinBoxPort->value())
                )
            ) {

            Application::addToLog(
                ui->textEditLog,
                tr("Сервер открыт для входящих подключений на порту %1")
                    .arg(ui->spinBoxPort->value()),
                Application::LogTypeWarning);
        }
        else {

            Application::addToLog(
                ui->textEditLog,
                tr("Не удалось открыть сервер (%1)").arg(server.errorString()),
                Application::LogTypeError);
        }
    }

    ui->pushButtonConnect->setEnabled(true);
    updateControls();
}
//==============================================================================
void MainWindow::newConnection()
{
    QTcpSocket* socket = server.nextPendingConnection();

    if (!socket)
        return;

    clients.append(socket);

    connect(socket, &QTcpSocket::readyRead, this, &MainWindow::clientRead);
    connect(socket, &QTcpSocket::disconnected, this, &MainWindow::clientDisconnect);

    QHostAddress clientAddress = socket->peerAddress();
    quint16 clientPort = socket->peerPort();

    Application::addToLog(
        ui->textEditLog,
        tr("Входящее подключение. Адрес клиента: %1; Порт клиента: %2")
            .arg(clientAddress.toString()).arg(clientPort),
        Application::LogTypeWarning);
}
//==============================================================================
void MainWindow::clientRead()
{
    QTcpSocket* socket = qobject_cast<QTcpSocket*>(sender());

    if (!socket)
        return;

    QHostAddress clientAddress = socket->peerAddress();

    Application::addToLog(
        ui->textEditLog, tr("Чтение входящих данных с %1").arg(clientAddress.toString()));

    QByteArray readData;
    QElapsedTimer timer;

    timer.start();

    while (readData.isEmpty() && (timer.elapsed() < timeout)) {

        readData = socket->readAll();
    }

    if (readData.isEmpty()) {

        Application::addToLog(
            ui->textEditLog,
            tr("Таймаут ожидания данных с %1").arg(clientAddress.toString()),
            Application::LogTypeError);
        return;
    }

    Application::addToLog(
        ui->textEditLog,
        tr("Принятые данные c %1: %2 (%3 байт)")
            .arg(clientAddress.toString(), QString(readData.toHex(' ')))
            .arg(readData.size()),
        Application::LogTypeData);

    Application::addToLog(
        ui->textEditLog,
        tr("Обработка массива %1 байт").arg(readData.size()));

    QByteArray sendData;

    // Преобразование данных в выходной массив:
    // если значение 0x00 или 0xFF, заменить на 0xAA
    // иначе на четных индексах увеличить значение на 1
    // на нечетных уменьшить значение на 1

    for (auto i = 0; i < readData.size(); ++i) {

        quint8 byte = static_cast<quint8>( readData.at(i) );

        if ((byte == 0) || (byte == 0xFF))
            byte = 0xAA;
        else if ((i % 2) == 0)
            ++byte;
        else
            --byte;

        sendData.append( static_cast<char>(byte) );
    }

    Application::addToLog(
        ui->textEditLog, tr("Данные после обработки: %1")
            .arg(
                QString(sendData.toHex(' '))
                ),
        Application::LogTypeData
        );

    Application::addToLog(
        ui->textEditLog,
        tr("Отправка данных клиенту %1").arg(clientAddress.toString()));

    qsizetype sendCount {0};
    timer.restart();

    while ((sendCount < sendData.size()) && (timer.elapsed() < timeout)) {

        qsizetype count = socket->write(sendData.mid(
            static_cast<int>(sendCount)
            ));

        if (count < 0) {

            Application::addToLog(
                ui->textEditLog, tr("Ошибка отправки данных на %1")
                    .arg(clientAddress.toString()),
                Application::LogTypeError );
        }
        else if (count > 0) {

            Application::addToLog(
                ui->textEditLog, tr("Отправка данных на %1: %2 (%3 байт)")
                    .arg(clientAddress.toString(),
                         QString(sendData.mid(
                                             static_cast<int>(sendCount),
                                             static_cast<int>(count)
                                             ).toHex(' ')))
                    .arg(count),
                Application::LogTypeData
                );
            sendCount += count;
        }
    }

    if (sendCount < sendData.size()) {

        Application::addToLog(
            ui->textEditLog, tr("Таймаут отправки данных на %1. Всего отправлено %2 байт из %3")
                .arg(clientAddress.toString()).arg(sendCount).arg(sendData.size()),
            Application::LogTypeError );
    }
}
//==============================================================================
void MainWindow::clientDisconnect()
{
    QString clientAddressStr;

    if (sender()) {

        QTcpSocket* socket = qobject_cast<QTcpSocket*>(sender());

        if (socket) {

            QHostAddress clientAddress = socket->peerAddress();
            clientAddressStr = clientAddress.toString();
        }
    }

    Application::addToLog(
        ui->textEditLog,
        tr("Закрытие входящего подключения %1").arg(clientAddressStr),
        Application::LogTypeWarning);
}
//==============================================================================

} // mamespace //===============================================================