//    Copyright (C) 2021 Jakub Melka
//
//    This file is part of Pdf4Qt.
//
//    Pdf4Qt is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Lesser General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    with the written consent of the copyright owner, any later version.
//
//    Pdf4Qt is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Lesser General Public License for more details.
//
//    You should have received a copy of the GNU Lesser General Public License
//    along with Pdf4Qt.  If not, see <https://www.gnu.org/licenses/>.

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include "pdfwidgetutils.h"
#include "pdfdocumentreader.h"

#include <QFileDialog>
#include <QMessageBox>
#include <QInputDialog>
#include <QDesktopWidget>
#include <QClipboard>
#include <QToolBar>

namespace pdfdocpage
{

MainWindow::MainWindow(QWidget* parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow),
    m_model(new PageItemModel(this)),
    m_delegate(new PageItemDelegate(m_model, this))
{
    ui->setupUi(this);

    m_delegate->setPageImageSize(getDefaultPageImageSize());

    ui->documentItemsView->setModel(m_model);
    ui->documentItemsView->setItemDelegate(m_delegate);
    setMinimumSize(pdf::PDFWidgetUtils::scaleDPI(this, QSize(800, 600)));

    ui->actionCloneSelection->setData(int(Operation::CloneSelection));
    ui->actionRemoveSelection->setData(int(Operation::RemoveSelection));
    ui->actionReplaceSelection->setData(int(Operation::ReplaceSelection));
    ui->actionRestoreRemovedItems->setData(int(Operation::RestoreRemovedItems));
    ui->actionCut->setData(int(Operation::Cut));
    ui->actionCopy->setData(int(Operation::Copy));
    ui->actionPaste->setData(int(Operation::Paste));
    ui->actionRotate_Left->setData(int(Operation::RotateLeft));
    ui->actionRotate_Right->setData(int(Operation::RotateRight));
    ui->actionGroup->setData(int(Operation::Group));
    ui->actionUngroup->setData(int(Operation::Ungroup));
    ui->actionSelect_None->setData(int(Operation::SelectNone));
    ui->actionSelect_All->setData(int(Operation::SelectAll));
    ui->actionSelect_Even->setData(int(Operation::SelectEven));
    ui->actionSelect_Odd->setData(int(Operation::SelectOdd));
    ui->actionSelect_Portrait->setData(int(Operation::SelectPortrait));
    ui->actionSelect_Landscape->setData(int(Operation::SelectLandscape));
    ui->actionZoom_In->setData(int(Operation::ZoomIn));
    ui->actionZoom_Out->setData(int(Operation::ZoomOut));
    ui->actionUnited_Document->setData(int(Operation::Unite));
    ui->actionSeparate_to_Multiple_Documents->setData(int(Operation::Separate));
    ui->actionSeparate_to_Multiple_Documents_Grouped->setData(int(Operation::SeparateGrouped));

    QToolBar* mainToolbar = addToolBar(tr("Main"));
    mainToolbar->setObjectName("main_toolbar");
    mainToolbar->addAction(ui->actionAddDocument);
    mainToolbar->addSeparator();
    mainToolbar->addActions({ ui->actionCloneSelection, ui->actionRemoveSelection });
    mainToolbar->addSeparator();
    mainToolbar->addActions({ ui->actionCut, ui->actionCopy, ui->actionPaste });
    mainToolbar->addSeparator();
    mainToolbar->addActions({ ui->actionGroup, ui->actionUngroup });
    QToolBar* insertToolbar = addToolBar(tr("Insert"));
    insertToolbar->setObjectName("insert_toolbar");
    insertToolbar->addActions({ ui->actionInsert_Page_from_PDF, ui->actionInsert_Image, ui->actionInsert_Empty_Page });
    QToolBar* selectToolbar = addToolBar(tr("Select"));
    selectToolbar->setObjectName("select_toolbar");
    selectToolbar->addActions({ ui->actionSelect_None, ui->actionSelect_All, ui->actionSelect_Even, ui->actionSelect_Odd, ui->actionSelect_Portrait, ui->actionSelect_Landscape });
    QToolBar* zoomToolbar = addToolBar(tr("Zoom"));
    zoomToolbar->setObjectName("zoom_toolbar");
    zoomToolbar->addActions({ ui->actionZoom_In, ui->actionZoom_Out });
    QToolBar* makeToolbar = addToolBar(tr("Make"));
    makeToolbar->setObjectName("make_toolbar");
    makeToolbar->addActions({ ui->actionUnited_Document, ui->actionSeparate_to_Multiple_Documents, ui->actionSeparate_to_Multiple_Documents_Grouped });

    QSize iconSize = pdf::PDFWidgetUtils::scaleDPI(this, QSize(24, 24));
    auto toolbars = findChildren<QToolBar*>();
    for (QToolBar* toolbar : toolbars)
    {
        toolbar->setIconSize(iconSize);
    }

    connect(&m_mapper, QOverload<int>::of(&QSignalMapper::mapped), this, &MainWindow::onMappedActionTriggered);
    connect(ui->documentItemsView->selectionModel(), &QItemSelectionModel::selectionChanged, this, &MainWindow::updateActions);

    QList<QAction*> actions = findChildren<QAction*>();
    for (QAction* action : actions)
    {
        QVariant actionData = action->data();
        if (actionData.isValid())
        {
            connect(action, &QAction::triggered, &m_mapper, QOverload<>::of(&QSignalMapper::map));
            m_mapper.setMapping(action, actionData.toInt());
        }
    }

    loadSettings();
    updateActions();
}

MainWindow::~MainWindow()
{
    saveSettings();
    delete ui;
}

QSize MainWindow::getMinPageImageSize() const
{
    return pdf::PDFWidgetUtils::scaleDPI(this, QSize(40, 40));
}

QSize MainWindow::getDefaultPageImageSize() const
{
    return pdf::PDFWidgetUtils::scaleDPI(this, QSize(100, 100));
}

QSize MainWindow::getMaxPageImageSize() const
{
    return pdf::PDFWidgetUtils::scaleDPI(this, QSize(250, 250));
}

void MainWindow::on_actionClose_triggered()
{
    close();
}

void MainWindow::on_actionAddDocument_triggered()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Select PDF document"), m_settings.directory, tr("PDF document (*.pdf)"));
    if (!fileName.isEmpty())
    {
        addDocument(fileName);
    }
}

void MainWindow::onMappedActionTriggered(int actionId)
{
    performOperation(static_cast<Operation>(actionId));
}

void MainWindow::updateActions()
{
    QList<QAction*> actions = findChildren<QAction*>();
    for (QAction* action : actions)
    {
        QVariant actionData = action->data();
        if (actionData.isValid())
        {
            action->setEnabled(canPerformOperation(static_cast<Operation>(actionData.toInt())));
        }
    }
}

void MainWindow::loadSettings()
{
    QSettings settings(QSettings::IniFormat, QSettings::UserScope, QCoreApplication::organizationName(), QCoreApplication::applicationName());
    settings.beginGroup("MainWindow");
    QByteArray geometry = settings.value("geometry", QByteArray()).toByteArray();
    if (geometry.isEmpty())
    {
        QRect availableGeometry = QApplication::desktop()->availableGeometry(this);
        QRect windowRect(0, 0, availableGeometry.width() / 2, availableGeometry.height() / 2);
        windowRect = windowRect.translated(availableGeometry.center() - windowRect.center());
        setGeometry(windowRect);
    }
    else
    {
        restoreGeometry(geometry);
    }

    QByteArray state = settings.value("windowState", QByteArray()).toByteArray();
    if (!state.isEmpty())
    {
        restoreState(state);
    }
    settings.endGroup();

    settings.beginGroup("Settings");
    m_settings.directory = settings.value("directory").toString();
    settings.endGroup();
}

void MainWindow::saveSettings()
{
    QSettings settings(QSettings::IniFormat, QSettings::UserScope, QCoreApplication::organizationName(), QCoreApplication::applicationName());
    settings.beginGroup("MainWindow");
    settings.setValue("geometry", saveGeometry());
    settings.setValue("windowState", saveState());
    settings.endGroup();

    settings.beginGroup("Settings");
    settings.setValue("directory", m_settings.directory);
    settings.endGroup();
}

void MainWindow::addDocument(const QString& fileName)
{
    auto queryPassword = [this](bool* ok)
    {
        *ok = false;
        return QInputDialog::getText(this, tr("Encrypted document"), tr("Enter password to access document content"), QLineEdit::Password, QString(), ok);
    };

    // Mark current directory as this
    QFileInfo fileInfo(fileName);
    m_settings.directory = fileInfo.dir().absolutePath();

    // Try to open a new document
    pdf::PDFDocumentReader reader(nullptr, qMove(queryPassword), true, false);
    pdf::PDFDocument document = reader.readFromFile(fileName);

    QString errorMessage = reader.getErrorMessage();
    pdf::PDFDocumentReader::Result result = reader.getReadingResult();
    if (result == pdf::PDFDocumentReader::Result::OK)
    {
        const pdf::PDFSecurityHandler* securityHandler = document.getStorage().getSecurityHandler();
        if (securityHandler->isAllowed(pdf::PDFSecurityHandler::Permission::Assemble) ||
            securityHandler->isAllowed(pdf::PDFSecurityHandler::Permission::Modify))
        {
            m_model->addDocument(fileName, qMove(document));
        }
        else
        {
            QMessageBox::critical(this, tr("Error"), tr("Document security doesn't permit to organize pages."));
        }
    }
    else if (result == pdf::PDFDocumentReader::Result::Failed)
    {
        QMessageBox::critical(this, tr("Error"), errorMessage);
    }

    updateActions();
}

bool MainWindow::canPerformOperation(Operation operation) const
{
    QModelIndexList selection = ui->documentItemsView->selectionModel()->selection().indexes();
    const bool isSelected = !selection.isEmpty();
    const bool isModelEmpty = m_model->rowCount(QModelIndex()) == 0;

    switch (operation)
    {
        case Operation::CloneSelection:
        case Operation::RemoveSelection:
        case Operation::ReplaceSelection:
            return isSelected;

        case Operation::RestoreRemovedItems:
            return !m_trashBin.empty();

        case Operation::Cut:
        case Operation::Copy:
            return isSelected;

        case Operation::Paste:
            return !QApplication::clipboard()->text().isEmpty();

        case Operation::RotateLeft:
        case Operation::RotateRight:
            return isSelected;

        case Operation::Group:
            return isSelected;
        case Operation::Ungroup:
            return m_model->isGrouped(selection);

        case Operation::SelectNone:
            return isSelected;

        case Operation::SelectAll:
        case Operation::SelectEven:
        case Operation::SelectOdd:
        case Operation::SelectPortrait:
        case Operation::SelectLandscape:
            return !isModelEmpty;

        case Operation::ZoomIn:
            return m_delegate->getPageImageSize() != getMaxPageImageSize();

        case Operation::ZoomOut:
            return m_delegate->getPageImageSize() != getMinPageImageSize();

        case Operation::Unite:
        case Operation::Separate:
        case Operation::SeparateGrouped:
            return !isModelEmpty;

        default:
            Q_ASSERT(false);
            break;
    }

    return false;
}

void MainWindow::performOperation(Operation operation)
{
    switch (operation)
    {
        case Operation::CloneSelection:
        case Operation::RemoveSelection:
        case Operation::ReplaceSelection:
        case Operation::RestoreRemovedItems:
        case Operation::Cut:
        case Operation::Copy:
        case Operation::Paste:
        case Operation::RotateLeft:
        case Operation::RotateRight:
            break;

        case Operation::Group:
        case Operation::Ungroup:
            break;

        case Operation::SelectNone:
            ui->documentItemsView->clearSelection();
            break;

        case Operation::SelectAll:
            ui->documentItemsView->selectAll();
            break;

        case Operation::SelectEven:
            ui->documentItemsView->selectionModel()->select(m_model->getSelectionEven(), QItemSelectionModel::ClearAndSelect);
            break;

        case Operation::SelectOdd:
            ui->documentItemsView->selectionModel()->select(m_model->getSelectionOdd(), QItemSelectionModel::ClearAndSelect);
            break;

        case Operation::SelectPortrait:
            ui->documentItemsView->selectionModel()->select(m_model->getSelectionPortrait(), QItemSelectionModel::ClearAndSelect);
            break;

        case Operation::SelectLandscape:
            ui->documentItemsView->selectionModel()->select(m_model->getSelectionLandscape(), QItemSelectionModel::ClearAndSelect);
            break;

        case Operation::ZoomIn:
        {
            QSize pageImageSize = m_delegate->getPageImageSize();
            pageImageSize *= 1.2;
            pageImageSize = pageImageSize.boundedTo(getMaxPageImageSize());

            if (pageImageSize != m_delegate->getPageImageSize())
            {
                m_delegate->setPageImageSize(pageImageSize);
            }
            break;
        }

        case Operation::ZoomOut:
        {
            QSize pageImageSize = m_delegate->getPageImageSize();
            pageImageSize /= 1.2;
            pageImageSize = pageImageSize.expandedTo(getMinPageImageSize());

            if (pageImageSize != m_delegate->getPageImageSize())
            {
                m_delegate->setPageImageSize(pageImageSize);
            }
            break;
        }

        case Operation::Unite:
        case Operation::Separate:
        case Operation::SeparateGrouped:

        default:
            Q_ASSERT(false);
            break;
    }

    updateActions();
}

}   // namespace pdfdocpage