/*
 * Copyright (C) 2013 ~ 2018 National University of Defense Technology(NUDT) & Tianjin Kylin Ltd.
 *
 * Authors:
 *  Kobe Lee    xiangli@ubuntukylin.com/kobe24_lixiang@126.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "filesystemlistwidget.h"
#include <QTimer>
#include <QApplication>
#include <QDebug>
#include <QEvent>
#include <QMenu>
#include <QStyleFactory>
#include <QWheelEvent>
#include <QPainter>
#include <QtMath>
#include <QPen>
#include <QDesktopServices>

FileSystemListWidget::FileSystemListWidget(QList<bool> toBeDisplayedColumns, QWidget *parent) : QWidget(parent)
  ,m_titlePadding(10)
  ,m_titleHeight(34)
  ,m_rowHeight(29)
  ,m_offSet(0)
  ,m_origOffset(0)
  ,m_scrollbarWidth(10)
  ,m_titleHoverColumn(-1)
  ,m_titlePressColumn(-1)
  ,m_mouseAtScrollArea(false)
  ,m_mouseDragScrollbar(false)
{
    this->m_lastItem = NULL;
    this->m_listItems = new QList<FileSystemListItem*>();
    this->m_selectedItems = new QList<FileSystemListItem*>();

    this->columnTitles << tr("Device") << tr("Directory") << tr("Type") << tr("Total") << tr("Free") << tr("Available") << tr("Used");
    QList<int> widths;
    widths << 150 << -1 << 60 << 60 << 60 << 60 << 180;//-1时让改行填充所有剩余空间

    QFont font;
    font.setPixelSize(12);//需要和填充所有剩余空间的那个的文字字体大小一致 font.setPointSize(9)
    QFontMetrics fm(font);

    this->m_columnWidths.clear();
    for (int i = 0; i < widths.length(); i++) {
        if (widths[i] == -1) {
            this->m_columnWidths << widths[i];
        } else {//-1时让改行填充所有剩余空间
            int maxWidth = fm.width(this->columnTitles[i]) + this->m_titlePadding + /*m_upArrowPixmap.width() / m_upArrowPixmap.devicePixelRatio() +*/ 2 * 2;
            this->m_columnWidths << std::max(widths[i], maxWidth);
        }
    }

    this->m_columnVisibles.clear();
    for (int i = 0; i < toBeDisplayedColumns.count(); i++) {
        this->m_columnVisibles.append(toBeDisplayedColumns[i]);
    }

    this->setFocus();
}

FileSystemListWidget::~FileSystemListWidget()
{
    if (this->m_hideScrollbarTimer != NULL) {
        disconnect(this->m_hideScrollbarTimer,SIGNAL(timeout()),this,SLOT(hideScrollbar()));
        if(this->m_hideScrollbarTimer->isActive()) {
            this->m_hideScrollbarTimer->stop();
        }
        delete this->m_hideScrollbarTimer;
        this->m_hideScrollbarTimer = nullptr;
    }

    delete this->m_lastItem;
    delete this->m_listItems;
    delete this->m_selectedItems;
}

void FileSystemListWidget::clearItems()
{
    qDeleteAll(this->m_listItems->begin(), this->m_listItems->end());
    this->m_listItems->clear();
}

void FileSystemListWidget::addSelectedItems(QList<FileSystemListItem*> items, bool recordLastItem)
{
    this->m_selectedItems->append(items);

    if (recordLastItem && this->m_selectedItems->count() > 0) {
        this->m_lastItem = this->m_selectedItems->last();
    }
}

void FileSystemListWidget::clearSelectedItems(bool clearLast)
{
    this->m_selectedItems->clear();
    if (clearLast) {
        this->m_lastItem = NULL;
    }
}

void FileSystemListWidget::refreshFileSystemItems(QList<FileSystemListItem*> items)
{
    QList<FileSystemListItem*> *allItems = new QList<FileSystemListItem*>();
    FileSystemListItem *newLastItem = NULL;

    for (FileSystemListItem *item:items) {
        for (FileSystemListItem *selectionItem:*this->m_selectedItems) {
            if (item->isSameItem(selectionItem)) {
                allItems->append(item);
                break;
            }
        }
    }
    if (this->m_lastItem != NULL) {
        for (FileSystemListItem *item:items) {
            if (item->isSameItem(this->m_lastItem)) {
                newLastItem = item;
                break;
            }
        }
    }

    clearItems();
    this->m_listItems->append(items);

    clearSelectedItems();
    addSelectedItems(*allItems, false);

    this->m_lastItem = newLastItem;
    this->m_offSet = setOffset(this->m_offSet);

    repaint();
}

void FileSystemListWidget::leaveEvent(QEvent * event)
{
    hideScrollbar();
    QWidget::leaveEvent(event);
}

void FileSystemListWidget::hideScrollbar()
{
    this->m_mouseAtScrollArea = false;
    this->m_origOffset = this->m_offSet;

    repaint();
}

void FileSystemListWidget::mouseMoveEvent(QMouseEvent *mouseEvent)
{
    if (this->m_mouseDragScrollbar) {
        this->m_offSet = setOffset((mouseEvent->y() - getScrollbarHeight() / 2 - this->m_titleHeight) / (getTheScrollAreaHeight() * 1.0) * this->getItemsTotalHeight());
        repaint();
    }
    else if (mouseAtScrollArea(mouseEvent->x()) != this->m_mouseAtScrollArea) {
        this->m_mouseAtScrollArea = mouseAtScrollArea(mouseEvent->x());
        repaint();
    }
}

void FileSystemListWidget::mouseDoubleClickEvent(QMouseEvent *event)
{
    bool isTitleArea = mouseAtTitleArea(event->y());
    bool isScrollArea = mouseAtScrollArea(event->x());
    if (!isTitleArea && !isScrollArea) {
        int pressedItemIndex = (this->m_offSet + event->y() - this->m_titleHeight) / this->m_rowHeight;
        if (pressedItemIndex >= this->m_listItems->count()) {
            clearSelectedItems();
            repaint();
        }
        else {
            if (event->button() == Qt::LeftButton) {
                FileSystemListItem *pressItem = (*this->m_listItems)[pressedItemIndex];
                bool pressInSelectionArea = false;
                for (FileSystemListItem *item : *this->m_selectedItems) {
                    if (item == pressItem) {
                        pressInSelectionArea = true;
                        break;
                    }
                }
                if (pressInSelectionArea) {
                    //open the mount dir
                    FileSystemListItem *item = static_cast<FileSystemListItem*>(pressItem);
                    QString targetPath = QString("file://%1").arg(item->getDirectory());
                    QDesktopServices::openUrl(QUrl(targetPath));//xdg-open
                }
            }
        }
    }

    QWidget::mouseDoubleClickEvent(event);
}

void FileSystemListWidget::mousePressEvent(QMouseEvent *mouseEvent)
{
    setFocus();

    bool isTitleArea = mouseAtTitleArea(mouseEvent->y());
    bool isScrollArea = mouseAtScrollArea(mouseEvent->x());

    if (isTitleArea) {//点击列表的标题栏区域
        if (mouseEvent->button() == Qt::RightButton) {
            if (m_columnVisibles.count() == this->columnTitles.count()) {
                QMenu *menu = new QMenu();
                menu->setObjectName("MonitorMenu");
                for (int i = 0; i < m_columnVisibles.count(); i++) {
                    if (i != 0) {//让第一行总是显示，不可以设置显示或者不显示，其他行可以设置
                        QAction *action = new QAction(menu);
                        action->setText(this->columnTitles[i]);
                        action->setCheckable(true);
                        action->setChecked(m_columnVisibles[i]);
                        connect(action, &QAction::triggered, this, [this, action, i] {
                                m_columnVisibles[i] = !m_columnVisibles[i];
                                emit this->changeColumnVisible(i, m_columnVisibles[i], m_columnVisibles);
                                repaint();
                            });
                        menu->addAction(action);
                    }
                }
                menu->exec(this->mapToGlobal(mouseEvent->pos()));
                delete menu;
            }
        }
    }
    else if (isScrollArea) {//点击滚动条区域
        int barHeight = getScrollbarHeight();
        int barY = getScrollbarY();
        if (mouseEvent->y() > barY && mouseEvent->y() < barY + barHeight) {
            this->m_mouseDragScrollbar = true;
        }
        else {
            this->m_offSet = setOffset((mouseEvent->y() - barHeight / 2 - this->m_titleHeight) / (getTheScrollAreaHeight() * 1.0) * this->getItemsTotalHeight());
            repaint();
        }
    }
    else {
        int pressedItemIndex = (this->m_offSet + mouseEvent->y() - this->m_titleHeight) / this->m_rowHeight;
        if (pressedItemIndex >= this->m_listItems->count()) {
            clearSelectedItems();
            repaint();
        }
        else {
            if (mouseEvent->button() == Qt::LeftButton) {
                if (pressedItemIndex < this->m_listItems->count()) {
                    if (mouseEvent->modifiers() == Qt::ControlModifier) {
                        FileSystemListItem *item = (*this->m_listItems)[pressedItemIndex];
                        if (this->m_selectedItems->contains(item)) {
                            this->m_selectedItems->removeOne(item);
                        } else {
                            QList<FileSystemListItem*> items = QList<FileSystemListItem*>();
                            items << item;
                            addSelectedItems(items);
                        }
                    }
                    else {
                        clearSelectedItems();
                        QList<FileSystemListItem*> items = QList<FileSystemListItem*>();
                        items << (*this->m_listItems)[pressedItemIndex];
                        addSelectedItems(items);
                    }
                    repaint();
                }
            }
            else if (mouseEvent->button() == Qt::RightButton) {
                FileSystemListItem *pressItem = (*this->m_listItems)[pressedItemIndex];
                bool pressInSelectionArea = false;
                for (FileSystemListItem *item : *this->m_selectedItems) {
                    if (item == pressItem) {
                        pressInSelectionArea = true;
                        break;
                    }
                }
                if (pressInSelectionArea) {
                    emit this->rightMouseClickedItem(this->mapToGlobal(mouseEvent->pos()));
                }
            }
        }
    }
}

void FileSystemListWidget::mouseReleaseEvent(QMouseEvent *)
{
    if (this->m_mouseDragScrollbar) {
        this->m_mouseDragScrollbar = false;
        repaint();
    }
    else {
        if (this->m_titlePressColumn != -1) {
            this->m_titlePressColumn = -1;
            repaint();
        }
    }
}

void FileSystemListWidget::wheelEvent(QWheelEvent *event)
{
    if (event->orientation() == Qt::Vertical) {
        this->m_origOffset = this->m_offSet;
        qreal scrollStep = event->angleDelta().y() / 100.0;
        this->m_offSet = setOffset(this->m_offSet - scrollStep * this->m_rowHeight);
        repaint();
    }
    event->accept();
}

void FileSystemListWidget::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing, true);

    QList<int> titleItemsWidths = getTitleItemsWidths();

    painter.setOpacity(0.05);

    int penWidth = 1;
    QPainterPath framePath;
    framePath.addRoundedRect(QRect(rect().x() + penWidth, rect().y() + penWidth, rect().width() - penWidth * 2, rect().height() - penWidth * 2), 5, 5);//背景弧度
    painter.setClipPath(framePath);

    //标题的背景
    if (this->m_titleHeight > 0) {
        QPainterPath titlePath;
        titlePath.addRect(QRectF(rect().x(), rect().y(), rect().width(), this->m_titleHeight));
        painter.setOpacity(0.02);
        painter.fillPath(titlePath, QColor("#ffffff"));
    }

    int title_Y = 0;
    int title_Height = 0;
    if (this->m_titleHeight > 0) {
        int counter = 0;
        int posX = 0;
        for (int itemWidth:titleItemsWidths) {
            if (itemWidth > 0) {
                //标题文字
                painter.setOpacity(1);
                QFont font = painter.font();
                font.setPixelSize(12);
                painter.setFont(font);
                painter.setPen(QPen(QColor("#999999")));

                if (this->columnTitles[counter] == tr("Device") || this->columnTitles[counter] == tr("Directory") || this->columnTitles[counter] == tr("Used"))
                    painter.drawText(QRect(posX + this->m_titlePadding, 0, itemWidth, this->m_titleHeight), Qt::AlignBottom | Qt::AlignLeft, this->columnTitles[counter]);
                else
                    painter.drawText(QRect(posX, 0, itemWidth - this->m_titlePadding, this->m_titleHeight), Qt::AlignBottom | Qt::AlignRight, this->columnTitles[counter]);

                //水平下划线
                painter.setOpacity(0.8);
                QPainterPath h_separatorPath;
                h_separatorPath.addRect(QRectF(posX, rect().y() + this->m_titleHeight - 1, itemWidth, 1));
                painter.fillPath(h_separatorPath, QColor("#e0e0e0"));

                if (counter < titleItemsWidths.size()) {//垂直分割线
                    QPainterPath v_separatorPath;
                    v_separatorPath.addRect(QRectF(rect().x() + posX - 1, rect().y() + 5, 1, this->m_titleHeight - 5));
                    painter.fillPath(v_separatorPath, QColor("#e0e0e0"));
                }

                posX += itemWidth;
            }
            counter++;
        }

        title_Y += this->m_titleHeight;
        title_Height += this->m_titleHeight;
    }

    //去掉列表标题栏后的列表显示区域的背景
    painter.setOpacity(0.05);
    QPainterPath backgroundPath;
    backgroundPath.addRect(QRectF(rect().x(), rect().y() + this->m_titleHeight, rect().width(), rect().height() - this->m_titleHeight));
    painter.fillPath(backgroundPath, QColor("#ffffff"));

    //挂载的磁盘文件系统信息
    QPainterPath scrollAreaPath;
    scrollAreaPath.addRect(QRectF(rect().x(), rect().y() + this->m_titleHeight, rect().width(), getTheScrollAreaHeight()));

    int rowCounter = 0;
    for (FileSystemListItem *item:*this->m_listItems) {
        if (rowCounter > ((this->m_offSet - this->m_rowHeight) / this->m_rowHeight)) {
            QPainterPath itemPath;
            itemPath.addRect(QRect(0, title_Y + rowCounter * this->m_rowHeight - this->m_offSet, rect().width(), this->m_rowHeight));
            painter.setClipPath((framePath.intersected(scrollAreaPath)).intersected(itemPath));

            bool isSelect = this->m_selectedItems->contains(item);
            painter.save();
            item->drawBackground(QRect(0, title_Y + rowCounter * this->m_rowHeight - this->m_offSet, rect().width(), this->m_rowHeight), &painter, rowCounter, isSelect);
            painter.restore();

            int columnCounter = 0;
            int columnTitleX = 0;
            for (int titleItemWidth : titleItemsWidths) {
                if (titleItemWidth > 0) {
                    painter.save();
                    if (columnCounter < titleItemsWidths.size() - 1)
                        item->drawForeground(QRect(columnTitleX, title_Y + rowCounter * this->m_rowHeight - this->m_offSet, titleItemWidth, this->m_rowHeight), &painter, columnCounter, rowCounter, isSelect, true);
                    else
                        item->drawForeground(QRect(columnTitleX, title_Y + rowCounter * this->m_rowHeight - this->m_offSet, titleItemWidth, this->m_rowHeight), &painter, columnCounter, rowCounter, isSelect, false);
                    painter.restore();
                    columnTitleX += titleItemWidth;
                }
                columnCounter++;
            }
            title_Height += this->m_rowHeight;
            if (title_Height > rect().height()) {
                break;
            }
        }
        rowCounter++;
    }
    painter.setClipPath(framePath);

    //没有挂载的磁盘文件系统信息时绘制提示文字
    if (this->m_listItems->size() == 0) {
        painter.setOpacity(1);
        painter.setPen(QPen(QColor("#666666")));
        QFont font = painter.font() ;
        font.setPointSize(22);
        painter.setFont(font);
        painter.drawText(QRect(rect().x(), rect().y() + this->m_titleHeight, rect().width(), rect().height() - this->m_titleHeight), Qt::AlignCenter, tr("No File System Info"));
    }

    //背景
//    QPen framePen;
//    framePen.setColor(QColor("#F5F5F5"));
//    painter.setPen(framePen);
    painter.setOpacity(0.2);
    painter.drawPath(framePath);

    //垂直滚动条
    if (this->m_mouseAtScrollArea) {
        paintScrollbar(&painter);
    } else if (this->m_origOffset != this->m_offSet) {
        paintScrollbar(&painter);
        readyToHideScrollbar();
    }
}

void FileSystemListWidget::paintScrollbar(QPainter *painter)
{
    if (this->getItemsTotalHeight() > getTheScrollAreaHeight()) {
        qreal opacitry = 0;
        if (this->m_mouseDragScrollbar) {
            opacitry = 0.8;
        }
        else {
            if (this->m_mouseAtScrollArea)
                opacitry = 0.7;
            else
                opacitry = 0.5;
        }

        int barWidth = (this->m_mouseAtScrollArea || this->m_mouseDragScrollbar) ? this->m_scrollbarWidth : 6;
        int barY = getScrollbarY();
        int barHeight = getScrollbarHeight();
        painter->setOpacity(opacitry);
        QPainterPath path;
        path.addRoundedRect(
            QRectF(rect().x() + rect().width() - barWidth - 4, barY + 2, barWidth, barHeight - 2 * 2), 2, 2);//2 is radius
        painter->fillPath(path, QColor("#0B95D7"));

        QPen pen;
        pen.setColor(QColor("#0B95D7"));
        pen.setWidth(1);
        painter->setOpacity(0);
        painter->setPen(pen);
        painter->drawPath(path);
    }
}

QList<int> FileSystemListWidget::getTitleItemsWidths()
{
    QList<int> titleItemsWidths;
    if (this->m_columnWidths.length() > 0) {
        if (this->m_columnWidths.contains(-1)) {
            for (int i = 0; i < this->m_columnWidths.count(); i++) {
                if (this->m_columnWidths[i] != -1) {
                    if (m_columnVisibles[i]) {
                        titleItemsWidths << this->m_columnWidths[i];
                    } else {
                        titleItemsWidths << 0;
                    }
                } else {
                    if (m_columnVisibles[i]) {
                        int totalWidth = 0;
                        for (int j = 0; j < this->m_columnWidths.count(); j++) {
                            if (this->m_columnWidths[j] != -1 && m_columnVisibles[j]) {
                                totalWidth += this->m_columnWidths[j];
                            }
                        }
                        titleItemsWidths << rect().width() - totalWidth;
                    }
                    else {
                        titleItemsWidths << 0;
                    }
                }
            }
        } else {
            for (int i = 0; i < this->m_columnWidths.count(); i++) {
                if (m_columnVisibles[i]) {
                    titleItemsWidths << this->m_columnWidths[i];
                }
                else {
                    titleItemsWidths << 0;
                }
            }
        }
    }
    else {
        titleItemsWidths << rect().width();
    }

    return titleItemsWidths;
}

bool FileSystemListWidget::mouseAtScrollArea(int x)
{
    return (x > rect().x() + rect().width() - this->m_scrollbarWidth) && (x < rect().x() + rect().width());
}

bool FileSystemListWidget::mouseAtTitleArea(int y)
{
    return (y > rect().y() && y < rect().y() + this->m_titleHeight);
}

int FileSystemListWidget::setOffset(int offset)
{
    return std::max(0, std::min(offset, getBottomOffset()));
}

int FileSystemListWidget::getItemsTotalHeight()
{
    return m_listItems->count() * m_rowHeight;
}

int FileSystemListWidget::getTheScrollAreaHeight()
{
    return this->rect().height() - this->m_titleHeight;
}

int FileSystemListWidget::getScrollbarY()
{
    return static_cast<int>((this->m_offSet / (this->getItemsTotalHeight() * 1.0)) * getTheScrollAreaHeight() + this->m_titleHeight);
}

int FileSystemListWidget::getScrollbarHeight()
{
    return std::max(static_cast<int>(getTheScrollAreaHeight() / (this->getItemsTotalHeight() * 1.0) * rect().height()), 30);//30 is min height
}

int FileSystemListWidget::getBottomOffset()
{
    int itemsHeight = this->getItemsTotalHeight();
    if (itemsHeight > rect().height() - this->m_titleHeight) {
        return this->getItemsTotalHeight() - rect().height() + this->m_titleHeight;
    } else {
        return 0;
    }
}

void FileSystemListWidget::readyToHideScrollbar()
{
    if (this->m_hideScrollbarTimer) {
         if (this->m_hideScrollbarTimer->isActive())
            this->m_hideScrollbarTimer->stop();
    }
    else {
        this->m_hideScrollbarTimer = new QTimer();
        this->m_hideScrollbarTimer->setSingleShot(true);
        connect(this->m_hideScrollbarTimer, SIGNAL(timeout()), this, SLOT(hideScrollbar()));
    }
    this->m_hideScrollbarTimer->start(2000);
}