/**
 * @file PaiComboBox.cpp
 * @date 2011-10-17
 */
#include <QStyledItemDelegate>
#include <QApplication>
#include <QPainter>
#include <QValidator>
#include <QKeyEvent>
#include <QLineEdit>
#include <QPaintEvent>
#include <QDesktopWidget>
#include <QFontMetrics>
#include <QAbstractItemView>

#include "PaiComboBox.h"

using namespace pai::gui;

/**
 * @class PaiComboBoxItemDelegate
 * @brief 用来绘制ComboBox弹出选择框Item
 */
class PAI_WIDGET_EXPORT PaiComboBoxItemDelegate : public QStyledItemDelegate
{
public:
    PaiComboBoxItemDelegate(QObject *pParent = 0) :
        QStyledItemDelegate(pParent)
    {
    }

protected:
    /**
     * @brief 重新实现重绘函数
     * @param[in] pPainter 画笔
     * @param[in] option 类型选项
     * @param[in] index Model 索引
     */
    void paint(QPainter *pPainter, const QStyleOptionViewItem & option, const QModelIndex & index) const
    {
        QStyleOptionViewItemV4 opt = option;
        initStyleOption(&opt, index);
        opt.state = opt.state & ~QStyle::State_Selected;

        if((option.state & QStyle::State_Selected) && (option.state & QStyle::State_Enabled))
        {
            QLinearGradient linearGrad(opt.rect.topLeft(), opt.rect.bottomLeft());
            linearGrad.setColorAt(0, QColor("#FFFFFF"));
            linearGrad.setColorAt(1, QColor("#EAF2F4"));
            opt.backgroundBrush = QBrush(linearGrad);
        }
        else
        {
            opt.backgroundBrush = QBrush("#EFF5FA");
        }

        const QWidget *pWidget = opt.widget;
        if(pWidget == NULL)
        {
            return;
        }
        QStyle *pStyle = pWidget ? pWidget->style() : QApplication::style();

        pStyle->drawControl(QStyle::CE_ItemViewItem, &opt, pPainter, pWidget);

        if((option.state & QStyle::State_Selected) && (option.state & QStyle::State_Enabled))
        {
            pPainter->save();

            pPainter->setPen(QColor("#AACEDB"));
            pPainter->drawRoundedRect(option.rect.adjusted(1, 1, -2, -2), 1, 1);

            pPainter->restore();
        }
    }

    /**
     * @brief 重设高度
     * @param[in] option 类型选项
     */
     QSize sizeHint(const QStyleOptionViewItem & option, const QModelIndex & /*index*/) const
     {
         return QSize(option.rect.width(), 24);
     }
};

/////////////////////////////////////////////////////////////////////
PaiComboBox::PaiComboBox(QWidget *pParent) :
        QComboBox(pParent),
        m_AddButton(false)
{
    InitComboBox();
}

PaiComboBox::PaiComboBox(bool showAddButton, QWidget *pParent)
    : QComboBox(pParent),
      m_AddButton(showAddButton)
{
    InitComboBox();
    SetShowAddButton(m_AddButton);
}

PaiComboBox::~PaiComboBox()
{
}

void PaiComboBox::InitComboBox()
{
    m_pEditButton = NULL;
    m_RealTimeValidate = false;
    m_MaxVisibleItems = 10; // 默认显示10个

    QAbstractItemView *pView = view();
    // 将view初始设置为最小，防止调整位置和大小时闪烁
    pView->parentWidget()->setFixedSize(QSize(0, 0));
    pView->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    // 当Item文本过长，则在右侧用“...”代替
    pView->setTextElideMode(Qt::ElideRight);
    const QObjectList objs = view()->parentWidget()->children ();
    // 隐藏多余控件
    foreach(QObject *pObj, objs)
    {
        QWidget *pWgt = qobject_cast<QWidget*>(pObj);
        if(pWgt && (pWgt != pView))
        {
            pWgt->setMaximumHeight(0);
        }
    }

    setItemDelegate(new PaiComboBoxItemDelegate(this));
}

void PaiComboBox::SetShowAddButton(bool show)
{
    if (show && m_pEditButton == NULL)
    {
        m_AddButton = true;
        m_pEditButton = new QToolButton(this);
        m_pEditButton->setIcon(QIcon(":/Edit.png"));
        m_pEditButton->setStyleSheet(
                "QToolButton{ background-color: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
                "stop: 0.0 #FFFFFF, stop: 0.4 #F7FAFD,stop: 0.4 #E5EFF8, stop: 1.0 #BDD7EC);"
                "border: 1px solid #839CB6; border-left:0px;"
                "border-top-right-radius: 2px; border-bottom-right-radius: 2px}"
                "QToolButton:hover { background-color: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
                "stop: 0.0 #F1F9FE, stop: 0.4 #E1F3FC, stop: 0.4 #C9E9F9, stop: 1.0 #9BD7F1);}"
                "QToolButton:focus { background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
                "stop: 0 #E6F5FB, stop: 0.38 #D0ECF8, stop: 0.39 #AADDF2, stop: 1.0 #70C5EA);}"
                );

        connect(m_pEditButton, SIGNAL(clicked()), this, SIGNAL(EditButtonClicked()));
    }
    else if(!show && m_pEditButton)
    {
        // 去掉按钮所占空间
        setStyleSheet(QString::fromUtf8("QComboBox{margin-right:0px}"));

        m_pEditButton->hide();
    }
}

void PaiComboBox::showPopup ()
{
    QComboBox::showPopup();

    if(count() == 0)
    {
        return;
    }

    // 每条Item的高度为24;
    const int ITEM_HEIGHT = 24;
    int popWidgetHeight = ITEM_HEIGHT * (m_MaxVisibleItems < count() ? m_MaxVisibleItems : count()) + 2;
    QPoint popWidgetPos(0, 0);

    // 屏幕高度
    int iHeightOfScreen = QApplication::desktop()->height();
    // 下方空间高度
    int iBottomSpace = iHeightOfScreen - mapToGlobal(rect().bottomLeft()).y();
    // 上方空间高度
    int iTopSpace = mapToGlobal(rect().topLeft()).y();

    if(iBottomSpace >= popWidgetHeight) //如果下方区域足够显示选择列表则在下方显示
    {
        popWidgetPos = mapToGlobal(rect().bottomLeft()) - QPoint( -m_margin.left(), m_margin.bottom());
    }
    else if(iTopSpace >= popWidgetHeight) //如果下方空间不足，而上方空间充足，则上方显示
    {
        popWidgetPos = mapToGlobal(rect().topLeft()) - QPoint(0, popWidgetHeight) + QPoint(m_margin.left(), m_margin.top());
    }
    else    // 如果上下空间都不足，则调整显示条数
    {
        if(iBottomSpace > iTopSpace)
        {
            popWidgetHeight = iBottomSpace;
            popWidgetPos = mapToGlobal(rect().bottomLeft()) - QPoint( -m_margin.left(), m_margin.bottom());
        }
        else
        {
            popWidgetHeight = iTopSpace;
            popWidgetPos = mapToGlobal(rect().topLeft()) - QPoint(0, popWidgetHeight) + QPoint(m_margin.left(), m_margin.top());
        }
    }

    // 调整view的位置和大小
    QAbstractItemView *pView = view();
    if(pView && pView->parentWidget())
    {
        pView->parentWidget()->setFixedHeight(popWidgetHeight);
        pView->parentWidget()->move(popWidgetPos);

        int minWidth = rect().width() - m_margin.left() - m_margin.right();
        int widthOfScreen = QApplication::desktop()->width();
        // 如果ComboBox的宽度小于屏幕三分之一，根据每行Item文字长度调节下拉框宽度
        if(rect().width() < widthOfScreen / 3)
        {
            // 根据每行Item文字长度，确定List的最小宽度
            QFontMetrics metrics(pView->font());
            QString text;

            for(int i = 0; i < count(); i++)
            {
                text = itemText(i) + "   ";//添空格为边框占位
                minWidth = minWidth > metrics.width(text) ? minWidth : metrics.width(text);
            }
            // 如果下拉框宽度超过显示屏宽度三分之一，则将其宽度设置为屏幕宽度的三分之一
            if(minWidth > widthOfScreen / 3)
            {
                minWidth = widthOfScreen / 3;
            }
        }

        pView->parentWidget()->setFixedWidth(minWidth);
    }
}

int PaiComboBox::GetMaxVisibleItems() const
{
    return m_MaxVisibleItems;
}

void PaiComboBox::SetMaxVisibleItems(const int count)
{
    m_MaxVisibleItems = count;
}

void PaiComboBox::setStyleSheet(const QString & styleSheet)
{
    QComboBox::setStyleSheet(styleSheet);
    QRegExp reg("(margin)\\s*:\\s*\\d+\\s*(px)(.*);");

    int offset = styleSheet.toLower().indexOf(reg);
    if(offset != -1)
    {
        int end = styleSheet.indexOf(";", offset);
        QString str = styleSheet.mid(offset, end - offset);
        QStringList items = str.split(" ");

        if(items.size() == 1)
        {
            QRegExp num("(\\d+)");
            int pos = num.indexIn(items[0]);
            QString value;
            if (pos > -1)
            {
                value = num.cap(1);
            }

            bool ok;
            int margin = value.toInt(&ok, 10);
            if(ok)
            {
                m_margin = QMargins(margin, margin, margin, margin);
            }
        }
        else if(items.size() == 4)
        {
            QRegExp num("(\\d+)");
            int pos;
            bool ok;
            QString value;
            int left, top, right, bottom;

            pos = num.indexIn(items[0]);
            if (pos > -1)
            {
                value = num.cap(1);
            }
            left = value.toInt(&ok, 10);

            if(!ok)
            {
                return;
            }

            pos = num.indexIn(items[1]);
            if (pos > -1)
            {
                value = num.cap(1);
            }
            top = value.toInt(&ok, 10);

            if(!ok)
            {
                return;
            }

            pos = num.indexIn(items[2]);
            if (pos > -1)
            {
                value = num.cap(1);
            }
            right = value.toInt(&ok, 10);

            if(!ok)
            {
                return;
            }

            pos = num.indexIn(items[3]);
            if (pos > -1)
            {
                value = num.cap(1);
            }
            bottom = value.toInt(&ok, 10);

            if(!ok)
            {
                return;
            }

            m_margin = QMargins(left, top, right, bottom);
        }
    }
    else
    {
        int left;
        QRegExp regLeft("(margin-left)\\s*:\\s*\\d+\\s*(px)\\s*;");
        offset = styleSheet.toLower().indexOf(regLeft);

        if(offset == -1)
        {
            left = 0;
        }
        else
        {
            int end = styleSheet.indexOf(";", offset);
            QString str = styleSheet.mid(offset, end - offset);

            QRegExp num("(\\d+)");
            int pos = num.indexIn(str);
            QString value;
            if (pos > -1)
            {
                value = num.cap(1);
            }

            bool ok;
            int margin = value.toInt(&ok, 10);
            if(ok)
            {
                left = margin;
            }
        }

        int top;
        QRegExp regTop("(margin-top)\\s*:\\s*\\d+\\s*(px)\\s*;");
        offset = styleSheet.toLower().indexOf(regTop);

        if(offset == -1)
        {
            top = 0;
        }
        else
        {
            int end = styleSheet.indexOf(";", offset);
            QString str = styleSheet.mid(offset, end - offset);

            QRegExp num("(\\d+)");
            int pos = num.indexIn(str);
            QString value;
            if (pos > -1)
            {
                value = num.cap(1);
            }

            bool ok;
            int margin = value.toInt(&ok, 10);
            if(ok)
            {
                top = margin;
            }
        }

        int right;
        QRegExp regRight("(margin-right)\\s*:\\s*\\d+\\s*(px)\\s*;");
        offset = styleSheet.toLower().indexOf(regRight);

        if(offset == -1)
        {
            right = 0;
        }
        else
        {
            int end = styleSheet.indexOf(";", offset);
            QString str = styleSheet.mid(offset, end - offset);

            QRegExp num("(\\d+)");
            int pos = num.indexIn(str);
            QString value;
            if (pos > -1)
            {
                value = num.cap(1);
            }

            bool ok;
            int margin = value.toInt(&ok, 10);
            if(ok)
            {
                right = margin;
            }
        }

        int bottom;
        QRegExp regBottom("(margin-top)\\s*:\\s*\\d+\\s*(px)\\s*;");
        offset = styleSheet.toLower().indexOf(regBottom);

        if(offset == -1)
        {
            bottom = 0;
        }
        else
        {
            int end = styleSheet.indexOf(";", offset);
            QString str = styleSheet.mid(offset, end - offset);

            QRegExp num("(\\d+)");
            int pos = num.indexIn(str);
            QString value;
            if (pos > -1)
            {
                value = num.cap(1);
            }

            bool ok;
            int margin = value.toInt(&ok, 10);
            if(ok)
            {
                bottom = margin;
            }
        }
       m_margin = QMargins(left, top, right, bottom);
    }
}

void PaiComboBox::SetRealTimeValidate(bool flag)
{
    m_RealTimeValidate = flag;
}


void PaiComboBox::keyPressEvent(QKeyEvent *pEvent)
{
    if(pEvent->key() == Qt::Key_Return)
    {
        QComboBox::keyPressEvent(pEvent);
        pEvent->accept();   // 过滤事件,使其不往父窗体传递
        return;
    }

    if((!m_RealTimeValidate) || (pEvent->key() == Qt::Key_Backspace) || (pEvent->key() == Qt::Key_Delete))
    {
        QComboBox::keyPressEvent(pEvent);
        return;
    }

    QString currentStr = currentText();
    QLineEdit *pLineEdit = lineEdit();
    QString selectedText = pLineEdit->selectedText();
    QString pressAfterStr;
    int pos = pLineEdit->cursorPosition();
    if(selectedText.isEmpty())
    {
        pressAfterStr = currentStr.insert(pos, pEvent->text());
    }
    else
    {
        pressAfterStr = currentStr.replace(pLineEdit->selectionStart(), selectedText.size(), pEvent->text());
    }

    const QValidator *pValidator = validator();
    int postion = pressAfterStr.size();
    if(pValidator && (pValidator->validate(pressAfterStr, postion) == QValidator::Invalid))
    {
        pEvent->accept();
    }
    else
    {
       QComboBox::keyPressEvent(pEvent);
    }

    return;
}

void PaiComboBox::resizeEvent(QResizeEvent *pEvent)
{
    QComboBox::resizeEvent(pEvent);
    // 请不要添加m_pEditButton->isVisible()条件，因为没有paint之前控件是不可见的
    if(m_AddButton && m_pEditButton)
    {
        // 为按钮所准备空间
        setStyleSheet(QString::fromUtf8("QComboBox{margin-right:%1px}").arg(height()));
    }
}

void PaiComboBox::paintEvent(QPaintEvent *pEvent)
{
    QComboBox::paintEvent(pEvent);
    if(m_AddButton && m_pEditButton && m_pEditButton->isVisible())
    {
        // 添加限制条件确保这里不会频繁的调用
        QRect rect(width()-height() - 1, 0, height() + 1, height());
        if(m_pEditButton->geometry() != rect)
        {
            m_pEditButton->setGeometry(rect);
        }

        QPainter painter(this);
        painter.setPen(QColor("#839CB6"));
        painter.drawLine(width()-height() - 2, 6, width() - height() - 2, height() - 6);
    }
}