/*      _______   __   __   __   ______   __   __   _______   __   __
 *     / _____/\ / /\ / /\ / /\ / ____/\ / /\ / /\ / ___  /\ /  |\/ /\
 *    / /\____\// / // / // / // /\___\// /_// / // /\_/ / // , |/ / /
 *   / / /__   / / // / // / // / /    / ___  / // ___  / // /| ' / /
 *  / /_// /\ / /_// / // / // /_/_   / / // / // /\_/ / // / |  / /
 * /______/ //______/ //_/ //_____/\ /_/ //_/ //_/ //_/ //_/ /|_/ /
 * \______\/ \______\/ \_\/ \_____\/ \_\/ \_\/ \_\/ \_\/ \_\/ \_\/
 *
 * Copyright (c) 2004, 2005, 2006, 2007 Olof Naessén and Per Larsson
 *
 *                                                         Js_./
 * Per Larsson a.k.a finalman                          _RqZ{a<^_aa
 * Olof Naessén a.k.a jansem/yakslem                _asww7!uY`>  )\a//
 *                                                 _Qhm`] _f "'c  1!5m
 * Visit: http://guichan.darkbits.org             )Qk<P ` _: :+' .'  "{[
 *                                               .)j(] .d_/ '-(  P .   S
 * License: (BSD)                                <Td/Z <fP"5(\"??"\a.  .L
 * Redistribution and use in source and          _dV>ws?a-?'      ._/L  #'
 * binary forms, with or without                 )4d[#7r, .   '     )d`)[
 * modification, are permitted provided         _Q-5'5W..j/?'   -?!\)cam'
 * that the following conditions are met:       j<<WP+k/);.        _W=j f
 * 1. Redistributions of source code must       .$%w\/]Q  . ."'  .  mj$
 *    retain the above copyright notice,        ]E.pYY(Q]>.   a     J@\
 *    this list of conditions and the           j(]1u<sE"L,. .   ./^ ]{a
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 * 2. Redistributions in binary form must        )_]X{Z('a_"a7'<a"a,  ]"[
 *    reproduce the above copyright notice,       #}<]m7`Za??4,P-"'7. ).m
 *    this list of conditions and the            ]d2e)Q(<Q(  ?94   b-  LQ/
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 *    documentation and/or other materials      .Z!=J ]e []('-4f _ ) -.)m]'
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 *    names of its contributors may be used     =3)= _f  (_yQmWW$#(    "
 *    to endorse or promote products derived     -   W,  sQQQQmZQ#Wwa]..
 *    from this software without specific        (js, \[QQW$QWW#?!V"".
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 *                                                 -]n w/ '         [.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT       )/ )/           !
 * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY         <  (; sac    ,    '
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * For comments regarding functions please see the header file.
 */

#include "guisan/widgets/listbox.hpp"

#include "guisan/font.hpp"
#include "guisan/graphics.hpp"
#include "guisan/key.hpp"
#include "guisan/listmodel.hpp"
#include "guisan/mouseinput.hpp"
#include "guisan/selectionlistener.hpp"

namespace gcn
{
    ListBox::ListBox() : ListBox(nullptr)
    {}

    ListBox::ListBox(ListModel* listModel)
    {
        setWidth(100);
        setListModel(listModel);
        setFocusable(true);

        addMouseListener(this);
        addKeyListener(this);
    }

    void ListBox::draw(Graphics* graphics)
    {
        graphics->setColor(getBackgroundColor());
        graphics->fillRectangle(Rectangle(0, 0, getWidth(), getHeight()));

        if (mListModel == nullptr)
        {
            return;
        }

        graphics->setColor(getForegroundColor());
        graphics->setFont(getFont());

        // Check the current clip area so we don't draw unnecessary items
        // that are not visible.
        const auto currentClipArea = graphics->getCurrentClipArea();
        const int rowHeight = getRowHeight();

        // Calculate the number of rows to draw by checking the clip area.
        // The addition of two makes covers a partial visible row at the top
        // and a partial visible row at the bottom.
        auto numberOfRows = currentClipArea.height / rowHeight + 2;

        if (numberOfRows > mListModel->getNumberOfElements())
        {
            numberOfRows = mListModel->getNumberOfElements();
        }

        // Calculate which row to start drawing. If the list box
        // has a negative y coordinate value we should check if
        // we should drop rows in the beginning of the list as
        // they might not be visible. A negative y value is very
        // common if the list box for instance resides in a scroll
        // area and the user has scrolled the list box downwards.
        int startRow;
        if (getY() < 0)
        {
            startRow = -1 * (getY() / rowHeight);
        }
        else
        {
            startRow = 0;
        }

        const auto inactive_color = getSelectionColor() - 0x303030;

        // The y coordinate where we start to draw the text is
        // simply the y coordinate multiplied with the font height.
        auto y = rowHeight * startRow;

        for (auto i = startRow; i < startRow + numberOfRows; ++i)
        {
            if (i == mSelected)
            {
                if (isFocused())
                    graphics->setColor(getSelectionColor());
                else
                    graphics->setColor(inactive_color);
                graphics->fillRectangle(Rectangle(0, y, getWidth(), rowHeight));
                graphics->setColor(getForegroundColor());
            }

            // If the row height is greater than the font height we
            // draw the text with a center vertical alignment.
            if (rowHeight > getFont()->getHeight())
            {
                graphics->drawText(mListModel->getElementAt(i), 2, y + rowHeight / 2 - getFont()->getHeight() / 2);
            }
            else
            {
                graphics->drawText(mListModel->getElementAt(i), 2, y);
            }

            y += rowHeight;
        }
    }

    void ListBox::logic()
    {
        adjustSize();
    }

    int ListBox::getSelected() const
    {
        return mSelected;
    }

    void ListBox::setSelected(int selected)
    {
        if (mListModel == nullptr)
        {
            mSelected = -1;
        }
        else
        {
            if (selected < 0)
            {
                mSelected = -1;
            }
            else if (selected >= mListModel->getNumberOfElements())
            {
                mSelected = mListModel->getNumberOfElements() - 1;
            }
            else
            {
                mSelected = selected;
            }
        }
        Rectangle scroll;

        if (mSelected < 0)
        {
            scroll.y = 0;
        }
        else
        {
            scroll.y = getRowHeight() * mSelected;
        }

        scroll.height = getRowHeight();
        showPart(scroll);

        distributeValueChangedEvent();
    }

    void ListBox::keyPressed(KeyEvent& keyEvent)
    {
        const Key key = keyEvent.getKey();

        if (key.getValue() == Key::Enter || key.getValue() == Key::Space)
        {
            distributeActionEvent();
            keyEvent.consume();
        }
        else if (key.getValue() == Key::Up)
        {
            setSelected(mSelected - 1);

            if (mSelected == -1)
            {
                if (mWrappingEnabled)
                {
                    setSelected(getListModel()->getNumberOfElements() - 1);
                }
                else
                {
                    setSelected(0);
                }
            }

            keyEvent.consume();
        }
        else if (key.getValue() == Key::Down)
        {
            if (mWrappingEnabled
                && getSelected() == getListModel()->getNumberOfElements() - 1)
            {
                setSelected(0);
            }
            else
            {
                setSelected(getSelected() + 1);
            }

            keyEvent.consume();
        }
        else if (key.getValue() == Key::Home)
        {
            setSelected(0);
            keyEvent.consume();
        }
        else if (key.getValue() == Key::End)
        {
            setSelected(getListModel()->getNumberOfElements() - 1);
            keyEvent.consume();
        }
    }

    void ListBox::mousePressed(MouseEvent& mouseEvent)
    {
        if (mouseEvent.getButton() == MouseEvent::Left)
        {
            setSelected(mouseEvent.getY() / getRowHeight());
            distributeActionEvent();
        }
    }

    void ListBox::mouseWheelMovedUp(MouseEvent& mouseEvent)
    {
        if (isFocused())
        {
            if (getSelected() > 0 )
            {
                setSelected(getSelected() - 1);
            }

            mouseEvent.consume();
        }
    }

    void ListBox::mouseWheelMovedDown(MouseEvent& mouseEvent)
    {
        if (isFocused())
        {
            setSelected(getSelected() + 1);

            mouseEvent.consume();
        }
    }

    void ListBox::mouseDragged(MouseEvent& mouseEvent)
    {
        mouseEvent.consume();
    }

    void ListBox::setListModel(ListModel *listModel)
    {
        mSelected = -1;
        mListModel = listModel;
        adjustSize();
    }

    ListModel* ListBox::getListModel()
    {
        return mListModel;
    }

    void ListBox::adjustSize()
    {
        if (mListModel != nullptr)
        {
            int maxElementWidth = getWidth();
            for (int i = 0; i < mListModel->getNumberOfElements(); i++)
            {
                const auto elementLength = getFont()->getWidth(mListModel->getElementAt(i));
                if (elementLength > maxElementWidth)
                {
                    maxElementWidth = elementLength;
                }
            }
            if (maxElementWidth > getWidth())
                setWidth(maxElementWidth + 4);
            setHeight(getRowHeight() * mListModel->getNumberOfElements());
        }
    }

    bool ListBox::isWrappingEnabled() const
    {
        return mWrappingEnabled;
    }

    void ListBox::setWrappingEnabled(bool wrappingEnabled)
    {
        mWrappingEnabled = wrappingEnabled;
    }

    void ListBox::addSelectionListener(SelectionListener* selectionListener)
    {
        mSelectionListeners.push_back(selectionListener);
    }

    void ListBox::removeSelectionListener(SelectionListener* selectionListener)
    {
        mSelectionListeners.remove(selectionListener);
    }

    void ListBox::distributeValueChangedEvent()
    {
        const SelectionEvent event(this);

        for (SelectionListener* selectionListener : mSelectionListeners)
        {
            selectionListener->valueChanged(event);
        }
    }

    unsigned int ListBox::getRowHeight() const
    {
        return getFont()->getHeight();
    }
}
