#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
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## modification, are permitted provided that the following conditions are
## met:
##   * Redistributions of source code must retain the above copyright
##     notice, this list of conditions and the following disclaimer.
##   * Redistributions in binary form must reproduce the above copyright
##     notice, this list of conditions and the following disclaimer in
##     the documentation and/or other materials provided with the
##     distribution.
##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
##     the names of its contributors may be used to endorse or promote
##     products derived from this software without specific prior written
##     permission.
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## $QT_END_LICENSE$
##
#############################################################################


from PyQt5 import QtCore, QtWidgets


class FlowLayout(QtWidgets.QLayout):
    def __init__(self, parent=None, margin=-1, hspacing=-1, vspacing=-1):
        super(FlowLayout, self).__init__(parent)
        self._hspacing = hspacing
        self._vspacing = vspacing
        self._items = []
        self.setContentsMargins(margin, margin, margin, margin)

    def __del__(self):
        del self._items[:]

    def addItem(self, item):
        self._items.append(item)

    def horizontalSpacing(self):
        if self._hspacing >= 0:
            return self._hspacing
        else:
            return self.smartSpacing(QtWidgets.QStyle.PM_LayoutHorizontalSpacing)

    def verticalSpacing(self):
        if self._vspacing >= 0:
            return self._vspacing
        else:
            return self.smartSpacing(QtWidgets.QStyle.PM_LayoutVerticalSpacing)

    def count(self):
        return len(self._items)

    def itemAt(self, index):
        if 0 <= index < len(self._items):
            return self._items[index]

    def takeAt(self, index):
        if 0 <= index < len(self._items):
            return self._items.pop(index)

    def expandingDirections(self):
        return QtCore.Qt.Orientations(0)

    def hasHeightForWidth(self):
        return True

    def heightForWidth(self, width):
        return self.doLayout(QtCore.QRect(0, 0, width, 0), True)

    def setGeometry(self, rect):
        super(FlowLayout, self).setGeometry(rect)
        self.doLayout(rect, False)

    def sizeHint(self):
        return self.minimumSize()

    def minimumSize(self):
        size = QtCore.QSize()
        for item in self._items:
            size = size.expandedTo(item.minimumSize())
        left, top, right, bottom = self.getContentsMargins()
        size += QtCore.QSize(left + right, top + bottom)
        return size

    def doLayout(self, rect, testonly):
        left, top, right, bottom = self.getContentsMargins()
        effective = rect.adjusted(+left, +top, -right, -bottom)
        x = effective.x()
        y = effective.y()
        lineheight = 0
        for item in self._items:
            widget = item.widget()
            hspace = self.horizontalSpacing()
            if hspace == -1:
                hspace = widget.style().layoutSpacing(
                    QtWidgets.QSizePolicy.PushButton,
                    QtWidgets.QSizePolicy.PushButton,
                    QtCore.Qt.Horizontal,
                )
            vspace = self.verticalSpacing()
            if vspace == -1:
                vspace = widget.style().layoutSpacing(
                    QtWidgets.QSizePolicy.PushButton,
                    QtWidgets.QSizePolicy.PushButton,
                    QtCore.Qt.Vertical,
                )
            nextX = x + item.sizeHint().width() + hspace
            if nextX - hspace > effective.right() and lineheight > 0:
                x = effective.x()
                y = y + lineheight + vspace
                nextX = x + item.sizeHint().width() + hspace
                lineheight = 0
            if not testonly:
                item.setGeometry(QtCore.QRect(QtCore.QPoint(x, y), item.sizeHint()))
            x = nextX
            lineheight = max(lineheight, item.sizeHint().height())
        return y + lineheight - rect.y() + bottom

    def smartSpacing(self, pm):
        parent = self.parent()
        if parent is None:
            return -1
        elif parent.isWidgetType():
            return parent.style().pixelMetric(pm, None, parent)
        else:
            return parent.spacing()