from ..Qt import QtGui, QtCore

__all__ = ['LayoutWidget']
class LayoutWidget(QtGui.QWidget):
    """
    Convenience class used for laying out QWidgets in a grid.
    (It's just a little less effort to use than QGridLayout)
    """

    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.layout = QtGui.QGridLayout()
        self.setLayout(self.layout)
        self.items = {}
        self.rows = {}
        self.currentRow = 0
        self.currentCol = 0
    
    def nextRow(self):
        """Advance to next row for automatic widget placement"""
        self.currentRow += 1
        self.currentCol = 0
        
    def nextColumn(self, colspan=1):
        """Advance to next column, while returning the current column number 
        (generally only for internal use--called by addWidget)"""
        self.currentCol += colspan
        return self.currentCol-colspan
        
    def nextCol(self, *args, **kargs):
        """Alias of nextColumn"""
        return self.nextColumn(*args, **kargs)
        
        
    def addLabel(self, text=' ', row=None, col=None, rowspan=1, colspan=1, **kargs):
        """
        Create a QLabel with *text* and place it in the next available cell (or in the cell specified)
        All extra keyword arguments are passed to QLabel().
        Returns the created widget.
        """
        text = QtGui.QLabel(text, **kargs)
        self.addItem(text, row, col, rowspan, colspan)
        return text
        
    def addLayout(self, row=None, col=None, rowspan=1, colspan=1, **kargs):
        """
        Create an empty LayoutWidget and place it in the next available cell (or in the cell specified)
        All extra keyword arguments are passed to :func:`LayoutWidget.__init__ <pyqtgraph.LayoutWidget.__init__>`
        Returns the created widget.
        """
        layout = LayoutWidget(**kargs)
        self.addItem(layout, row, col, rowspan, colspan)
        return layout
        
    def addWidget(self, item, row=None, col=None, rowspan=1, colspan=1):
        """
        Add a widget to the layout and place it in the next available cell (or in the cell specified).
        """
        if row == 'next':
            self.nextRow()
            row = self.currentRow
        elif row is None:
            row = self.currentRow
            
        
        if col is None:
            col = self.nextCol(colspan)
            
        if row not in self.rows:
            self.rows[row] = {}
        self.rows[row][col] = item
        self.items[item] = (row, col)
        
        self.layout.addWidget(item, row, col, rowspan, colspan)

    def getWidget(self, row, col):
        """Return the widget in (*row*, *col*)"""
        return self.row[row][col]

    #def itemIndex(self, item):
        #for i in range(self.layout.count()):
            #if self.layout.itemAt(i).graphicsItem() is item:
                #return i
        #raise Exception("Could not determine index of item " + str(item))
    
    #def removeItem(self, item):
        #"""Remove *item* from the layout."""
        #ind = self.itemIndex(item)
        #self.layout.removeAt(ind)
        #self.scene().removeItem(item)
        #r,c = self.items[item]
        #del self.items[item]
        #del self.rows[r][c]
        #self.update()
    
    #def clear(self):
        #items = []
        #for i in list(self.items.keys()):
            #self.removeItem(i)


