from .GraphicsWidget import GraphicsWidget
from .LabelItem import LabelItem
from ..Qt import QtGui, QtCore
from .. import functions as fn

__all__ = ['LegendItem']

class LegendItem(GraphicsWidget):
    """
    Displays a legend used for describing the contents of a plot.

    Note that this item should not be added directly to a PlotItem. Instead,
    Make it a direct descendant of the PlotItem::

        legend.setParentItem(plotItem)

    """
    def __init__(self, size, offset):
        GraphicsWidget.__init__(self)
        self.setFlag(self.ItemIgnoresTransformations)
        self.layout = QtGui.QGraphicsGridLayout()
        self.setLayout(self.layout)
        self.items = []
        self.size = size
        self.offset = offset
        self.setGeometry(QtCore.QRectF(self.offset[0], self.offset[1], self.size[0], self.size[1]))
        
    def addItem(self, item, title):
        """
        Add a new entry to the legend. 

        =========== ========================================================
        Arguments
        item        A PlotDataItem from which the line and point style
                    of the item will be determined
        title       The title to display for this item. Simple HTML allowed.
        =========== ========================================================
        """
        label = LabelItem(title)
        sample = ItemSample(item)
        row = len(self.items)
        self.items.append((sample, label))
        self.layout.addItem(sample, row, 0)
        self.layout.addItem(label, row, 1)
        
    def boundingRect(self):
        return QtCore.QRectF(0, 0, self.size[0], self.size[1])
        
    def paint(self, p, *args):
        p.setPen(fn.mkPen(255,255,255,100))
        p.setBrush(fn.mkBrush(100,100,100,50))
        p.drawRect(self.boundingRect())
        
        
class ItemSample(GraphicsWidget):
    def __init__(self, item):
        GraphicsWidget.__init__(self)
        self.item = item
    
    def boundingRect(self):
        return QtCore.QRectF(0, 0, 20, 20)
        
    def paint(self, p, *args):
        p.setPen(fn.mkPen(self.item.opts['pen']))
        p.drawLine(2, 18, 18, 2)