"""
====
Menu
====

"""
import numpy as np
import matplotlib.colors as colors
import matplotlib.patches as patches
import matplotlib.mathtext as mathtext
import matplotlib.pyplot as plt
import matplotlib.artist as artist
import matplotlib.image as image


class ItemProperties:
    def __init__(self, fontsize=14, labelcolor='black', bgcolor='yellow',
                 alpha=1.0):
        self.fontsize = fontsize
        self.labelcolor = labelcolor
        self.bgcolor = bgcolor
        self.alpha = alpha

        self.labelcolor_rgb = colors.to_rgba(labelcolor)[:3]
        self.bgcolor_rgb = colors.to_rgba(bgcolor)[:3]


class MenuItem(artist.Artist):
    parser = mathtext.MathTextParser("Bitmap")
    padx = 5
    pady = 5

    def __init__(self, fig, labelstr, props=None, hoverprops=None,
                 on_select=None):
        artist.Artist.__init__(self)

        self.set_figure(fig)
        self.labelstr = labelstr

        if props is None:
            props = ItemProperties()

        if hoverprops is None:
            hoverprops = ItemProperties()

        self.props = props
        self.hoverprops = hoverprops

        self.on_select = on_select

        x, self.depth = self.parser.to_mask(
            labelstr, fontsize=props.fontsize, dpi=fig.dpi)

        if props.fontsize != hoverprops.fontsize:
            raise NotImplementedError(
                'support for different font sizes not implemented')

        self.labelwidth = x.shape[1]
        self.labelheight = x.shape[0]

        self.labelArray = np.zeros((x.shape[0], x.shape[1], 4))
        self.labelArray[:, :, -1] = x/255.

        self.label = image.FigureImage(fig, origin='upper')
        self.label.set_array(self.labelArray)

        # we'll update these later
        self.rect = patches.Rectangle((0, 0), 1, 1)

        self.set_hover_props(False)

        fig.canvas.mpl_connect('button_release_event', self.check_select)

    def check_select(self, event):
        over, junk = self.rect.contains(event)
        if not over:
            return

        if self.on_select is not None:
            self.on_select(self)

    def set_extent(self, x, y, w, h):
        print(x, y, w, h)
        self.rect.set_x(x)
        self.rect.set_y(y)
        self.rect.set_width(w)
        self.rect.set_height(h)

        self.label.ox = x + self.padx
        self.label.oy = y - self.depth + self.pady/2.

        self.hover = False

    def draw(self, renderer):
        self.rect.draw(renderer)
        self.label.draw(renderer)

    def set_hover_props(self, b):
        if b:
            props = self.hoverprops
        else:
            props = self.props

        r, g, b = props.labelcolor_rgb
        self.labelArray[:, :, 0] = r
        self.labelArray[:, :, 1] = g
        self.labelArray[:, :, 2] = b
        self.label.set_array(self.labelArray)
        self.rect.set(facecolor=props.bgcolor, alpha=props.alpha)

    def set_hover(self, event):
        """
        Update the hover status of event and return whether it was changed.
        """
        b, junk = self.rect.contains(event)

        changed = (b != self.hover)

        if changed:
            self.set_hover_props(b)

        self.hover = b
        return changed


class Menu:
    def __init__(self, fig, menuitems):
        self.figure = fig
        fig.suppressComposite = True

        self.menuitems = menuitems
        self.numitems = len(menuitems)

        maxw = max(item.labelwidth for item in menuitems)
        maxh = max(item.labelheight for item in menuitems)

        x0 = 100
        y0 = 400

        width = maxw + 2*MenuItem.padx
        height = maxh + MenuItem.pady

        for item in menuitems:
            left = x0
            bottom = y0 - maxh - MenuItem.pady

            item.set_extent(left, bottom, width, height)

            fig.artists.append(item)
            y0 -= maxh + MenuItem.pady

        fig.canvas.mpl_connect('motion_notify_event', self.on_move)

    def on_move(self, event):
        draw = False
        for item in self.menuitems:
            draw = item.set_hover(event)
            if draw:
                self.figure.canvas.draw()
                break


fig = plt.figure()
fig.subplots_adjust(left=0.3)
props = ItemProperties(labelcolor='black', bgcolor='yellow',
                       fontsize=15, alpha=0.2)
hoverprops = ItemProperties(labelcolor='white', bgcolor='blue',
                            fontsize=15, alpha=0.2)

menuitems = []
for label in ('open', 'close', 'save', 'save as', 'quit'):
    def on_select(item):
        print('you selected %s' % item.labelstr)
    item = MenuItem(fig, label, props=props, hoverprops=hoverprops,
                    on_select=on_select)
    menuitems.append(item)

menu = Menu(fig, menuitems)
plt.show()