import numpy as np
from bokeh.plotting import figure, output_file, show, VBox
from bokeh.models import Plot, Range1d, ColumnDataSource
from bokeh.properties import Instance
from bokeh.server.app import bokeh_app
from bokeh.server.utils.plugins import object_page
from bokeh.models.widgets import HBox, Slider, TextInput, VBoxForm

xr = Range1d(start=-3, end=3)
yr = Range1d(0, 1)

class SlidersApp(HBox):
    """An example of a browser-based, interactive plot with slider controls."""

    extra_generated_classes = [["SlidersApp", "SlidersApp", "HBox"]]

    inputs = Instance(VBoxForm)

    text = Instance(TextInput)

    a = Instance(Slider)

    p1 = Instance(Plot)
    source = Instance(ColumnDataSource)

    @classmethod
    def create(cls):
        """One-time creation of app's objects.

        This function is called once, and is responsible for
        creating all objects (plots, datasources, etc)
        """
        obj = cls()

        obj.source = ColumnDataSource(data=dict(x=[], y=[]))

        obj.text = TextInput(
            title="title", name='title', value='cubic function'
        )

        obj.a = Slider(title="a", name='a', value=4, start=0, end=4, step=0.1)

#        toolset = "crosshair,pan,reset,resize,save,wheel_zoom"
        toolset = ''

        # Generate a figure container
        p1 = figure(title_text_font_size="12pt",
                      plot_height=400,
                      plot_width=400,
                      tools=toolset,
                      title=obj.text.value,
                      x_range=xr, y_range=yr,
                      background_fill='#59636C'
        )

        # Plot the line by the x,y values in the source property
        p1.line('x', 'y', source=obj.source, line_width=3, color='orange')

        obj.p1 = p1
        obj.update_data()

        obj.inputs = VBoxForm(
            children=[
                obj.text, obj.a,
            ]
        )

        obj.children.append(obj.inputs)
        obj.children.append(VBox(obj.p1,))

        return obj

    def setup_events(self):
        """Attaches the on_change event to the value property of the widget.

        The callback is set to the input_change method of this app.
        """
        super(SlidersApp, self).setup_events()
        if not self.text:
            return

        # Text box event registration
        self.text.on_change('value', self, 'input_change')

        # Slider event registration
        for w in ['a', ]:
            getattr(self, w).on_change('value', self, 'input_change')

    def input_change(self, obj, attrname, old, new):
        """Executes whenever the input form changes.

        It is responsible for updating the plot, or anything else you want.

        Args:
            obj : the object that changed
            attrname : the attr that changed
            old : old value of attr
            new : new value of attr
        """
        self.update_data()

    def update_data(self):
        """Called each time that any watched property changes.

        This updates the sin wave data with the most recent values of the
        sliders. This is stored as two numpy arrays in a dict into the app's
        data source property.
        """
        N = 1000

        # Get the current slider value
        a = self.a.value

        # Generate the wavefunction
        x = np.linspace(-3, 3, N)
        y = x**3

        self.source.data = dict(x=x, y=y)

        self.p1.y_range.start = np.min(y) * 1.2
        self.p1.y_range.end = np.max(y) * 1.2

        px = x[N//2:N//2+a*100]
        px = np.append(px, px[::-1])
        py = y[N//2:N//2+a*100]
        py = np.append(py, np.zeros(len(px//2)))
        print('YYYYYY',type(self.p1))
        self.p1.patch(px, py, color='orange', fill_alpha=0.4)


# The following code adds a "/bokeh/sliders/" url to the bokeh-server. This
# URL will render this sine wave sliders app. If you don't want to serve this
# applet from a Bokeh server (for instance if you are embedding in a separate
# Flask application), then just remove this block of code.
@bokeh_app.route("/cubic/")
@object_page("cubic")
def make_cubic():
    app = SlidersApp.create()
    return app