import numpy as np
import pandas as pd

from bokeh.models import Circle, ColumnDataSource, Range1d, HoverTool, CustomJS
from bokeh.transform import factor_cmap
from bokeh.plotting import figure, show, output_file

output_file("hover_linked_samples.html")

raw_array=np.random.rand(80,2)
fields = ["I", "II", "III", "IV"]
samples = np.arange(20)
index = pd.MultiIndex.from_product([samples, fields], names=['ID', 'field'])

data = pd.DataFrame(data=raw_array, 
                    columns=['x', 'y'],
                    index=index)
data.reset_index(inplace=True)
data['alpha'] = 0.4
source = ColumnDataSource(data)

xdr = Range1d(start=-0.05, end=1.05)
ydr = Range1d(start=-0.05, end=1.05)
s = figure(plot_width=500, plot_height=500, x_range=xdr, y_range=ydr, title="Hover over points", )

cr = s.scatter("x", "y", source=source, legend="field", fill_alpha='alpha', size=20,
          color=factor_cmap('field', 'Category10_5', fields))

# Add a hover tool, that highlights all fields from the hovered sample.
code = """
var cdata = circle.data;
var indices = cb_data.index['1d'].indices;
for (var i = 0; i < cdata['ID'].length; i++){
    cdata['alpha'][i] = 0.4;
}
for (var j = 0; j < indices.length; j++){
    ind0=indices[j];
    id = cdata['ID'][ind0];
    for (var k = 0; k < cdata['ID'].length; k++){
        if (id==cdata['ID'][k]){
            cdata['alpha'][k] = 1;
        }
    }
}
circle.data = cdata;
circle.change.emit();
""" 

callback = CustomJS(args={'circle': cr.data_source}, code=code)
s.add_tools(HoverTool(tooltips=None, callback=callback, renderers=[cr]))

show(s)