# -*- coding: utf-8 -*-
import pandas as pd

from bokeh.core.properties import field
from bokeh.io import curdoc
from bokeh.layouts import layout
from bokeh.models import (
    ColumnDataSource, HoverTool, SingleIntervalTicker, Slider, Button, Label,
    CategoricalColorMapper,
)
from bokeh.palettes import Spectral6
from bokeh.plotting import figure

from data import process_data

fertility_df, life_expectancy_df, population_df_size, regions_df, years, regions_list = process_data()

sources = {}

region_name = regions_df.Group
region_name.name = 'region'

for year in years:
    fertility = fertility_df[year]
    fertility.name = 'fertility'
    life = life_expectancy_df[year]
    life.name = 'life'
    population = population_df_size[year]
    population.name = 'population'
    df = pd.concat([fertility, life, population, region_name], axis=1)
    df = df.fillna('NaN')
    sources[year] = ColumnDataSource(df)

source = sources[years[0]]

plot = figure(x_range=(1, 9), y_range=(20, 100), title='Gapminder Data', plot_height=300)
plot.xaxis.ticker = SingleIntervalTicker(interval=1)
plot.xaxis.axis_label = "Children per woman (total fertility)"
plot.yaxis.ticker = SingleIntervalTicker(interval=20)
plot.yaxis.axis_label = "Life expectancy at birth (years)"

label = Label(x=1.1, y=18, text=str(years[0]), text_font_size='70pt', text_color='#eeeeee')
plot.add_layout(label)

color_mapper = CategoricalColorMapper(palette=Spectral6, factors=regions_list)
plot.circle(
    x='fertility',
    y='life',
    size='population',
    source=source,
    fill_color={'field': 'region', 'transform': color_mapper},
    fill_alpha=0.8,
    line_color='#7c7e71',
    line_width=0.5,
    line_alpha=0.5,
    legend=field('region'),
)
plot.add_tools(HoverTool(tooltips="@index", show_arrow=False, point_policy='follow_mouse'))


def animate_update():
    year = slider.value + 1
    if year > years[-1]:
        year = years[0]
    slider.value = year


def slider_update(attrname, old, new):
    year = slider.value
    label.text = str(year)
    source.data = sources[year].data

slider = Slider(start=years[0], end=years[-1], value=years[0], step=1, title="Year")
slider.on_change('value', slider_update)


def animate():
    if button.label == '► Play':
        button.label = '❚❚ Pause'
        curdoc().add_periodic_callback(animate_update, 200)
    else:
        button.label = '► Play'
        curdoc().remove_periodic_callback(animate_update)

button = Button(label='► Play', width=60)
button.on_click(animate)

layout = layout([
    [plot],
    [slider, button],
], sizing_mode='scale_width')

curdoc().add_root(layout)
curdoc().title = "Gapminder"
