# Standard Library
from functools import partial
import os
# Third Party
from bokeh.document import without_document_lock
from bokeh.models import GMapPlot, GMapOptions, DataRange1d, ColumnDataSource, Circle, PanTool, WheelZoomTool, BoxSelectTool
from bokeh.plotting import curdoc
from concurrent.futures import ThreadPoolExecutor
from tornado import gen

# gps update orchestrator
@gen.coroutine
@without_document_lock
def gps_update():
    data = yield executor.submit(get_gps_points)
    doc.add_next_tick_callback(partial(update_gps_plots, data))


def get_gps_points():
    return {'lat': [32.921, 32.932], 'lon': [-97.06, -97.07]}

@gen.coroutine
def update_gps_plots(data):
    source.stream(data)


def get_48_states():
    return GMapPlot(plot_width=900,
                    plot_height=375,
                    x_range=DataRange1d(),
                    y_range=DataRange1d(),
                    map_options=GMapOptions(lat=38.50, lng=-96.35, map_type="roadmap", zoom=4),
                    api_key=api_key,
                    webgl=True)

#init
doc = curdoc()
executor = ThreadPoolExecutor(max_workers=10)
source = ColumnDataSource(data=dict(lat=[], lon=[]))
# api key for google
api_key = "api_key"
# get a map
map = get_48_states()
# init circles
circle = Circle(x="lon", y="lat", size=15, fill_color="blue", fill_alpha=0.8, line_color=None)
# add circles based on source
map.add_glyph(source, circle)
# add tools
map.add_tools(PanTool(), WheelZoomTool(), BoxSelectTool())
# map to doc
doc.add_root(map)
# add callback
doc.add_periodic_callback(gps_update, 1000)