#!/usr/bin/env python

from time import sleep, time
from random import random
import numpy as np
from epics import PV
from bokeh.plotting import curdoc, figure
from bokeh.models import ColumnDataSource
from bokeh.layouts import row


data = {
    "x": [],
    "y": []
}

source = ColumnDataSource(data=data)
histo = ColumnDataSource(dict(left=[], right=[], top=[]))

fig1 = figure()
fig1.step(x="x", y="y", source=source, mode="after")
fig1.circle(x="x", y="y", source=source)

fig2 = figure()
fig2.quad(left="left", right="right", top="top", bottom=0, source=histo)

pv = PV("MTEST:RAND0")

cache = {
    "x": [],
    "y": []
}

def cb(value=None, **kwargs):
    x = time()
    y = value
    cache["x"].append(x)
    cache["y"].append(y)

def update():
    source.stream(cache, rollover=50)
    cache["x"] = []
    cache["y"] = []
    data = source.data["y"]
    counts, edges = np.histogram(data, bins="auto")
    histo.data.update(left=edges[:-1], right=edges[1:], top=counts)



pv.add_callback(cb)
doc = curdoc()
doc.add_periodic_callback(update, 1000)
plt = row(fig1, fig2)
doc.add_root(plt)