#!/usr/bin/env python
import sys
import sys
if sys.version_info[0] >= 3:
    import PySimpleGUI as sg
else:
    import PySimpleGUI27 as sg
import time
import random
import psutil
from threading import Thread


STEP_SIZE=3
SAMPLES = 300
SAMPLE_MAX = 500
CANVAS_SIZE = (300,200)


g_interval = .25
g_cpu_percent = 0
g_procs = None
g_exit = False

def CPU_thread(args):
    global g_interval, g_cpu_percent, g_procs, g_exit

    while not g_exit:
        try:
            g_cpu_percent = psutil.cpu_percent(interval=g_interval)
            g_procs = psutil.process_iter()
        except:
            pass

def main():
    global g_exit, g_response_time
    # start ping measurement thread

    sg.ChangeLookAndFeel('Black')
    sg.SetOptions(element_padding=(0,0))

    layout = [  [sg.Quit( button_color=('white','black')), sg.T('', pad=((100,0),0), font='Any 15', key='output')],
               [sg.Graph(CANVAS_SIZE, (0,0), (SAMPLES,SAMPLE_MAX),background_color='black', key='graph')],]

    window = sg.Window('CPU Graph', grab_anywhere=True, keep_on_top=True, background_color='black', no_titlebar=True, use_default_focus=False).Layout(layout)

    graph = window.FindElement('graph')
    output = window.FindElement('output')
    # start cpu measurement thread
    thread = Thread(target=CPU_thread,args=(None,))
    thread.start()

    last_cpu = i = 0
    prev_x, prev_y = 0, 0
    while True:                                 # the Event Loop
        time.sleep(.5)
        event, values = window.Read(timeout=0)
        if event == 'Quit' or event is None:  # always give ths user a way out
            break
        # do CPU measurement and graph it
        current_cpu = int(g_cpu_percent*10)
        if current_cpu == last_cpu:
            continue
        output.Update(current_cpu/10)           # show current cpu usage at top
        if current_cpu > SAMPLE_MAX:
            current_cpu = SAMPLE_MAX
        new_x, new_y = i, current_cpu
        if i >= SAMPLES:
            graph.Move(-STEP_SIZE,0)            # shift graph over if full of data
            prev_x = prev_x - STEP_SIZE
        graph.DrawLine((prev_x, prev_y), (new_x, new_y), color='white')
        prev_x, prev_y = new_x, new_y
        i += STEP_SIZE if i < SAMPLES else 0
        last_cpu = current_cpu

    g_exit = True
    window.Close()
if __name__ == '__main__':
    main()