#!/usr/bin/env python3

import matplotlib.pyplot as plt
import numpy as np
import os
import sys
from matplotlib.ticker import MultipleLocator

def detach_display():
    fig, ax = plt.subplots()
    t, x, y, h, u, v  = np.loadtxt(
        'hu_specific_points.dat', delimiter='\t', unpack=True)
    plt.xlabel('time / s')
    plt.ylabel('water height / m')
    plt.plot(t,h, color='tab:cyan', label='elevation')
    #ax.yaxis.set_minor_locator(MultipleLocator(200))
    #plt.grid(True, which='minor')

    def on_press(event):
        #print('press', event.key)
        #sys.stdout.flush()
        if event.key == 'x':
            plt.clf()
            t, x, y, h, u, v  = np.loadtxt(
                'hu_specific_points.dat', delimiter='\t', unpack=True)
            plt.xlabel('time / s')
            plt.ylabel('water height / m')
            plt.plot(t,h, color='tab:cyan', label='elevation')
            fig.canvas.draw()
    fig.canvas.mpl_connect('key_press_event', on_press)

    plt.show()

if os.fork():
    # parent
    pass
else:
    # child
    detach_display()