from PyQt4 import QtCore, QtGui
import pyqtgraph as pg
import random
import serial
from collections import deque
import sys
import os

ser = serial.Serial("COM3", 115200)

def updateBPM(bpm):
     newString = ("HR:\n" + bpm)
     with open(os.path.join(os.path.dirname(__file__), "currentBPM.txt"), "w+") as bpmFile:
          bpmFile.write(newString)

class MainWindow(QtGui.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.central_widget = QtGui.QStackedWidget()
        self.setCentralWidget(self.central_widget)
        self.login_widget = LoginWidget(self)
        self.login_widget.button.clicked.connect(self.plotter)
        self.central_widget.addWidget(self.login_widget)

    def plotter(self):
        self.data = deque(maxlen=450)
        self.curve = self.login_widget.plot.getPlotItem().plot()
        self.timer = QtCore.QTimer()
        self.timer.timeout.connect(self.updater)
        self.timer.start(0)
        
    def updater(self):
        while (ser.inWaiting()==0):
            pass
        try:
             data = str(ser.readline()).split(",")
             bpm = data[0][2:]
             cl = int(float(data[2][:-5]))
        except:
             return
        updateBPM(bpm)
        self.data.append(cl)
        self.curve.setData(self.data)
         


          

class LoginWidget(QtGui.QWidget):
    def __init__(self, parent=None):
        super(LoginWidget, self).__init__(parent)
        layout = QtGui.QHBoxLayout()
        self.button = QtGui.QPushButton('Start Plotting')
        layout.addWidget(self.button)
        self.plot = pg.PlotWidget()
        layout.addWidget(self.plot)
        self.setLayout(layout)

if __name__ == '__main__':
    app = QtGui.QApplication([])
    window = MainWindow()
    window.resize(1083,334)
    window.show()
    app.exec_()