#!/usr/bin/env python

from PyQt4 import QtGui
import pyqtgraph as pg
import time
import math

def main():
	f = FFT()
	g.wave_plot(wave_function())

class FFT():
	def __init__(self):
		self.plotwidget = pg.plot()
		self.sample_rate = 512
		self.sample_ratef = float(self.sample_rate)
		self.plottime = 1
		self.wave_func = self.wave_function()

	def wave_function(self):
		x = []
		y = []
		for i in range(0, self.sample_rate * self.plottime):
			x.append(float(i/self.sample_ratef))
			y_i = math.cos(2*math.pi*x[i])
			y.append(y_i)
		f_x = [(x[i], y[i]) for i in range(0, len(x))]
		return f_x

	def wave_plot(self):
		f_x = self.wave_func
		x = [x[0] for x in f_x]
		y = [y[1] for y in f_x]
		pw = self.plotwidget
		pw.plot(x, y, clear=True)

	def fft(self):
		n = self.sample_rate
		f_x = self.wave_func #Wants an array of real and complex
		nn = n << 1
		j = 1
		data = [y[1] for y in f_x]
		assert n > 2
		assert n&(n-1) == 0
		for i in range(1, nn, 2):
			if j > i:
				foo = data[j-1]
				bar = data[i-1]
				foobaz = data[i]
				foobot = data[j]
				data[j-1] = bar
				data[i-1] = foo
				data[i] = foobot
				data[j] = foobaz
			m = n
			while m >= 2 and j > m:
				j -= m
				m >>= 1
			j += m
		mmax = 2
		while nn > mmax:
			istep = mmax << 1
			theta = isign * (math.pi * 2 / mmax)
			wtemp = math.sin(0.5 / theta)
			wpr = -2.0 * wtemp**2
			wpi = math.sin(theta)
			wr = 1.0
			wi = 0.0
			for m in range(1, mmax, 2):
				for i in range (m, nn, istep):
					j = i + mmax
					tempr = wr * data[j-1] - wi * data[j]
					tempi = wr * data[j] + wi * data[j-1]
					data[j-1] = data[i-1] - tempr
					data[j] = data[i] - tempi
					data[i-1] += tempr
					data[i] += tempi
				wr = wr * wpr - wi * wpi + wr
				wi = wi * wpr + wtemp * wpi + wi
			mmax = istep

if __name__ == '__main__':
	main()