"""

John Rachlin
DS 2000: Intro to Programming with Data

Filename: dataproc.py
    
Description: A personal library of data processing utilities

    
"""


import math
import random as rnd
import matplotlib.pyplot as plt

    
def deg2rad(theta):
    """ Convert an angle, theta, from degrees to radians """
    return theta * math.pi / 180.0


def rad2deg(theta):
    """ Convert an angle, theta, from radians to degrees """
    return theta * 180.0 / math.pi


def avg(L):
    """ Compute the numerical average of a list of numbers.
    If list is empty, return None """
    
    if len(L) > 0:
        return sum(L) / len(L)
    else:
        return None
    

def moving_average(L, window_size=10):
    """ Compute a moving average using a specified window size. 
    L - A list of numbers
    window_size - The window size for data smoothing (default=10) """

    mavg = []

    for i in range(len(L)):
        lower = max(i - window_size // 2, 0)
        upper = i + window_size // 2
        window = L[lower:upper]
        smooth = avg(window)
        mavg.append(smooth)

    return mavg


def percentiles(L):
    """ Compute percentiles of values in a list """
    srt = sorted(L) # Sort items in assending order
    length = len(L)
    
    pct = [0.0]  # smallest value is at the zeroth percentile
    for i in range(1, length):
        if srt[i] == srt[i-1]: # value unchanged
            pct.append(pct[i-1])
        else:
            pct.append(i / length)
            
    return pct



def main():
    
    # Some test code to 'exercise' our functions 
    
    alist = [math.sin(deg2rad(deg))+rnd.uniform(-0.2,0.2)  for deg in range(360)]
    plt.figure(figsize=(10,10), dpi=150)
    plt.scatter(range(360), alist)
    mavg = moving_average(alist, window_size=20)
    plt.plot(mavg, color='r')
    
    
if __name__ == '__main__':
    main()