#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Felix Muzny
DS 2000
Lecture 9
10/07/2022

A program to read and analyze earnings data for city of boston employees
"""
# start with our imports
import matplotlib.pyplot as plt


# define our constants
# if I want to switch between data sets
# this is the only string that I need to edit
DATA = "boston_earnings.csv"


# define our non-main functions next

def read_data_column(filename, column_index):
    """
    Reads in the data from one column in a given file
    and stores each value into a list from top to bottom
    of the file (line 1's value for the target column will
    be at index 0 of the list).    

    Parameters
    ----------
    filename : string
        name of the file
    column_index : int
        0-indexed number indicating which column to read 

    Returns
    -------
    column : list
        list of string values for all lines for the target column

    """
    file = open(filename, "r")
    column = []
    for line in file:
        pieces = line.strip().split(",")
        column.append(pieces[column_index])
    return column
    

def convert_to_floats(ls):
    """
    Create a new list with all list elements converted into 
    floats. Empty strings are ignored. This does not guarantee 
    that the resulting list has the same number of elements as
    the original list.

    Parameters
    ----------
    ls : list
        list of values to be converted to float

    Returns
    -------
    ls_as_flts : list
        list of values floats converted to float

    """
    ls_as_flts = []
    for element in ls:
        # What to do with empty strings???
        if element != "":    
            ls_as_flts.append(float(element))
        # for certain kinds of data, we might 
        # want to replace with a 0
        # else:
        #     ls_as_flts.append(0)
    return ls_as_flts


def average(ls):
    """
    Calculate the average of a list of values.

    Parameters
    ----------
    ls : list
        list of numbers

    Returns
    -------
    float
        Average value contained in the given list.

    """
    return sum(ls) / len(ls)

def create_hist(number_ls, x_axis, y_axis, title):
    """
    Creates a histogram of the given list of number 
    data with axis labels and a title!

    Parameters
    ----------
    number_ls : list
        values to be used in the histogram
    x_axis : str
        label for the x-axis
    y_axis : str
        label for the y-axis
    title : str
        title of the graph

    Returns
    -------
    None.

    """
    plt.hist(number_ls, bins = 10)
    plt.xlabel(x_axis)
    plt.ylabel(y_axis)
    plt.title(title)
    plt.show()

# define our main function
# start here
def main():
    salaries = read_data_column(DATA, 1)
    salary_nums = convert_to_floats(salaries)
    avg_salary = average(salary_nums)
    print("This is the average salary:", round(avg_salary, 2))
    # make a histogram to display this
    create_hist(salary_nums, "Salaries ($)", "Number of employees with this Salary",
                "Salary counts for the City of Boston")

    # what if we wanted to do all of these tasks for overtime as well?
    overtime = read_data_column(DATA, 2)
    overtime = convert_to_floats(overtime)
    avg_over = average(overtime)
    print("This is the average overtime:", round(avg_over, 2))
    # make a histogram to display this
    create_hist(overtime, "Overtimes ($)", "Number of employees with this Overtime",
                "Overtime counts for the City of Boston")

# call our main function
main()