'''
    DS2000
    Spring 2022
    Writing and calling functions -- dunkin donuts!
    
    In this version, from 2/25, we've added some fun things...
    
    - Read from the DD_US.csv file using the csv library. 
        This library is specifically designed for CSV files,
        so it makes everything a little more simple and elegant.
        
        We first import the csv library ("import csv") and then
        we don't need to use while, true, break, or split to read
        from a file.
        
    - Called a function knowing only its name, params, and return type
        In class, we scoped out a funciton called read_csv and 
        figure out how to call it (data = read_csv(DD_FILE))
        
        Then we wrote the function too! It uses the CSV library
        to read in all the dunks locations in the US and return it
        as a 2d list of strings.
        
    - Wrote a function to find the dunks locations in a city.
        We wrote a function called get_local, which takes in a 2d list
        of strings, the name of a city, and a col number to look at,
        and returns a similar but smaller 2d list that is the dunks
        just in that city
        
    - Look how small and easy to follow main is! That's why we
        love functions!

'''


import csv
import matplotlib.pyplot as plt

DD_FILE = "DD_US.csv"

LANEY_LAT = 42.30537
LANEY_LONG = -71.061
LAT_COL = 1
LONG_COL = 0
ADDRESS_COL = 2

def euclidean(x1, y1, x2, y2):
    ''' Function: euclidean
        Parameters: four floats, repping two points in the x/y plane
        Returns: a float, the euclidean distance between the points
    '''
    x_diff = (x2 - x1) ** 2
    y_diff = (y2 - y1) ** 2
    distance = x_diff + y_diff
    distance = distance ** .5
    return distance
    
def get_lat_long(dd, lat_col, long_col):
    ''' Function: get_lat_long
        Parameter: a 1d list, one line from the DD csv file
                    and two ints for lat column and long column
        Returns: a list of two floats -- the lat/long of a DD location
    '''
    lat = float(dd[lat_col])
    long = float(dd[long_col])
    lst = [lat, long]
    return lst

def read_csv(filename):
    ''' Function: read_csv
        parameter: filename, a string
        Returns: 2d list of strings, the contents of the file
    '''
    data = []
    with open(filename, "r") as infile:
        csvfile = csv.reader(infile, delimiter = ",")
        for row in csvfile:
            data.append(row)
    return data   
        
def get_local(lst, city, col):
    ''' Function: get_local
        Parameters: 2d list of strings,
         a city to look for, and the column where to look for the city
        Returns: a 2d list of strings, subset of the original
                but where the city was found
    '''
    locs = []
    for row in lst:
        if city in row[col]:
            locs.append(row)
    return locs

def main():
    # Step one: gather data from the file into a 2d list
    data = read_csv(DD_FILE)
    
    # Step two: computation!
    # Find all the locations in a city
    city = input("Enter a city\n")
    locations = get_local(data, city, ADDRESS_COL)
    
    # Step three: communication!
    # Print out the locations and also plot them on a map
    print(locations)
    lats = []
    longs = []
    for dd in locations:
        coords = get_lat_long(dd, LAT_COL, LONG_COL)
        lats.append(coords[0])
        longs.append(coords[1])
    plt.scatter(longs, lats, color = "orange")
    


main()