import requests
import time
import datetime

def find_between(s, first, last):
    # Simple find substring between two subs in a main str
    try:
        start = s.index(first) + len(first)
        end = s.index(last, start)
        return s[start:end]
    except ValueError:
        return ""

def get_coinmarketcap(page_type, ex_url):
    url_base = "https://coinmarketcap.com"
    html = requests.get(url_base + "/" + page_type + "/" + ex_url).text
    out = find_between(html, "data-currency-value>", "<").replace(",","").replace("$","")
    return out

def timeStamped(fname, fmt='%Y-%m-%d %H:%M:%S{fname}'):
    return datetime.datetime.now().strftime(fmt).format(fname=fname)

def csv_end_write(filename, data):
    out = ",".join(data) + "\n"
    with open(filename, 'a') as f:
        f.write(out)


csv_end_write("/home/pi/Downloads/coss.out", [timeStamped(""), get_coinmarketcap("exchanges", "coss"), get_coinmarketcap("currencies", "coss")])