Given a stream of href links, backward operations, or forward operations, output a stream of the full url the browser should visit after each event in the input stream.

browsing_href.py

'''
Given a stream of href links, backward operations, or forward operations, output
a stream of the full url the browser should visit after each event in the input stream.
'''

def full_url(paths):
    '''
    In this implementation, I am assuming that a user cannot go backwards more
    than once consequentively.
    '''
    if paths == '':
        print("Please provide the strings")
    else:
        path_list = paths.split("\n")
        for path in path_list:
            if "https://" in path:
                visits = []
                visits.append(path)
                print path
            elif path == "BACK":
                try:
                    if len(visits) > 0:
                        previous = len(visits) - 2
                        back = visits[previous]
                        visits.append("B")
                        print back
                except:
                    print "Sorry, nothing to go back to..."
            elif path == "FORWARD":
                try:
                    previous = len(visits) - 1
                    if len(visits) > 0 and visits[previous] == "B":
                        forward = visits[previous-1]
                        print forward
                except:
                    print "Sorry, nothing to go forward to..."
                visits.pop(previous)
            else:
                previous = len(visits) - 1
                if visits[previous] == "B":
                    visits.pop(previous)

                if path[0] == "/":
                    new_path = visits[0] + path
                    visits.append(new_path)
                    print new_path
                else:
                    latest = len(visits)
                    new_path = visits[latest-1] + "/" + path
                    visits.append(new_path)
                    print new_path

if __name__ == '__main__':
    full_url("https://google.com\n/search\nquery\nterm/kittens\n/calendar/today\nevents/mine\nhttps://reddit.com\nr/kittens\nBACK\nFORWARD\nnew")