#!/usr/bin/env python

"""Collect utilities here
__VERSION: 0.1
__AUTHOR: xiconet
"""

MAXLEN = 60
START_AT = 2


def shorten(s, maxlen=MAXLEN):
    """Shorten a string while keeping its last two words"""
    words = s.split(" ")
    left_part = words[:-2]
    right_part = words[-2:]
    while len(s) > maxlen:
        left_part.pop()
        s = " ".join(left_part + ["..."] + right_part)
    return s
        

def shorten_at(s, start_at=START_AT, maxlen=MAXLEN):
    """shorten a string at the chosen word position, 
    counting from the LEFT end
    """
    if len(s) == maxlen:
        return s
    words = s.split(" ")
    N = start_at
    if not 0 < N < len(words):
        print "error: start_at must be an integer N such as 0 < N < num(words in string)"
        return s
    lp = words[:-N]
    rp = words[-N:]
    while len(s) > maxlen:
        try:
            left_part.pop()
        except IndexError as err:
            print "error: unsuited start_at value: %s" % err
            return s
        s = " ".join(lp + ["..."] + rp)
    return s