#---------- reformat_para.py----------#
# Simple paragraph reformatter.  Allows specification
# of left and right margins, and of justification style
# (using constants defined in module).

LEFT,RIGHT,CENTER = 'LEFT','RIGHT','CENTER'

def reformat_para(para='',left=0,right=72,just=LEFT):
    words = para.split()
    lines = []
    line  = ''
    word = 0
    end_words = 0
    while not end_words:
        if len(words[word]) > right-left: # Handle very long words
            line = words[word]
            word +=1
            if word >= len(words):
                end_words = 1
        else:                             # Compose line of words
            while len(line)+len(words[word]) <= right-left:
                line += words[word]+' '
                word += 1
                if word >= len(words):
                    end_words = 1
                    break
        lines.append(line)
        line = ''
    if just==CENTER:
        r, l = right, left
        return '\n'.join([' '*left+ln.center(r-l) for ln in lines])
    elif just==RIGHT:
        return '\n'.join([line.rjust(right) for line in lines])
    else: # left justify
        return '\n'.join([' '*left+line for line in lines])

if __name__=='__main__':
    import sys
    if len(sys.argv) <> 4:
        print "Please specify left_margin, right_marg, justification"
    else:
        left  = int(sys.argv[1])
        right = int(sys.argv[2])
        just  = sys.argv[3].upper()

        # Simplistic approach to finding initial paragraphs
        for p in sys.stdin.read().split('\n\n'):
            print reformat_para(p,left,right,just),'\n'