#!/usr/bin/env ruby

# Solution to Ruby Quiz #149 (see http://www.rubyquiz.com/quiz149.html)
# by Pawel Radecki (pawel.j.rade...@gmail.com).

require 'logger'

$LOG = Logger.new($stderr)

#logging
#$LOG.level = Logger::DEBUG #DEBUG
$LOG.level = Logger::ERROR  #PRODUCTION

NO_LOOP_TEXT = "No loop."

class String
    private
    def compose_word_loop_array (index1, index2)
        a = Array.new(self.length) {|i| Array.new(self.length, " ") }

        i=0
        while (i<index1)
            a[1][i] = self[i].chr
            i+=1
        end

        #repeated letter, first occurrence, loop point
        a[1][index1]=self[index1].chr

        i=index1+1
        boundary = (index2-index1)/2+index1
        while(i<boundary)
            a[1][i] = self[i].chr
            i+=1
        end

        i=index2-1; j=index1
        while(i>boundary-1)
            a[0][j] = self[i].chr
            j+=1; i-=1
        end

        i=index2+1; j=2
        while (i<self.length)
            a[j][index1] = self[i].chr
            i+=1; j+=1
        end

        #cut all empty rows
        a.slice!(j..self.length-1)
        a
    end

    public
    def word_loop
        if (self.length<=4)
            return NO_LOOP_TEXT
        end
        s = self
        index1 = index2 = nil
            #find repeated letter suitable for a loop by
            #taking 1st letter and comparing to 5th, 7th, 9th, 11th, etc.
            #taking 2nd letter and comparing to 6th, 8th, 10th, 12th, etc.
            #taking 3rd letter and comparing to 7th, 9th, 11th etc.
            #etc.
            i = 0
            while i<s.length-1
                j=i+4
                while j<s.length
                    $LOG.debug("i: #{i}")
                    $LOG.debug("j: #{j}")
                    $LOG.debug("s[i]: #{s[i].chr}")
                    $LOG.debug("s[j]: #{s[j].chr}")
                    $LOG.debug("\n")
                    if s[i] == s[j]
                        return compose_word_loop_array(i, j)
                    end
                    j+=2
                end
                i+=1
            end
        return NO_LOOP_TEXT
    end
end

USAGE = <<ENDUSAGE
Usage:
   word_loop <message>
ENDUSAGE

if ARGV.length!=1
    puts USAGE
    exit
end

input_word = ARGV[0]
a = input_word.word_loop
if a.instance_of? Array
    a.each {|x| puts x.join("") }
else
    print a
end

exit