#!/usr/local/bin/ruby

start = Time.now

# Arrays for each class of word
fourLetters = Array.new
threeLetters = Array.new
twoLetters = Array.new
sixLetters = Array.new

# Loop over the word list, segregating the words
#  to their respective array
IO.foreach("wordlist.txt") do |line|
    line.chomp!.downcase!

    case line.length
    when 2
        twoLetters << line
    when 3
        threeLetters << line
    when 4
        fourLetters << line
    when 6
        sixLetters << line
    end
end

candidates = Array.new

# Build up all combinations of four letters + two letters
#  and store in them as candidates
fourLetters.each do |four|
    twoLetters.each do |two|
        wc = four + two

        candidates << wc
    end
end

# Build up all combinations of three letters + three
#  letters and store them as candidates
threeLetters.each do |three|
    threeLetters.each do |otherThree|
        wc = three + otherThree
        candidates << wc
    end
end

# Finally, all combinations of two letters + two letters
#  + two letters and store those as candidates
twoLetters.each do |firstTwo|
    twoLetters.each do |secondTwo|
        twoLetters.each do |thirdTwo|
            wc = firstTwo + secondTwo + thirdTwo
            candidates << wc
        end
    end
end

# Now get rid of dups and sort in place
candidates.uniq!.sort!
puts "Candidates = #{candidates.length}" #

# And the two arrays together leaving only those words
#  that appear in both lists
matches = sixLetters & candidates

# Now write the matches to a file
File.open("matches.txt", "w") do |file|
    matches.each do |word|
        file.puts(word)
    end
end

finish = Time.now

puts "Started at #{start}"
puts "Finished at #{finish}"
puts "Total time #{finish.to_i - start.to_i}"