#!/usr/bin/ruby

re_sender = Regexp.new( 'From' )
re_day = Regexp.new( '(Sun|Mon|Tue|Wed|Thu|Fri|Sat)' )
messages = IO.readlines( ARGV[0] )
sender_lines = []
messages.each_index do |index|
  puts "looking at: #{ messages[index] }"
  if re_sender =~ messages[index] and re_day =~ messages[index] then
    sender_lines << index
  end
end
message_id = 0
filename = "message_#{ message_id }"
sender_lines.each_index do |index|
  File.open( filename, "w" ) do |file|
    unless (index + 1) == sender_lines.length
      messages[sender_lines[index]..sender_lines[index+1]-1].each do |message_line|
        file.puts message_line
      end
    else
      messages[sender_lines[index]..messages.length-1].each do |message_line|
        file.puts message_line
      end
    end
  end
  message_id += 1
  filename = "message_#{ message_id }"
end