#!/usr/bin/env ruby
#
# unknown source :(

require 'socket'

DEBUG = false

def data(sock)
  s = ""

  sock.print "354 End data with <CR><LF>.<CR><LF>\r\n"
  while(line = sock.gets)
    puts line if DEBUG
    break if line =~ /^\.\r?\n?$/
    s += line
  end
  s
end

def session(sock)
  sock.print "220 localhost SMTP mockmail\r\n"
  from = nil
  to = []
  body = nil
  while(line = sock.gets)
    line.chomp!
    puts line if DEBUG
    sock.print case line
      when /HELO/: "250 localhost\r\n"
      when /RSET/: "250 Ok\r\n"
      when /VRFY/:
        /VRFY [^\s]/ =~ line
        "252 #{$1}\r\n"
      when /MAIL FROM/:
        /MAIL FROM:\s*\<?([^\s<>]+)\>?/ =~ line
        from = $1
        puts from if DEBUG
        "250 Ok\r\n"
      when /RCPT TO/:
        /RCPT TO:\s*\<?([^\s\r\n\t\f<>]+)\>?/ =~ line
        to << $1
        puts to if DEBUG
        "250 Ok\r\n"
      when /DATA/:
        body = data(sock)
        "250 Ok\r\n"
      when /QUIT/:
        sock.print "221 Bye\r\n"
        break
      else "500 Err\r\n"
    end
  end
  puts "from: #{from}"
  puts "to: #{to.join '; '}"
  puts "---"
  puts body
  puts "==="
  open("mockmail.txt", "a") { |f|
    f.puts "from: #{from}"
    f.puts "to: #{to.join '; '}"
    f.puts "---"
    f.puts body
    f.puts "==="
  }
  sock.close
end

def main
  begin
    server = TCPServer.new('localhost',25)
    Thread.start {
      loop { sleep 1 }
    }
    loop do 
      Thread.start(server.accept) { |sock|
        begin
          session(sock)
        rescue Exception => e
          p e
        end
      }
    end
  rescue Interrupt => i
    puts "ending..."
  end
end

main