#!/usr/bin/env ruby

# $Id$
# $URL$

#
# Copyright (c) 2007 Ward Wouts <ward@wouts.nl>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

message = Array.new
boundary = nil
boundaries = Array.new
pgpstart = nil
pgpend = nil
pgpblocks = Array.new

$stdin.each{|line|
	message.push line
}

# Eerst uitzoeken wat de mime boundaries zijn
message.each{|line|
	if line.match("Content-Type: multipart/mixed") &&  line.match(/boundary=\"(.*)\"/)
		if !boundary.nil?
			raise "More than one MIME boundary detected"
		else
			boundary=$1
		end
	end
}

message.each_index{|x|
	if message[x].match(/^--#{Regexp.escape(boundary)}/)
		boundaries.push x
	end
	if message[x].match(/^-----BEGIN PGP MESSAGE-----$/)
		if !pgpstart.nil?
			raise "Multiple PGP starts found in a row"
		end
		pgpstart = x
	end
	if message[x].match(/^-----END PGP MESSAGE-----$/)
		if pgpstart.nil?
			raise "PGP end, but no start found"
		end
		pgpblocks.push pgpstart
		pgpstart = nil
	end
}

# magic om uit te rekenen in welke blokken het Content-Type gefixed moet worden
# er vanuit gaande dat dat steeds tussen een mime-boundry en een pgp start moet
pgpblocks.reverse_each{|p|
	boundaries.reverse_each{|b|
		if b > p
			next
		else
			(b...p).each{|x|
				if message[x].match(/^Content-Type: .*/)
					message[x] = "Content-Type: application/pgp; format=text; x-action=encrypt"
				end
			}
			break
		end
	}
}

message.each{|line|
	puts line
}