#! /usr/bin/env ruby

# This code is in the public domain
# Written by Robbert Haarman

usage = "USAGE: #{File.basename $0} [ options ] file recipient ..."
options = <<EOT
-e encoding	Set encoding. Can be "base64" or "plain".
		The default is "plain" if the MIME type starts in "text/",
		and "base64" otherwise
-f sender	Set the from header (defaults to $USER@$HOST)
-h		Print help message and exit
-s subject	Set subject. Defaults to filename
-t type		Set MIME type. Defaults to "text/plain"
EOT

## Run the specified command, returning its standard input, standard output,
## and standard error
## Arguments are as for Kernel::exec
def pipecmd cmd, *args
	input_c, input_p = IO.pipe
	output_p, output_c = IO.pipe
	error_p, error_c = IO.pipe
	fork do
		input_p.close
		output_p.close
		error_p.close
		$stdin.reopen input_c
		$stdout.reopen output_c
		$stderr.reopen error_c
		exec cmd, *args
	end
	input_c.close
	output_c.close
	error_c.close
	[input_p, output_p, error_p]
end

## Initialiaze variables
encoding = nil
file = nil
from = 'inglorion@inglorion.net'
recipients = []
subject = nil
type = 'text/plain'

## Parse command line
i = 0
while i < ARGV.length
	case ARGV[i]
	when '-e', '--encoding'
		i = i + 1
		encoding = ARGV[i]
	when '-f', '--from'
		i = i + 1
		from = ARGV[i]
	when '-h', '--help'
		puts usage
		puts options
		exit
	when '-s', '--subject'
		i = i + 1
		subject = ARGV[i]
	when '-t', '--type'
		i = i + 1
		type = ARGV[i]
	when /^-/
		$stderr.puts "Unknown option: #{ARGV[i]}\n#{usage}"
		exit 0x80
	else
		if file
			recipients = recipients << ARGV[i]
		else
			file = ARGV[i]
		end
	end
	i = i + 1
end

## Check if mandatory options were given
if !file
	$stderr.puts "No file specified"
	exit 0x80
elsif recipients.length == 0
	$stderr.puts "No recipients specified"
	exit 0x80
end

name = File.basename file

## Check setting for encoding
if encoding && encoding != 'base64' && encoding != 'plain'
	$stderr.puts "Encoding must be one of \"base64\" or \"plain\""
	exit 0x80
end

## Fill in some default values where necessary
subject = file unless subject
encoding = (type =~ /^text\// ? 'plain' : 'base64') unless encoding

## Open the file, through base64-encode if necessary
if encoding == 'plain'
	input = File.new file, 'r'
else
	_, input, _ = pipecmd 'base64-encode', file
end

## Send the file
output, _, errors = pipecmd 'post-message', '-f', from, '--', *recipients
output.print "From: #{from}\015\012" +
	"To: #{recipients.join ', '}\015\012" +
	"Subject: #{subject}\015\012" +
	"Content-Type: #{type}\015\012" +
	(encoding == 'plain' ? '' :
		"Content-Transfer-Encoding: base64\015\012") +
	"Content-Disposition: attachment; filename=#{name.gsub '"', '\"'}\015\012" +
	"\015\012" + input.read
input.close
output.close
$stderr.print errors.read