#! /usr/bin/env python

# Convert  MH directories (1 message per file) or MMDF mailboxes (4x^A
# delimited) to unix mailbox (From ... delimited) on stdout.
# If -f is given, files contain one message per file (e.g. MH messages)

import rfc822
import sys
import time
import os
import stat
import getopt
import regex

def main():
	dofile = mmdf
	try:
		opts, args = getopt.getopt(sys.argv[1:], 'f')
	except getopt.error, msg:
		sys.stderr.write('%s\n' % msg)
		sys.exit(2)
	for o, a in opts:
		if o == '-f':
			dofile = message
	if not args:
		args = ['-']
	sts = 0
	for arg in args:
		if arg == '-' or arg == '':
			sts = dofile(sys.stdin) or sts
		elif os.path.isdir(arg):
			sts = mh(arg) or sts
		elif os.path.isfile(arg):
			try:
				f = open(arg)
			except IOError, msg:
				sys.stderr.write('%s: %s\n' % (arg, msg))
				sts = 1
				continue
			sts = dofile(f) or sts
			f.close()
		else:
			sys.stderr.write('%s: not found\n' % arg)
			sts = 1
	if sts:
		sys.exit(sts)

numeric = regex.compile('[1-9][0-9]*')

def mh(dir):
	sts = 0
	msgs = os.listdir(dir)
	for msg in msgs:
		if numeric.match(msg) != len(msg):
			continue
		fn = os.path.join(dir, msg)
		try:
			f = open(fn)
		except IOError, msg:
			sys.stderr.write('%s: %s\n' % (fn, msg))
			sts = 1
			continue
		sts = message(f) or sts
	return sts

def mmdf(f):
	sts = 0
	while 1:
		line = f.readline()
		if not line:
			break
		if line == '\1\1\1\1\n':
			sts = message(f, line) or sts
		else:
			sys.stderr.write(
				'Bad line in MMFD mailbox: %s\n' % `line`)
	return sts

counter = 0 # for generating unique Message-ID headers

def message(f, delimiter = ''):
	sts = 0
	# Parse RFC822 header
	m = rfc822.Message(f)
	# Write unix header line
	fullname, email = m.getaddr('From')
	tt = m.getdate('Date')
	if tt:
		t = time.mktime(tt)
	else:
		sys.stderr.write(
			'Unparseable date: %s\n' % `m.getheader('Date')`)
		t = os.fstat(f.fileno())[stat.ST_MTIME]
	print 'From', email, time.ctime(t)
	# Copy RFC822 header
	for line in m.headers:
		print line,
	# Invent Message-ID header if none is present
	if not m.has_key('message-id'):
		global counter
		counter = counter + 1
		msgid = "<%s.%d>" % (hex(t), counter)
		sys.stderr.write("Adding Message-ID %s (From %s)\n" %
				 (msgid, email))
		print "Message-ID:", msgid
	print
	# Copy body
	while 1:
		line = f.readline()
		if line == delimiter:
			break
		if not line:
			sys.stderr.write('Unexpected EOF in message\n')
			sts = 1
			break
		if line[:5] == 'From ':
			line = '>' + line
		print line,
	# Print trailing newline
	print
	return sts

main()
