#!/usr/bin/perl

# "Simple but Perfect" mbox to Maildir converter v0.1
# by Philip Mak <pmak@aaanime.net>

# Usage: perfect_maildir ~/Maildir < mbox

# Simple  - only converts one mbox (can use script in one-liners)
# Perfect - message Flags/X-Flags are converted; "^>From ." line is unescaped

# I wrote this script after being unsatisfied with existing mbox to
# maildir converters. By making it "Simple", code complexity is kept
# low thus making it easy to program and debug. At the same time,
# since it only converts one mbox at a time, it is perfect for use in
# a shell ``for'' loop (for example).

# As for being "Perfect", to the best of my knowledge this script does
# the conversion correctly in all cases; it will translate "Status"
# and "X-Status" fields into maildir info, and it correctly detects
# where messages begin and end. (This is only version 0.1 so I may
# have messed something up though. Please send me feedback!)

# NOTE: The MUA ``mutt'' has a bug/feature where in the message index,
# it claims that all maildir messages have 0 lines unless they have a
# "Lines:" header set. perfect_maildir does not attempt to add the
# "Lines:" header; you may want to reconfigure ``mutt' to display byte
# size instead of lines instead by adding the following line to your
# ~/.muttrc file:
#
# set index_format="%4C %Z %{%b %d} %-15.15L (%4c) %s"

# check for valid arguments
my ($maildir) = @ARGV;
if (!$maildir) {
  print STDERR "Usage: perfect_maildir ~/Maildir < mbox\n";
    exit 1;
    }

    # check for writable maildir
    unless (-w "$maildir/cur") {
      print STDERR "Cannot write to $maildir/cur\n";
        exit 1;
	}
	unless (-w "$maildir/new") {
	  print STDERR "Cannot write to $maildir/new\n";
	    exit 1;
	    }

	    my $num = 0;
	    my $time = time;

	    repeat:

	    # read header
	    my $headers = '';
	    my $flags = '';
	    my $subject = '';
	    while (my $line = <STDIN>) {
	      # detect end of headers
	        last if $line eq "\n";

		  # strip "From" line from header
		    $headers .= $line unless $line =~ /^From ./;

		      # detect flags
		        $flags .= $1 if $line =~ /^Status: ([A-Z]+)/;
			  $flags .= $1 if $line =~ /^X-Status: ([A-Z]+)/;
			    $subject = $1 if $line =~ /^Subject: (.*)$/;
			    }
			    $num++;

			    # open output file
			    my $file;
			    if ($flags =~ /O/) {
			      $file = "$maildir/cur/$time.$num.$ENV{HOSTNAME}";
			        my $extra = '';
				  $extra .= 'F' if $flags =~ /F/; # flagged
				    $extra .= 'R' if $flags =~ /A/; # replied
				      $extra .= 'S' if $flags =~ /R/; # seen
				        $extra .= 'T' if $flags =~ /D/; # trashed
					  $file .= ":2,$extra" if $extra;
					  } else {
					    $file = "$maildir/new/$time.$num.$ENV{HOSTNAME}";
					    }

					    # filter out the "DON'T DELETE THIS MESSAGE -- FOLDER INTERNAL DATA" message
					    $file = '/dev/null' if ($num == 1 and $subject eq "DON'T DELETE THIS MESSAGE -- FOLDER 
					    INTERNAL DATA");

					    open(FILE, ">$file");
					    print FILE "$headers\n";
					    while (my $line = <STDIN>) {
					      # detect end of message
					        last if $line =~ /^From ./;

						  # unescape "From"
						    $line =~ s/^>From (.)/From $1/;

						      print FILE $line;
						      }
						      close(FILE);

						      goto repeat unless eof(STDIN);

						      my $elapsed = time - $time;
						      print "Inserted $num messages into maildir $maildir in $elapsed seconds\n";