#! /usr/local/bin/perl

# This script runs either standalone or as a CGI program, and converts
# ChangeLogs as created by GNU Emacs into HTML representations for
# viewing on the Web.

# Caveat: this has been tested across a range of "reasonable"
# ChangeLog files, but may not produce beautiful output under all
# circumstances.  Your mileage may vary.

# Use the "--anchor" flag to create links to files.  This will not
# work correctly if your source tree lives outside your Web hierarchy,
# or if you list multiple file names before the ":" in the log entry.
# If you use "--anchor", you can use "--root" to give a Web-visible
# path to the source tree.

# Bryan O'Sullivan  <bos@Eng.Sun.COM>  10.95

require 5.000;

# See whether we are a CGI script or being run standalone.

if (defined $ENV{"REQUEST_METHOD"}) {
    $using_cgi = 1;
    if ($ENV{"REQUEST_METHOD"} eq "POST")
    {
	$length = $ENV{"CONTENT_LENGTH"}
            or die "No content length given!";

	read(STDIN, $url_query, $length)
	    or die "No data given!";
    } else {
	$url_query = $ENV{"QUERY_STRING"};
    }

    my (%query) = &decode($url_query);
    $opt_root = $query{"root"};
    @files = ($query{"file"});
    $opt_anchor = 1;
} else {
    use Getopt::Long;

    &usage unless GetOptions("anchor", "filter", "root=s", "help");
    &usage if ($opt_help);

    @files = @ARGV;
}

# Some variables which deal with munging plain text into HTML.

%escs = qw {
    &	amp
    <	lt
    >   gt
    "   quot
};

$escapes = join("", keys %escs);

$opt_root =~ s@/+$@@g;	# remove trailing slashes

# We use a state machine to keep track of what closing tags we should
# be inserting.

foreach $logfile (@files) {
    open(IN, "< $logfile")
	or die "$logfile: $!";

    $first_header = 1;

    foreach $line (<IN>) {
	if ($line =~ /^(\w+)\s+(\w+)\s+(\d+)\s+(?# day, month, day of month
		      )([\d:]+)\s+(\d+)\s+(?# time, year
		      )([^(<]+)[(<]([^>)]+)[>)](?# name, email address
		      )$/) {
	    ($day, $month, $date, $time, $year, $name, $email) =
		&quote($1, $2, $3, $4, $5, $6, $7);
	    $name =~ s/\s*$//g;
	    $name =~ s/\s/&nbsp;/g;
	    $first_entry = 1;
	    @outie = ("<TR><TR><TD COLSPAN=3><HR></TD></TR>\n",
		      "<TD ALIGN=LEFT><B>$day $month $date $year, $time</B></TD>",
		      "<TD></TD><TD ALIGN=RIGHT><A HREF=\"mailto:$email\">$name</A>",
		      "</TD></TR>\n",);
	    if ($first_header) {
		$first_header = 0;
		push @out, @outie;
	    } else {
		push @out, ("</TD></TR>", @outie);
	    }
	} elsif ($line =~ /^\s+(\*\s*)?([^:]+):\s*([^\n]+)$/) {
	    ($file_place, $text) = ($2, $3);
	    if ($file_place =~ /^(\S*)\s*\(([^\)]+)\)$/) {
		$file = $1;
		$place = $2;
	    } else {
		$file = $file_place;
		$place = "";
	    }
	    if ($opt_anchor) {
		$file = "<A HREF=\"$root/$file\">$file</A>";
	    }
	    ($text) = &quote(ucfirst $text);
	    @outie = ("<TR><TD ALIGN=RIGHT>$file</TD><TD ALIGN=CENTER>$place</TD>",
		      "<TD ALIGN=LEFT>$text\n");
	    if ($first_entry) {
		$first_entry = 0;
		push @out, @outie;
	    } else {
		push @out, ("</TD></TR>", @outie);
	    }
	} elsif ($line =~ /^\s+\*\s*([^\n]+)$/) {
	    ($text) = &quote(ucfirst $1);
	    @outie = ("<TR><TD COLSPAN=2></TD><TD ALIGN=LEFT>$textd#\n");
	    if ($first_entry) {
		$first_entry = 0;
		push @out, @outie;
	    } else {
		push @out, ("</TD></TR>", @outie);
	    }
	} elsif ($line ne "\n") {
	    $line =~ s/^\s*(.*)\s*$/$1/g;
	    ($line) = &quote($line);
	    push @out, "$line\n";
	}
    }

    if (!$first_header) {
	push @out, "</TR>\n";
    }

    if (!$using_cgi) {
	$logfile_html = ($opt_filter || ($logfile eq "-"))
	    ? "-" : "$logfile.html";
	open(OUT, "> $logfile_html")
	    or die "$logfile_html: $!";
    }

    if ($#out >= 0) {
	@out = ("<CENTER>\n<TABLE>\n",
		"<!-- Brought to you by cl2html.cgi on ", scalar localtime, ". \n",
		"     Bryan O'Sullivan - bos\@Eng.Sun.COM - October 1995. -->\n",
		"<TR><TH ALIGN=RIGHT>File name</TH><TH>Place</TH>",
		"<TH ALIGN=LEFT>Change made</TH></TR>\n",
		@out,
		"</TABLE>\n</CENTER>\n");
	$out = join("", @out);
    } else {
	$out = "Empty ChangeLog.";
    }

    close(IN);

    if ($using_cgi) {
	print ("Content-Type: text/html\n",
	       "Content-Length: ", length $out, "\n",
	       "\n",
	       $out);
    } else {
	print OUT $out;
	close(OUT);
    }
}

exit(0);


# Print out a usage message and die.

sub usage {
    print STDERR ("usage: cl2html [--help] [--anchor] [--filter] ",
		  "[--root=www-root-dir] logfile ...\n");
    exit(1);
}


# Split up and de-munge a URL-encoded string, returning the resulting
# (key, value) pairs in an associative array.

sub decode {
    my ($orig) = @_;
    my (@spl, @urls);
    my ($out, $val, %decoded);

    @urls = split(/\&/, $orig);

    foreach $thing (@urls) {
	@spl = split(/=/, $thing);
	($val, $out) = @spl;
	$out =~ s/\+/ /g;
	$out =~ s/%(..)/pack("H2", $1)/ge;
	$decoded{$val} = $out;
    }

    return %decoded;
}


# Quote plain text for printing in HTML.
# NOTE: this returns a LIST, not a single string!

sub quote {
    my (@text) = @_;
    my (@out, $tmp);

    foreach $string (@text) {
	$tmp = $string;
	$tmp =~ s/([$escapes])/&$escs{$1};/go;
	push @out, $mp;
    }
    return @text;
};