#!/usr/bin/perl
# $Id: diff,v 1.2 2006/12/07 04:59:38 reed%reedloden.com Exp $

# diff -- Display diff output with markup.
#
#  Arne Georg Gleditsch <argggh@ifi.uio.no>
#  Per Kristian Gjermshus <pergj@ifi.uio.no>
#
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

######################################################################

use lib 'lib';
use SimpleParse;
use LXR::Common;
use LXR::Config;
use DB_File;


sub htmlsub {
  my ($s, $l) = @_;
  my $x = $s;
  while ($x =~ s#<style>(.*?)</style>##) {
    $l += length $1;
  }
  my @s = split(/(<[^>]*>|&[\#\w\d]+;?)/, $s);
  $s = '';

  while (@s) {
    my $f = substr(shift(@s), 0, $l);
    $l -= length($f);
    $s .= $f;
    $f = shift(@s);
    if ($f =~ /^&/) {
      if ($l > 0) {
        $s .= $f;
        $l--;
      }
    } else {
      $s .= $f;
    }
  }
  $s .= ' ' x $l;
  return $s;
}

my $file;
my $file2;

sub treeoption {
  my ($tree, $defaulttree, $novalue) = @_;
  my $value = " value='$tree'";
  my $selected;
  if ($tree eq $defaulttree) {
    $selected = ' selected=1';
    $value = '' if $novalue;
  }
  return " <option$selected$value>$tree</option>
";
}
sub cleanhtml {
  my $text = shift;
  $text =~ s/"/&quot;/g;
  $text =~ s/'/&#039;/g;
  $text =~ s/&/&amp;/g;
  $text =~ s/</&lt;/g;
  $text =~ s/>/&gt;/g;
  return $text;
}

sub printdiff {
  my ($virt, $file) = (cleanhtml $Path->{'virt'}, cleanhtml $Path->{'file'});
  my @similartrees = ();
  my @othertrees = ();
  my @treelist = @{$Conf->{'trees'}};
  print "<p class=desc>
</p>
<form name='diff' id='diff' class='beforecontent'>
<label for='file'>Base file to compare:</label>
<input id='file' name='file' size=60 value='$virt$file'>
";
  if (scalar @treelist > 0) {
    foreach my $othertree (@treelist) {
      my $otherpath = $Conf->{'treehash'}{$othertree}.'/'.$virt.'/'.$file;
      if (-e $otherpath) {
        push @similartrees, $othertree;
      } else {
        push @othertrees, $othertree;
      }
    }

    print "
<label for='tree'>in</label>
<select name='tree' id='tree'>
";
    foreach my $othertree (@treelist) {
      print treeoption($othertree, $Conf->{'treename'}, 1);
    }
    print '
</select>
<br>
<label for="diffvar" title="Please select">Tree against which you wish to
compare this file:</label>
<select name="diffvar" id="diffvar">
';
    if (scalar @similartrees) {
      print " <option value=''>--(this path)--</option>
";
      foreach my $othertree (@similartrees) {
        print treeoption($othertree, $diffvar);
      }
    }
    if (scalar @othertrees) {
      print " <option value=''>--(another path)--</option>
";
      foreach my $othertree (@othertrees) {
        print treeoption($othertree, $diffvar);
      }
    }
    print '</select>
';
  }
  print qq{
<br>
<label for="file2">
You can
};
  print "also " if (scalar @similartrees > 1);
  print "
compare against a different file:</label>
<input id='file2' name='file2' size=60 value='$file2'>
<br>
<label for='diffw'>Ignore whitespace changes:</label>
<input type=checkbox name='diffw' id='diffw' value='1'";
  print " checked=1" if $diffw;
  print '>

<hr>
<input type=submit>
</form>
';

  return unless (scalar @treelist == 0) || $diffvar;

  my $file = $Path->{'file'};
  unless ($file) {
    print("<h3 align=center>Diff not yet supported for directories.</h3>\n");
    return;
  }

  my $virt = $Path->{'virt'};
  $origvirt = $virt . $file;
  $origreal = $Path->{'real'} . $file;

  $origval = $Conf->variable($diffvar);
  $Conf->variable($diffvar, $diffval);
  $file2 ||= $Path->{'virt'} . $file;
  $diffvirt = $file2;
  if ($diffvar) {
    $diffreal = $Conf->{'treehash'}{$diffvar} . $diffvirt;
  } else {
    $diffreal = $Conf->{'sourceroot'} . $diffvirt;
  }
  $Conf->variable($diffvar, $origval);

  &fflush;

  unless (-f $origreal && -f $diffreal) {
    print "<h1>Can not find one of the specified files</h1>
";
    return;
  }
  unless (-r $origreal && -r $diffreal) {
    print "<h1>Can not read one of the specified files</h1>
";
    return;
  }
  unless (open(DIFF, "-|")) {
    open(STDERR, ">&STDOUT");
    my @args = ('diff', '-U0');
    push @args, '-w' if $diffw;
    push @args, ($origreal, $diffreal);
    exec @args;
    print "*** Diff subprocess died unexpectedly: $!\n";
    exit;
  }
  my $diff = 1;
  my $diffn = 2;
  while (<DIFF>) {
    if (($os, $ol, $ns, $nl) =
      /@@ -(\d+)(?:,(\d+)|) \+(\d+)(?:,(\d+)|) @@/) {
      # this seems to be a gnu hack
      $os++ if $ol eq '0' && $nl eq '';
      $ns++ if $nl eq '0' && $ol eq '';
      $ol = 1 unless defined($ol);
      $nl = 1 unless defined($nl);

      $bo = $os + $ofs;

      # link to the next/previous change ...
      my ($remove, $change, $additt) = ('&lt;', '!', '&gt;');
      my ($removep, $changep, $addittp) = ($remove, $change, $additt);
      my $nextd = "<a name='d$diff' href='#d$diffn'>";
      my $removen = "$nextd$remove</a>";
      my $changen = "$nextd$change</a>";
      my $addittn = "$nextd$additt</a>";
      if ($diff > 1) {
        my $prevd = "<a href='#d" . ($diff - 1) . "'>";
        $removep = "$prevd$remove</a>";
        $changep = "$prevd$change</a>";
        $addittp = "$prevd$additt</a>";
      }
      $diff = $diffn++;
      $remove = $removep . $removen;
      $change = $changep . $changen;
      $additt = $addittp . $addittn;

      if ($ol < $nl) {
        $ofs += $nl - $ol;

        $dir = $additt;
        $ms  = $nl - $ol;
        $ml  = $ol;
        $orig{$os+$ol} = $ms;
      } else {
        $dir = $remove;
        $ms  = $ol - $nl;
        $ml  = $nl;
        $new{$ns+$nl} = $ms;
      }
      foreach (0..$ml - 1) {
        $chg{$bo + $_} = $change;
      }
      foreach (0..$ms - 1) {
        $chg{$bo + $ml + $_} = $dir;
      }
    }
  }
  close(DIFF);


  my ($tree1, $tree2) = ($Conf->{'treename'}, $diffvar);
  if ($tree1 eq $tree2) {
    $tree1 = $tree2 = '';
  } else {
    $tree1 = " <i>($tree1)</i>";
    $tree2 = " <i>($tree2)</i>";
  }
  my $path = $diffvirt;
  $path =~ s|([^-a-zA-Z0-9.+\@/_\r\n])|sprintf("%%%02X", ord($1))|ge;
  $path = qq{<a href="../$diffvar/source$path">$path$tree2</a>};
  print "<h1>Diff markup</h1>
<h3><a href='#d1'>Differences</a> between " .
&fileref("$origvirt$tree1", $origvirt, undef, "") .
" and $path (<a href='diff?tree=$diffvar&diffvar=" .
$Conf->{'treename'} .
"&file=$diffvirt&file2=$origvirt'>reverse</a>)
</h3><hr>
<style>.x, .x > a { color: red; text-decoration: none } </style>";

#  "<table width=\"100%\" border=0 cellpadding=0><tr><td>",
#
#  &fileref("<b>$origvirt <i>(".$Conf->vardescription($diffvar).
#           " $origval)</i></b>", $origvirt, undef, "$diffvar=$origval"),
#           "<hr></td>\n<td></td>\n<td>",
#
#  &fileref("<b>$diffvirt <i>(".$Conf->vardescription($diffvar).
#           " $diffval)</i></b>",$diffvirt, undef, "$diffvar=$diffval"),
#           "<hr></td>\n</tr></table>\n");


  open(FOO, $origreal);
  $orig = '';
  &markupfile(\*FOO, $Path->{'virt'}, $Path->{'file'},
    sub { $orig .= shift }, 1);
  $len = $.+$ofs;
  close(FOO);

  $Conf->variable($diffvar, $diffval);

  open(FOO, $diffreal);
  $new = '';
  &markupfile(\*FOO, $Conf->mappath($Path->{'virt'}), $Path->{'file'},
    sub { $new .= shift }, 1);
  close(FOO);

  $Conf->variable($diffvar, $origval);

  $i = 1; $orig =~ s/^/"\n" x ($orig{$i++})/mge;
  $i = 1; $new  =~ s/^/"\n" x ($new{$i++})/mge;

  @orig = split(/\n/, $orig);
  @new  = split(/\n/, $new);

  print("<pre>");
  foreach $i (0..$len) {
    $o = &htmlsub($orig[$i], 80);
    $n = &htmlsub($new[$i], 999);
#    $n = $new[$i];

#    print("<tr><td><code>$o</code></td>".
#          "<td><font color=red> ", $chg{$i+1}, " </font></td>".
#          "<td><code>$n</code></td></tr>\n");
    print("$o <span class=x>", ($chg{$i+1} || "  "), "</span> $n\n");
  }
  print("</pre>");

#    print("</td></tr></table>");
}


($Conf, $HTTP, $Path, $head) = &init;

my $tree = $HTTP->{'param'}->{'tree'};
$diffvar = $HTTP->{'param'}->{'diffvar'};
$diffval = $HTTP->{'param'}->{'diffval'};
$diffw = $HTTP->{'param'}->{'diffw'} eq '1';
$file2 = cleanhtml $HTTP->{'param'}->{'file2'};
if ($file2 ne '') {
  if ($file2 =~ m{^//([^/]+)(/.*|$)}) {
    ($diffvar, $file2) = ($1, $2);
  } elsif ($file2 !~ m{^/}) {
    $file2 = '/'.$file2;
  }
}

if ($file2 ne $HTTP->{'param'}->{'file2'} || $tree) {
  my @tail = ();
  push @tail, "file=" . url_quote($Path->{'virt'}.$Path->{'file'}) if $Path->{'file'} ne '';
  push @tail, "file2=" . url_quote($file2) if $file2 ne '';
  push @tail, "diffvar=" . url_quote($diffvar) if $diffvar ne '';
  push @tail, "diffval=" . url_quote($diffval) if $diffval ne '';
  push @tail, "diffw=" . url_quote($diffw) if $diffw;
  my $tail = $#tail >= 0 ? '?' . join "&", @tail : '';
  my $newtree = $Conf->{'treename'};
  if ($tree ne $newtree) {
    my @treelist = @{$Conf->{'trees'}};
    foreach my $othertree (@treelist) {
      $newtree = $tree, last if $othertree eq $tree;
    }
  }
  $head .= "Refresh: 0; url=../$newtree/diff$tail
";
}
print "$head
";

&makeheader('diff');
&printdiff;
&makefooter('diff');

1;