#!/usr/local/bin/perl

my( $verbose, $veroffset );

$USAGE = '
USAGE:    cvs-ver [OPTIONS] [FILE_REGEXP] 
SYNOPSIS: show cvs version of files, with -N show older versions.
AUTHOR:   GPL(C) Mohsin Ahmed, http://www.cs.albany.edu/~mosh
REGEXP:   Print only matching lines.
OPTIONS: -+N    Add N to old version, or
         --N    Subtract N from version of file, and prints
                    cvs diff   -r old -r new file
                    cvs update -r old -p     file > file.old
         -v     verbose .. not used.
         -w     Run windiff.
NOTES:  
  Reads ./CVS/Tag and ./CVS/Entries.
EXAMPLES:
  > cvs-ver                  .. Show version of files in current dir.
  > cvs-ver --1 Makefile     .. Show how to get Makefile-(version-1)
  > cvs-ver -+1 Makefile     .. Show how to get Makefile-(version+1)
  > cvs-ver --0 file.c       .. Show how to see your edits in windiff.
  > cvs-ver -w  file.c       .. See your changes in windiff. 
';

while( $_ = $ARGV[0],  m/^-/ ){ shift; last if /^--$/;
    if( m/^-v/ ){
        $verbose++;
        next;
    }
    if( m/^-([-+]?\d+)/ ){
        $veroffset = $1;
        next;
    }
    if( m/^-w/ ){
        $runwindiff++;
        $veroffset = 0;
        next;
    }
    die $USAGE            if m/^-[h?]/;
}

my $regexp = shift || '';
warn "# cvs-ver m/$regexp/, veroffset='$veroffset'\n";


unless( -d "CVS" ){
  die "Need ./CVS dir in pwd to get info\n";
}

if( -r 'CVS/Tag' ){
    $atag = `cat CVS/Tag`;
    $atag  =~ s/^T//;
    $atag  =~ s/\n//;
}else{
    warn "Cannot read CVS/Tag\n";
}

my( @cvsdiff, @cvsrev, @cvswindiff );

open( CVSENTRIES, "< CVS/Entries" )
    or die "Cannot open('CVS/Entries')\n";

LINE:
while( <CVSENTRIES> ){
  chomp;
  my ($dummy, $file,$ver,$date,$tag) = split( '\/+' );
  #  Tue Dec 21 17:41:15 1999
  $date =~ s/^\s*[A-Z][a-z][a-z]\s+//;  # No Sat/Sun
  $date =~ s/\d\d:\d\d:\d\d //;  # No time
  $date =~ s/\s+/-/g;   # Space to dash.
  $tag  =~ s/^T//;  # Tags begin with CapT.

  next LINE
    unless $file =~ m/\S/;   # Skip blank lines.

  my $out = sprintf( "# %-18s %-18s %-12s %-10s\n"
            ,$ver ,$file ,$date ,$tag || $atag );
  next LINE
    if $regexp and $out !~ m/$regexp/o;

  print $out;
  next LINE
    unless defined $veroffset;

  my $newver = $ver;
    $newver =~ s/\.(\d+)$/sprintf(".%s",$1+$veroffset)/e;  # 7.4.2-1 => 7.4.1
  my $newfile = "$file-v$newver";

  push(@cvsdiff,sprintf("cvs diff -r %-8s -r %-8s %s\n", $newver,$ver, $file))
    if $veroffset != 0;

  my $cmd1 = "cvs up -p -r $newver $file > $newfile\n";
  my $cmd2 = "windiff $file $newfile\n";
  push(@cvsrev     , $cmd1 );
  push(@cvswindiff , $cmd2 );

  if( $runwindiff ){
    my $cmd3 = "rm -v $newfile\n";
    print "system: $cmd1"; system($cmd1);
    print "system: $cmd2"; system($cmd2);
    print "system: $cmd3"; system($cmd3);
    die "\n";
  }
}
close CVSENTRIES;

if( $veroffset ){
    print @cvsdiff;
    print @cvsrev;
    print @cvswindiff;
}

# EOF