#
# Start of a script to recursively process all files in a directory to change the copyright notice.
#
use File::Find;
use strict;
use warnings;

my @unhandled_files = ();
my @handled_files = ();

sub process_file {
		my $oldValue = 2006; 		# the minimal value for a year to be replaced		
    
    my $shouldChange = 0; 	# flag only set when file was changed in a year later than it's copyright notice year.
    
    my $file = $_;
    
    # only handle files, not directories
    return unless -f $file;
    
    # only handle text files
    return unless -T $file;
    
    # only handle file if it is writable
    return unless -w $file;
    
    # open file for reading and writing
    open(FILE, "+< $file") or die "can't open file $File::Find::name: $!";
            
     
    
    my $filename = $File::Find::name;
    
    
    
    unless (-e $filename) {
    	die "File $filename does not exist!\n";
    } else {
    	print "Handling file $filename\n";
    }
   
    print "Getting SVN info from $File::Find::name...\n";
    my $str = "svn info $filename > svninfo.txt"; 
    print "\nExecuting:\n$str";
    
    # <allison> kjs: may make sense to just use 'capture_output' from lib/Parrot/Configure/Step.pm
    # (instead of system)           
    system($str);                 
    open(TEMPFILE, "< svninfo.txt") or die "cannot open file svninfo.txt";
        
    my $SVNYear = undef;					# to store the year according to SVN    
    while(<TEMPFILE>) {
    	
    	# get the year from that line:
    	if ($_ =~ m/Last Changed Date:\s+(\d\d\d\d).*/) {
    		print "\nMatched: $_'\nYear: $1\n";        
    		
    		$SVNYear = $1;    		
    	}
    }
        
    close(TEMPFILE);    
    
    
    
    unless (defined $SVNYear) {
    	print "Mmmm: no 'Last Changed Date' according to SVN\nSkipping file $File::Find::name\n";
    	push @unhandled_files, $filename;
    	return;
    }
        
    
    # buffer to store file contents
    my $filebuffer = '';   
    
    # read file line by line
    while(<FILE>) {
    	
    	# flag indicating whether the file has been changed yet
    	my $changed = 0;    	        	    	    		    	
    		
    	# check for copyright lines containing only 1 year; note the matching space here.
    	if ($_ =~ m/.*[cC]opyright[^[\d\d\d\d\-]]*(\d\d\d\d).*/ ) { # check for match
    		 
    		print "Found copyright notice with year $1\n";
    		# ok found it, now compare with $SVNYear
    		# only change when SVN Year > current
    		if ($SVNYear > $1) {
    				    
    			print "CASE 1\n";			
    			print "Ok, the 'Last Changed Date' according to SVN is: $SVNYear.\n";
    			print "This is a later date than the current copyright notice date, which is $1.\n";
    			print "I'll change\n\t'$_'\n\tinto: ";
    			
    			# change a notice like '2006' into '2006-2007'
    			$_ =~ s/$1/$1\-$SVNYear/;
    			
    			print $_;
    			print "\n";
    			
    			
    			# add line to file buffer
    			$filebuffer .= $_;    		
    			
    			# set changed flag
    			$changed = 1;
    		}
    	}    
    	# check for copyright lines like X-Y    		
    	elsif ($_ =~ m/.*[cC]opyright[^\d]*\d\d\d\d\-(\d\d\d\d).*/ ) {
    		
    		if ($SVNYear > $1) {
    		
    			print "CASE 2\n";
    			print "Ok, the 'Last Changed Date' according to SVN is: $SVNYear.\n";
    			print "This is a later date than the current copyright notice date, which is $1.\n";
    			print "I'll change\n\t'$_'\n\tinto: ";    			
    			
    			# make sure only the 'Y', not 'X', in 'X-Y' is changed
    			$_ =~ s/\-$1/\-$SVNYear/;
    			
    			print $_;
    			print "\n";
    			
    			$filebuffer .= $_;
    			$changed = 1;    			
    		}
    	}
    	 		    		    		    	
    	
    	# if the line was not changed, it was not a copyright notice,
    	# therefore not added yet. So add it to the buffer now.
    	if($changed == 0) {
    		$filebuffer .= $_;
    	}
    }
  	
  	# end of file reached, now write the buffer back to file again.
  	# this code is taken from the Perl Cookbook.
  	seek(FILE, 0, 0)               or die "can't seek to start of $file: $!";
		print FILE $filebuffer         or die "can't print to $file: $!";        
		truncate(FILE, tell(FILE))     or die "can't truncate $file: $!";        
		close(FILE)                    or die "can't close $file: $!";           
    
    print "Handled file $file\n";
    push @handled_files, $filename;
    
    
}

if (@ARGV < 1) {
	print <<'USAGE' 

Usage: perl changeCopyright <directory>

	Updates the copyright notice to the year from SVN according to the 'Last Changed Date' for all files in <directory>.
	Please give the FULL path to the directory (on windows this could be 'c:\parrot')
	
USAGE

}
else {
	my @DIRLIST = ();
	push @DIRLIST, $ARGV[0];
	find(\&process_file, @DIRLIST);
	
	if(@unhandled_files) {
		open UNHANDLED, "> unhandledfiles.txt";
		
		print "Unhandled files:\n";
		while(@unhandled_files) {
			my $file = shift @unhandled_files;
			print UNHANDLED "$file\n";
		}
		
		close UNHANDLED;
		
	}
	
	if(@handled_files) {
		open HANDLED, "> handledfiles.txt";
		
		print "handled files:\n";
		while(@handled_files) {
			my $file = shift @handled_files;
			print HANDLED "$file\n";
		}
		
		close HANDLED;
	}
}


# TODO: compile a list of files that has been changed by this script.