########################################################################
# Method:  display
# Use:     Default method, bucket "unveils" itself to requester
#          Branches to metadata if requested by other than a browser.
# Created: 07/17/1997 Del Croom  (d.r.croom@larc.nasa.gov)
# Seriously Changed: 08/03/1998 MLN
#
# Assumptions:
# - Bucket contents resides under this directory path
#
########################################################################

sub display

{
        local($package) = $in{"pkg_name"};
        local($element) = $in{"element_name"};
        local($redirect) = $in{"redirect"};

        &parse_bibfile;

        if ($redirect) {
                print "Location: $redirect\n\n";        # http status 302
                &log("display","OK","redirect = $redirect");
        }
        elsif (!($element eq "") && !($package eq "") )
        {
                &display_element($package,$element);
                &log("display","OK","package = $package, element = $element");
        } else {
                &display_default;
                &log("display","OK","default display");
        }

}

########################################################################
# Subroutine:   parse_bibfile
# Called by:    display
# Use:          populates the global assoc. array %BIB_FIELDS to prepare
#               for pretty HTML printing
# Created: 08/03/1998 MLN
########################################################################

sub parse_bibfile
{
        local($more_abstract);

        foreach $line (@BIBFILE)
        {
                chop $line;
 
                # get document id 'docid' from the ID tag in bib
                if ($line =~ /^ID::/) {
                        @docid=split('//',$line);
                        $BIB_FIELDS{"id"}=$docid[1];
                }
 
                # get title (titles may be present in packages)
                if ($line =~ /^TITLE::/) {
                        $BIB_FIELDS{"title"}=$line;
                        $BIB_FIELDS{"title"} =~ s/TITLE:: //;
                        $BIB_FIELDS{"title"} =~ s/\n//g;
                }

                # get authors (in array, not necessarily in consecutive order)
                if ($line =~ /^AUTHOR::/) {
                        $line =~ s/AUTHOR:: //g;
                        if ($BIB_FIELDS{"authors"} eq "") {
                                $BIB_FIELDS{"authors"} = $line
                        }
                        else {
                                $BIB_FIELDS{"authors"} .= $author_delimiter . $line;
                        }
                }

                # get date (dates may be present in packages)
                if ($line =~ /^DATE::/) {
                        $BIB_FIELDS{"date"}=$line;
                        $BIB_FIELDS{"date"} =~ s/DATE:: //;
                }

                # get copyright (may be present in packages)
                if ($line =~ /^COPYRIGHT::/) {
                        $BIB_FIELDS{"copyright"}=$line;
                        $BIB_FIELDS{"copyright"} =~ s/COPYRIGHT:: //;
                }

                # get abstract (multiple lines with no tags following the first)
                # check for end of abstract first
                if ( ($more_abstract) && ($line =~ /^.*::/) ) {
                        $more_abstract=0;
                }
                if ( ($line =~ /^ABSTRACT::/) || ($more_abstract) ) {
                        $more_abstract=1;
                        $line =~ s/ABSTRACT:://;
                        if ($line =~/^\n/) { $line = "<p>"; }
                        # extra space to keep line1 and line2 from butting
                        $BIB_FIELDS{"abstract"} .= $line . " ";
                }
        } #end-foreach

        $BIB_FIELDS{"abstract"} =~s/[\r\t\f\b\0]//g; # remove non-printing chars

}

########################################################################
# Subroutine:   display_metadata
# Purpose:      displays bucket metadata.  this routine does not set up
#               or close down the html page
# Called by:    display_default, display_element
# Created:      08/04/98  MLN
########################################################################

sub display_metadata
{

print <<EOF;
<center>
<h1>
$BIB_FIELDS{"title"}
</h1>
<p>
EOF
        # do the right thing with "," and "and" in the author list
        @authors = split(/$author_delimiter/,$BIB_FIELDS{"authors"});
        while (@authors)
        {
                $a = shift(@authors);
                print "$a";
                if ($authors[1]) { print ", ";}         # at least 2 more
                elsif ($authors[0]) {print " and ";}    # just 1 more
        }
print <<EOF;
<br>
$BIB_FIELDS{"id"}
<br>
$BIB_FIELDS{"date"}
<p>
<i>Abstract</i>
<p>
</center>
$BIB_FIELDS{"abstract"}
<p>
EOF

}

########################################################################
# Subroutine:   display_element
# Purpose:      "displays" an element
#               if the element is a directory, we treat it as a scanned
#               set of files (I don't like this assumption right now)
#               otherwise, its a file, so we serve up the file ourselves
#
#               need to think about how to handle URL elements...
#
#               if an element is an html file, it can be a file in a dir
#               below a package:        1.pkg/2.element/3.html
#               its up to the html file to maintain its links correctly
#
# Called by:    display
#
# Called by:    display
# Created:      08/04/98  MLN
########################################################################

sub display_element
{
        local($package,$element) = @_;
        local($name, $first, @extension, $mime_header, $encoding_header);

        if (-d "$package/$element") {
                &display_scanned_element($package,$element);
        } else { # default is that type is file
                $name = $element;
                @extension = split(/\./,$name);
                $first = pop(@extension);
                if ($encoding_type{"$first"}) {
                        $encoding_header = $encoding_type{"$first"};
                        $first = pop(@extension);
                }
                if ($mime_type{"$first"}) {
                        $mime_header= $mime_type{"$first"};
                }
                if ($encoding_header) {
                        $header = "$mime_header\nContent-encoding: $encoding_header";
                } elsif (!$mime_header) {
                        $header = "text/plain";         # default mime type
                } else {
                        $header = "$mime_header";
                }

                &http_header("$header");
                open(E, "$package/$element");
                while (<E>)
                {
                        print $_;
                }
                close (E);
        }
}

########################################################################
# Subroutine:   display_scanned_element
# Purpose:      displays a package as a group of objects.  taken from the
#               NACA DL
# Called by:    display
# Created:      08/04/98  MLN
########################################################################

sub display_scanned_element
{
        local($package, $element) = @_;
        # if we're here, look for these values too...
        local($page) = $in{"page"};
        local($thumbnail) = $in{"thumbnail"};

        if ($page) {
                &display_scanned_page($package,$element,$page);
        } elsif ($thumbnail) {
                &display_scanned_thumbnails($package,$element,$thumbnail);
        } else {
                # start at page 1 if no page is provided...
                &display_scanned_thumbnails($package,$element,"1");
        }

	# go back up so &log will work
	chdir($real_current_dir);
}

########################################################################
# Subroutine:   display_scanned_page
# Purpose:      displays a scanned image
# Called by:    display_scanned_element
#
# Note:         this is taken from the NACA DL...
# Created:      08/04/98  MLN
########################################################################

sub display_scanned_page

{
        local($package, $element, $page) = @_;
        local($title) = $BIB_FIELDS{"title"};

        &http_header("text/html");

        chdir ("$package/$element");
        opendir (D, ".");

        #
        # *[0-9].gif eliminates the thumbnails (*-t.gif)
        #

        @allgifs = sort(grep(/.*[0-9]\.gif/,readdir(D)));
        $firstpage = $allgifs[0];               # first in list
        $lastpage = $allgifs[$#allgifs];        # last in list

        foreach $p (@allgifs)
        {
                if (defined($last))
                {
                        $next = $p;
                        last;
                }
                if ($p ne $page)
                {
                        $previous = $p;
                        next;
                }
                else
                {
                        $last = 1;
                        next;
                }
        }

        print "<html><head><title> $title </title></head><body> ";
        print "<center> ";
        $print_now = 1;

      foreach $i (0 .. 1)
      {
        $top = &MyBaseUrl;
        $top =~ s/index.cgi//;
        $top =~ s/$restricted//;
        print "<a href=$top>Top</a> | ";
        if ($page eq $lastpage)
        {
                print "Next | ";
        } else {
                print "<a href=?method=display&pkg_name=$package&element_name=$element&page=$next>Next</a> | ";
        }
        if ($page eq $firstpage)
        {
                print "Previous | ";
        } else {
                print "<a href=?method=display&pkg_name=$package&element_name=$element&page=$previous>Previous</a> | ";
        }
        print "<a href=?method=display&pkg_name=$package&element_name=$element&page=$firstpage>First</a> | ";
        print "<a href=?method=display&pkg_name=$package&element_name=$element&page=$lastpage>Last</a> ";

        if (defined($print_now))
        {
		$url = &MyBaseUrl;
		$url =~ s/index.cgi//g;
		$url =~ s/$restricted//g;
                print "<br><img src=$url$package/$element/$page><br> ";
                undef($print_now);
        }

       } # end of for loop

        print "<br><hr><p>Note: no documents have access restrictions, even if the individual page indicates otherwise.<p><hr><p>";
        print "</center></body></html> ";

        closedir(D);
}

########################################################################
# Subroutine:   display_scanned_thumbnails
# Purpose:      displays the scanned thumbnails
# Called by:    display_scanned_element
#
# Note:         this is taken from the NACA DL...
# Created:      08/04/98  MLN
########################################################################

sub display_scanned_thumbnails

{
        local($package, $element,$start) = @_;
        chdir ("$package/$element");
        &http_header("text/html");
        opendir(D,".");

        print <<EOF;
<html>
<head>
<title>
$BIB_FIELDS{"title"}
</title>
</head>
<body>
EOF
        &display_metadata;
        # a bunch of other stuff has to go here...

        $end = $start + $thumbnail_increment - 1;
        @allthumbnails = sort(grep(/.*-t\.gif/,readdir(D)));
        $total = $#allthumbnails + 1;   # add 1 b/c array index starts at 0

        print "<A name=start>\n";
        $counter = 1;
        foreach $t (@allthumbnails)
        {
                if ($counter < $start)
                {
                        $counter = $counter + 1;
                        next;
                }
                if ( ($counter > $end) || ($counter > $total) )
                {
                        last;
                }

                $big = $t;
                $big =~ s/-t.gif/.gif/g;
		$url = &MyBaseUrl;
		$url =~ s/index.cgi//g;
		$url =~ s/$restricted//g;
                print "<A href=?method=display&pkg_name=$package&element_name=$element&page=$big><img src=$url$package/$element/$t alt=\"$t\"></a>\n";

                $counter = $counter + 1;
        }

        print "<hr><br>";

        $base = &MyBaseUrl;
        $base =~ s/index.cgi//;
        $base =~ s/$restricted//;
        print "<A href=$base>Top</a> | ";

        if ( $end < $total)
        {
                $next = $end + 1;
                print "<A href=?method=display&pkg_name=$package&element_name=$element&thumbnail=$next#start>Next</a> | ";

        }
        else
        {
                print "Next | ";
        }

        if ( $start != 1 )
        {
                $previous = $start - $thumbnail_increment;
                if ( $previous < 1 )
                {
                        $previous = 1;
                }
                print "<A href=?method=display&pkg_name=$package&element_name=$element&thumbnail=$previous#start>Previous</a> | ";
        }
        else
        {
                print "Previous | ";
        }

        if ( $start !=1 )
        {
                print "<A href=?method=display&pkg_name=$package&element_name=$element&thumbnail=1#start>First Page</a> | ";
        }
        else
        {
                print "First Page | ";
        }


        if ( $total > $start + $thumbnail_increment - 1 )
        {
                $last = $total - $thumbnail_increment + 1;
                print "<A href=?method=display&pkg_name=$package&element_name=$element&thumbnail=$last#start>Last Page</a> ";
        }
        else
        {
                print "Last Page ";
        }

        print <<EOF;
</body>
</html>
EOF

}

########################################################################
# Subroutine:   display_default
# Purpose:      displays bucket contents when nothing else was asked for
# Called by:    display
# Created:      08/03/98  MLN
########################################################################

sub display_default
{
        local($line, $pkg_dir, $pkg_title);
        local($element, $element_title);
        &http_header("text/html");

print <<EOF;
<html>
<head>
<title>
$BIB_FIELDS{"title"}
</title>
</head>
<body>
EOF

        &display_metadata;
        print "<p> Contents: <p>\n";
	print "<img src=image.pkg/green.jpg> -Content is inside bucket   </img>  <img src=image.pkg/yellow.jpg> -outside service</img>  <img src=image.pkg/red.jpg> -outside link </img>\n";
        print "<ul>\n";
        foreach $line (@BIBFILE)
        {
                if ($line =~ /\s*PACKAGE::/) {
                        $line =~ s/\s*PACKAGE:: //;
                        $pkg_dir = $line;
                }
                if ($line =~ /\s*PACKAGE-TITLE::/) {
                        $line =~ s/\s*PACKAGE-TITLE:: //;
                        $pkg_title = $line;
                        #print "<li> <A href=?method=display&pkg_name=$pkg_dir>$pkg_title</a>\n";
                        # uncomment the above if we will allow "displaying"
                        # a package... - mln
                        print "<p>\n<li> $pkg_title\n";
                        print "<ul>\n";
                }
                if ($line =~ /\s*PACKAGE-END::/) {
                        print "</ul>\n";
                }
                if ($line =~ /\s*ELEMENT::/) {
                        $line =~ s/\s*ELEMENT:: //;
                        $element = $line;
                }
                if ($line =~ /\s*ELEMENT-TITLE::/) {
                        $line =~ s/\s*ELEMENT-TITLE:: //;
                        $element_title = $line;
                }
                if ($line =~ /\s*ELEMENT-END::/) {
			# compute some stuff that we might need below...
                        $size = &file_size("$pkg_dir/$element");
                        $base = &MyBaseUrl;
                        $base =~ s/index.cgi//;
                        $base =~ s/$restricted//;

			if (&isaurl($element)) {
				$element =~ s/$myurlhere/$base/g;
				print "<li> <A href=?method=display&redirect=$element>$element_title</a>";	
                        } elsif ($element =~ /\.html?/) {
                                # add redirect
                                print "<li> <A href=?method=display&pkg_name=$pkg_dir&element_name=$element&redirect=$base$pkg_dir/$element>$element_title</a> <i>$size</i>\n";
                        } else {
                                print "<li> <A href=?method=display&pkg_name=$pkg_dir&element_name=$element>$element_title</a> <i>$size</i>\n";
                        }
                }
        }
        print "</ul>\n";

print <<EOF;
</body>
</html>
EOF

}

########################################################################
# Subroutine:   isaurl
# Purpose:      returns true if the argument appears to be an absolute
#		URL, false if otherwise
# Called by:    display
# Created:      08/03/98  MLN
########################################################################

sub isaurl 
{
	local($check) = @_;
	@urls = ("http://", "ftp://", "gopher://", "mailto://", "wais://", "https://");

	foreach $u (@urls)
	{
		if ($check =~ /$u/) { return(1) };
	}
	
	return (0);

}

1;