# http://somesite.com/cgi-bin/display.pl?current_page=12

# display.pl

#!/usr/bin/perl -w

use strict;
use CGI;
#use DBI;

my $SCRIPT = 'http://somesite.com/cgi-bin/display.pl';
my $RECS_PER_PAGE = 10;

my $q = new CGI;
print $q->header;
#my $dbh = DBI->connect( etc.... );

if ( $q->param('start')) {
    display_this_db_section( $q->param('start'), $q->param('end'), $q->param('current_page') );
}
else {
    my $count = get_record_count();
    my $page = $q->param('current_page') || 1;
    my $html = get_current_page($page);
    $html .= generate_links($count, $page );
    print $html;
}

exit 0;

#### SUBS ####

sub display_this_db_section {
    my ($start, $end, $current_page ) = @_;
    $current_page ||= $start;
    my $count = get_record_count;
    die_nice ( 'Invalid' ) if $start > $count
                           or $start < 1 
                           or $end > $count
                           or $end < 1 
                           or $start > $end
                           or $start > $current_page
                           or $end < $current_page;
    print "<h3>Here is $current_page of $start-$end<h3>\n";
    print "<p>", generate_links( $count, $current_page )
    # blah
}

sub generate_links {
    my ($count, $current_page ) = @_;
    my $html = '';
    for ( my $start = 1; $start <= $count; $start += $RECS_PER_PAGE ) {
        my $end = $start + $RECS_PER_PAGE -1;
        $end = $count if $end > $count;
        $html .= ( $start <= $current_page and $current_page <= $end ) ?
                 "[$start-$end] " :
                 qq!<a href="$SCRIPT?start=$start&end=$end">[$start-$end]</a> \n!;
    }
  return $html;
}

sub get_current_page {
    my $page = shift;
    # validate page, get data, format, return html
  return "<p>This is the content for page $page<p>\n";
}

sub get_record_count {
    # get count of records, simulate here
    return 42;
}

sub die_nice { print shift and exit }