#!/usr/bin/perl -w
use strict;
use DB_File;
$|++;

use vars qw(%db %result %names @keywords @found @match @pairs 
            $isfound $start $original_Query $parse_over);

my $MAXHITS = 10;
my $query ="query";
# only a key name for %result
my $keyCount = "Just_Silly_Name"; 
my $script_name = &query_env('SCRIPT_NAME');
dbmopen(%db,"search_index.db",0) or die "dbmopen: $!";

&parse_form;
## store keywords and count of each matching file
foreach my $keyword (@keywords) {
    if (defined (my $filelist = $db{lc $keyword})) {
        $isfound =1;
        # accumulate the number of keywords matched & record the keyword
        foreach my $fileno ($filelist=~ /(-\d+)/g) {
            $result{$fileno}{$keyCount}++;
	    $result{$fileno}{$keyword} = $keyword;
        }
    }
}

## print the result and matched keywords if found
if ($isfound) {
    # start print links that match the most keywords to least.
    foreach my $key (sort hashValueDesc keys(%result) ) {
        push @found,$db{$key};
        # collect the matching keywords
        push @match,[grep { $_ ne $keyCount } keys %{ $result{$key} }];
    }
    my $low = $start;
    $low = 0 if ($low < 0 or $low > $#found);
    my $high = $low + $MAXHITS -1;
    $high = $#found if $high > $#found;
    print "Content-Type: text/html\n\n";
    print "<P>Your search for <b>@keywords</b> found ".@found." results on easyya.com\n";
    print "<br>Result ",$low+1," - ",$high+1," shown below.</P>\n";
    print "<hr width=\"75%\">\n";
    foreach ($low..$high) {
        print "<P>$found[$_] <font size=-1>matches <b>@{$match[$_]}</b></font></P>\n";
	print "<font size=-1> $1 </font><br>\n" if $found[$_] =~ /"(.*?)"/;	
    } 
    print "<P><hr width=\"75%\"></P>\n";
    print "<center><h3>\n";
    if ($low > 0) {
        $start = $low - $MAXHITS;
        $start =0 if ($start < 0);
        print "<A href=\"$script_name?$query=$original_Query&start=$start\">Previous</A>\n";
    }
    if ($high < $#found) {
        print "<b>| </b><A href=\"$script_name?$query=$original_Query&start=",$low + $MAXHITS,"\">Next</A>\n";
    } 
    print "</h3></center>\n";        
} else  { 
    print "Content-Type: text/html\n\n";
    print "No result's been found.\n"; 
}

sub hashValueDesc {
    $result{$b}{$keyCount} <=> $result{$a}{$keyCount};
}

sub parse_form {  
    if ("\U$ENV{'REQUEST_METHOD'}\E" eq 'GET') {
        @pairs = split(/&/, $ENV{'QUERY_STRING'});
    } 
    elsif ("\U$ENV{'REQUEST_METHOD'}\E" eq 'POST') {
        read(STDIN,my $buffer, $ENV{'CONTENT_LENGTH'});
        @pairs = split(/&/, $buffer);
    }
    else {
        &error('whoops! unknown request method');
    } ## End of if   
    foreach my $pair (@pairs) {
        my ($name, $value) = split(/=/,$pair);      
        $original_Query =$value if (!(defined $original_Query));
        $name  =~ tr/+/ /;
        $value =~ tr/+/ /;
        $name  =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
        $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
        $value =~ s/\W+/ /g;

        if (!(exists $names{$query})) {
	    # condition order is important!
            if ($name ne $query or $value =~ /^\s*$/) {
	        print "Location: http://www.easyya.com\n\n";
	    } else {
	        $names{$query} = "";
	        @keywords = split /\s+/,$value;
	    }
        } else {
	    # if doesn't match, we still get start=0 
	    if ($value =~ /^\d+$/) { 
	        $start = $value; 
		$parse_over = 1;
	    }
        }
	## exit after two pairs done. no wasting time if user fake out something!
        last if $parse_over;
    } ## End of foreach
}

sub error {
    my ($msg) = @_;
    print "Content-Type: text/html\n\n";
    print "<CENTER><H2>$msg</H2></CENTER>\n";
    exit;
}

sub query_env {
    my ($name,$default) = @_;
    if (($ENV{$name}) and ($ENV{$name} =~ /^(.*)$/s)) {
        return $1;
    }
    elsif (defined($default)) {
        return $default;
    }
    else {
        return '';
    }
}
1;
__END__