#! /usr/bin/perl -w
# History: Theory and Culture
# counter.cgi: The visitor counter.

#  Copyright (c) 2003-2021 imacat.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

# Author: imacat <imacat@mail.imacat.idv.tw>
# First written: 2003-04-07

use 5.008;
use strict;
use warnings;
use lib $ENV{"DOCUMENT_ROOT"} . qw(/magicat/lib/perl5);
use Selima::htc;
local $SIG{"__DIE__"} = \&http_500;
my $d = new Selima::Destroy;
# Prototype declaration
sub main();
sub dont_update();
sub read_counter();
sub update_counter();
sub log_visitor($);
sub counter_cookie();
sub html_image($);

use Fcntl qw(:seek);
use Date::Format qw(time2str);
use GD;
use IO::NestedCapture qw(CAPTURE_STDOUT);
use Net::CIDR::Lite qw();

use constant DATA_FILE => $ENV{"DOCUMENT_ROOT"} . "/magicat/data/counter.dat";
use constant LOG_FILE => "/var/log/apache2/htc/counter.log";
use vars qw($OUR_NETWORKS @FGCOLOR @BGCOLOR $FONT);
# People in our networks will not be counted
$OUR_NETWORKS = Net::CIDR::Lite->new(
    qw(127.0.0.1/8 10.0.0.0/8 211.20.30.96/29));
@FGCOLOR = (0, 0, 0);           # #000000 Black
@BGCOLOR = (255, 255, 255);     # #FFFFFF White
$FONT = gdLargeFont;
use constant TRANSPARENT => 1;
use constant COOKIE_NAME => "counter";
use constant COUNT_ARG => "countme";
use constant IGNORE_ARG => "ignoreme";
initenv(    -allowed    => [qw(GET HEAD)],
            -session    => 0,
            -dbi        => DBI_NONE,
            -lastmod    => 0,
            -multilang  => 0);

main;
exit 0;

sub main() {
    local ($_, %_);
    
    # If we should not update the counter
    if (dont_update) {
        # Check last-modified here
        my (@tables, @files);
        @tables = qw();
        @files = (DATA_FILE);
        http_304 if not_modified @tables, @files;
        html_image read_counter;
    
    # Update the counter
    } else {
        $_ = html_image update_counter;
        # Log the visitor
        log_visitor $_;
    }
    
    # Set the counter cookie
    $NEWCOOKIES{COOKIE_NAME()} = $_ if defined ($_ = counter_cookie);
    
    return;
}

# dont_update: If we should not update the counter
sub dont_update() {
    local ($_, %_);
    # Find any reason that we should not update the counter
    # If this visitor came from our own network
    return 1 if $OUR_NETWORKS->find($ENV{"REMOTE_ADDR"});
    # If this visitor had been counted
    return 1 if exists $COOKIES{COOKIE_NAME()};
    # If we are not told to count this visitor
    return 1 if !defined $GET->param(COUNT_ARG);
    # Well, update it
    return 0;
}

# read_counter: Read the counter
sub read_counter() {
    return -s DATA_FILE? xfread DATA_FILE: 0;
}

# update_counter: Update the counter
sub update_counter() {
    local ($_, %_);
    # File exists
    if (-s DATA_FILE) {
        my $FH;
        open $FH, "+<", DATA_FILE   or http_500 DATA_FILE . ": $!";
        flock $FH, LOCK_EX          or http_500 DATA_FILE . ": $!";
        $_ = <$FH>;
        $_++;
        seek $FH, 0, SEEK_SET       or http_500 DATA_FILE . ": $!";
        truncate $FH, 0             or http_500 DATA_FILE . ": $!";
        print $FH $_                or http_500 DATA_FILE . ": $!";
        flock $FH, LOCK_UN          or http_500 DATA_FILE . ": $!";
        close $FH                   or http_500 DATA_FILE . ": $!";
    
    # Not exists or zero sized -- create a new one
    } else {
        xfwrite DATA_FILE, ($_ = 1);
    }
    return $_;
}

# log_visitor: Log the visitor
sub log_visitor($) {
    local ($_, %_);
    my ($host, $user, $date, $uri, $size, $referer, $ua, $langs, $FD);
    $size = $_[0];
    
    # Gather the infomation to log
    $host = (defined remote_host)? remote_host: $ENV{"REMOTE_ADDR"};
    $user = (exists $ENV{"REMOTE_USER"} && $ENV{"REMOTE_USER"} ne "")?
        $ENV{"REMOTE_USER"}: "-";
    $date = time2str("%d/%b/%Y:%T %z", time);
    $uri = $REQUEST_URI;
    $referer = (exists $ENV{"HTTP_REFERER"} && $ENV{"HTTP_REFERER"} ne "")?
        $ENV{"HTTP_REFERER"}: "-";
    $ua = (exists $ENV{"HTTP_USER_AGENT"} && $ENV{"HTTP_USER_AGENT"} ne "")?
        $ENV{"HTTP_USER_AGENT"}: "=";
    $langs = (exists $ENV{"HTTP_ACCEPT_LANGUAGE"} && $ENV{"HTTP_ACCEPT_LANGUAGE"} ne "")?
        $ENV{"HTTP_ACCEPT_LANGUAGE"}: "-";
    
    # Compose the log record 組合紀錄行
    $_ = sprintf "%s - %s [%s] \"%s %s %s\" 200 %s \"%s\" \"%s\" \"%s\" %s %s\n",
        $host, $user, $date, $ENV{"REQUEST_METHOD"}, $uri,
        $ENV{"SERVER_PROTOCOL"}, $size, $referer, $ua, $langs,
        $ENV{"REMOTE_ADDR"}, country_lookup($ENV{"REMOTE_ADDR"});
    
    # Save the log record 儲存記錄
    xfappend LOG_FILE, $_;
    
    return;
}

# counter_cookie: Set the counter cookie
sub counter_cookie() {
    local ($_, %_);
    # Leave our network alone
    return if $OUR_NETWORKS->find($ENV{"REMOTE_ADDR"});
    # Already set
    return if exists $COOKIES{COOKIE_NAME()};
    # Count me
    return new CGI::Cookie( -name=>COOKIE_NAME,
                            -value=>"counted",
                            -path=>$REQUEST_PATH)
        if defined $GET->param(COUNT_ARG);
    # Ignore me
    return new CGI::Cookie( -name=>COOKIE_NAME,
                            -value=>"ignored",
                            -path=>$REQUEST_PATH)
        if defined $GET->param(IGNORE_ARG);
    # Leave it alone
    return;
}

# html_image: Make the image from the counter value 
sub html_image($) {
    local $_;
    my ($counter, $image, $width, $height, $fgcolor, $bgcolor);
    $counter = $_[0];
    
    # Group the counter with commas at thousand digits.
    $counter = fmtno($counter);
    
    # Initialize the image object
    # Get the width and height
    $width = $FONT->width * (length $counter);
    $height = $FONT->height;
    # Create an image object
    $image = GD::Image->new($width, $height);
    # Create the forground/background color objects
    $fgcolor = $image->colorAllocate(@FGCOLOR);
    $bgcolor = $image->colorAllocate(@BGCOLOR);
    
    # Draw the image
    # Set the transparent background
    $image->transparent($bgcolor) if TRANSPARENT;
    # Paint the background
    $image->filledRectangle(0, 0, $width, $height, $bgcolor);
    # Write the text
    $image->string($FONT, 0, 0, $counter, $fgcolor);
    
    # Output
    $CONTENT_TYPE = "image/png";
    binmode IO::NestedCapture->instance->{"STDOUT_current"}[-1], ":raw";
    $_ = $image->png;
    print $_;
    
    return length $_;
}