<?php

    session_start();

    class KStats{

        private static $url = null;
        private static $default_settings = [
            "engine" => "mysql",
            "database" => "KStats",
            "host" => "localhost",
            "port" => 3306,
            "charset" => "utf8",
            "user" => "root",
            "password" => "",
            "connection_string" => "{engine}:dbname={database};host={host};port={port};charset={charset}",
            "allow_all" => false,
            "data_key" => "kstats_data",
            "ip_keys_ordered" => ["HTTP_CF_CONNECTING_IP", "HTTP_X_FORWARDED_FOR", "HTTP_X_REAL_IP", "HTTP_CLIENT_IP", "REMOTE_ADDR"]
        ];
        private $input = [];
        private $connection = null;
        private $token = null;
        private $type = null;
        private $method = null;
        private $mode = null;
        private $id = null;
        private $query = null;
        private $session = null;
        private $request_data = null;

        public static function is_dictionary($value){
            return is_array($value) && array_values($value) != $value;
        }

        public static function is_secure(){
            return (isset($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] == "on") || $_SERVER["SERVER_PORT"] == 443;
        }

        private static function get_url(){
            return self::$url ? self::$url : (self::$url = (
                isset($_SERVER["HTTP_REFERER"]) ?
                $_SERVER["HTTP_REFERER"] :
                "http" . (self::is_secure() ? "s" : "") . "://" . $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"]
            ));
        }

        public function default_value($default = null, $nulls = null){
            return $default !== null || (is_bool($nulls) ? $nulls : $this->settings("nulls", null, false, false)) ? $default : $this->settings(["default_value", "default"], null, null, true);
        }

        private function settings($names = null, $inputs = null, $default = null, $nulls = null){
            if(!$names)
                return $this->default_value($default, $nulls);

            !is_bool($nulls) && ($nulls = $this->settings("nulls", null, false, false));
            !is_array($names) && ($names = [$names]);

            foreach(array_merge(is_array($inputs) ? (self::is_dictionary($inputs) ? [$input] : $input) : [], [$this->input, self::$default_settings]) as $input)
                if(self::is_dictionary($input))
                    foreach($names as $name)
                        if($name && isset($input[$name]) && ($nulls || $input[$name] !== null))
                            return $input[$name];
            return $this->default_value($default, $nulls);
        }

        public function get_ip(){
            foreach($this->settings("ip_keys_ordered") as $key){
                if(!empty($_SERVER[$key]))
                    return explode(",", $_SERVER[$key])[0];
                if($ips = getenv($key))
                    return explode(",", $ips)[0];
            };
            return null;
        }

        private function get_token(){
            return preg_replace('/^\/api\/([^\/]+)(\/.*)?$/', "$1", $_SERVER["REQUEST_URI"]);
        }

        public static function string_variables($string, $variables = null, $default = null){

            if(!is_array($variables))
                $variables = [];
            elseif(self::is_dictionary($variables))
                $variables = [$variables];

            return preg_replace_callback('/\{([^\{\}]+)\}/', function($values) use($variables){
                foreach($variables as $set)
                    if(isset($set[$values[1]]))
                        return $set[$values[1]];
                return $values[0];
            }, $string);
        }

        private function query($query, $variables){

            $used = [];
            $results = [
                "tables" => [],
                "variables" => []
            ];

            if(!is_array($variables))
                $variables = [];
            elseif(self::is_dictionary($variables))
                $variables = [$variables];

            preg_replace_callback('/\@([a-zA-Z0-9_]+)/', function($values) use(&$used){
                !in_array($values[1], $used) && ($used[] = $values[1]);
            }, is_array($variables) ? ($query = preg_replace_callback('/\{([^\{\}]+)\}/', function($values) use($variables){
                foreach($variables as $set)
                    if(isset($set[$values[1]]))
                        return (
                            $set[$values[1]] === null ? "null" : (
                            is_bool($set[$values[1]]) ? ($set[$values[1]] ? "true" : "false") : (
                            is_string($set[$values[1]]) ? "'" . preg_replace('/([\\\\\'])/', "\\\\$1", $set[$values[1]]) . "'" : (
                            $set[$values[1]]
                        ))));
                return "null";
            }, $query)) : $query);

            if(!empty($used)){
                $subquery = "";
                foreach($used as $key)
                    $subquery .= ($subquery ? "," : "") . " @" . $key . " as '" . $key . "'";
                $query .= (preg_match('/;$/', $query) ? "" : ";") . "select" . $subquery . ";";
            }

            if(!$this->connection){
                $this->connection = new \PDO(self::string_variables($this->settings(["connection_string", "string_connection"]), [
                    "engine" => $this->settings(["connection_engine", "engine"]),
                    "database" => $this->settings(["connection_database", "database"]),
                    "host" => $this->settings(["connection_host", "host"]),
                    "port" => $this->settings(["connection_port", "port"]),
                    "charset" => $this->settings(["connection_charset", "charset"])
                ]), $this->settings(["connection_user", "user"]), $this->settings(["connection_password", "password"]));
                $this->connection->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
                $this->connection->beginTransaction();
            };

            $this->query = $query;

            ($statement = $this->connection->prepare($query))->execute();

            do{
                try{
                    $table = [];
                    foreach($statement->rowCount() == 0 ? [] : $statement->fetchAll(\PDO::FETCH_ASSOC) as $new_row){
                        $row = [];
                        foreach($new_row as $key => $value){
                            if($value && is_string($value) && in_array($value[0], ["[", "{"])){
                                try{
                                    $row[$key] = json_decode(utf8_encode($value), true);
                                }catch(\Exception $exception){}
                                !$row[$key] && ($row[$key] = utf8_encode($value));
                            }else
                                $row[$key] = $value;
                        };
                        $table[] = $row;
                    };
                    $results["tables"][] = $table;
                }catch(\Exception $exception){};
            }while($statement->nextRowset());

            if(preg_match('/(,\s+?|\()\@/', $query)){
                $l = count($results["tables"]) - 1;
                foreach($results["tables"][$l][0] as $key => $value)
                    $results["variables"][$key] = $value;
                unset($results["tables"][$l]);
            };

            $this->connection->commit();

            return $results;
        }

        private function save(){

            $results = null;

            if(!in_array($this->type, ["js", "ecma"]) || $this->settings("allow_all")){

                // isset($_SERVER["HTTP_REFERER"]) &&
                $results = $this->query("call register({session}, {from}, {token}, {ip}, {url}, @error, @current_session, @id);", [
                    "session" => $this->session ? $this->session : null,
                    "from" => $this->id ? $this->id : null,
                    "token" => $this->get_token(),
                    "ip" => $this->get_ip(),
                    "url" => $this->request_data && isset($this->request_data["url"]) ? $this->request_data["url"] : self::get_url()
                ]);

                $results &&
                ($_SESSION["kstats_id"] = $results["variables"]["current_session"]);

            };

            return $results;
        }

        private function print($data){

            switch($this->type){
                case "js":
                    header("content-type: text/javascript");
                    echo file_get_contents(__DIR__ . "/../Public/js/KStats.js");
                break;
                case "ecma":
                    header("content-type: text/javascript");
                    echo file_get_contents(__DIR__ . "/../Public/ecma/KStats.ecma.js");
                break;
                case "image":
                case "img":
                    header("content-type: image/png");
                    echo file_get_contents(__DIR__ . "/../Public/images/min.png");
                break;
                case "css":
                    header("content-type: text/css");
                    echo "kstats-tag-link::after{content : '" . $data . "';}";
                break;
                case "json":
                    header("content-type: application/json");
                    echo json_encode([
                        "ok" => true,
                        "code" => 200,
                        "data" => $data
                    ]);
                break;
                case "test":
                    header("content-type: text/javascript");
                    echo "console.log(" . json_encode([
                        "session" => $_SESSION
                    ]) . ");console.log(document.cookie.split(';'));";
                break;
                default:
                    header("content-type: text/plain");
                    echo "";
                break;
            };

            exit(0);

        }

        public function __construct($input = null){

            is_array($input) && ($this->input = $input);

            if(preg_match('/^\/api\/([^\/]+)\/([^\/]+)\/([^\/]+)\/([^\/\?]+)(\/([^\?]+))?/', $_SERVER["REQUEST_URI"], $matches)){

                $data_key = $this->settings("data_key");

                $this->token = $matches[1];
                $this->session = intval($matches[2]);
                $this->type = $matches[3];

                foreach([$_POST, $_GET, $_COOKIE] as $set)
                    if(isset($set[$data_key])){
                        $this->request_data = json_decode(base64_decode(urldecode($set[$data_key])), true);
                        break;
                    };

                // print_r(["request_data", $this->request_data, "get" => $_GET]);

                switch($this->method = $matches[4]){
                    case "set":
                        isset($matches[6]) && $matches[6] && ($this->id = intval($matches[6]));
                        $response = $this->save();
                        $this->print(array_merge(is_array($response) ? $response : [], [
                            "url" => self::get_url(),
                            "query" => $this->query
                        ]));
                };

            };

            $this->print(false);

        }

        public function close(){

            if($this->connection){
                try{
                    $this->connection->commit();
                }catch(\Exception $exception){
                    try{
                        $this->connection->rollback();
                    }catch(\Exception $subexception){};
                };
            };
            $this->connection = null;

        }

        public function __destruct(){

            $this->close();

        }

    };