<?php
function invite($db){
        if($_SERVER['REQUEST_METHOD'] == 'POST') {

		if(!$_SESSION["login"]){
			header("Refresh: 0; /login");
			return false;
		}

                $name=$_SESSION["username"];
                $safe_name = SQLite3::escapeString("$name");

                $email=$_POST["email"];
                $safe_email=SQLite3::escapeString("$email");

                $invite_db = $db->query("SELECT invites FROM user WHERE name='" . $safe_name . "';");
                $invite_ar = $invite_db->fetchArray(SQLITE3_NUM);
                $invite = $invite_ar[0];

                if($invite > 0){ 

        /*Generates the invite key => [-_0-9a-zA-Z]{11}*/

                        $key_array = array("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "_", "-", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" );

                        $length = count($key_array);
                        $key = ""; 

                        for ($i=0;$i<11;$i++){
                                $index = mt_rand(0,$length-1);
                                $key = "$key".$key_array[$index];
                        }   

                        $id_db = $db->query("SELECT id FROM USER WHERE name=' " . $safe_name . "';");
                        $id_ar = $id_db->fetchArray(SQLITE3_NUM);
                        $id = $id_ar[0];

        /*Generates the new user and decrease the invites*/

                        $invite = $invite - 1;

                        if($db->exec("
                                BEGIN TRANSACTION;
                                INSERT INTO user (id, name, email, senpai, key, status) VALUES (NULL, NULL, '" . $safe_email . "', '" . $id . "', '" . $key . "', 0);
                                UPDATE user SET invites='" . $invite . "' WHERE id='" . $id . "'; 
                                COMMIT;")
                        ){  
                                $subject="Welcome, you were invited to the new virtual filesystem.\nYour key is" . $key . "\nVisit files.iamfabulous.de/register to complete your registration.";

                                mail($email, "Invite", $subject, "From: mail@iamfabulous.de");

                                header("Refresh: 0; /invite?reason=success");
                                return true;

                        } else {
                                header("Refresh: 0; /invite?reason=database");
                                return false;
                        }   

                } else {
                        header("Refresh: 0; /invite?reason=invites");
			return false;
		}
	} else {
		include("invite.php");
		return false;
	}
}