<?php
function invite($db){

	$name=$_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){ 
		return INVITE_INVITES;
	}

	$email_db = $db->query("Select 1 FROM user WHERE email='" . $safe_email . "';");
	$email_ar = $email_db->fetchArray(SQLITE3_NUM);

	if($email_ar[0] == 1){
		return INVITE_USEREXISTS;
	}

        /*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.";

		// Doesn't work with GMX or Web.de atm.
                mail($email, "Invite", $subject, "From: mail@iamfabulous.de");

                return INVITE_SUCCESSFULL;

         } else {
              	return INVITE_DATABASE;
         }   
}