    <?php
    require_once 'init.php';
    require_once 'user.php';
    require_once 'string.php';
    require_once 'notificationcode.php';
    require_once 'topic.php';

        class Comment {
            private $id;
            private $content;
            private $topic;
            const MIN_CONTENT_LENGTH = 15;
            const CONTENT_TOO_SHORT = NotificationCode::CONTENT_TOO_SHORT;
            const PATH = 'comment';
            private $isExists = false;
            private $lastedit;
            private $posttime;
            private $author;


            function __construct($id) {
                $this->id = $id;
                if (is_dir('database/'.Comment::PATH.'/'.$id)) {
                    $isExists = true;
                    $content = new String(file_get_contents('database/'.Comment::PATH.'/'.$this->id.'/content'));
                    $topic = new Topic(file_get_contents('database/'.Comment::PATH.'/'.$this->id.'/topic'));
                    $lastedit = file_get_contents('database/'.Comment::PATH.'/'.$this->id.'/lastedit');
                    $posttime = file_get_contents('database/'.Comment::PATH.'/'.$this->id.'/posttime');
                    $author = new User(file_get_contents('database/'.Comment::PATH.'/'.$this->id.'/author'));
                }
            }

            function isExists() {
                return $this->isExists;
            }

            function getAuthor() {
                return $this->author;
            }
            function getLastEdit() {
                return $this->lastedit;
            }

            function getPostTime() {
                return $this->posttime;
            }

            function getContent() {
                return $this->content;
            }

            function setContent(String $content) {
                if ($this->isExists()) {
                    if ($this->setLastEdit(time())) {
                        Functional::writeFile('database/'.Comment::PATH.'/'.$this->id.'/content', $content->getText(), 'w');
                        return true;
                    }
                }
                return false;
            }

            private function setLastEdit($time) {
                if ($this->isExists()) {
                    Functional::writeFile('database/'.Comment::PATH.'/'.$this->id.'/lastedit', $time, 'w');
                    return true;
                }
                return false;
            }

            static function isValid(String $comment, User $author) {
                if (strlen($comment->getText()) < Comment::MIN_CONTENT_LENGTH)
                    return Comment::CONTENT_TOO_SHORT;
                return NotificationCode::VALID;
                
            }
            
            private function setAuthor(User $author) {
                Functional::writeFile('database/'.Comment::PATH.'/'.$this->id.'/author', $author->getID(), 'w');
            }

            private function setPostTime($time) {
                Functional::writeFile('database/'.Comment::PATH.'/'.$this->id.'/posttime', $time, 'w');
            }

            //Mỗi comment sẽ thuộc 1 topic nào đó
            private function setTopic(Topic $topic) {
                if ($this->isExists()) {
                    Functional::writeFile('database/'.Comment::PATH.'/'.$this->id.'/topic', $topic->getID(), 'w');
                    $this->topic = $topic;
                    return true;
                } 
                return false;
            }

            function getTopic() {
                return $this->topic;
            }


            static function createComment(Topic $topic, String $content, User $author) {
                if (Comment::isValid($content, $author) != NotificationCode::VALID)
                    return Comment::isValidComment($content, $author);

                $id = count(scandir('database/'.Comment::PATH)) + 1;

                $comment = new Comment($id);
                if ($comment->isExists())
                    return Comment::CREATE_ERROR;
                
                mkdir('database/'.Comment::PATH.'/'.$id);
                //Add comment vào topic
                Functional::writeFile('database/'.Topic::PATH.'/'.$topic->getID().'/comment/'.$id, '', 'w');
                //Create comment
                $posttime = time();
                Functional::writeFile('database/'.Comment::PATH.'/'.$id.'/content', $content->getText(), 'w'); //Ghi content
                Functional::writeFile('database/'.Comment::PATH.'/'.$id.'/author', $author->getID(), 'w'); //Ghi author
                Functional::writeFile('database/'.Comment::PATH.'/'.$id.'/posttime', $posttime, 'w'); //Ghi posttime
                Functional::writeFile('database/'.Comment::PATH.'/'.$id.'/lastedit', $posttime, 'w'); //Ghi lastedit
                Functional::writeFile('database/'.Comment::PATH.'/'.$id.'/topic', $topic->getID(), 'w');
                $comment = new Comment($id);
                return $comment;
            }

            function getID() {
                return $this->id;
            }

            static function getInstance($id) {
                $comment = new Comment($id);
                if ($comment->isExists())
                    return $comment;
                return null;
            }
        }
    ?>