<?php

class Document
{
	private $file_id;
	private $user_id;
	private $team_id;
	private $problem;
	private $uploaded_at;
	private $version;

	private function __construct() {}

	public static function fromId($id)
	{
		global $DB;
		$req = $DB->prepare("SELECT * FROM `documents` WHERE `file_id` = ?;");
		$req->execute([htmlspecialchars($id)]);
		$data = $req->fetch();

		if ($data === false)
			return null;

		return self::fromData($data);
	}

	public static function fromData($data)
	{
		$doc = new Document();
		$doc->fill($data);
		return $doc;
	}

	private function fill($data)
	{
		$this->file_id = $data["file_id"];
		$this->user_id = $data["user"];
		$this->team_id = $data["team"];
		$this->problem = $data["problem"];
		$this->uploaded_at = $data["uploaded_at"];
		$this->version = isset($data["version"]) ? $data["version"] : 1;
	}

	public function getFileId()
	{
		return $this->file_id;
	}

	public function getUserId()
	{
		return $this->user_id;
	}

	public function getTeamId()
	{
		return $this->team_id;
	}

	public function getProblem()
	{
		return $this->problem;
	}

	public function getUploadedAt()
	{
		return $this->uploaded_at;
	}

	public function getVersion()
	{
		return $this->version;
	}


	public static function getAllDocuments($problem, $team_id = -1)
	{
		global $DB;
		$req = $DB->query("SELECT * FROM `documents` AS `t1` "
			. "INNER JOIN (SELECT `user`, `problem`, MAX(`uploaded_at`) AS `last_upload`, COUNT(`team`) AS `version` FROM `documents` GROUP BY `problem`, `user`) `t2` "
			. "ON `t1`.`user` = `t2`.`user` AND `t1`.`problem` = `t2`.`problem` "
			. "WHERE `t1`.`uploaded_at` = `t2`.`last_upload` AND `t1`.`problem` = $problem " . ($team_id >= 0 ? "AND `team` = $team_id" : "") . " ORDER BY `t1`.`user`;");

		$docs = [];

		while (($data = $req->fetch()) !== false)
			$docs[] = Document::fromData($data);

		return $docs;
	}
}