perm

<?php

/*

This file is subject to the terms and conditions defined in
file 'LICENSE', which is part of this source code package.

© 2022 OtteIT s.r.o.
All Rights Reserved.

Author: Vilem Otte <dev@otte.cz>

*/

require_once(__DIR__."/../db.php");

/**
 * Permission class
 *
 * Functionality for permission creating, deleting, reading and updating
 */
class Permission
{
    /**
     * Database class instance
     */
    private $conn;

    /**
     * Permission ID
     */
    public $id;

    /**
     * User's ID (for whom the permission record is)
     */
    public $user_id;

    /**
     * User's role
     */
    public $role;

    /**
     * User's permission level
     */
    public $level;

    /**
     * READ permission (allows reading records)
     */
    public const READ = 1;

    /**
     * WRITE_SELF permission (allows reading and updating own records)
     */
    public const WRITE_SELF = 2;

    /**
     * WRITE permission (allows reading and writing records)
     */
    public const WRITE = 4;

    /**
     * Constructor
     *
     * @param Database Database connection instance - dbconn
     */
    public function __construct($dbconn)
    {
        $this->conn = $dbconn;

        $this->id = null;
        $this->user_id = null;
        $this->role = null;
        $this->level = null;
    }

    /**
     * Creates permission record
     *
     * Creates single permission record for specific user, with specific role and level. If such record exists, error is raised
     *
     * @return mixed Permission record ID on success, null on failure
     */
    public function Create()
    {
        $queryCheck = "SELECT * FROM permission WHERE user_id = '" . $this->conn->EscapeString($this->user_id) . "' AND role = '" . $this->conn->EscapeString($this->role) . "'";
        $resultCheck = $this->conn->Query($queryCheck);
        if ($resultCheck != false)
        {
            if ($this->conn->GetRowsCount($resultCheck) > 0)
            {
                $this->conn->SetError("Permission record for user ID '" . $this->conn->EscapeString($this->user_id) . "' and role '" . $this->conn->EscapeString($this->role) . "' already exists!");
                return null;
            }
        }

        $query = "INSERT INTO permission (user_id, role, level) VALUES('" . $this->conn->EscapeString($this->user_id) . "', '" . $this->conn->EscapeString($this->role) . "', '" . $this->conn->EscapeString($this->level) . "')";

        $result = $this->conn->Query($query);

        if ($result == false)
        {
            return null;
        }
        else
        {
            $this->id = $this->conn->GetLastInsertID();
            return $this->id;
        }
    }

    /**
     * Reads permission records
     *
     * Reads permission records, optionally for specific user and/or role
     *
     * @return mixed Null on failure, array of objects on success
     */
    public function Read()
    {
        $query = "SELECT * FROM permission WHERE 1 = 1 ";

        if ($this->user_id != null)
        {
            $query .= " AND user_id = '" . $this->conn->EscapeString($this->user_id) . "'";
        }

        if ($this->role != null)
        {
            $query .= " AND role = '" . $this->conn->EscapeString($this->role) . "'";
        }

        $result = $this->conn->Query($query);
        if ($result == false)
        {
            return null;
        }
        else
        {
            $numRows = $this->conn->GetRowsCount($result);

            if ($numRows > 0)
            {
                $output = [];

                for ($i = 0; $i < $numRows; $i++)
                {
                    $row = $this->conn->GetRow($result, $i);

                    $output[$i] = (object)array();
                    $output[$i]->id = $row['id'];
                    $output[$i]->user_id = $row['user_id'];
                    $output[$i]->role = $row['role'];
                    $output[$i]->level = $row['level'];
                }

                return $output;
            }
            else
            {
                $output = [];

                $output[0] = (object)array();
                $output[0]->id = $row['id'];
                $output[0]->user_id = $row['user_id'];
                $output[0]->role = $row['role'];
                $output[0]->level = Permission::READ;

                return $output;
            }
        }
    }

    /**
     * Check permission
     *
     * Checks permission for specific user with specific role at required level
     *
     * @param int $user_id User ID for which we check permission
     * @param string $role Permission role to check for user
     * @param int $level Permission level that is required
     *
     * @return mixed Null on query failure, false when permission is not granted, true when granted
     */
    public function Check($user_id, $role, $level)
    {
        $query = "SELECT * FROM permission WHERE user_id = '" . $this->conn->EscapeString($user_id) . "' AND role = '" . $this->conn->EscapeString($role) . "'";

        $result = $this->conn->Query($query);
        if ($result == false)
        {
            return null;
        }
        else
        {
            $numRows = $this->conn->GetRowsCount($result);

            for ($i = 0; $i < $numRows; $i++)
            {
                $row = $this->conn->GetRow($result, $i);

                if ((intval($level) & intval($row['level'])) > 0)
                {
                    return true;
                }
            }
        }

        return false;
    }

    /**
     * Update permission record
     *
     * Updates single permission record, sets permission role and permission level for given record
     *
     * @return mixed Null on failure, true on success
     */
    public function Update()
    {
        $query = "UPDATE permission SET
            role = '" . $this->conn->EscapeString($this->role) . "',
            level = '" . $this->conn->EscapeString($this->level) . "' ";

        $query .= "WHERE id = '" . $this->conn->EscapeString($this->id) . "'";

        $result = $this->conn->Query($query);
        if ($result == false)
        {
            return null;
        }
        else
        {
            return true;
        }
    }

    /**
     * Delete permission record
     *
     * Removes permission record from database
     *
     * @return mixed Null on failure, true on success
     */
    public function Delete()
    {
        $query = "DELETE FROM permission WHERE id = '" . $this->conn->EscapeString($this->id) . "'";

        $result = $this->conn->Query($query);
        if ($result == false)
        {
            return null;
        }
        else
        {
            return true;
        }
    }
}