<?php
/**
 * Created by PhpStorm.
 * User: ~~~
 * Date: 19/07/2018
 * Time: 9:01 AM
 */

class ContentLock_Model extends CI_Model
{
    /**
     * @var integer
     */
    private $content_id;
    /**
     * @var string
     */
    private $content_type;
    /**
     * @var integer
     */
    private $user_id;
    /**
     * @var string
     */
    private $time_limit;
    /**
     * content locks table
     */
    const CONTENT_LOCK_TABLE = 'content_locks';

    /**
     * ContentLock_Model constructor.
     */
    public function __construct()
    {
        parent::__construct();
        $this->content_type = 'job';
        $this->time_limit = '-5 minutes';
    }

    /**
     * @param $id
     */
    public function setContentId($id)
    {
        $this->content_id = $id;
    }

    /**
     * @param $user_id
     */
    public function setUserId($user_id)
    {
        $this->user_id = $user_id;
    }

    /**
     * Checks if the specified content has a lock on it
     * @return bool
     */
    public function isContentLocked()
    {
        $contentLock = $this->getContentLock();

        $num_rows = $contentLock['num_rows'];
        $result = $contentLock['result'];

        // If empty, add a new content lock
        if($num_rows < 1) {
            $this->addContentLock();
            return false;
        }

        // If the lock belongs to the requesting user, return false
        if($this->isOwnLock($result->user_id)) {
            return false;
        }

        // If sufficient time has elapsed, set the user to the content lock with current time
        if($this->hasTimeElapsed($result->timestamp)) {
            $this->updateLockTime();
            $this->updateLockUser();
            return false;
        }

        return true;
    }

    /**
     * Gets the content lock record
     * @return array
     */
    private function getContentLock()
    {
        $criteria = array(
            'content_id' => $this->content_id,
            'content_type' => $this->content_type
        );

        $query = $this->db
            ->select(array("timestamp", "user_id"))
            ->from(self::CONTENT_LOCK_TABLE)
            ->where($criteria)
            ->get();

        return array(
            'result' => $query->row(),
            'num_rows' => $query->num_rows()
        );
    }

    /**
     * Deletes the content lock record
     */
    public function clearContentLock()
    {
        $criteria = array(
            'content_id' => $this->content_id,
            'content_type' => $this->content_type,
            'user_id' => $this->user_id
        );

        $this->db
            ->where($criteria)
            ->delete(self::CONTENT_LOCK_TABLE);
    }

    /**
     * Inserts a new content lock record
     */
    public function addContentLock()
    {

        $data = array(
            'content_type' => $this->content_type,
            'user_id' => $this->user_id,
            'timestamp' => date('Y-m-d H:i:s'),
            'content_id' => $this->content_id
        );

        $this->db->insert(self::CONTENT_LOCK_TABLE, $data);
    }

    /**
     * Updates the content lock timestamp record
     */
    private function updateLockTime()
    {
        $criteria = array(
            'content_id' => $this->content_id,
            'content_type' => $this->content_type
        );

        $this->db
            ->set('timestamp', date('Y-m-d H:i:s'))
            ->where($criteria)
            ->update(self::CONTENT_LOCK_TABLE);
    }

    /**
     * Updates the content lock user
     */
    private function updateLockUser()
    {
        $criteria = array(
            'content_id' => $this->content_id,
            'content_type' => $this->content_type
        );

        $this->db
            ->set('user_id', date($this->user_id))
            ->where($criteria)
            ->update(self::CONTENT_LOCK_TABLE);
    }

    /**
     * Checks if the time has elapsed on the given record
     * @param $content_timestamp
     * @return bool
     */
    private function hasTimeElapsed($content_timestamp)
    {
        if(strtotime($content_timestamp) < strtotime($this->time_limit)) {
            return true;
        } else {
            return false;
        }
    }

    /**
     * Checks if lock belongs to the given owner
     * @param $content_user_id
     * @return bool
     */
    private function isOwnLock($content_user_id)
    {
        if($content_user_id === $this->user_id) {
            return true;
        } else {
            return false;
        }
    }
}