functions.php

<?php

$counter = new Counter(1);

class Counter
{
    private $imanager;
    private $slug;
    private $catId;
    private $itemMapper;
    private $min = 0;

    public function __construct($catId)
    {
        $this->imanager = imanager();
        $this->itemMapper = $this->imanager->getItemMapper();
        $this->slug = $this->imanager->sanitizer->pageName(get_page_slug(false));
        $this->catId = $catId;
    }

    public function getCount($slug = null)
    {
        $slug = (is_null($slug) ? $this->slug : $this->imanager->sanitizer->pageName($slug));
        $this->itemMapper->alloc($this->catId);
        $sItems = $this->itemMapper->getSimpleItems('name='.$slug);
        if($sItems) $sItem = current($sItems);
        return (!empty($sItem->total) ? (int)$sItem->total : 0);
    }

    public function increment($slug = null)
    {
        $slug = (is_null($slug) ? $this->slug : $this->imanager->sanitizer->pageName($slug));
        $this->itemMapper->alloc($this->catId);
        $this->itemMapper->init($this->catId);
        $item = $this->itemMapper->getItem('name='.$slug);
        if(empty($item)) { $item = $this->createItem($slug); }
        $item->setFieldValue('total', (int)$item->fields->total->value + 1);
        $item->save();
        $this->itemMapper->simplify($item);
        $this->itemMapper->save();
    }

    public function decrement($slug = null)
    {
        $slug = (is_null($slug) ? $this->slug : $this->imanager->sanitizer->pageName($slug));
        $this->itemMapper->alloc($this->catId);
        $this->itemMapper->init($this->catId);
        $item = $this->itemMapper->getItem('name='.$slug);
        if(!empty($item))
        {
            if((int)$item->fields->total->value <= $this->min) return;
            $item->setFieldValue('total', (int)$item->fields->total->value - 1);
            $item->save();
            $this->itemMapper->simplify($item);
            $this->itemMapper->save();
        }
    }

    public function remove($slug = null)
    {
        $slug = (is_null($slug) ? $this->slug : $this->imanager->sanitizer->pageName($slug));
        $this->itemMapper->init($this->catId);
        $item = $this->itemMapper->getItem('name='.$slug);
        if(!empty($item)) { return $this->imanager->deleteItem($item->id, $item->categoryid); }
    }

    private function createItem($slug)
    {
        $item = new Item($this->catId);
        $item->name = $slug;
        $item->setFieldValue('total', 0);
        $item->active = 1;
        $item->save();
        return $item;
    }
}