Product_model.php

<?php defined('BASEPATH') OR exit('No direct script access allowed');

class Product_model extends CI_Model
{
    private $_table = "products";

    public $product_id;
    public $name;
    public $price;
    public $image = "default.jpg";
    public $description;

    public function rules()
    {
        return [
            ['field' => 'name',
            'label' => 'Name',
            'rules' => 'required'],

            ['field' => 'price',
            'label' => 'Price',
            'rules' => 'numeric'],

            ['field' => 'description',
            'label' => 'Description',
            'rules' => 'required']
        ];
    }

    public function getAll()
    {
        return $this->db->get($this->_table)->result();
    }

    public function getById($id)
    {
        return $this->db->get_where($this->_table, ["product_id" => $id])->row();
    }

    public function save()
    {
        $post = $this->input->post();
        $this->product_id = uniqid();
        $this->name = $post["name"];
        $this->price = $post["price"];
        $this->image = $this->_uploadImage();
        $this->description = $post["description"];
        return $this->db->insert($this->_table, $this);
    }

    public function update()
    {
        $post = $this->input->post();
        $this->product_id = $post["id"];
        $this->name = $post["name"];
        $this->price = $post["price"];

        if (!empty($_FILES["image"]["name"])) {
            $this->image = $this->_uploadImage();
        }
        else {
            $this->image = $post["old_image"];
        }

        $this->description = $post["description"];
        return $this->db->update($this->_table, $this, array('product_id' => $post['id']));
    }

    public function delete($id)
    {
        $this->_deleteImage($id);
        return $this->db->delete($this->_table, array("product_id" => $id));
    }

    private function _uploadImage()
    {
        $config['upload_path']      = './upload/product/';
        $config['allowed_types']    = 'gif|jpg|png';
        $config['file_name']        = $this->product_id;
        $config['overwrite']        = true;
        $config['max_size']         = 1024; // 1MB
        // $config['max_width']     = 1024;
        // $config['max_height']    = 768;

        $this->load->library('upload', $config);

        if ($this->upload->do_upload('image')) {
            return $this->upload->data("file_name");
        }

        return "default.jpg";
    }

    private function _deleteImage($id)
    {
        $product = $this->getById($id);
        if ($product->image != "default.jpg") {
            $filename = explode(".", $product->image)[0];
            return array_map('unlink', glob(FCPATH."upload/product/$filename.*"));
        }
    }
}