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

const TEMP_DIRECTORY_UPLOAD = 'application/cache/upload';

// RESPONSE FUNCTION
function verbose($ok = 1, $info = "")
{
    // THROW A 400 ERROR ON FAILURE
    if ($ok == 0) {
        http_response_code(400);
    }
    die(json_encode(["ok" => $ok, "info" => $info]));
}

function upload_file()
{
    // INVALID UPLOAD
    if (empty($_FILES) || $_FILES['file']['error']) {
        verbose(0, "Failed to move uploaded file.");
    }

    // THE UPLOAD DESITINATION - CHANGE THIS TO YOUR OWN
    $filePath = $_SERVER['DOCUMENT_ROOT']
                . DIRECTORY_SEPARATOR
                . TEMP_DIRECTORY_UPLOAD;
    if (!file_exists($filePath)) {
        if (!mkdir($filePath, 0777, true)) {
            verbose(0, "Failed to create $filePath");
        }
    }
    $fileName = isset($_REQUEST["name"]) ? $_REQUEST["name"] : $_FILES["file"]["name"];
    $filePath = $filePath . DIRECTORY_SEPARATOR . $fileName;

    // DEAL WITH CHUNKS
    $chunk = isset($_REQUEST["chunk"]) ? intval($_REQUEST["chunk"]) : 0;
    $chunks = isset($_REQUEST["chunks"]) ? intval($_REQUEST["chunks"]) : 0;
    $out = @fopen("{$filePath}.part", $chunk == 0 ? "wb" : "ab");
    if ($out) {
        $in = @fopen($_FILES['file']['tmp_name'], "rb");
        if ($in) {
            while ($buff = fread($in, 4096)) {
                fwrite($out, $buff);
            }
        } else {
            verbose(0, "Failed to open input stream");
        }
        @fclose($in);
        @fclose($out);
        @unlink($_FILES['file']['tmp_name']);
    } else {
        verbose(0, "Failed to open output stream");
    }

    // CHECK IF FILE HAS BEEN UPLOADED
    if (!$chunks || $chunk == $chunks - 1) {
        rename("{$filePath}.part", $filePath);
    }
    verbose(1, "Upload OK");
}