<?php
$todayInput = $_GET['today'];
$today = new DateTime(str_replace("/", "-", $todayInput));
$input = $_GET['invoices'];
//$todayInput = "07/08/2015";
//$today = new DateTime(str_replace("/", "-", $todayInput));
//$input =   array (
//    0 => '11/05/2013 | Sopharma    | Paracetamol | 20.54lv.',
//    1 => '02/12/2011 | Actavis | Aulin | 120.54lv.',
//    2 => '13/05/2009 | Sopharma | Tamiflu | 221.54lv.',
//    3 => '23/01/2014 | Actavis | Paracetamol | 7.54lv.',
//    4 => '11/05/2013 | Sopharma | Analgin | 20.54lv.',
//    5 => '11/05/2013 | Test | Tamiflu | 20.54lv.',
//    6 => '11/05/2013 | Test | Devin | 20.54lv.',
//);

$fiveYearsAgo = new DateTime(str_replace("/", "-", $todayInput));
$fiveYearsAgo->modify("-5 years");
$costSum = 0;
$dates = [];

foreach ($input as $token) {
    $invoice = explode("|", $token);
    $company = trim($invoice[1]);
    $drug = trim($invoice[2]);
    $cost = (double)trim($invoice[3]);
    $date = new DateTime(str_replace("/", "-", trim($invoice[0])));

    if ($date >= $fiveYearsAgo && $date <= $today) {

        $date = $date->format('d-m-Y');

        if (!array_key_exists($date, $dates)) {
            $dates[$date] = [];
        }

        if (!array_key_exists($company, $dates[$date])) {
            $dates[$date][$company] = [];
        }

        if (!array_key_exists($drug, $dates[$date][$company])) {
            $dates[$date][$company][$drug] = 0;
        }

        $dates[$date][$company][$drug] += $cost;
    }
}

uksort($dates, function($d1, $d2) {
    $d1 = new DateTime($d1);
    $d2 = new DateTime($d2);
    return $d1 > $d2;
});

echo "<ul>";
foreach ($dates as $date => $companies) {
    echo '<li><p>' . date('d/m/Y', strtotime($date)) . '</p><ul>';
    ksort($companies);
    foreach ($companies as $company => $drugs) {
        echo '<li><p>' . $company . '</p><ul><li><p>';
        ksort($drugs);
        $drugsArr = [];
        $numDrugs = count($drugs);
        $i = 0;
        foreach ($drugs as $drug => $cost) {
            $costSum += $cost;
            echo $drug;
            if(++$i != $numDrugs) {
                echo ",";
            }
        }
        echo "-".$costSum."lv";
        $costSum = 0;
        echo '</p></li></ul></li>';
    }
    echo '</ul></li>';
}
echo "</ul>";
?>