diff --git a/.htaccess b/.htaccess
new file mode 100644
index 0000000..53cac3b
--- /dev/null
+++ b/.htaccess
@@ -0,0 +1,4 @@
+<IfModule mod_rewrite.c>
+RewriteEngine on
+RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization},L]
+</IfModule>
\ No newline at end of file
diff --git a/ics.php b/ics.php
index 5b930aa..671def2 100644
--- a/ics.php
+++ b/ics.php
@@ -1,169 +1,150 @@
-<?php
-	require 'settings.php';
-
-	if (isset($_POST['password']))
-	{
-		$password = $_POST['password'];
-
-		$curl = curl_init();
-
-		curl_setopt($curl, CURLOPT_URL, $url);
-		curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
-		curl_setopt($curl, CURLOPT_USERPWD, $user . ':' . $password);
-		curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
-		$result = curl_exec($curl);
-
-		if (!$result)
-		{
-			die('error');
-		}
-		curl_close($curl);
-		die($result);
-	}
-?>
-
+<!DOCTYPE html>
 <html>
-	<header>
-		<title>Evénements à venir</title>
-	</header>
-	<body style="font-family: helvetica; line-height: 24px; font-size: 16px;">
-		<div id="content">Récupération du calendrier...</div>
-		<script type="text/javascript">
-function ics2json(input)
+    <head>
+        <title>Evénements à venir</title>
+        <meta charset="utf-8">
+    </head>
+    <body style="font-family: helvetica; line-height: 24px; font-size: 16px;">
+        <div id="content">
+<?php
+
+require 'settings.php';
+
+// authent
+if ($password && (!isset($_SERVER['PHP_AUTH_PW']) || $_SERVER['PHP_AUTH_PW'] != $password))
 {
-	var id = 0;
-	var root = {};
-	var curr = root;
-	input.split("\r\n").forEach(l =>
-	{
-		var key = l.split(":")[0].split(";")[0];
-		var val = l.split(":")[1];
-		if (key == "BEGIN")
-		{
-			if (curr[val])
-			{
-				val += "_" + (id++);
-			}
-			curr[val] = {
-				parent: curr
-			};
-			curr = curr[val];
-		}
-		else if (key == "END")
-		{
-			var parent = curr.parent;
-			delete curr.parent;
-			curr = parent;
-		}
-		else
-		{
-			curr[key] = key.startsWith("DT") ? dt(val) : val;
-		}
-
-	});
-
-	root.VCALENDAR.VEVENTS = [];
-	Object.keys(root.VCALENDAR)
-	.filter(k => (k == "VEVENT" || k.startsWith("VEVENT_")))
-	.forEach(k =>
-	{
-		root.VCALENDAR.VEVENTS.push(root.VCALENDAR[k]);
-		delete root.VCALENDAR[k];
-	});
-
-	return root.VCALENDAR;
+	header('WWW-Authenticate: Basic realm="bbn"');
+	header('HTTP/1.0 401 Unauthorized');
+	echo '<p>Access denied.</p></body></html>';
+	exit;
 }
 
-function dt(s)
-{
-	var formatted = s.substr(0,4) + "-" + s.substr(4,2) + "-" + s.substr(6,2);
-	if (s.length > 8)
-	{
-		formatted += "T" + s.substr(9,2) + ":" + s.substr(11,2) + ":" + s.substr(13,2);
-	}
-	return new Date(formatted);
+// Enable error reporting for debugging
+//error_reporting(E_ALL);
+//ini_set('display_errors', 1);
+
+function ics2json($input) {
+    $id = 0;
+    $root = [];
+    $curr = &$root;
+    $lines = explode("\r\n", $input);
+    foreach ($lines as $line) {
+        $parts = explode(":", $line, 2);
+        $key = explode(";", $parts[0])[0];
+        $val = isset($parts[1]) ? $parts[1] : '';
+        if ($key == "BEGIN") {
+            if (isset($curr[$val])) {
+                $val .= "_" . ($id++);
+            }
+            $curr[$val] = ['parent' => &$curr];
+            $curr = &$curr[$val];
+        } elseif ($key == "END") {
+            $parent = &$curr['parent'];
+            unset($curr['parent']);
+            $curr = &$parent;
+        } else {
+            $curr[$key] = (strpos($key, "DT") === 0) ? dt($val) : $val;
+        }
+    }
+    $root['VCALENDAR']['VEVENTS'] = [];
+    foreach ($root['VCALENDAR'] as $k => $v) {
+        if ($k == "VEVENT" || strpos($k, "VEVENT_") === 0) {
+            $root['VCALENDAR']['VEVENTS'][] = $v;
+            unset($root['VCALENDAR'][$k]);
+        }
+    }
+    return $root['VCALENDAR'];
 }
 
-function formatdate(d)
-{
-	return d.toLocaleString('fr-FR', { timeZone: 'Europe/Paris', dateStyle: "full", timeStyle: "short" });
+function dt($s) {
+    $formatted = substr($s, 0, 4) . "-" . substr($s, 4, 2) . "-" . substr($s, 6, 2);
+    if (strlen($s) > 8) {
+        $formatted .= "T" . substr($s, 9, 2) . ":" . substr($s, 11, 2) . ":" . substr($s, 13, 2);
+    }
+    return new DateTime($formatted);
 }
 
-function showresult()
-{
-	if (xhr.status == 200)
-	{
-		var params = new URLSearchParams(window.location.search);
-		var recent = parseInt(params.get("recent"));
-		if (isNaN(recent))
-		{
-			recent = 7;
-		}
-
-		var recentonly = params.get("recentonly");
-
-		var html = "<h1>Evénements à venir</h1>";
-		html += `<h3>${formatdate(new Date)}</h3>`;
-		html += `<div>En gras: modifié les ${recent} derniers jours</div>`;
-
-		var weblink = params.get("weblink");
-		if (weblink)
-		{
-			html += `<div><a target="_blank" href="${weblink}">Lien vers calendrier web</a></div>`;
-		}
-
-		var o = ics2json(xhr.responseText);
-
-		var lastmodified = new Date();
-		lastmodified.setDate(lastmodified.getDate() - recent);
-		var group = {};
-
-		o.VEVENTS
-		.filter(e => e.DTSTART >= (new Date) && (!recentonly || e.DTSTAMP >= lastmodified))
-		.sort( (a,b) => a.DTSTART - b.DTSTART)
-		.forEach(e => {
-			var formatteddate = formatdate(e.DTSTART);
-			var splitdate = formatteddate.split(" ");
-			var year = splitdate[3];
-			var month = splitdate[2];
-
-			if (!group[year])
-			{
-				html += `<h2>${year}</h2>`;
-				group[year] = {};
-			}
-
-			if (!group[year][month])
-			{
-				html += `<h3>${month}</h3>`;
-				group[year][month] = true;
-			}
-
-			var line = `<li title="modifié le ${formatdate(e.DTSTAMP)}"> ${formatteddate}: ${e.SUMMARY}`;
-			if (e.DTSTAMP >= lastmodified)
-			{
-				line = `<b>${line}</b>`;
-			}
-			html += line;
-		});
-
-		content.innerHTML = html;
-	}
+function formatdate($d) {
+    return strftime('%A, %e %B %Y %H:%M', $d->getTimestamp());
 }
 
-var password = localStorage.getItem("icspassword");
-if (!password)
-{
-	password = prompt("password:");
-	localStorage.setItem("icspassword", password);
+function getWeek($date) {
+    $dto = new DateTime();
+    $dto->setISODate($date->format('o'), $date->format('W'));
+    return $dto->format('W');
 }
 
-var xhr = new XMLHttpRequest();
-xhr.onload = showresult;
-xhr.open("POST", "ics.php");
-xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
-xhr.send("password=" + password);
+setlocale(LC_TIME, 'fr_FR.UTF-8');
 
-		</script>
-	</body>
-</html>
+$curl = curl_init();
+curl_setopt($curl, CURLOPT_URL, $davurl);
+curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
+curl_setopt($curl, CURLOPT_USERPWD, $davuser . ':' . $davpassword);
+curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
+$result = curl_exec($curl);
+if (!$result) {
+    die('error');
+}
+curl_close($curl);
+
+$params = [];
+parse_str($_SERVER['QUERY_STRING'], $params);
+$recent = isset($params['recent']) ? (int)$params['recent'] : 7;
+$recentonly = isset($params['recentonly']);
+$weblink = isset($params['weblink']) ? $params['weblink'] : '';
+
+$html = "<h1>Evénements à venir</h1>";
+$html .= "<h2>" . strftime('%A, %e %B %Y %H:%M') . "</h2>";
+$html .= "<div>En gras: modifié les $recent derniers jours</div>";
+if ($weblink) {
+    $html .= "<div><a target=\"_blank\" href=\"$weblink\">Lien vers calendrier web</a></div>";
+}
+
+$o = ics2json($result);
+$lastmodified = new DateTime();
+$lastmodified->modify("-$recent days");
+$group = [];
+usort($o['VEVENTS'], function($a, $b) {
+    return $a['DTSTART'] <=> $b['DTSTART'];
+});
+
+foreach ($o['VEVENTS'] as $e) {
+    if ($e['DTSTART'] >= new DateTime() && (!$recentonly || $e['DTSTAMP'] >= $lastmodified)) {
+
+        $formatteddate = strftime('%A %d %B %Y %H:%M', $e['DTSTART']->getTimestamp());
+        $splitdate = explode(' ', $formatteddate);
+        $year = $splitdate[3];
+        $month = $splitdate[2];
+        $week = getWeek($e['DTSTART']);
+        if (!isset($group[$year])) {
+            $html .= "<h2>$year</h2>";
+            $group[$year] = [];
+        }
+        if (!isset($group[$year][$month])) {
+            $html .= "<h3>$month</h3>";
+            $group[$year][$month] = [];
+        }
+        if (!isset($group[$year][$month][$week])) {
+            $html .= "<h4>Semaine $week</h4>";
+            $group[$year][$month][$week] = true;
+        }
+        $line = "<li title=\"modifié le " . strftime('%A, %e %B %Y %H:%M', $e['DTSTAMP']->getTimestamp()) . "\">";
+		if ($e['DTSTAMP'] >= $lastmodified) {
+            $line .= "<b>";
+        }
+        $line .= "$formatteddate: " . $e['SUMMARY'];
+        if ($e['DTSTAMP'] >= $lastmodified) {
+            $line .= "</b>";
+        }
+        $line .= '</li>';
+        if ($e['DTSTAMP'] >= $lastmodified) {
+            $line = "<b>$line</b>";
+        }
+        $html .= $line;
+    }
+}
+echo $html;
+?>
+        </div>
+    </body>
+</html>
\ No newline at end of file
diff --git a/settings.php.sample.php b/settings.php.sample.php
index 3de1331..b229194 100644
--- a/settings.php.sample.php
+++ b/settings.php.sample.php
@@ -1,4 +1,6 @@
 <?php
-	$url = 'https://caldav.example.com/path/to/calendar';
-	$user = 'caldavuser';
+	$davurl = 'https://caldav.example.com/path/to/calendar';
+	$davuser = 'caldavuser';
+	$davpassword = 'caldavpassword';
+	$password = 'httppassword';
 ?>
