diff --git a/src/php/time/Date.php b/src/php/time/Date.php
new file mode 100644
index 0000000..60f6fa7
--- /dev/null
+++ b/src/php/time/Date.php
@@ -0,0 +1,20 @@
+<?php
+namespace nur\sery\php\time;
+
+use DateTimeZone;
+
+/**
+ * Class Date: une date
+ */
+class Date extends DateTime {
+  const DEFAULT_FORMAT = "d/m/Y";
+
+  function __construct($datetime="now", DateTimeZone $timezone=null) {
+    parent::__construct($datetime, $timezone);
+    $this->setTime(0, 0, 0, 0);
+  }
+
+  function format($format=self::DEFAULT_FORMAT): string {
+    return \DateTime::format($format);
+  }
+}
diff --git a/src/php/time/DateInterval.php b/src/php/time/DateInterval.php
new file mode 100644
index 0000000..3fdc7f0
--- /dev/null
+++ b/src/php/time/DateInterval.php
@@ -0,0 +1,49 @@
+<?php
+namespace nur\sery\php\time;
+
+class DateInterval extends \DateInterval {
+  protected static function to_string(DateInterval $interval) {
+    $string = "P";
+    $y = $interval->y;
+    $m = $interval->m;
+    $d = $interval->d;
+    if ($y > 0) $string .= "${y}Y";
+    if ($m > 0) $string .= "${m}M";
+    if ($d > 0) $string .= "${d}D";
+    $string .= "T";
+    $h = $interval->h;
+    $i = $interval->i;
+    $s = $interval->s;
+    if ($h > 0) $string .= "${h}H";
+    if ($i > 0) $string .= "${i}M";
+    if ($s > 0 || $string == "PT") $string .= "${s}S";
+    if ($interval->invert == 1) $string = "-$string";
+    return $string;
+  }
+
+  function __construct($duration) {
+    if ($duration instanceof DateInterval) {
+      $this->y = $duration->y;
+      $this->m = $duration->m;
+      $this->d = $duration->d;
+      $this->h = $duration->h;
+      $this->i = $duration->i;
+      $this->s = $duration->s;
+      $this->invert = $duration->invert;
+      $this->days = $duration->days;
+    } else {
+      if (substr($duration, 0, 1) == "-") {
+        $duration = substr($duration, 1);
+        $invert = true;
+      } else {
+        $invert = false;
+      }
+      parent::__construct($duration);
+      if ($invert) $this->invert = 1;
+    }
+  }
+
+  function __toString(): string {
+    return self::to_string($this);
+  }
+}
diff --git a/src/php/time/DateTime.php b/src/php/time/DateTime.php
new file mode 100644
index 0000000..8d61dc4
--- /dev/null
+++ b/src/php/time/DateTime.php
@@ -0,0 +1,65 @@
+<?php
+namespace nur\sery\php\time;
+
+use DateTimeInterface;
+use DateTimeZone;
+use InvalidArgumentException;
+
+/**
+ * Class DateTime: une date et une heure
+ *
+ * @property-read string $year
+ * @property-read string $month
+ * @property-read string $day
+ * @property-read string $hour
+ * @property-read string $minute
+ * @property-read string $second
+ * @property-read string $timezone
+ */
+class DateTime extends \DateTime {
+  const DEFAULT_FORMAT = "d/m/Y H:i:s";
+
+  static function clone(DateTimeInterface $dateTime): self {
+    if ($dateTime instanceof static) return clone $dateTime;
+    $clone = new static();
+    $clone->setTimestamp($dateTime->getTimestamp());
+    $clone->setTimezone($dateTime->getTimezone());
+    return $clone;
+  }
+
+  function __construct($datetime="now", DateTimeZone $timezone=null) {
+    if ($datetime instanceof \DateTimeInterface) {
+      if ($timezone === null) $timezone = $datetime->getTimezone();
+      parent::__construct();
+      $this->setTimestamp($datetime->getTimestamp());
+      $this->setTimezone($timezone);
+    } else {
+      parent::__construct($datetime, $timezone);
+    }
+  }
+
+  function diff($target, $absolute=false): DateInterval {
+    return new DateInterval(parent::diff($target, $absolute));
+  }
+
+  function format($format=self::DEFAULT_FORMAT): string {
+    return \DateTime::format($format);
+  }
+
+  function __toString(): string {
+    return $this->format();
+  }
+
+  function __get($name) {
+    switch ($name) {
+    case "year": return $this->format("Y");
+    case "month": return $this->format("m");
+    case "day": return $this->format("d");
+    case "hour": return $this->format("H");
+    case "minute": return $this->format("i");
+    case "second": return $this->format("s");
+    case "timezone": return $this->format("P");
+    default: throw new InvalidArgumentException("Unknown property $name");
+    }
+  }
+}
diff --git a/src/php/time/Delay.php b/src/php/time/Delay.php
new file mode 100644
index 0000000..1df71ae
--- /dev/null
+++ b/src/php/time/Delay.php
@@ -0,0 +1,139 @@
+<?php
+namespace nur\sery\php\time;
+
+use DateTimeInterface;
+use InvalidArgumentException;
+
+/**
+ * Class Delay: une durée jusqu'à un moment destination. le moment destination
+ * est calculé à la création de l'objet en fonction du moment courant.
+ *
+ * La durée peut-être:
+ * - un nombre, qui est le nombre de secondes jusqu'au moment destination
+ * - une chaine de la forme "x[WDHMS]y" où x et y sont des nombres et la lettre
+ * est l'unité de temps: W représente une semaine, D une journée, H une heure,
+ * M une minute et S une seconde.
+ *
+ * Dans cette dernière forme, le timestamp destination est calculé en ajoutant x
+ * unités. puis l'unité inférieure est ramenée à (0 + y)
+ * par exemple,
+ * - "1D5" signifie le lendemain à 5h (+1 jour, puis ramené à 5h)
+ * - "2H0" signifie au plus deux heures plus tard
+ * - "0W5" signifie à 5 le dimanche de la semaine en cours
+ *
+ * NB: la valeur y pour l'unité S est ignorée
+ */
+class Delay {
+  /** valeurs par défaut de x et y pour les unités supportées */
+  const DEFAULTS = [
+    "w" => [0, 5],
+    "d" => [1, 5],
+    "h" => [1, 0],
+    "m" => [1, 0],
+    "s" => [1, 0],
+  ];
+
+  static function compute_dest(int $x, string $u, ?int $y, DateTime $from): array {
+    $dest = DateTime::clone($from);
+    switch ($u) {
+    case "w":
+      if ($x > 0) {
+        $x *= 7;
+        $dest->add(new \DateInterval("P${x}D"));
+      }
+      $w = 7 - intval($dest->format("w"));
+      $dest->add(new \DateInterval("P${w}D"));
+      $u = "h";
+      break;
+    case "d":
+      $dest->add(new \DateInterval("P${x}D"));
+      $u = "h";
+      break;
+    case "h":
+      $dest->add(new \DateInterval("PT${x}H"));
+      $u = "m";
+      break;
+    case "m":
+      $dest->add(new \DateInterval("PT${x}M"));
+      $u = "s";
+      break;
+    case "s":
+      $dest->add(new \DateInterval("PT${x}S"));
+      $u = null;
+      break;
+    }
+    if ($y !== null && $u !== null) {
+      $h = intval($dest->format("H"));
+      $m = intval($dest->format("i"));
+      switch ($u) {
+      case "h":
+        $dest->setTime($y, 0, 0, 0);
+        break;
+      case "m":
+        $dest->setTime($h, $y, 0, 0);
+        break;
+      case "s":
+        $dest->setTime($h, $m, $y, 0);
+        break;
+      }
+    }
+    $repr = $y !== null? "$x$y$y": "$x";
+    return [$dest, $repr];
+  }
+
+  function __construct($delay, ?DateTimeInterface $from=null) {
+    if ($from === null) $from = new DateTime();
+    if (is_int($delay)) {
+      [$dest, $repr] = self::compute_dest($delay, "s", null, $from);
+    } elseif (is_string($delay) && preg_match('/^\d+$/', $delay)) {
+      $x = intval($delay);
+      [$dest, $repr] = self::compute_dest($x, "s", null, $from);
+    } elseif (is_string($delay) && preg_match('/^(\d*)([wdhms])(\d*)$/i', $delay, $ms)) {
+      [$x, $u, $y] = [$ms[1], $ms[2], $ms[3]];
+      $u = strtolower($u);
+      $default = self::DEFAULTS[$u];
+      if ($x === "") $x = $default[0];
+      else $x = intval($x);
+      if ($y === "") $y = $default[1];
+      else $y = intval($y);
+      [$dest, $repr] = self::compute_dest($x, $u, $y, $from);
+    } else {
+      throw new InvalidArgumentException("invalid delay");
+    }
+    $this->dest = $dest;
+    $this->repr = $repr;
+  }
+
+  /** @var DateTime */
+  protected $dest;
+
+  function getDest(): DateTime {
+    return $this->dest;
+  }
+
+  /** @var string */
+  protected $repr;
+
+  function __toString(): string {
+    return $this->repr;
+  }
+
+  protected function _getDiff(?DateTimeInterface $now=null): \DateInterval {
+    if ($now === null) $now = new DateTime();
+    return $this->dest->diff($now);
+  }
+
+  /** retourner true si le délai imparti est écoulé */
+  function isElapsed(?DateTimeInterface $now=null): bool {
+    return $this->_getDiff($now)->invert == 0;
+  }
+
+  /**
+   * retourner l'intervalle entre le moment courant et la destination.
+   *
+   * l'intervalle est négatif si le délai n'est pas écoulé, positif sinon
+   */
+  function getDiff(?DateTimeInterface $now=null): DateInterval {
+    return new DateInterval($this->_getDiff($now));
+  }
+}
diff --git a/tests/php/time/DateTest.php b/tests/php/time/DateTest.php
new file mode 100644
index 0000000..a9c1a68
--- /dev/null
+++ b/tests/php/time/DateTest.php
@@ -0,0 +1,31 @@
+<?php
+namespace nur\sery\php\time;
+
+use DateTimeZone;
+use PHPUnit\Framework\TestCase;
+
+class DateTest extends TestCase {
+  protected static function dt(string $datetime): Date {
+    return new Date($datetime, new DateTimeZone("Indian/Reunion"));
+  }
+
+  function testDate() {
+    $date = self::dt("2024-04-05 09:15:23");
+
+    self::assertEquals("05/04/2024", $date->format());
+    self::assertEquals("05/04/2024", strval($date));
+    self::assertEquals("2024", $date->year);
+    self::assertEquals("04", $date->month);
+    self::assertEquals("05", $date->day);
+    self::assertEquals("00", $date->hour);
+    self::assertEquals("00", $date->minute);
+    self::assertEquals("00", $date->second);
+    self::assertEquals("+04:00", $date->timezone);
+  }
+
+  function testClone() {
+    $date = self::dt("now");
+    $clone = Date::clone($date);
+    self::assertInstanceOf(DateTime::class, $clone);
+  }
+}
diff --git a/tests/php/time/DateTimeTest.php b/tests/php/time/DateTimeTest.php
new file mode 100644
index 0000000..d2bc5f2
--- /dev/null
+++ b/tests/php/time/DateTimeTest.php
@@ -0,0 +1,33 @@
+<?php
+namespace nur\sery\php\time;
+
+use DateTimeZone;
+use nur\sery\php\time\Date;
+use nur\sery\php\time\DateTime;
+use PHPUnit\Framework\TestCase;
+
+class DateTimeTest extends TestCase {
+  protected static function dt(string $datetime): DateTime {
+    return new DateTime($datetime, new DateTimeZone("Indian/Reunion"));
+  }
+
+  function testDateTime() {
+    $date = self::dt("2024-04-05 09:15:23");
+
+    self::assertEquals("05/04/2024 09:15:23", $date->format());
+    self::assertEquals("05/04/2024 09:15:23", strval($date));
+    self::assertEquals("2024", $date->year);
+    self::assertEquals("04", $date->month);
+    self::assertEquals("05", $date->day);
+    self::assertEquals("09", $date->hour);
+    self::assertEquals("15", $date->minute);
+    self::assertEquals("23", $date->second);
+    self::assertEquals("+04:00", $date->timezone);
+  }
+
+  function testClone() {
+    $date = self::dt("now");
+    $clone = DateTime::clone($date);
+    self::assertInstanceOf(DateTime::class, $clone);
+  }
+}
diff --git a/tests/php/time/DelayTest.php b/tests/php/time/DelayTest.php
new file mode 100644
index 0000000..f2fc5cf
--- /dev/null
+++ b/tests/php/time/DelayTest.php
@@ -0,0 +1,85 @@
+<?php
+namespace nur\sery\php\time;
+
+use DateTimeZone;
+use nur\sery\php\time\DateTime;
+use nur\sery\php\time\Delay;
+use nur\t\TestCase;
+
+class DelayTest extends TestCase {
+  protected static function dt(string $datetime): DateTime {
+    return new DateTime($datetime, new DateTimeZone("Indian/Reunion"));
+  }
+
+  function testDelay() {
+    $from = self::dt("2024-04-05 09:15:23");
+
+    $delay = new Delay(10, $from);
+    self::assertEquals(self::dt("2024-04-05 09:15:33"), $delay->getDest());
+
+    $delay = new Delay("10", $from);
+    self::assertEquals(self::dt("2024-04-05 09:15:33"), $delay->getDest());
+
+    $delay = new Delay("10s", $from);
+    self::assertEquals(self::dt("2024-04-05 09:15:33"), $delay->getDest());
+
+    $delay = new Delay("s", $from);
+    self::assertEquals(self::dt("2024-04-05 09:15:24"), $delay->getDest());
+
+    $delay = new Delay("5m", $from);
+    self::assertEquals(self::dt("2024-04-05 09:20:00"), $delay->getDest());
+
+    $delay = new Delay("5m0", $from);
+    self::assertEquals(self::dt("2024-04-05 09:20:00"), $delay->getDest());
+
+    $delay = new Delay("5m2", $from);
+    self::assertEquals(self::dt("2024-04-05 09:20:02"), $delay->getDest());
+
+    $delay = new Delay("m", $from);
+    self::assertEquals(self::dt("2024-04-05 09:16:00"), $delay->getDest());
+
+    $delay = new Delay("5h", $from);
+    self::assertEquals(self::dt("2024-04-05 14:00:00"), $delay->getDest());
+
+    $delay = new Delay("5h0", $from);
+    self::assertEquals(self::dt("2024-04-05 14:00:00"), $delay->getDest());
+
+    $delay = new Delay("5h2", $from);
+    self::assertEquals(self::dt("2024-04-05 14:02:00"), $delay->getDest());
+
+    $delay = new Delay("h", $from);
+    self::assertEquals(self::dt("2024-04-05 10:00:00"), $delay->getDest());
+
+    $delay = new Delay("5d", $from);
+    self::assertEquals(self::dt("2024-04-10 05:00:00"), $delay->getDest());
+
+    $delay = new Delay("5d2", $from);
+    self::assertEquals(self::dt("2024-04-10 02:00:00"), $delay->getDest());
+
+    $delay = new Delay("5d0", $from);
+    self::assertEquals(self::dt("2024-04-10 00:00:00"), $delay->getDest());
+
+    $delay = new Delay("d", $from);
+    self::assertEquals(self::dt("2024-04-06 05:00:00"), $delay->getDest());
+
+    $delay = new Delay("2w", $from);
+    self::assertEquals(self::dt("2024-04-21 05:00:00"), $delay->getDest());
+
+    $delay = new Delay("2w2", $from);
+    self::assertEquals(self::dt("2024-04-21 02:00:00"), $delay->getDest());
+
+    $delay = new Delay("2w0", $from);
+    self::assertEquals(self::dt("2024-04-21 00:00:00"), $delay->getDest());
+
+    $delay = new Delay("w", $from);
+    self::assertEquals(self::dt("2024-04-07 05:00:00"), $delay->getDest());
+  }
+
+  function testElapsed() {
+    $delay = new Delay(5);
+    sleep(2);
+    self::assertFalse($delay->isElapsed());
+    sleep(5);
+    self::assertTrue($delay->isElapsed());
+  }
+}