refactor(EventList): simplify sorting logic with a dedicated comparator

Author: OzzyCzech

src/EventsList.php

@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace om;
 
@@ -23,12 +24,7 @@ public function getArrayCopy(): array {
 	 * Return sorted EventList (the newest dates are first)
 	 */
 	public function sorted(): EventsList {
-		$this->uasort(static function ($a, $b): int {
-			if ($a['DTSTART'] === $b['DTSTART']) {
-				return 0;
-			}
-			return ($a['DTSTART'] < $b['DTSTART']) ? -1 : 1;
-		});
+		$this->uasort($this->comparator(true));
 
 		return $this;
 	}
@@ -37,14 +33,59 @@ public function sorted(): EventsList {
 	 * Return reversed sorted EventList (the oldest dates are first)
 	 */
 	public function reversed(): EventsList {
-		$this->uasort(static function ($a, $b): int {
-			if ($a['DTSTART'] === $b['DTSTART']) {
+		$this->uasort($this->comparator(false));
+
+		return $this;
+	}
+
+	/**
+	 * Return a comparator callable for DTSTART values.
+	 * @param bool $ascending When true, sorts ascending (older first) like the original implementation; false inverts order.
+	 */
+	private function comparator(bool $ascending): callable {
+		return function ($a, $b) use ($ascending): int {
+			$ad = $a['DTSTART'] ?? null;
+			$bd = $b['DTSTART'] ?? null;
+
+			// both equal (including both null)
+			if ($ad === $bd) {
 				return 0;
 			}
-			return ($a['DTSTART'] > $b['DTSTART']) ? -1 : 1;
-		});
 
-		return $this;
+			// decide ordering for nulls: nulls sort last
+			if ($ad === null) {
+				return 1;
+			}
+			if ($bd === null) {
+				return -1;
+			}
+
+			$at = $this->dtTimestamp($ad);
+			$bt = $this->dtTimestamp($bd);
+
+			if ($at === $bt) {
+				return 0;
+			}
+
+			if ($ascending) {
+				return ($at < $bt) ? -1 : 1;
+			}
+			return ($at > $bt) ? -1 : 1;
+		};
+	}
+
+	/**
+	 * Normalize a DTSTART value to an integer timestamp for stable comparisons.
+	 */
+	private function dtTimestamp(mixed $value): int {
+		if ($value instanceof \DateTimeInterface) {
+			return $value->getTimestamp();
+		}
+		if (is_int($value) || is_float($value) || is_numeric($value)) {
+			return (int) $value;
+		}
+		$ts = strtotime((string) $value);
+		return $ts === false ? 0 : $ts;
 	}
 
 }