From e994ae908634a69ee29a1af63ce0b277d8634b7a Mon Sep 17 00:00:00 2001
From: Markus Poerschke <markus@poerschke.nrw>
Date: Mon, 5 Jul 2021 22:21:25 +0200
Subject: [PATCH 1/2] Add LAST-MODIFIED property

---
 src/Domain/Entity/Event.php                    | 18 ++++++++++++++++++
 src/Presentation/Factory/EventFactory.php      |  4 ++++
 .../Presentation/Factory/EventFactoryTest.php  | 14 +++++++++++++-
 website/docs/maturity-matrix.md                |  2 +-
 4 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/Domain/Entity/Event.php b/src/Domain/Entity/Event.php
index 220d4501..13a1f835 100644
--- a/src/Domain/Entity/Event.php
+++ b/src/Domain/Entity/Event.php
@@ -28,6 +28,7 @@ class Event
     private ?Occurrence $occurrence = null;
     private ?Location $location = null;
     private ?Organizer $organizer = null;
+    private ?Timestamp $lastModified = null;
 
     /**
      * @var array<Alarm>
@@ -200,4 +201,21 @@ public function getAttachments(): array
     {
         return $this->attachments;
     }
+
+    public function getLastModified(): Timestamp
+    {
+        return $this->lastModified;
+    }
+
+    public function hasLastModified(): bool
+    {
+        return $this->lastModified !== null;
+    }
+
+    public function setLastModified(?Timestamp $lastModified): self
+    {
+        $this->lastModified = $lastModified;
+
+        return $this;
+    }
 }
diff --git a/src/Presentation/Factory/EventFactory.php b/src/Presentation/Factory/EventFactory.php
index bf2039ef..fb289e5d 100644
--- a/src/Presentation/Factory/EventFactory.php
+++ b/src/Presentation/Factory/EventFactory.php
@@ -76,6 +76,10 @@ protected function getProperties(Event $event): Generator
         yield new Property('UID', new TextValue((string) $event->getUniqueIdentifier()));
         yield new Property('DTSTAMP', new DateTimeValue($event->getTouchedAt()));
 
+        if ($event->hasLastModified()) {
+            yield new Property('LAST-MODIFIED', new DateTimeValue($event->getLastModified()));
+        }
+
         if ($event->hasSummary()) {
             yield new Property('SUMMARY', new TextValue($event->getSummary()));
         }
diff --git a/tests/Unit/Presentation/Factory/EventFactoryTest.php b/tests/Unit/Presentation/Factory/EventFactoryTest.php
index 14946ca3..4226afdf 100644
--- a/tests/Unit/Presentation/Factory/EventFactoryTest.php
+++ b/tests/Unit/Presentation/Factory/EventFactoryTest.php
@@ -44,12 +44,24 @@ public function testMinimalEvent()
             )
         );
 
-        $event = (new Event(new UniqueIdentifier('event1')))->touch($currentTime);
+        $lastModified = new Timestamp(
+            DateTimeImmutable::createFromFormat(
+                'Y-m-d H:i:s',
+                '2019-10-09 10:11:22',
+                new DateTimeZone('UTC')
+            )
+        );
+
+        $event = (new Event(new UniqueIdentifier('event1')))
+            ->touch($currentTime)
+            ->setLastModified($lastModified)
+        ;
 
         $expected = implode(ContentLine::LINE_SEPARATOR, [
             'BEGIN:VEVENT',
             'UID:event1',
             'DTSTAMP:20191110T112233Z',
+            'LAST-MODIFIED:20191009T101122Z',
             'END:VEVENT',
             '',
         ]);
diff --git a/website/docs/maturity-matrix.md b/website/docs/maturity-matrix.md
index 65efd05e..8bc58c3f 100644
--- a/website/docs/maturity-matrix.md
+++ b/website/docs/maturity-matrix.md
@@ -42,7 +42,7 @@ See [RFC 5545 section 3.6.1](https://tools.ietf.org/html/rfc5545#section-3.6.1).
 | created                     |     ✖     |
 | description                 |     ✔     |
 | geo                         |     ✔     |
-| last-mod                    |     ✖     |
+| last-mod                    |     ✔     |
 | location                    |     ✔     |
 | organizer                   |     ✔     |
 | priority                    |     ✖     |

From ba57710677ed32972ec9c4e394ab4379be977fec Mon Sep 17 00:00:00 2001
From: Markus Poerschke <markus@poerschke.nrw>
Date: Mon, 5 Jul 2021 22:26:14 +0200
Subject: [PATCH 2/2] Add LAST-MODIFIED property

---
 CHANGELOG.md                | 4 ++++
 src/Domain/Entity/Event.php | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2c08454b..7a062c32 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+-   Event LAST-MODIFIED property [#298](https://github.com/markuspoerschke/iCal/pull/298)
+
 ## [2.2.0] - 2021-05-03
 
 ### Added
diff --git a/src/Domain/Entity/Event.php b/src/Domain/Entity/Event.php
index 13a1f835..036220c3 100644
--- a/src/Domain/Entity/Event.php
+++ b/src/Domain/Entity/Event.php
@@ -204,6 +204,8 @@ public function getAttachments(): array
 
     public function getLastModified(): Timestamp
     {
+        assert($this->lastModified !== null);
+
         return $this->lastModified;
     }