Create a customized myers diff based system for snip content

src/Service/SnipContent/SnipContentService.php

@@ -8,49 +8,96 @@ use Doctrine\ORM\EntityManagerInterface;
 
 readonly class SnipContentService
 {
+
     public function __construct(
-        private Snip                   $snip,
         private EntityManagerInterface $em,
     ) {}
 
-    public function update(string $snipContents): void
+    public function update(Snip $snip, string $snipContents): void
     {
-        if ($this->snip->getActiveVersion()?->getText() === $snipContents) {
+        $parentContent = $snip->getActiveVersion();
+        if ($this->rebuildText($parentContent) === $snipContents) {
             return;
         }
+
         // Create new snipContent entity with previous one as parent
         $content = new SnipContent();
         $content
             ->setText($snipContents)
-            ->setSnip($this->snip)
+            ->setSnip($snip)
         ;
-        if ($this->snip->getActiveVersion() !== null) {
-            $content->setParent($this->snip->getActiveVersion());
+        if ($parentContent !== null) {
+            $content->setParent($parentContent);
+            $this->contentToRelative($parentContent);
         }
 
         $this->em->persist($content);
         $this->em->flush();
 
-        $this->snip->setActiveVersion($content);
-        $this->em->persist($this->snip);
+        $snip->setActiveVersion($content);
+        $this->em->persist($snip);
         $this->em->flush();
     }
 
-    // Shortcut to get the active text
-    public function getActiveText(): string
+    public function getActiveText(Snip $snip): string
     {
         $contentRepo = $this->em->getRepository(SnipContent::class);
-        return $contentRepo->find($this->snip->getActiveVersion())->getText();
+        return $this->rebuildText($contentRepo->find($snip->getActiveVersion()));
     }
 
-    public function setVersion(SnipContent $version): void
+    public function rebuildText(SnipContent $snipContent): string
     {
-        $this->snip->setActiveVersion($version);
-        $this->em->persist($this->snip);
+        if ($snipContent->getText()) {
+            return $snipContent->getText();
+        }
+
+        $parentContent = $snipContent->getParent();
+        if ($parentContent === null && $snipContent->getDiff() === null) {
+            return '---Something went very wrong, cant rebuild the text---';
+        }
+
+        return MyersDiff::rebuildBFromCompact(
+            $this->rebuildText($parentContent), $snipContent->getDiff()
+        );
+    }
+
+    public function setVersion(Snip $snip, SnipContent $version): void
+    {
+        $activeVersion = $snip->getActiveVersion();
+        $this->contentToAbsolute($version);
+        $this->contentToRelative($activeVersion);
+
+        $snip->setActiveVersion($version);
+        $this->em->persist($snip);
         $this->em->flush();
     }
 
-    public function delete(): void
+    public function contentToRelative(SnipContent $content): void
+    {
+        if ($content->getText() === null || $content->getParent() === null) {
+            return;
+        }
+        $contentText = $content->getText();
+        $parentText = $this->rebuildText($content->getParent());
+        $diff = MyersDiff::calculate($parentText, $contentText);
+        $content->setDiff($diff);
+        $content->setText(null);
+        $this->em->persist($content);
+        $this->em->flush();
+    }
+
+    public function contentToAbsolute(SnipContent $content): void
+    {
+        if ($content->getDiff() === null) {
+            return;
+        }
+        $content->setText($this->rebuildText($content));
+        $content->setDiff(null);
+        $this->em->persist($content);
+        $this->em->flush();
+    }
+
+    public function delete(Snip $snip): void
     {
         // Cleanup the versions
     }