From cc3e050304f2c88696ea23dc31ac6b7b5f11f080 Mon Sep 17 00:00:00 2001
From: Tim <git@loken.nl>
Date: Wed, 23 Apr 2025 21:27:47 +0200
Subject: [PATCH] Add compare function between snipsContents

---
 src/Controller/SnipContentController.php      |  41 +++++++
 src/Service/SnipContent/DiffTypeEnum.php      |  15 +++
 src/Service/SnipContent/MyersDiff.php         | 101 ++++++++++++++----
 .../SnipContent/SnipContentService.php        |   3 +-
 templates/content/compare.html.twig           |  38 +++++++
 templates/snip/single.html.twig               |   3 +
 6 files changed, 179 insertions(+), 22 deletions(-)
 create mode 100644 src/Controller/SnipContentController.php
 create mode 100644 src/Service/SnipContent/DiffTypeEnum.php
 create mode 100644 templates/content/compare.html.twig

diff --git a/src/Controller/SnipContentController.php b/src/Controller/SnipContentController.php
new file mode 100644
index 0000000..af57b9c
--- /dev/null
+++ b/src/Controller/SnipContentController.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace App\Controller;
+
+use App\Entity\SnipContent;
+use App\Security\Voter\SnipVoter;
+use App\Service\SnipContent\MyersDiff;
+use App\Service\SnipContent\SnipContentService;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
+
+#[Route('/content', name: 'content')]
+class SnipContentController extends AbstractController
+{
+    public function __construct(
+        private readonly SnipContentService $contentService,
+    ) {}
+
+    #[Route('/compare/{to}/{from}', name: '_compare')]
+    public function compare(SnipContent $to, ?SnipContent $from = null): Response
+    {
+        $this->denyAccessUnlessGranted(SnipVoter::VIEW, $to->getSnip());
+
+        if ($from === null) {
+            $from = $to->getParent();
+        }
+
+        $diff = MyersDiff::buildDiffLines(
+            $this->contentService->rebuildText($from),
+            $this->contentService->rebuildText($to),
+        );
+
+        dump($diff);
+
+        return $this->render('content/compare.html.twig', [
+            'snip' => $to->getSnip(),
+            'diff' => $diff,
+        ]);
+    }
+}
\ No newline at end of file
diff --git a/src/Service/SnipContent/DiffTypeEnum.php b/src/Service/SnipContent/DiffTypeEnum.php
new file mode 100644
index 0000000..cfc1abc
--- /dev/null
+++ b/src/Service/SnipContent/DiffTypeEnum.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Service\SnipContent;
+
+enum DiffTypeEnum: string
+{
+    case INSERT = 'I';
+    case DELETE = 'D';
+    case KEEP = 'K';
+
+    public function is(string $diffType): bool
+    {
+        return $this->value === $diffType;
+    }
+}
diff --git a/src/Service/SnipContent/MyersDiff.php b/src/Service/SnipContent/MyersDiff.php
index b7342f6..155d804 100644
--- a/src/Service/SnipContent/MyersDiff.php
+++ b/src/Service/SnipContent/MyersDiff.php
@@ -52,7 +52,7 @@ class MyersDiff
                     $x++;
                     $count++;
                 }
-                $solution[] = ['D', $count];
+                $solution[] = [DiffTypeEnum::DELETE->value, $count];
             }
 
             // Insertions
@@ -63,10 +63,10 @@ class MyersDiff
                     $y++;
                 }
                 $solutionKey = count($solution) - 1;
-                if ($solutionKey >= 0 && $solution[$solutionKey][0] === 'I') {
+                if ($solutionKey >= 0 && DiffTypeEnum::INSERT->is($solution[$solutionKey][0])) {
                     $solution[$solutionKey][1] = array_merge($solution[$solutionKey][1], $values);
                 } else {
-                    $solution[] = ['I', $values];
+                    $solution[] = [DiffTypeEnum::INSERT->value, $values];
                 }
             }
 
@@ -78,7 +78,7 @@ class MyersDiff
                 $count++;
             }
             if ($count > 0) {
-                $solution[] = ['K', $count];
+                $solution[] = [DiffTypeEnum::KEEP->value, $count];
             }
         }
 
@@ -88,16 +88,24 @@ class MyersDiff
     /**
      * Calculate the shortest edit sequence to convert $x into $y.
      *
-     * @param string    $textFrom - tokens (characters, words or lines)
-     * @param string    $textTo - tokens (characters, words or lines)
-     * @param ?callable $compare - comparison function for tokens. Signature is compare($x, $y):bool. If null, === is used.
+     * @param string|array $textFrom - tokens (characters, words or lines)
+     * @param string|array $textTo - tokens (characters, words or lines)
+     * @param ?callable    $compare - comparison function for tokens. Signature is compare($x, $y):bool. If null, === is used.
      *
      * @return array[] - pairs of token and edit (-1 for delete, 0 for keep, +1 for insert)
      */
-    public static function calculate(string $textFrom, string $textTo, ?callable $compare = null): array
+    public static function calculate(string|array $textFrom, string|array $textTo, ?callable $compare = null): array
     {
-        $a = self::explode($textFrom);
-        $b = self::explode($textTo);
+        if (is_string($textFrom)) {
+            $a = self::explode($textFrom);
+        } else {
+            $a = $textFrom;
+        }
+        if (is_string($textTo)) {
+            $b = self::explode($textTo);
+        } else {
+            $b = $textTo;
+        }
 
         if ($compare === null) {
             $compare = function ($x, $y) {
@@ -144,22 +152,75 @@ class MyersDiff
         $x = 0;
 
         foreach ($diff as [$op, $data]) {
-            if ($op === 'K') {
-                for ($i = 0; $i < $data; $i++) {
-                    $b[] = $a[$x++];
-                }
-            } elseif ($op === 'D') {
-                $x += $data; // skip deleted
-            } elseif ($op === 'I') {
-                foreach ($data as $v) {
-                    $b[] = $v;
-                }
+            switch ($op) {
+                case DiffTypeEnum::KEEP->value:
+                    for ($i = 0; $i < $data; $i++) {
+                        $b[] = $a[$x++];
+                    }
+                    break;
+                case DiffTypeEnum::DELETE->value:
+                    $x += $data; // skip deleted
+                    break;
+                case DiffTypeEnum::INSERT->value:
+                    foreach ($data as $v) {
+                        $b[] = $v;
+                    }
+                    break;
+                default:
+                    throw new \InvalidArgumentException('Invalid diff operation');
             }
         }
 
         return self::implode($b);
     }
 
+    public static function buildDiffLines(string $textFrom, string $textTo): array
+    {
+        $a = self::explode($textFrom);
+        $b = self::explode($textTo);
+        $diff = MyersDiff::calculate($a, $b);
+
+        $lines = [];
+        $x = 0;
+        foreach ($diff as [$op, $data]) {
+            switch ($op) {
+                case DiffTypeEnum::KEEP->value:
+                    for ($i = 0; $i < $data; $i++) {
+                        $lines[] = [
+                            'type' => 'keep',
+                            'from' => $a[$x],
+                            'to' => $a[$x],
+                        ];
+                        $x++;
+                    }
+                    break;
+                case DiffTypeEnum::DELETE->value:
+                    for ($i = 0; $i < $data; $i++) {
+                        $lines[] = [
+                            'type' => 'delete',
+                            'from' => $a[$x],
+                            'to' => '',
+                        ];
+                        $x++;
+                    }
+                    break;
+                case DiffTypeEnum::INSERT->value:
+                    foreach ($data as $v) {
+                        $lines[] = [
+                            'type' => 'insert',
+                            'from' => '',
+                            'to' => $v,
+                        ];
+                    }
+                    break;
+                default:
+                    throw new \InvalidArgumentException('Invalid diff operation');
+            }
+        }
+
+        return $lines;
+    }
+
     private static function explode(string $text): array
     {
         return explode(self::NEWLINE, $text);
diff --git a/src/Service/SnipContent/SnipContentService.php b/src/Service/SnipContent/SnipContentService.php
index 09b4ba6..a615684 100644
--- a/src/Service/SnipContent/SnipContentService.php
+++ b/src/Service/SnipContent/SnipContentService.php
@@ -41,8 +41,7 @@ readonly class SnipContentService
 
     public function getActiveText(Snip $snip): string
     {
-        $contentRepo = $this->em->getRepository(SnipContent::class);
-        return $this->rebuildText($contentRepo->find($snip->getActiveVersion()));
+        return $this->rebuildText($snip->getActiveVersion());
     }
 
     public function rebuildText(?SnipContent $snipContent): string
diff --git a/templates/content/compare.html.twig b/templates/content/compare.html.twig
new file mode 100644
index 0000000..ac00bfd
--- /dev/null
+++ b/templates/content/compare.html.twig
@@ -0,0 +1,38 @@
+{% extends 'base/single.column.html.twig' %}
+
+{% set title = 'Snip compare ' ~ snip %}
+
+{% block body %}
+    <a href="{{ path('snip_single', {snip: snip.id}) }}" class="btn btn-primary">
+        <i class="fa fa-arrow-left"></i> Back
+    </a>
+    <br><br>
+    <table class="table table-condensed table-hover">
+        <thead>
+        <tr>
+            <th>Line</th>
+            <th>Old</th>
+            <th>New</th>
+        </tr>
+        </thead>
+        <tbody>
+        {% for line in diff %}
+            <tr>
+                <td class="table-{{ line.type == 'insert' ? 'success' : (line.type == 'delete' ? 'danger' : 'info') }}">
+                    {{ line.type }}
+                </td>
+                <td>
+                    {% if line.from %}
+                        {{ line.from }}
+                    {% endif %}
+                </td>
+                <td>
+                    {% if line.to %}
+                        {{ line.to }}
+                    {% endif %}
+                </td>
+            </tr>
+        {% endfor %}
+        </tbody>
+    </table>
+{% endblock %}
\ No newline at end of file
diff --git a/templates/snip/single.html.twig b/templates/snip/single.html.twig
index 50595c8..e246951 100644
--- a/templates/snip/single.html.twig
+++ b/templates/snip/single.html.twig
@@ -26,6 +26,9 @@
     <a href="{{ path('snip_raw', {snip: snip.id}) }}" class="btn btn-danger">
         <i class="fa fa-eye"></i> Raw
     </a>
+    <a href="{{ path('content_compare', {to: snip.activeVersion.id}) }}" class="btn btn-warning">
+        <i class="fa fa-eye"></i> Compare
+    </a>
     <br><br>
     <div class="card" style="width: 100%;">
         <h4 class="card-header">