feat(pm): messages anchor link (#4175)

extensions/messages/migrations/2025_01_31_000000_add_number_to_dialog_messages.php

@@ -0,0 +1,50 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Schema\Builder;
+
+return [
+    'up' => function (Builder $schema) {
+        $schema->table('dialog_messages', function (Blueprint $table) {
+            $table->unsignedBigInteger('number')->nullable()->after('content');
+        });
+
+        $numbers = [];
+
+        $schema->getConnection()
+            ->table('dialogs')
+            ->orderBy('id')
+            ->each(function (object $dialog) use ($schema, &$numbers) {
+                $numbers[$dialog->id] = 0;
+
+                $schema->getConnection()
+                    ->table('dialog_messages')
+                    ->where('dialog_id', $dialog->id)
+                    ->orderBy('id')
+                    ->each(function (object $message) use ($schema, &$numbers) {
+                        $schema->getConnection()
+                            ->table('dialog_messages')
+                            ->where('id', $message->id)
+                            ->update(['number' => ++$numbers[$message->dialog_id]]);
+                    });
+
+                unset($numbers[$dialog->id]);
+            });
+
+        $schema->table('dialog_messages', function (Blueprint $table) {
+            $table->unsignedBigInteger('number')->nullable(false)->change();
+        });
+    },
+    'down' => function (Builder $schema) {
+        $schema->table('dialog_messages', function (Blueprint $table) {
+            $table->dropColumn('number');
+        });
+    }
+];