Add merge

src/BaseCompiler.php

@@ -10,7 +10,14 @@ use Log;
 
 abstract class BaseCompiler implements Responsable
 {
-    protected File $file;
+    public function __construct(protected ?File $file = null)
+    {
+    }
+
+    public static function fromFile(string $file): static
+    {
+        return new static(new File($file, false));
+    }
 
     public function compile(Document $document): self
     {
@@ -41,6 +48,32 @@ abstract class BaseCompiler implements Responsable
         return $this;
     }
 
+    /**
+     * @param array<int, Documents> $documents
+     */
+    public function merge(array $documents): self
+    {
+        $outfile = '/tmp/' . Str::uuid()->toString() . '.pdf';
+        $paths = array_map(fn ($document) => static::compile($document)->getPath(), $documents);
+        $command = collect([
+            'pdfjam --nup 1x1 --outfile ' . $outfile,
+            ...array_map(fn ($path) => escapeshellarg($path), $paths),
+        ])->implode(' ');
+
+        exec($command, $output, $returnVar);
+
+        foreach ($paths as $path) {
+            @unlink($path);
+        }
+
+        if (0 !== $returnVar) {
+            Log::error('Merging failed', ['output' => $output]);
+            throw (new CompilerException('Compilation failed.'))->setOutput($output);
+        }
+
+        return static::fromFile($outfile);
+    }
+
     public function storeAs(string $directory, string $name, string $disk): string
     {
         $contents = $this->file->getContent();