Add registerConverter()

README.md

@@ -170,6 +170,14 @@ Basically what your implementation should be able to do, is convert subtitle fil
 Best example is to look how [SrtConverter.php](https://github.com/mantas783/subtitle-converter/blob/master/src/code/Converters/SrtConverter.php) is implemented.  
 And this is example of [.srt file](https://github.com/mantas783/subtitle-converter/blob/master/tests/files/srt.srt).
 
+## Registering your converter
+
+```php
+Subtitles::registerConverter(FakeDocxConverter::class, 'docx_fake', 'docx', 'Fake docx converter');
+```
+
+You can add a new converter or replace the existing one if the format name is the same (the second parameter).
+
 ### "Internal Format" 
 
 "Internal Format" is just a PHP array. It is used internally in library to be able to convert between different formats.

src/Subtitles.php

@@ -181,6 +181,20 @@ public static function getFormat($string)
         }
     }
 
+    public static function registerConverter($class, $string_format, $extension, $name)
+    {
+        // unset class if the name of format is the same
+        foreach (self::$formats as $k => $format) {
+            if ($format['format'] === $string_format) {
+                unset(self::$formats[$k]);
+            }
+        }
+        unset($format);
+
+        // add at the beginning
+        array_unshift(self::$formats, ['extension' => $extension, 'format' => $string_format, 'name' => $name, 'class' => $class]);
+    }
+
     public function getInternalFormat()
     {
         return $this->internal_format;

tests/PublicInterfaceTest.php

@@ -8,6 +8,7 @@
 use PHPUnit\Framework\TestCase;
 use Done\Subtitles\Subtitles;
 use Helpers\AdditionalAssertionsTrait;
+use Tests\Stubs\FakeDocxConverter;
 
 class PublicInterfaceTest extends TestCase
 {
@@ -360,4 +361,25 @@ public function testNotASubtitleFormatThrowsException()
         $srt_path = './tests/files/slick.bin';
         Subtitles::getFormat(file_get_contents($srt_path));
     }
+
+    public function testRegisterConverter()
+    {
+        // replacing the class
+        $initial_format_count = count(Subtitles::$formats);
+        Subtitles::registerConverter(FakeDocxConverter::class, 'docx', 'docx', 'Fake docx converter');
+        $after_format_count = count(Subtitles::$formats);
+        Subtitles::registerConverter(FakeDocxConverter::class, 'docx_fake', 'docx', 'Fake docx converter');
+        $final_format_count = count(Subtitles::$formats);
+        $this->assertEquals($initial_format_count, $after_format_count); // replaces with the same name (count the same)
+        $this->assertEquals($initial_format_count + 1, $final_format_count); // adds new
+
+        // from format
+        $actual_internal_format = Subtitles::loadFromString('fake_docx')->getInternalFormat();
+        $expected_internal_format = [['start' => 22, 'end' => 33, 'lines' => ['fake']]];
+        $this->assertInternalFormatsEqual($expected_internal_format, $actual_internal_format);
+
+        // to format
+        $actual = (new Subtitles)->add(1, 2, 'a')->content('docx');
+        $this->assertEquals('fake docx text', $actual);
+    }
 }

tests/Stubs/FakeDocxConverter.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Tests\Stubs;
+
+use Done\Subtitles\Code\Converters\ConverterContract;
+use Done\Subtitles\Code\Helpers;
+
+class FakeDocxConverter implements ConverterContract
+{
+    public function canParseFileContent($file_content, $original_file_content)
+    {
+        return Helpers::strContains($file_content, 'fake_docx');
+    }
+
+    public function fileContentToInternalFormat($file_content, $original_file_content)
+    {
+        return [[
+            'start' => 22,
+            'end' => 33,
+            'lines' => ['fake'],
+        ]];
+    }
+
+    public function internalFormatToFileContent(array $internal_format, array $options)
+    {
+        return 'fake docx text';
+    }
+}