Refactor writers for better DI (#427)

This commit is a big refactor that improves the code organization.
It focuses on how dependencies are injected into the different classes. This is now done via some factories.

Also, the code is now built around entities (data model that only exposes getters and setters), managers (used to manage an entity) and helpers (used by the managers to perform some specific tasks).

The refactoring is not fully complete, as some dependencies are still hidden...

src/Spout/Writer/Common/Helper/FileSystemWithRootFolderHelperInterface.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Box\Spout\Writer\Common\Helper;
+
+use \Box\Spout\Common\Helper\FileSystemHelperInterface;
+
+/**
+ * Class FileSystemHelperInterface
+ * This interface describes helper functions to help with the file system operations
+ * like files/folders creation & deletion
+ *
+ * @package Box\Spout\Writer\Common\Helper
+ */
+interface FileSystemWithRootFolderHelperInterface extends FileSystemHelperInterface
+{
+    /**
+     * Creates all the folders needed to create a spreadsheet, as well as the files that won't change.
+     *
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create at least one of the base folders
+     */
+    public function createBaseFilesAndFolders();
+
+    /**
+     * @return string
+     */
+    public function getRootFolder();
+}

src/Spout/Writer/Common/Helper/StyleHelperAbstract.php

@@ -3,12 +3,12 @@
 namespace Box\Spout\Writer\Common\Helper;
 
 /**
- * Class AbstractStyleHelper
+ * Class StyleHelperAbstract
  * This class provides helper functions to manage styles
  *
  * @package Box\Spout\Writer\Common\Helper
  */
-abstract class AbstractStyleHelper
+abstract class StyleHelperAbstract implements StyleHelperInterface
 {
     /** @var array [SERIALIZED_STYLE] => [STYLE_ID] mapping table, keeping track of the registered styles */
     protected $serializedStyleToStyleIdMappingTable = [];

src/Spout/Writer/Common/Helper/StyleHelperInterface.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace Box\Spout\Writer\Common\Helper;
+
+/**
+ * Interface StyleHelperInterface
+ *
+ * @package Box\Spout\Writer\Common\Helper
+ */
+interface StyleHelperInterface
+{
+    /**
+     * Registers the given style as a used style.
+     * Duplicate styles won't be registered more than once.
+     *
+     * @param \Box\Spout\Writer\Style\Style $style The style to be registered
+     * @return \Box\Spout\Writer\Style\Style The registered style, updated with an internal ID.
+     */
+    public function registerStyle($style);
+
+    /**
+     * Apply additional styles if the given row needs it.
+     * Typically, set "wrap text" if a cell contains a new line.
+     *
+     * @param \Box\Spout\Writer\Style\Style $style The original style
+     * @param array $dataRow The row the style will be applied to
+     * @return \Box\Spout\Writer\Style\Style The updated style
+     */
+    public function applyExtraStylesIfNeeded($style, $dataRow);
+}