Refactory Writer Styles to match new code organization (#433)

Decomposed old StyleHelper into StyleManager, StyleRegistry and StyleMerger.

src/Spout/Writer/XLSX/Manager/Style/StyleRegistry.php

@@ -0,0 +1,158 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Manager\Style;
+
+use Box\Spout\Writer\Common\Entity\Style\Style;
+
+/**
+ * Class StyleRegistry
+ * Registry for all used styles
+ *
+ * @package Box\Spout\Writer\XLSX\Manager\Style
+ */
+class StyleRegistry extends \Box\Spout\Writer\Common\Manager\Style\StyleRegistry
+{
+    /**
+     * @var array
+     */
+    protected $registeredFills = [];
+
+    /**
+     * @var array [STYLE_ID] => [FILL_ID] maps a style to a fill declaration
+     */
+    protected $styleIdToFillMappingTable = [];
+
+    /**
+     * Excel preserves two default fills with index 0 and 1
+     * Since Excel is the dominant vendor - we play along here
+     *
+     * @var int The fill index counter for custom fills.
+     */
+    protected $fillIndex = 2;
+
+    /**
+     * @var array
+     */
+    protected $registeredBorders = [];
+
+    /**
+     * @var array [STYLE_ID] => [BORDER_ID] maps a style to a border declaration
+     */
+    protected $styleIdToBorderMappingTable = [];
+
+    /**
+     * XLSX specific operations on the registered styles
+     *
+     * @param Style $style
+     * @return Style
+     */
+    public function registerStyle(Style $style)
+    {
+        $registeredStyle = parent::registerStyle($style);
+        $this->registerFill($registeredStyle);
+        $this->registerBorder($registeredStyle);
+
+        return $registeredStyle;
+    }
+
+    /**
+     * Register a fill definition
+     *
+     * @param Style $style
+     */
+    private function registerFill(Style $style)
+    {
+        $styleId = $style->getId();
+
+        // Currently - only solid backgrounds are supported
+        // so $backgroundColor is a scalar value (RGB Color)
+        $backgroundColor = $style->getBackgroundColor();
+
+        if ($backgroundColor) {
+            $isBackgroundColorRegistered = isset($this->registeredFills[$backgroundColor]);
+
+            // We need to track the already registered background definitions
+            if ($isBackgroundColorRegistered) {
+                $registeredStyleId = $this->registeredFills[$backgroundColor];
+                $registeredFillId = $this->styleIdToFillMappingTable[$registeredStyleId];
+                $this->styleIdToFillMappingTable[$styleId] = $registeredFillId;
+            } else {
+                $this->registeredFills[$backgroundColor] = $styleId;
+                $this->styleIdToFillMappingTable[$styleId] = $this->fillIndex++;
+            }
+
+        } else {
+            // The fillId maps a style to a fill declaration
+            // When there is no background color definition - we default to 0
+            $this->styleIdToFillMappingTable[$styleId] = 0;
+        }
+    }
+
+    /**
+     * @param int $styleId
+     * @return int|null Fill ID associated to the given style ID
+     */
+    public function getFillIdForStyleId($styleId)
+    {
+        return (isset($this->styleIdToFillMappingTable[$styleId])) ?
+            $this->styleIdToFillMappingTable[$styleId] :
+            null;
+    }
+
+    /**
+     * Register a border definition
+     *
+     * @param Style $style
+     */
+    private function registerBorder(Style $style)
+    {
+        $styleId = $style->getId();
+
+        if ($style->shouldApplyBorder()) {
+            $border = $style->getBorder();
+            $serializedBorder = serialize($border);
+
+            $isBorderAlreadyRegistered = isset($this->registeredBorders[$serializedBorder]);
+
+            if ($isBorderAlreadyRegistered) {
+                $registeredStyleId = $this->registeredBorders[$serializedBorder];
+                $registeredBorderId = $this->styleIdToBorderMappingTable[$registeredStyleId];
+                $this->styleIdToBorderMappingTable[$styleId] = $registeredBorderId;
+            } else {
+                $this->registeredBorders[$serializedBorder] = $styleId;
+                $this->styleIdToBorderMappingTable[$styleId] = count($this->registeredBorders);
+            }
+
+        } else {
+            // If no border should be applied - the mapping is the default border: 0
+            $this->styleIdToBorderMappingTable[$styleId] = 0;
+        }
+    }
+
+    /**
+     * @param int $styleId
+     * @return int|null Fill ID associated to the given style ID
+     */
+    public function getBorderIdForStyleId($styleId)
+    {
+        return (isset($this->styleIdToBorderMappingTable[$styleId])) ?
+            $this->styleIdToBorderMappingTable[$styleId] :
+            null;
+    }
+
+    /**
+     * @return array
+     */
+    public function getRegisteredFills()
+    {
+        return $this->registeredFills;
+    }
+
+    /**
+     * @return array
+     */
+    public function getRegisteredBorders()
+    {
+        return $this->registeredBorders;
+    }
+}