Option to return formatted dates instead of PHP objects (#226)

When reading spreadsheets, Spout should be able to return formatted dates, as shown when opened with Excel for instance.
It currently only returns DateTime/DateInterval objects, making it impossible to read + write, as the Writer does not accept objects.

src/Spout/Reader/ODS/Helper/CellValueFormatter.php

@@ -34,14 +34,19 @@ class CellValueFormatter
     const XML_ATTRIBUTE_CURRENCY = 'office:currency';
     const XML_ATTRIBUTE_C = 'text:c';
 
+    /** @var bool Whether date/time values should be returned as PHP objects or be formatted as strings */
+    protected $shouldFormatDates;
+
     /** @var \Box\Spout\Common\Escaper\ODS Used to unescape XML data */
     protected $escaper;
 
     /**
-     *
+     * @param bool $shouldFormatDates Whether date/time values should be returned as PHP objects or be formatted as strings
      */
-    public function __construct()
+    public function __construct($shouldFormatDates)
     {
+        $this->shouldFormatDates = $shouldFormatDates;
+
         /** @noinspection PhpUnnecessaryFullyQualifiedNameInspection */
         $this->escaper = new \Box\Spout\Common\Escaper\ODS();
     }
@@ -122,6 +127,7 @@ class CellValueFormatter
     {
         $nodeValue = $node->getAttribute(self::XML_ATTRIBUTE_VALUE);
         $nodeIntValue = intval($nodeValue);
+        // The "==" is intentionally not a "===" because only the value matters, not the type
         $cellValue = ($nodeIntValue == $nodeValue) ? $nodeIntValue : floatval($nodeValue);
         return $cellValue;
     }
@@ -144,15 +150,27 @@ class CellValueFormatter
      * Returns the cell Date value from the given node.
      *
      * @param \DOMNode $node
-     * @return \DateTime|null The value associated with the cell or NULL if invalid date value
+     * @return \DateTime|string|null The value associated with the cell or NULL if invalid date value
      */
     protected function formatDateCellValue($node)
     {
-        try {
-            $nodeValue = $node->getAttribute(self::XML_ATTRIBUTE_DATE_VALUE);
-            return new \DateTime($nodeValue);
-        } catch (\Exception $e) {
-            return null;
+        // The XML node looks like this:
+        // <table:table-cell calcext:value-type="date" office:date-value="2016-05-19T16:39:00" office:value-type="date">
+        //   <text:p>05/19/16 04:39 PM</text:p>
+        // </table:table-cell>
+
+        if ($this->shouldFormatDates) {
+            // The date is already formatted in the "p" tag
+            $nodeWithValueAlreadyFormatted = $node->getElementsByTagName(self::XML_NODE_P)->item(0);
+            return $nodeWithValueAlreadyFormatted->nodeValue;
+        } else {
+            // otherwise, get it from the "date-value" attribute
+            try {
+                $nodeValue = $node->getAttribute(self::XML_ATTRIBUTE_DATE_VALUE);
+                return new \DateTime($nodeValue);
+            } catch (\Exception $e) {
+                return null;
+            }
         }
     }
 
@@ -160,15 +178,27 @@ class CellValueFormatter
      * Returns the cell Time value from the given node.
      *
      * @param \DOMNode $node
-     * @return \DateInterval|null The value associated with the cell or NULL if invalid time value
+     * @return \DateInterval|string|null The value associated with the cell or NULL if invalid time value
      */
     protected function formatTimeCellValue($node)
     {
-        try {
-            $nodeValue = $node->getAttribute(self::XML_ATTRIBUTE_TIME_VALUE);
-            return new \DateInterval($nodeValue);
-        } catch (\Exception $e) {
-            return null;
+        // The XML node looks like this:
+        // <table:table-cell calcext:value-type="time" office:time-value="PT13H24M00S" office:value-type="time">
+        //   <text:p>01:24:00 PM</text:p>
+        // </table:table-cell>
+
+        if ($this->shouldFormatDates) {
+            // The date is already formatted in the "p" tag
+            $nodeWithValueAlreadyFormatted = $node->getElementsByTagName(self::XML_NODE_P)->item(0);
+            return $nodeWithValueAlreadyFormatted->nodeValue;
+        } else {
+            // otherwise, get it from the "time-value" attribute
+            try {
+                $nodeValue = $node->getAttribute(self::XML_ATTRIBUTE_TIME_VALUE);
+                return new \DateInterval($nodeValue);
+            } catch (\Exception $e) {
+                return null;
+            }
         }
     }