<?php

namespace moonland\phpexcel;

use yii\helpers\ArrayHelper;
use yii\base\InvalidConfigException;
use yii\base\InvalidParamException;
use yii\i18n\Formatter;

/**
 * Excel Widget for generate Excel File or for load Excel File.
 * 
 * Usage
 * -----
 * 
 * Exporting data into an excel file.
 * 
 * ~~~
 * 
 * // export data only one worksheet.
 * 
 * \moonland\phpexcel\Excel::widget([
 * 		'models' => $allModels,
 * 		'mode' => 'export', //default value as 'export'
 * 		'columns' => ['column1','column2','column3'],
 * 		//without header working, because the header will be get label from attribute label.
 * 		'header' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'],
 * ]);
 * 
 * \moonland\phpexcel\Excel::export([
 * 		'models' => $allModels,
 * 		'columns' => ['column1','column2','column3'],
 * 		//without header working, because the header will be get label from attribute label.
 * 		'header' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'],
 * ]);
 * 
 * // export data with multiple worksheet.
 * 
 * \moonland\phpexcel\Excel::widget([
 * 		'isMultipleSheet' => true,
 * 		'models' => [
 * 			'sheet1' => $allModels1, 
 * 			'sheet2' => $allModels2, 
 * 			'sheet3' => $allModels3
 * 		],
 * 		'mode' => 'export', //default value as 'export'
 * 		'columns' => [
 * 			'sheet1' => ['column1','column2','column3'],
 * 			'sheet2' => ['column1','column2','column3'],
 * 			'sheet3' => ['column1','column2','column3']
 * 		],
 * 		//without header working, because the header will be get label from attribute label.
 * 		'header' => [
 * 			'sheet1' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'], 
 * 			'sheet2' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'], 
 * 			'sheet3' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3']
 * 		],
 * ]);
 * 
 * \moonland\phpexcel\Excel::export([
 * 		'isMultipleSheet' => true,
 * 		'models' => [
 * 			'sheet1' => $allModels1, 
 * 			'sheet2' => $allModels2, 
 * 			'sheet3' => $allModels3
 * 		],
 * 		'columns' => [
 * 			'sheet1' => ['column1','column2','column3'],
 * 			'sheet2' => ['column1','column2','column3'],
 * 			'sheet3' => ['column1','column2','column3']
 * 		],
 * 		//without header working, because the header will be get label from attribute label.
 * 		'header' => [
 * 			'sheet1' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'], 
 * 			'sheet2' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'], 
 * 			'sheet3' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3']
 * 		],
 * ]);
 * 
 * ~~~
 * 
 * New Feature for exporting data, you can use this if you familiar yii gridview. 
 * That is same with gridview data column.
 * Columns in array mode valid params are 'attribute', 'header', 'format', 'value', and footer (TODO).
 * Columns in string mode valid layout are 'attribute:format:header:footer(TODO)'.
 * 
 * ~~~
 * 
 * \moonland\phpexcel\Excel::export([
 *  	'models' => Post::find()->all(),
 *     	'columns' => [
 *     		'author.name:text:Author Name',
 *     		[
 *     				'attribute' => 'content',
 *     				'header' => 'Content Post',
 *     				'format' => 'text',
 *     				'value' => function($model) {
 *     					return ExampleClass::removeText('example', $model->content);
 *     				},
 *     		],
 *     		'like_it:text:Reader like this content',
 *     		'created_at:datetime',
 *     		[
 *     				'attribute' => 'updated_at',
 *     				'format' => 'date',
 *     		],
 *     	],
 *     	'headers' => [
 *     		'created_at' => 'Date Created Content',
 * 		],
 * ]);
 * 
 * ~~~
 * 
 * 
 * Import file excel and return into an array.
 * 
 * ~~~
 * 
 * $data = \moonland\phpexcel\Excel::import($fileName, $config); // $config is an optional
 * 
 * $data = \moonland\phpexcel\Excel::widget([
 * 		'mode' => 'import',
 * 		'fileName' => $fileName,
 * 		'setFirstRecordAsKeys' => true, // if you want to set the keys of record column with first record, if it not set, the header with use the alphabet column on excel.
 * 		'setIndexSheetByName' => true, // set this if your excel data with multiple worksheet, the index of array will be set with the sheet name. If this not set, the index will use numeric.
 * 		'getOnlySheet' => 'sheet1', // you can set this property if you want to get the specified sheet from the excel data with multiple worksheet.
 * ]);
 * 
 * $data = \moonland\phpexcel\Excel::import($fileName, [
 * 		'setFirstRecordAsKeys' => true, // if you want to set the keys of record column with first record, if it not set, the header with use the alphabet column on excel.
 * 		'setIndexSheetByName' => true, // set this if your excel data with multiple worksheet, the index of array will be set with the sheet name. If this not set, the index will use numeric.
 * 		'getOnlySheet' => 'sheet1', // you can set this property if you want to get the specified sheet from the excel data with multiple worksheet.
 *	]);
 *
 * // import data with multiple file.
 * 
 * $data = \moonland\phpexcel\Excel::widget([
 * 		'mode' => 'import',
 * 		'fileName' => [
 * 			'file1' => $fileName1,
 * 			'file2' => $fileName2,
 * 			'file3' => $fileName3,
 * 		],
 * 		'setFirstRecordAsKeys' => true, // if you want to set the keys of record column with first record, if it not set, the header with use the alphabet column on excel.
 * 		'setIndexSheetByName' => true, // set this if your excel data with multiple worksheet, the index of array will be set with the sheet name. If this not set, the index will use numeric.
 * 		'getOnlySheet' => 'sheet1', // you can set this property if you want to get the specified sheet from the excel data with multiple worksheet.
 * ]);
 * 
 * $data = \moonland\phpexcel\Excel::import([
 * 			'file1' => $fileName1,
 * 			'file2' => $fileName2,
 * 			'file3' => $fileName3,
 * 		], [
 * 		'setFirstRecordAsKeys' => true, // if you want to set the keys of record column with first record, if it not set, the header with use the alphabet column on excel.
 * 		'setIndexSheetByName' => true, // set this if your excel data with multiple worksheet, the index of array will be set with the sheet name. If this not set, the index will use numeric.
 * 		'getOnlySheet' => 'sheet1', // you can set this property if you want to get the specified sheet from the excel data with multiple worksheet.
 *	]);
 *
 * ~~~
 * 
 * Result example from the code on the top :
 * 
 * ~~~
 * 
 * // only one sheet or specified sheet.
 * 
 * Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2));
 * 
 * // data with multiple worksheet
 * 
 * Array([Sheet1] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2)),
 * [Sheet2] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2)));
 * 
 * // data with multiple file and specified sheet or only one worksheet
 * 
 * Array([file1] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2)),
 * [file2] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2)));
 * 
 * // data with multiple file and multiple worksheet
 * 
 * Array([file1] => Array([Sheet1] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2)),
 * [Sheet2] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2))),
 * [file2] => Array([Sheet1] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2)),
 * [Sheet2] => Array([0] => Array([name] => Anam, [email] => moh.khoirul.anaam@gmail.com, [framework interest] => Yii2), 
 * [1] => Array([name] => Example, [email] => example@moonlandsoft.com, [framework interest] => Yii2))));
 * 
 * ~~~
 * 
 * @property string $mode is an export mode or import mode. valid value are 'export' and 'import'
 * @property boolean $isMultipleSheet for set the export excel with multiple sheet.
 * @property array $properties for set property on the excel object.
 * @property array $models Model object or DataProvider object with much data.
 * @property array $columns to get the attributes from the model, this valid value only the exist attribute on the model. 
 * If this is not set, then all attribute of the model will be set as columns.
 * @property array $headers to set the header column on first line. Set this if want to custom header. 
 * If not set, the header will get attributes label of model attributes.
 * @property string|array $fileName is a name for file name to export or import. Multiple file name only use for import mode, not work if you use the export mode.
 * @property string $savePath is a directory to save the file or you can blank this to set the file as attachment.
 * @property string $format for excel to export. Valid value are 'Excel5','Excel2007','Excel2003XML','00Calc','Gnumeric'.
 * @property boolean $setFirstTitle to set the title column on the first line. The columns will have a header on the first line.
 * @property boolean $asAttachment to set the file excel to download mode.
 * @property boolean $setFirstRecordAsKeys to set the first record on excel file to a keys of array per line. 
 * If you want to set the keys of record column with first record, if it not set, the header with use the alphabet column on excel.
 * @property boolean $setIndexSheetByName to set the sheet index by sheet name or array result if the sheet not only one
 * @property string $getOnlySheet is a sheet name to getting the data. This is only get the sheet with same name.
 * @property array|Formatter $formatter the formatter used to format model attribute values into displayable texts.
 * This can be either an instance of [[Formatter]] or an configuration array for creating the [[Formatter]]
 * instance. If this property is not set, the "formatter" application component will be used.
 * 
 * @author Moh Khoirul Anam <moh.khoirul.anaam@gmail.com>
 * @copyright 2014
 * @since 1
 */
class Excel extends \yii\base\Widget
{
	/**
	 * @var string mode is an export mode or import mode. valid value are 'export' and 'import'.
	 */
	public $mode = 'export';
	/**
	 * @var boolean for set the export excel with multiple sheet.
	 */
	public $isMultipleSheet = false;
	/**
	 * @var array properties for set property on the excel object.
	 */
	public $properties;
	/**
	 * @var Model object or DataProvider object with much data.
	 */
	public $models;
	/**
	 * @var array columns to get the attributes from the model, this valid value only the exist attribute on the model.
	 * If this is not set, then all attribute of the model will be set as columns.
	 */
	public $columns = [];
	/**
	 * @var array header to set the header column on first line. Set this if want to custom header. 
	 * If not set, the header will get attributes label of model attributes.
	 */
	public $headers = [];
	/**
	 * @var string|array name for file name to export or save.
	 */
	public $fileName;
	/**
	 * @var string save path is a directory to save the file or you can blank this to set the file as attachment.
	 */
	public $savePath;
	/**
	 * @var string format for excel to export. Valid value are 'Excel5','Excel2007','Excel2003XML','00Calc','Gnumeric'.
	 */
	public $format;
	/**
	 * @var boolean to set the title column on the first line.
	 */
	public $setFirstTitle = true;
	/**
	 * @var boolean to set the file excel to download mode.
	 */
	public $asAttachment = true;
	/**
	 * @var boolean to set the first record on excel file to a keys of array per line. 
	 * If you want to set the keys of record column with first record, if it not set, the header with use the alphabet column on excel.
	 */
	public $setFirstRecordAsKeys = true;
	/**
	 * @var boolean to set the sheet index by sheet name or array result if the sheet not only one.
	 */
	public $setIndexSheetByName = false;
	/**
	 * @var string sheetname to getting. This is only get the sheet with same name.
	 */
	public $getOnlySheet;
	/**
	 * @var boolean to set the import data will return as array.
	 */
	public $asArray;
	/**
	 * @var array to unread record by index number.
	 */
	public $leaveRecordByIndex = [];
	/**
	 * @var array to read record by index, other will leave.
	 */
	public $getOnlyRecordByIndex = [];
	/**
	 * @var array|Formatter the formatter used to format model attribute values into displayable texts.
	 * This can be either an instance of [[Formatter]] or an configuration array for creating the [[Formatter]]
	 * instance. If this property is not set, the "formatter" application component will be used.
	 */
	public $formatter;
	
	/**
	 * (non-PHPdoc)
	 * @see \yii\base\Object::init()
	 */
	public function init()
	{
		parent::init();
		if ($this->formatter == null) {
			$this->formatter = \Yii::$app->getFormatter();
		} elseif (is_array($this->formatter)) {
			$this->formatter = \Yii::createObject($this->formatter);
		}
		if (!$this->formatter instanceof Formatter) {
			throw new InvalidConfigException('The "formatter" property must be either a Format object or a configuration array.');
		}
	}
	
	/**
	 * Setting data from models
	 */
	public function executeColumns(&$activeSheet = null, $models, $columns = [], $headers = [])
	{
		if ($activeSheet == null) {
			$activeSheet = $this->activeSheet;
		}
		$hasHeader = false;
		$row = 1;
		$char = 26;
		foreach ($models as $model) {
			if (empty($columns)) {
				$columns = $model->attributes();
			}
			if ($this->setFirstTitle && !$hasHeader) {
				$isPlus = false;
				$colplus = 0;
				$colnum = 1;
				foreach ($columns as $key=>$column) {
					$col = '';
					if ($colnum > $char) {
						$colplus += 1;
						$colnum = 1;
						$isPlus = true;
					}
					if ($isPlus) {
						$col .= chr(64+$colplus);
					}
					$col .= chr(64+$colnum);
					$header = '';
					if (is_array($column)) {
						if (isset($column['header'])) {
							$header = $column['header'];
						} elseif (isset($column['attribute']) && isset($headers[$column['attribute']])) {
							$header = $headers[$column['attribute']];
						} elseif (isset($column['attribute'])) {
							$header = $model->getAttributeLabel($column['attribute']);
						}
					} else {
						$header = $model->getAttributeLabel($column);
					}
					$activeSheet->setCellValue($col.$row,$header);
					$colnum++;
				}
				$hasHeader=true;
				$row++;
			}
			$isPlus = false;
			$colplus = 0;
			$colnum = 1;
			foreach ($columns as $key=>$column) {
				$col = '';
				if ($colnum > $char) {
					$colplus++;
					$colnum = 1;
					$isPlus = true;
				}
				if ($isPlus) {
					$col .= chr(64+$colplus);
				}
				$col .= chr(64+$colnum);
				if (is_array($column)) {
					$column_value = $this->executeGetColumnData($model, $column);
				} else {
					$column_value = $this->executeGetColumnData($model, ['attribute' => $column]);
				}
				$activeSheet->setCellValue($col.$row,$column_value);
				$colnum++;
			}
			$row++;
		}
	}
	
	/**
	 * Setting label or keys on every record if setFirstRecordAsKeys is true.
	 * @param array $sheetData
	 * @return multitype:multitype:array
	 */
	public function executeArrayLabel($sheetData)
	{
		$keys = ArrayHelper::remove($sheetData, '1');
		
		$new_data = [];
		
		foreach ($sheetData as $values)
		{
			$new_data[] = array_combine($keys, $values);
		}
		
		return $new_data;
	}
	
	/**
	 * Leave record with same index number.
	 * @param array $sheetData
	 * @param array $index
	 * @return array
	 */
	public function executeLeaveRecords($sheetData = [], $index = [])
	{
		foreach ($sheetData as $key => $data)
		{
			if (in_array($key, $index))
			{
				unset($sheetData[$key]);
			}
		}
		return $sheetData;
	}
	
	/**
	 * Read record with same index number.
	 * @param array $sheetData
	 * @param array $index
	 * @return array
	 */
	public function executeGetOnlyRecords($sheetData = [], $index = [])
	{
		foreach ($sheetData as $key => $data)
		{
			if (!in_array($key, $index))
			{
				unset($sheetData[$key]);
			}
		}
		return $sheetData;
	}
	
	/**
	 * Getting column value.
	 * @param Model $model
	 * @param array $params
	 * @return Ambigous <NULL, string, mixed>
	 */
	public function executeGetColumnData($model, $params = [])
	{
		$value = null;
		if (isset($params['value']) && $params['value'] !== null) {
			if (is_string($params['value'])) {
				$value = ArrayHelper::getValue($model, $params['value']);
			} else {
				$value = call_user_func($params['value'], $model, $this);
			}
		} elseif (isset($params['attribute']) && $params['attribute'] !== null) {
			$value = ArrayHelper::getValue($model, $params['attribute']);
		}
		
		if (isset($params['format']) && $params['format'] != null)
			$value = $this->formatter()->format($value, $params['format']);
		
		return $value;
	}
	
	/**
	 * Populating columns for checking the column is string or array. if is string this will be checking have a formatter or header.
	 * @param array $columns
	 * @throws InvalidParamException
	 * @return multitype:multitype:array
	 */
	public function populateColumns($columns = [])
	{
		$_columns = [];
		foreach ($columns as $key => $value)
		{
			if (is_string($value))
			{
				$value_log = explode(':', $value);
				$_columns[$key] = ['attribute' => $value_log[0]];
				
				if (isset($value_log[1]) && $value_log[1] !== null) {
					$_columns[$key]['format'] = $value_log[1];
				}
				
				if (isset($value_log[2]) && $value_log[2] !== null) {
					$_columns[$key]['header'] = $value_log[2];
				}
			} elseif (is_array($value)) {
				if (!isset($value['attribute']) && !isset($value['value'])) {
					throw new InvalidParamException('Attribute or Value must be defined.');
				}
				$_columns[$key] = $value;
			}
		}
		
		return $_columns;
	}
	
	/**
	 * Formatter for i18n.
	 * @return Formatter
	 */
	public function formatter()
	{
		if (!isset($this->formatter))
			$this->formatter = \Yii::$app->getFormatter();
		
		return $this->formatter;
	}
	
	/**
	 * Setting header to download generated file xls
	 */
	public function setHeaders()
	{
		header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
		header('Content-Disposition: attachment;filename="' . $this->getFileName() .'"');
		header('Cache-Control: max-age=0');
	}
	
	/**
	 * Getting the file name of exporting xls file
	 * @return string
	 */
	public function getFileName()
	{
		$fileName = 'exports.xls';
		if (isset($this->fileName)) {
			$fileName = $this->fileName;
			if (strpos($fileName, '.xls') === false)
				$fileName .= '.xls';
		}
		return $fileName;
	}
	
	/**
	 * Setting properties for excel file
	 * @param PHPExcel $objectExcel
	 * @param array $properties
	 */
	public function properties(&$objectExcel, $properties = [])
	{
		foreach ($properties as $key => $value)
		{
			$keyname = "set" . ucfirst($key);
			$objectExcel->getProperties()->{$keyname}($value);
		}
	}
	
	/**
	 * saving the xls file to download or to path
	 */
	public function writeFile($sheet)
	{
		if (!isset($this->format))
			$this->format = 'Excel2007';
		$objectwriter = \PHPExcel_IOFactory::createWriter($sheet, $this->format);
		$path = 'php://output';
		if (isset($this->savePath) && $this->savePath != null) {
			$path = $this->savePath . '/' . $this->getFileName();
		}
		$objectwriter->save($path);
		exit();
	}
	
	/**
	 * reading the xls file
	 */
	public function readFile($fileName)
	{
		if (!isset($this->format))
			$this->format = \PHPExcel_IOFactory::identify($fileName);
		$objectreader = \PHPExcel_IOFactory::createReader($this->format);
		$objectPhpExcel = $objectreader->load($fileName);
		
		$sheetCount = $objectPhpExcel->getSheetCount();
		
		$sheetDatas = [];
		
		if ($sheetCount > 1) {
			foreach ($objectPhpExcel->getSheetNames() as $sheetIndex => $sheetName) {
				$objectPhpExcel->setActiveSheetIndexByName($sheetName);
				$indexed = $this->setIndexSheetByName==true ? $sheetName : $sheetIndex;
				$sheetDatas[$indexed] = $objectPhpExcel->getActiveSheet()->toArray(null, true, true, true);
				if ($this->setFirstRecordAsKeys) {
					$sheetDatas[$indexed] = $this->executeArrayLabel($sheetDatas[$indexed]);
				}
				if (!empty($this->getOnlyRecordByIndex) && isset($this->getOnlyRecordByIndex[$indexed]) && is_array($this->getOnlyRecordByIndex[$indexed])) {
					$sheetDatas = $this->executeGetOnlyRecords($sheetDatas, $this->getOnlyRecordByIndex[$indexed]);
				}
				if (!empty($this->leaveRecordByIndex) && isset($this->leaveRecordByIndex[$indexed]) && is_array($this->leaveRecordByIndex[$indexed])) {
					$sheetDatas[$indexed] = $this->executeLeaveRecords($sheetDatas[$indexed], $this->leaveRecordByIndex[$indexed]);
				}
			}
			if (isset($this->getOnlySheet) && $this->getOnlySheet != null) {
				$indexed = $this->setIndexSheetByName==true ? $this->getOnlySheet : $objectPhpExcel->getIndex($objectPhpExcel->getSheetByName($this->getOnlySheet));
				return $sheetDatas[$indexed];
			}
		} else {
			$sheetDatas = $objectPhpExcel->getActiveSheet()->toArray(null, true, true, true);
			if ($this->setFirstRecordAsKeys) {
				$sheetDatas = $this->executeArrayLabel($sheetDatas);
			}
			if (!empty($this->getOnlyRecordByIndex)) {
				$sheetDatas = $this->executeGetOnlyRecords($sheetDatas, $this->getOnlyRecordByIndex);
			}
			if (!empty($this->leaveRecordByIndex)) {
				$sheetDatas = $this->executeLeaveRecords($sheetDatas, $this->leaveRecordByIndex);
			}
		}
		
		return $sheetDatas;
	}
	
	/**
	 * (non-PHPdoc)
	 * @see \yii\base\Widget::run()
	 */
	public function run()
	{
		if ($this->mode == 'export') 
		{
	    	$sheet = new \PHPExcel();
	    	
	    	if (!isset($this->models))
	    		throw new InvalidConfigException('Config models must be set');
	    	
	    	if (isset($this->properties))
	    	{
	    		$this->properties($sheet, $this->properties);
	    	}
	    	
	    	if ($this->isMultipleSheet) {
	    		$index = 0;
	    		$worksheet = [];
	    		foreach ($this->models as $title => $models) {
	    			$sheet->createSheet($index);
	    			$sheet->getSheet($index)->setTitle($title);
	    			$worksheet[$index] = $sheet->getSheet($index);
	    			$columns = isset($this->columns[$title]) ? $this->columns[$title] : [];
	    			$headers = isset($this->headers[$title]) ? $this->headers[$title] : [];
	    			$this->executeColumns($worksheet[$index], $models, $this->populateColumns($columns), $headers);
	    			$index++;
	    		}
	    	} else {
	    		$worksheet = $sheet->getActiveSheet();
	    		$this->executeColumns($worksheet, $this->models, isset($this->columns) ? $this->populateColumns($this->columns) : [], isset($this->headers) ? $this->headers : []);
	    	}
	    	
	    	if ($this->asAttachment) {
	    		$this->setHeaders();
	    	}
	    	$this->writeFile($sheet);
		} 
		elseif ($this->mode == 'import') 
		{
			if (is_array($this->fileName)) {
				$datas = [];
				foreach ($this->fileName as $key => $filename) {
					$datas[$key] = $this->readFile($filename);
				}
				return $datas;
			} else {
				return $this->readFile($this->fileName);
			}
		}
	}
	
	/**
	 * Exporting data into an excel file.
	 * 
	 * ~~~
	 * 
	 * \moonland\phpexcel\Excel::export([
	 * 		'models' => $allModels,
	 * 		'columns' => ['column1','column2','column3'],
	 * 		//without header working, because the header will be get label from attribute label.
	 * 		'header' => ['column1' => 'Header Column 1','column2' => 'Header Column 2', 'column3' => 'Header Column 3'],
	 * ]);
	 * 
	 * ~~~
	 * 
	 * New Feature for exporting data, you can use this if you familiar yii gridview. 
	 * That is same with gridview data column.
	 * Columns in array mode valid params are 'attribute', 'header', 'format', 'value', and footer (TODO).
	 * Columns in string mode valid layout are 'attribute:format:header:footer(TODO)'.
	 * 
	 * ~~~
	 * 
	 * \moonland\phpexcel\Excel::export([
	 *  	'models' => Post::find()->all(),
	 *     	'columns' => [
	 *     		'author.name:text:Author Name',
	 *     		[
	 *     				'attribute' => 'content',
	 *     				'header' => 'Content Post',
	 *     				'format' => 'text',
	 *     				'value' => function($model) {
	 *     					return ExampleClass::removeText('example', $model->content);
	 *     				},
	 *     		],
	 *     		'like_it:text:Reader like this content',
	 *     		'created_at:datetime',
	 *     		[
	 *     				'attribute' => 'updated_at',
	 *     				'format' => 'date',
	 *     		],
	 *     	],
	 *     	'headers' => [
	 *     		'created_at' => 'Date Created Content',
	 * 		],
	 * ]);
	 * 
	 * ~~~
	 * 
	 * @param array $config
	 * @return string
	 */
	public static function export($config=[])
	{
		$config = ArrayHelper::merge(['mode' => 'export'], $config);
		return self::widget($config);
	}
	
	/**
	 * Import file excel and return into an array.
	 * 
	 * ~~~
	 * 
	 * $data = \moonland\phpexcel\Excel::import($fileName, ['setFirstRecordAsKeys' => true]);
	 * 
	 * ~~~
	 * 
	 * @param string!array $fileName to load.
	 * @param array $config is a more configuration.
	 * @return string
	 */
	public static function import($fileName, $config=[])
	{
		$config = ArrayHelper::merge(['mode' => 'import', 'fileName' => $fileName, 'asArray' => true], $config);
		return self::widget($config);
	}
	
	/**
	 * @param array $config
	 * @return string
	 */
	public static function widget($config = [])
	{
		if ($config['mode'] == 'import' && !isset($config['asArray'])) {
			$config['asArray'] = true;
		}
		
		if (isset($config['asArray']) && $config['asArray']==true)
		{
	        $config['class'] = get_called_class();
	        $widget = \Yii::createObject($config);
	        return $widget->run();
		} else {
			return parent::widget($config);
		}
	}
}