<?php if ( ! defined('BASEPATH')) exit('No se permite el acceso directo al script');
class ExportXLS {

	private $filename;	//Filename which the excel file will be returned as
	private $headerArray;	// Array which contains header information
	private $bodyArray;	// Array with the spreadsheet body
	private $rowNo = 0;	// Keep track of the row numbers


	#Class constructor
	function ExportXLS($filename='') {
		$this->filename = $filename;
	}


	/*
	-------------------------
	START OF PUBLIC FUNCTIONS
	-------------------------
	*/

	public function addHeader($header) {
	#Accepts an array or var which gets added to the top of the spreadsheet as a header.

		if(is_array($header)) {
			$this->headerArray[] = $header;
		}
		else
		{
			$this->headerArray[][0] = $header;
		}
	}

	public function addRow($row) {
	#Accepts an array or var which gets added to the spreadsheet body

		if(is_array($row)) {
			#check for multi dim array
			if(is_array($row[0])) {
				foreach($row as $key=>$array) {
					$this->bodyArray[] = $array;
				}
			}
			else
			{
				$this->bodyArray[] = $row;
			}
		}
		else
		{
			$this->bodyArray[][0] = $row;
		}

	}

	public function returnSheet() {
	# returns the spreadsheet as a variable

		#build the xls
		return $this->buildXLS();
	}

	public function sendFile() {

		#build the xls
		$xls = $this->buildXLS();

		#send headers
		header("Pragma: public");
		header("Expires: 0");
		header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
		header("Content-Type: application/force-download");
		header("Content-Type: application/octet-stream");
		header("Content-Type: application/download");
		header("Content-Disposition: attachment;filename=".$this->filename);
		header("Content-Transfer-Encoding: binary ");

		echo $xls;

		exit;
	}


	/*
	--------------------------
	START OF PRIVATE FUNCTIONS
	--------------------------
	*/

	private function buildXLS() {
	# build and return the xls

		#Excel BOF
		$xls = pack("ssssss", 0x809, 0x8, 0x0, 0x10, 0x0, 0x0);

		#build headers
		if(is_array($this->headerArray)) {
			$xls .= $this->build($this->headerArray);
		}

		#build body
		if(is_array($this->bodyArray)) {
			$xls .= $this->build($this->bodyArray);
		}

		$xls .= pack("ss", 0x0A, 0x00);

		return $xls;
	}

	private function build($array) {
	#build and return the headers
	$build=null;
		foreach($array as $key=>$row) {
			$colNo = 0;
			foreach($row as $key2=>$field) {
				if(is_numeric($field)) {
					$build .= $this->numFormat($this->rowNo, $colNo, $field);
				}
				else
				{
					$build .= $this->textFormat($this->rowNo, $colNo, $field);
				}

				$colNo++;
			}
			$this->rowNo++;
		}

		return $build;
	}

	private function textFormat($row, $col, $data) {
	# format and return the field as a header
		$data = utf8_decode($data);
		$length = strlen($data);
		$field = pack("ssssss", 0x204, 8 + $length, $row, $col, 0x0, $length);
		$field .= $data;

		return $field;
	}


	private function numFormat($row, $col, $data) {
	# format and return the field as a header
    		$field = pack("sssss", 0x203, 14, $row, $col, 0x0);
    		$field .= pack("d", $data);

		return $field;
	}
}
?>