<?php

namespace App\Helpers;

/**
 * Description of VideoStream
 *
 * @author Rana
 * @link http://codesamplez.com/programming/php-html5-video-streaming-tutorial
 **/
class VideoStream
{
	private $path = '';
	private $stream = '';
	private $buffer = 102400;
	private $start = -1;
	private $end = -1;
	private $size = 0;

	function __construct($filePath)
	{
		$this->path = $filePath;
	}

	/**
	 * Open stream
	 **/
	private function open()
	{
		if (! ($this->stream = fopen($this->path,'rb')) ) {
			die('Could not open stream for reading');
		}
	}

	/**
	 * Set proper header to serve the video content
	 **/
	private function setHeader()
	{
		ob_get_clean();
		header('Content-Type: video/mp4');
		header('Cache-Control: max-age=2592000, public');
		header('Expires: '.gmdate('D, d M Y H:i:s',time()+2592000) . ' GMT');
		header('Last-Modified: '.gmdate('D, d M Y H:i:s',@filemtime($this->path)) . ' GMT' );
		$this->start = 0;
		$this->size = filesize($this->path);
		$this->end = $this->size - 1;
		header('Accept-Ranges: 0-'.$this->end);

		if (isset($_SERVER['HTTP_RANGE'])) {

			$c_start = $this->start;
			$c_end = $this->end;

			list(,$range) = explode('=',$_SERVER['HTTP_RANGE'],2);
			if (strpos($range,',') !== false) {
				header('HTTP/1.1 416 Requested Range Not Satisfiable');
				header("Content-Range: bytes $this->start-$this->end/$this->size");
				exit;
			}
			if ($range == '-') {
				$c_start = $this->size - substr($range,1);
			}else{
				$range = explode('-',$range);
				$c_start = $range[0];

				$c_end = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $c_end;
			}
			$c_end = ($c_end > $this->end) ? $this->end : $c_end;
			if ($c_start > $c_end || $c_start > $this->size - 1 || $c_end >= $this->size) {
				header('HTTP/1.1 416 Requested Range Not Satisfiable');
				header("Content-Range: bytes $this->start-$this->end/$this->size");
				exit;
			}
			$this->start = $c_start;
			$this->end = $c_end;
			$length = $this->end - $this->start + 1;
			fseek($this->stream,$this->start);
			header('HTTP/1.1 206 Partial Content');
			header("Content-Length: ".$length);
			header("Content-Range: bytes $this->start-$this->end/".$this->size);
		}
		else
		{
			header("Content-Length: ".$this->size);
		}

	}

	/**
	 * close curretly opened stream
	 **/
	private function end()
	{
		fclose($this->stream);
		exit;
	}

	/**
	 * perform the streaming of calculated range
	 **/
	private function stream()
	{
		$i = $this->start;
		set_time_limit(0);
		while(!feof($this->stream) && $i <= $this->end) {
			$bytesToRead = $this->buffer;
			if (($i+$bytesToRead) > $this->end) {
				$bytesToRead = $this->end - $i + 1;
			}
			$data = fread($this->stream,$bytesToRead);
			echo $data;
			flush();
			$i += $bytesToRead;
		}
	}

	/**
	 * Start streaming video content
	 **/
	function start()
	{
		$this->open();
		$this->setHeader();
		$this->stream();
		$this->end();
	}
}