Vtt2Srt.php

<?php
/*
 * Copyright (C) 2015 Leda
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
namespace ledat;


class Vtt2Srt
{
    private $input_file;
    private $output_file;
    public function __construct($input_file, $output_file)
    {
        $this->input_file = $input_file;
        $this->output_file = $output_file;
    }
    public function run()
    {
        $contents = file_get_contents($this->input_file);
        if ($contents === false) {
            $message = "Error: Failed to read '{$this->input_file}'.";
            throw new Exception($message);
        }
        $output = $this->convert($contents);
        $result = file_put_contents($this->output_file, $output);
        if ($result === false) {
            $message = "Error: Failed to write to '{$this->output_file}'.";
            throw new Exception($message);
        }
        return 1;
    }
    private function convert($contents)
    {
        $lines = $this->split($contents);
        array_shift($lines); // removes the WEBVTT header
        $output = '';
        $i = 0;
        foreach ($lines as $line) {
            /*
             * at last version subtitle numbers are not working
             * as you can see that way is trustful than older
             *
             *
             * */
            $pattern1 = '#(\d{2}):(\d{2}):(\d{2})\.(\d{3})#'; // '01:52:52.554'
            $pattern2 = '#(\d{2}):(\d{2})\.(\d{3})#'; // '00:08.301'
            $m1 = preg_match($pattern1, $line);
            if (is_numeric($m1) && $m1 > 0) {
                $i++;
                $output .= $i;
                $output .= PHP_EOL;
                $line = preg_replace($pattern1, '$1:$2:$3,$4' , $line);
            }
            else {
                $m2 = preg_match($pattern2, $line);
                if (is_numeric($m2) && $m2 > 0) {
                    $i++;
                    $output .= $i;
                    $output .= PHP_EOL;
                    $line = preg_replace($pattern2, '00:$1:$2,$3', $line);
                }
            }

            $output .= $line . PHP_EOL;
        }
        return $output;
    }
    private function split($contents)
    {
        $lines = explode("\n", $contents);
        if (count($lines) === 1) {
            $lines = explode("\r\n", $contents);
            if (count($lines) === 1) {
                $lines = explode("\r", $contents);
            }
        }
        return $lines;
    }
}