<?php
/**
 * VideoDownload class.
 */

namespace Alltube;

use Chain\Chain;
use Symfony\Component\Process\Process;

/**
 * Extract info about videos.
 */
class VideoDownload
{
    /**
     * Config instance.
     *
     * @var Config
     */
    private $config;

    /**
     * VideoDownload constructor.
     *
     * @throws \Exception If youtube-dl is missing
     * @throws \Exception If Python is missing
     */
    public function __construct(Config $config = null)
    {
        if (isset($config)) {
            $this->config = $config;
        } else {
            $this->config = Config::getInstance();
        }
        if (!is_file($this->config->youtubedl)) {
            throw new \Exception("Can't find youtube-dl at ".$this->config->youtubedl);
        } elseif (!$this->checkCommand([$this->config->python, '--version'])) {
            throw new \Exception("Can't find Python at ".$this->config->python);
        }
    }

    /**
     * Return a youtube-dl process with the specified arguments
     *
     * @param string[] $arguments Arguments
     *
     * @return Process
     */
    private function getProcess(array $arguments)
    {
        return new Process(
            array_merge(
                [$this->config->python, $this->config->youtubedl],
                $this->config->params,
                $arguments
            )
        );
    }

    /**
     * List all extractors.
     *
     * @return string[] Extractors
     * */
    public function listExtractors()
    {
        return explode("\n", trim($this->getProp(null, null, 'list-extractors')));
    }

    /**
     * Get a property from youtube-dl.
     *
     * @param string $url      URL to parse
     * @param string $format   Format
     * @param string $prop     Property
     * @param string $password Video password
     *
     * @throws PasswordException If the video is protected by a password and no password was specified
     * @throws \Exception        If the password is wrong
     * @throws \Exception        If youtube-dl returns an error
     *
     * @return string
     */
    private function getProp($url, $format = null, $prop = 'dump-json', $password = null)
    {
        $arguments = [
            '--'.$prop,
            $url
        ];
        if (isset($format)) {
            $arguments[] = '-f '.$format;
        }
        if (isset($password)) {
            $arguments[] = '--video-password';
            $arguments[] = $password;
        }

        $process = $this->getProcess($arguments);
        //This is needed by the openload extractor because it runs PhantomJS
        $process->setEnv(['QT_QPA_PLATFORM'=>'offscreen']);
        $process->run();
        if (!$process->isSuccessful()) {
            $errorOutput = trim($process->getErrorOutput());
            if ($errorOutput == 'ERROR: This video is protected by a password, use the --video-password option') {
                throw new PasswordException($errorOutput);
            } elseif (substr($errorOutput, 0, 21) == 'ERROR: Wrong password') {
                throw new \Exception('Wrong password');
            } else {
                throw new \Exception($errorOutput);
            }
        } else {
            return trim($process->getOutput());
        }
    }

    /**
     * Get all information about a video.
     *
     * @param string $url      URL of page
     * @param string $format   Format to use for the video
     * @param string $password Video password
     *
     * @return object Decoded JSON
     * */
    public function getJSON($url, $format = null, $password = null)
    {
        return json_decode($this->getProp($url, $format, 'dump-single-json', $password));
    }

    /**
     * Get URL of video from URL of page.
     *
     * It generally returns only one URL.
     * But it can return two URLs when multiple formats are specified
     * (eg. bestvideo+bestaudio).
     *
     * @param string $url      URL of page
     * @param string $format   Format to use for the video
     * @param string $password Video password
     *
     * @return string[] URLs of video
     * */
    public function getURL($url, $format = null, $password = null)
    {
        return explode("\n", $this->getProp($url, $format, 'get-url', $password));
    }

    /**
     * Get filename of video file from URL of page.
     *
     * @param string $url      URL of page
     * @param string $format   Format to use for the video
     * @param string $password Video password
     *
     * @return string Filename of extracted video
     * */
    public function getFilename($url, $format = null, $password = null)
    {
        return trim($this->getProp($url, $format, 'get-filename', $password));
    }

    /**
     * Get filename of video with the specified extension.
     *
     * @param string $extension New file extension
     * @param string $url       URL of page
     * @param string $format    Format to use for the video
     * @param string $password  Video password
     *
     * @return string Filename of extracted video with specified extension
     */
    public function getFileNameWithExtension($extension, $url, $format = null, $password = null)
    {
        return html_entity_decode(
            pathinfo(
                $this->getFilename($url, $format, $password),
                PATHINFO_FILENAME
            ).'.'.$extension,
            ENT_COMPAT,
            'ISO-8859-1'
        );
    }

    /**
     * Get filename of audio from URL of page.
     *
     * @param string $url      URL of page
     * @param string $format   Format to use for the video
     * @param string $password Video password
     *
     * @return string Filename of converted audio file
     * */
    public function getAudioFilename($url, $format = null, $password = null)
    {
        return $this->getFileNameWithExtension('mp3', $url, $format, $password);
    }

    /**
     * Return arguments used to run rtmp for a specific video.
     *
     * @param object $video Video object returned by youtube-dl
     *
     * @return array
     */
    private function getRtmpProcessArguments(\stdClass $video)
    {
        $arguments = [
            $this->config->rtmpdump,
            '-q',
        ];
        foreach ([
            'url' => 'rtmp',
            'webpage_url' => 'pageUrl',
            'player_url' => 'swfVfy',
            'flash_version' => 'flashVer',
            'play_path' => 'playpath',
            'app' => 'app',
        ] as $property => $option) {
            if (isset($video->{$property})) {
                $arguments[] = '--'.$option;
                $arguments[] =  $video->{$property};
            }
        }

        return $arguments;
    }

    /**
     * Get a process that runs rtmp in order to download a video.
     *
     * @param object $video Video object returned by youtube-dl
     *
     * @throws \Exception If rtmpdump is missing
     *
     * @return \Symfony\Component\Process\Process Process
     */
    private function getRtmpProcess(\stdClass $video)
    {
        if (!$this->checkCommand([$this->config->rtmpdump, '--help'])) {
            throw(new \Exception('Can\'t find rtmpdump'));
        }
        $arguments = $this->getRtmpProcessArguments($video);
        if (isset($video->rtmp_conn)) {
            foreach ($video->rtmp_conn as $conn) {
                $arguments[] = '--conn';
                $arguments[] =  $conn;
            }
        }

        return new Process($arguments);
    }

    /**
     * Check if a command runs successfully.
     *
     * @param array $command Command and arguments
     *
     * @return bool False if the command returns an error, true otherwise
     */
    private function checkCommand(array $command)
    {
        $process = new Process($command);
        $process->run();

        return $process->isSuccessful();
    }

    /**
     * Get a process that runs avconv in order to convert a video to MP3.
     *
     * @param string $url URL of the video file
     *
     * @throws \Exception If avconv/ffmpeg is missing
     *
     * @return \Symfony\Component\Process\Process Process
     */
    private function getAvconvMp3Process($url)
    {
        if (!$this->checkCommand([$this->config->avconv, '-version'])) {
            throw(new \Exception('Can\'t find avconv or ffmpeg'));
        }

        $arguments = [
            $this->config->avconv,
            '-v', $this->config->avconvVerbosity,
            '-i', $url,
            '-f', 'mp3',
            '-b:a', $this->config->audioBitrate.'k',
            '-vn',
            'pipe:1',
        ];
        if ($url != '-') {
            //Vimeo needs a correct user-agent
            $arguments[] = '-user_agent';
            $arguments[] = $this->getProp(null, null, 'dump-user-agent');
        }

        return new Process($arguments);
    }

    /**
     * Get audio stream of converted video.
     *
     * @param string $url      URL of page
     * @param string $format   Format to use for the video
     * @param string $password Video password
     *
     * @throws \Exception If your try to convert and M3U8 video
     * @throws \Exception If the popen stream was not created correctly
     *
     * @return resource popen stream
     */
    public function getAudioStream($url, $format, $password = null)
    {
        $video = $this->getJSON($url, $format, $password);
        if (in_array($video->protocol, ['m3u8', 'm3u8_native'])) {
            throw(new \Exception('Conversion of M3U8 files is not supported.'));
        }

        if (parse_url($video->url, PHP_URL_SCHEME) == 'rtmp') {
            $process = $this->getRtmpProcess($video);
            $chain = new Chain($process);
            $chain->pipe($this->getAvconvMp3Process('-'));

            $stream = popen($chain->getProcess()->getCommandLine(), 'r');
        } else {
            $avconvProc = $this->getAvconvMp3Process($video->url);

            $stream = popen($avconvProc->getCommandLine(), 'r');
        }

        if (!is_resource($stream)) {
            throw new \Exception('Could not open popen stream.');
        }

        return $stream;
    }

    /**
     * Get video stream from an M3U playlist.
     *
     * @param \stdClass $video Video object returned by getJSON
     *
     * @throws \Exception If avconv/ffmpeg is missing
     * @throws \Exception If the popen stream was not created correctly
     *
     * @return resource popen stream
     */
    public function getM3uStream(\stdClass $video)
    {
        if (!$this->checkCommand([$this->config->avconv, '-version'])) {
            throw(new \Exception('Can\'t find avconv or ffmpeg'));
        }

        $process = new Process(
            [
                $this->config->avconv,
                '-v', 'quiet',
                '-i', $video->url,
                '-f', $video->ext,
                '-c', 'copy',
                '-bsf:a', 'aac_adtstoasc',
                '-movflags', 'frag_keyframe+empty_moov',
                'pipe:1',
            ]
        );

        $stream = popen($process->getCommandLine(), 'r');
        if (!is_resource($stream)) {
            throw new \Exception('Could not open popen stream.');
        }

        return $stream;
    }

    /**
     * Get an avconv stream to remux audio and video.
     *
     * @param array $urls URLs of the video ($urls[0]) and audio ($urls[1]) files
     *
     * @throws \Exception If the popen stream was not created correctly
     *
     * @return resource popen stream
     */
    public function getRemuxStream(array $urls)
    {
        $process = new Process(
            [
                $this->config->avconv,
                '-v', 'quiet',
                '-i', $urls[0],
                '-i', $urls[1],
                '-c', 'copy',
                '-map', '0:v:0 ',
                '-map', '1:a:0',
                '-f', 'matroska',
                'pipe:1',
            ]
        );

        $stream = popen($process->getCommandLine(), 'r');
        if (!is_resource($stream)) {
            throw new \Exception('Could not open popen stream.');
        }

        return $stream;
    }

    /**
     * Get video stream from an RTMP video.
     *
     * @param \stdClass $video Video object returned by getJSON
     *
     * @throws \Exception If the popen stream was not created correctly
     *
     * @return resource popen stream
     */
    public function getRtmpStream(\stdClass $video)
    {
        $stream = popen($this->getRtmpProcess($video)->getCommandLine(), 'r');
        if (!is_resource($stream)) {
            throw new \Exception('Could not open popen stream.');
        }

        return $stream;
    }

    /**
     * Get a Tar stream containing every video in the playlist piped through the server.
     *
     * @param object $video  Video object returned by youtube-dl
     * @param string $format Requested format
     *
     * @throws \Exception If the popen stream was not created correctly
     *
     * @return resource
     */
    public function getPlaylistArchiveStream(\stdClass $video, $format)
    {
        $playlistItems = [];
        foreach ($video->entries as $entry) {
            $playlistItems[] = urlencode($entry->url);
        }
        $stream = fopen('playlist://'.implode(';', $playlistItems).'/'.$format, 'r');
        if (!is_resource($stream)) {
            throw new \Exception('Could not fopen popen stream.');
        }

        return $stream;
    }
}