<?php

$DEBUG = false;
$NEED_TRANSLATION = false;


/**
 * Implements the functions required by Audio Station/DSAudio.
 *
 * @author Ludy Su (https://github.com/LudySu/Synology-LrcPlugin)
 * @see https://global.download.synology.com/download/Document/DeveloperGuide/AS_Guide.pdf
 */
class LudysuNetEaseLrc {
    private $LUCKY_PREFIX = "@@@";

    /**
     * Searches for a lyric with the artist and title, and returns the result list.
     */
    public function getLyricsList($artist, $title, $info) {
        $artist = trim($artist);
        $title = trim($title);
        if ($this->isNullOrEmptyString($title)) {
            return 0;
        }

        $response = $this->search($title);
        if ($this->isNullOrEmptyString($response)) {
            return 0;
        }

        $json = json_decode($response, true);
        $songArray = $json['result']['songs'];
        $foundArray = array();

        if(count($songArray) == 0) {
            return 0;
        }

        // Try to find the titles that match exactly
        $exactMatchArray = array();
        $partialMatchArray = array();
        foreach ($songArray as $song) {
            if (strtolower($title) === strtolower($song['name'])) {
                array_push($exactMatchArray, $song);
            } else if (strpos($song['name'], $title) || strpos($title, $song['name'])) {
                array_push($partialMatchArray, $song);
            }
        }

        if (count($exactMatchArray) != 0) {
            $songArray = $exactMatchArray;
        } else if (count($partialMatchArray != 0)) {
            $songArray = $partialMatchArray;
        }

        // Try to find the artists that match exactly
        $artistMatchArray = array();
        foreach ($songArray as $song) {
            $elem = array(
                'id' => $song['id'],
                'artist' => $song['artists'][0]["name"],
                'title' => $song['name'],
                'alt' => $song['alias'][0] . "; Album: " . $song['album']['name']
            );
            array_push($foundArray, $elem);

            // Match artist
            // TODO artist in title like feat.
            foreach ($song['artists'] as $item) {
                if (strtolower($item['name']) === strtolower($artist)) {
                    $elem['artist'] = $item['name'];
                    array_push($artistMatchArray, $elem);
                    break;
                }
            }
        }

        if (count($artistMatchArray) > 0) {
            $foundArray = $artistMatchArray;
        }

        // It's not easy for user to select the best match, so randomize the first match so that next time a new one will be returned
        $info->addTrackInfoToList($artist, $title,
            $this->LUCKY_PREFIX . $foundArray[rand(0, count($foundArray) - 1)]['id'], // Audio Statio will deduplicate, so add a special prefix
            "I'm feeling lucky. Random result of the best matches.");
        foreach ($foundArray as $song) {
            // add artist, title, id, lrc preview (or additional comment)
            $info->addTrackInfoToList($song['artist'], $song['title'], $song['id'], $song['id'] . "; " . $song['alt']);
        }

        return count($foundArray) + 1;
    }

    /**
     * Downloads a file with the specific ID
     */
    public function getLyrics($id, $info) {
        if (substr($id, 0, strlen($this->LUCKY_PREFIX)) === $this->LUCKY_PREFIX) {
            $id = substr($id, strlen($this->LUCKY_PREFIX), strlen($id));
        }

        //TODO combine translated lrc
        $lrc = $this->downloadLyric($id);
        if ($this->isNullOrEmptyString($lrc)) {
            printf("download lyrics from server failed\n");
            return FALSE;
        }

        $info->addLyrics($lrc, $id);

        return true;
    }

    private static function search($word) {
        $params = array(
            's' => $word,
            'offset' => '0', 'limit' => '20',
            'total' => true,
            'type' => '1', //搜索单曲(1)，歌手(100)，专辑(10)，歌单(1000)，用户(1002)
        );

        $headers = array(
            'Connection: close', 'Content-Type: application/x-www-form-urlencoded',
            'Host: music.163.com', 'Cookie: appver=1.5.0.75771;');

        $curl = curl_init();
        curl_setopt_array($curl, array(
            CURLOPT_URL => "http://music.163.com/api/search/pc",
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => http_build_query($params),
            // CURLOPT_REFERER => "http://music.163.com/",
            // CURLOPT_HTTPHEADER => $headers,
        ));

        $output = curl_exec($curl);
        curl_close($curl);

        return $output;
    }

    /**
     * Gets all lyrics, apart from original one, translated and karaoke versions will also be returned if available.
     */
    private function downloadLyric($music_id) {
        // lv = original version; tv = translated version; kv = karaoke version, rarely available. Set value to 0 if don't want
        $url = "http://music.163.com/api/song/lyric?os=pc&id=" . $music_id . "&lv=-1&kv=0&tv=-1";
        $response = $this->download($url);
        if ($this->isNullOrEmptyString($response)) {
            return NULL;
        }

        $json = json_decode($response, true);
        return $json['lrc']['lyric'];
    }

    // Function for basic field validation (present and neither empty nor only white space
    private static function isNullOrEmptyString($question){
        return (!isset($question) || trim($question)==='');
    }

    private static function download($url) {
        $header[] = "Cookie: appver=1.5.0.75771;";
        $curl = curl_init();
        curl_setopt_array($curl, array(
            CURLOPT_URL => $url,
            // CURLOPT_HTTPHEADER => $header,
            CURLOPT_RETURNTRANSFER => true,
            // CURLOPT_BINARYTRANSFER => true,
            // CURLOPT_REFERER => "http://music.163.com/",
        ));
        $output = curl_exec($curl);
        curl_close($curl);
        return $output;
    }
}


////////////////////////// Debug ////////////////////////////////////

if ($DEBUG == true) {
   class TestObj {
        private $items;

        function __construct() {
            $this->items = array();
        }

        public function addLyrics($lyric, $id) {
            printf("\n");
            printf("song id: %s\n", $id);
            printf("\n");
            printf("== lyric ==\n");
            printf("%s\n", $lyric);
            printf("** END of lyric **\n\n");
        }

        public function addTrackInfoToList($artist, $title, $id, $prefix) {
            printf("\n");
            printf("song id: %s\n", $id);
            printf("artist [%s]\n", $artist);
            printf("title [%s]\n", $title);
            printf("prefix [%s]\n", $prefix);
            printf("\n");

            array_push($this->items, array(
                'artist' => $artist,
                'title'  => $title,
                'id'     => $id
            ));
        }

        function getItems() {
            return $this->items;
        }

        function getFirstItem() {
            if (count($this->items) > 0) {
                return $this->items[0];
            } else {
                return NULL;
            }
        }
    }

    /**
     * Main
     */
    $artist = " lisa";
    $title = "catch the moment ";
    echo "Trying to find lyrics for ['$title'] by artist ['$artist'] ...</br>";

    $testObj = new TestObj();
    $downloader = (new ReflectionClass("LudysuNetEaseLrc"))->newInstance();
    $count = $downloader->getLyricsList($artist, $title, $testObj);
    if ($count > 0) {
        $item = $testObj->getFirstItem();

        if (array_key_exists('id', $item)) {
            $downloader->getLyrics($item['id'], $testObj);
        } else {
            echo "\nno id to query lyric\n";
        }
    } else {
        echo " ****************************\n";
        echo " *** Failed to find lyric ***\n";
        echo " ****************************\n";
    }
}