librespot/metadata/src/lib.rs

#![allow(clippy::unused_io_amount)]

#[macro_use]
extern crate log;

#[macro_use]
extern crate async_trait;

pub mod cover;

use std::collections::HashMap;

use librespot_core::mercury::MercuryError;
use librespot_core::session::Session;
use librespot_core::spclient::SpClientError;
use librespot_core::spotify_id::{FileId, SpotifyAudioType, SpotifyId};
use librespot_protocol as protocol;
use protobuf::{Message, ProtobufError};

use thiserror::Error;

pub use crate::protocol::metadata::AudioFile_Format as FileFormat;

fn countrylist_contains(list: &str, country: &str) -> bool {
    list.chunks(2).any(|cc| cc == country)
}

fn parse_restrictions<'s, I>(restrictions: I, country: &str, catalogue: &str) -> bool
where
    I: IntoIterator<Item = &'s protocol::metadata::Restriction>,
{
    let mut forbidden = "".to_string();
    let mut has_forbidden = false;

    let mut allowed = "".to_string();
    let mut has_allowed = false;

    let rs = restrictions
        .into_iter()
        .filter(|r| r.get_catalogue_str().contains(&catalogue.to_owned()));

    for r in rs {
        if r.has_countries_forbidden() {
            forbidden.push_str(r.get_countries_forbidden());
            has_forbidden = true;
        }

        if r.has_countries_allowed() {
            allowed.push_str(r.get_countries_allowed());
            has_allowed = true;
        }
    }

    !(has_forbidden && countrylist_contains(forbidden.as_str(), country)
        || has_allowed && !countrylist_contains(allowed.as_str(), country))
}

// A wrapper with fields the player needs
#[derive(Debug, Clone)]
pub struct AudioItem {
    pub id: SpotifyId,
    pub uri: String,
    pub files: HashMap<FileFormat, FileId>,
    pub name: String,
    pub duration: i32,
    pub available: bool,
    pub alternatives: Option<Vec<SpotifyId>>,
}

impl AudioItem {
    pub async fn get_audio_item(session: &Session, id: SpotifyId) -> Result<Self, MetadataError> {
        match id.audio_type {
            SpotifyAudioType::Track => Track::get_audio_item(session, id).await,
            SpotifyAudioType::Podcast => Episode::get_audio_item(session, id).await,
            SpotifyAudioType::NonPlayable => Err(MetadataError::NonPlayable),
        }
    }
}

pub type AudioItemResult = Result<AudioItem, MetadataError>;

#[async_trait]
trait AudioFiles {
    async fn get_audio_item(session: &Session, id: SpotifyId) -> AudioItemResult;
}

#[async_trait]
impl AudioFiles for Track {
    async fn get_audio_item(session: &Session, id: SpotifyId) -> AudioItemResult {
        let item = Self::get(session, id).await?;
        let alternatives = {
            if item.alternatives.is_empty() {
                None
            } else {
                Some(item.alternatives)
            }
        };

        Ok(AudioItem {
            id,
            uri: format!("spotify:track:{}", id.to_base62()),
            files: item.files,
            name: item.name,
            duration: item.duration,
            available: item.available,
            alternatives,
        })
    }
}

#[async_trait]
impl AudioFiles for Episode {
    async fn get_audio_item(session: &Session, id: SpotifyId) -> AudioItemResult {
        let item = Self::get(session, id).await?;

        Ok(AudioItem {
            id,
            uri: format!("spotify:episode:{}", id.to_base62()),
            files: item.files,
            name: item.name,
            duration: item.duration,
            available: item.available,
            alternatives: None,
        })
    }
}

#[derive(Debug, Error)]
pub enum MetadataError {
    #[error("could not get metadata over HTTP: {0}")]
    Http(#[from] SpClientError),
    #[error("could not get metadata over Mercury: {0}")]
    Mercury(#[from] MercuryError),
    #[error("could not parse metadata: {0}")]
    Parsing(#[from] ProtobufError),
    #[error("response was empty")]
    Empty,
    #[error("audio item is non-playable")]
    NonPlayable,
}

pub type MetadataResult = Result<bytes::Bytes, MetadataError>;

#[async_trait]
pub trait Metadata: Send + Sized + 'static {
    type Message: protobuf::Message;

    async fn request(session: &Session, id: SpotifyId) -> MetadataResult;
    fn parse(msg: &Self::Message, session: &Session) -> Self;

    async fn get(session: &Session, id: SpotifyId) -> Result<Self, MetadataError> {
        let response = Self::request(session, id).await?;
        let msg = Self::Message::parse_from_bytes(&response)?;
        Ok(Self::parse(&msg, session))
    }
}

// TODO: expose more fields available in the protobufs

#[derive(Debug, Clone)]
pub struct Track {
    pub id: SpotifyId,
    pub name: String,
    pub duration: i32,
    pub album: SpotifyId,
    pub artists: Vec<SpotifyId>,
    pub files: HashMap<FileFormat, FileId>,
    pub alternatives: Vec<SpotifyId>,
    pub available: bool,
}

#[derive(Debug, Clone)]
pub struct Album {
    pub id: SpotifyId,
    pub name: String,
    pub artists: Vec<SpotifyId>,
    pub tracks: Vec<SpotifyId>,
    pub covers: Vec<FileId>,
}

#[derive(Debug, Clone)]
pub struct Episode {
    pub id: SpotifyId,
    pub name: String,
    pub external_url: String,
    pub duration: i32,
    pub language: String,
    pub show: SpotifyId,
    pub files: HashMap<FileFormat, FileId>,
    pub covers: Vec<FileId>,
    pub available: bool,
    pub explicit: bool,
}

#[derive(Debug, Clone)]
pub struct Show {
    pub id: SpotifyId,
    pub name: String,
    pub publisher: String,
    pub episodes: Vec<SpotifyId>,
    pub covers: Vec<FileId>,
}

#[derive(Debug, Clone)]
pub struct Playlist {
    pub revision: Vec<u8>,
    pub user: String,
    pub name: String,
    pub tracks: Vec<SpotifyId>,
}

#[derive(Debug, Clone)]
pub struct Artist {
    pub id: SpotifyId,
    pub name: String,
    pub top_tracks: Vec<SpotifyId>,
}

#[async_trait]
impl Metadata for Track {
    type Message = protocol::metadata::Track;

    async fn request(session: &Session, track_id: SpotifyId) -> MetadataResult {
        session
            .spclient()
            .get_track_metadata(track_id)
            .await
            .map_err(MetadataError::Http)
    }

    fn parse(msg: &Self::Message, session: &Session) -> Self {
        debug!("MESSAGE: {:?}", msg);
        let country = session.country();

        let artists = msg
            .get_artist()
            .iter()
            .filter(|artist| artist.has_gid())
            .map(|artist| SpotifyId::from_raw(artist.get_gid()).unwrap())
            .collect::<Vec<_>>();

        let files = msg
            .get_file()
            .iter()
            .filter(|file| file.has_file_id())
            .map(|file| {
                let mut dst = [0u8; 20];
                dst.clone_from_slice(file.get_file_id());
                (file.get_format(), FileId(dst))
            })
            .collect();

        Track {
            id: SpotifyId::from_raw(msg.get_gid()).unwrap(),
            name: msg.get_name().to_owned(),
            duration: msg.get_duration(),
            album: SpotifyId::from_raw(msg.get_album().get_gid()).unwrap(),
            artists,
            files,
            alternatives: msg
                .get_alternative()
                .iter()
                .map(|alt| SpotifyId::from_raw(alt.get_gid()).unwrap())
                .collect(),
            available: parse_restrictions(msg.get_restriction(), &country, "premium"),
        }
    }
}

#[async_trait]
impl Metadata for Album {
    type Message = protocol::metadata::Album;

    async fn request(session: &Session, album_id: SpotifyId) -> MetadataResult {
        session
            .spclient()
            .get_album_metadata(album_id)
            .await
            .map_err(MetadataError::Http)
    }

    fn parse(msg: &Self::Message, _: &Session) -> Self {
        let artists = msg
            .get_artist()
            .iter()
            .filter(|artist| artist.has_gid())
            .map(|artist| SpotifyId::from_raw(artist.get_gid()).unwrap())
            .collect::<Vec<_>>();

        let tracks = msg
            .get_disc()
            .iter()
            .flat_map(|disc| disc.get_track())
            .filter(|track| track.has_gid())
            .map(|track| SpotifyId::from_raw(track.get_gid()).unwrap())
            .collect::<Vec<_>>();

        let covers = msg
            .get_cover_group()
            .get_image()
            .iter()
            .filter(|image| image.has_file_id())
            .map(|image| {
                let mut dst = [0u8; 20];
                dst.clone_from_slice(image.get_file_id());
                FileId(dst)
            })
            .collect::<Vec<_>>();

        Album {
            id: SpotifyId::from_raw(msg.get_gid()).unwrap(),
            name: msg.get_name().to_owned(),
            artists,
            tracks,
            covers,
        }
    }
}

#[async_trait]
impl Metadata for Playlist {
    type Message = protocol::playlist4changes::SelectedListContent;

    // TODO:
    // * Add PlaylistAnnotate3 annotations.
    // * Find spclient endpoint and upgrade to that.
    async fn request(session: &Session, playlist_id: SpotifyId) -> MetadataResult {
        let uri = format!("hm://playlist/v2/playlist/{}", playlist_id.to_base62());
        let response = session.mercury().get(uri).await?;
        match response.payload.first() {
            Some(data) => Ok(data.to_vec().into()),
            None => Err(MetadataError::Empty),
        }
    }

    fn parse(msg: &Self::Message, _: &Session) -> Self {
        let tracks = msg
            .get_contents()
            .get_items()
            .iter()
            .map(|item| {
                let uri_split = item.get_uri().split(':');
                let uri_parts: Vec<&str> = uri_split.collect();
                SpotifyId::from_base62(uri_parts[2]).unwrap()
            })
            .collect::<Vec<_>>();

        if tracks.len() != msg.get_length() as usize {
            warn!(
                "Got {} tracks, but the playlist should contain {} tracks.",
                tracks.len(),
                msg.get_length()
            );
        }

        Playlist {
            revision: msg.get_revision().to_vec(),
            name: msg.get_attributes().get_name().to_owned(),
            tracks,
            user: msg.get_owner_username().to_string(),
        }
    }
}

#[async_trait]
impl Metadata for Artist {
    type Message = protocol::metadata::Artist;

    async fn request(session: &Session, artist_id: SpotifyId) -> MetadataResult {
        session
            .spclient()
            .get_artist_metadata(artist_id)
            .await
            .map_err(MetadataError::Http)
    }

    fn parse(msg: &Self::Message, session: &Session) -> Self {
        let country = session.country();

        let top_tracks: Vec<SpotifyId> = match msg
            .get_top_track()
            .iter()
            .find(|tt| !tt.has_country() || countrylist_contains(tt.get_country(), &country))
        {
            Some(tracks) => tracks
                .get_track()
                .iter()
                .filter(|track| track.has_gid())
                .map(|track| SpotifyId::from_raw(track.get_gid()).unwrap())
                .collect::<Vec<_>>(),
            None => Vec::new(),
        };

        Artist {
            id: SpotifyId::from_raw(msg.get_gid()).unwrap(),
            name: msg.get_name().to_owned(),
            top_tracks,
        }
    }
}

// Podcast
#[async_trait]
impl Metadata for Episode {
    type Message = protocol::metadata::Episode;

    async fn request(session: &Session, episode_id: SpotifyId) -> MetadataResult {
        session
            .spclient()
            .get_album_metadata(episode_id)
            .await
            .map_err(MetadataError::Http)
    }

    fn parse(msg: &Self::Message, session: &Session) -> Self {
        let country = session.country();

        let files = msg
            .get_audio()
            .iter()
            .filter(|file| file.has_file_id())
            .map(|file| {
                let mut dst = [0u8; 20];
                dst.clone_from_slice(file.get_file_id());
                (file.get_format(), FileId(dst))
            })
            .collect();

        let covers = msg
            .get_cover_image()
            .get_image()
            .iter()
            .filter(|image| image.has_file_id())
            .map(|image| {
                let mut dst = [0u8; 20];
                dst.clone_from_slice(image.get_file_id());
                FileId(dst)
            })
            .collect::<Vec<_>>();

        Episode {
            id: SpotifyId::from_raw(msg.get_gid()).unwrap(),
            name: msg.get_name().to_owned(),
            external_url: msg.get_external_url().to_owned(),
            duration: msg.get_duration().to_owned(),
            language: msg.get_language().to_owned(),
            show: SpotifyId::from_raw(msg.get_show().get_gid()).unwrap(),
            covers,
            files,
            available: parse_restrictions(msg.get_restriction(), &country, "premium"),
            explicit: msg.get_explicit().to_owned(),
        }
    }
}

#[async_trait]
impl Metadata for Show {
    type Message = protocol::metadata::Show;

    async fn request(session: &Session, show_id: SpotifyId) -> MetadataResult {
        session
            .spclient()
            .get_show_metadata(show_id)
            .await
            .map_err(MetadataError::Http)
    }

    fn parse(msg: &Self::Message, _: &Session) -> Self {
        let episodes = msg
            .get_episode()
            .iter()
            .filter(|episode| episode.has_gid())
            .map(|episode| SpotifyId::from_raw(episode.get_gid()).unwrap())
            .collect::<Vec<_>>();

        let covers = msg
            .get_cover_image()
            .get_image()
            .iter()
            .filter(|image| image.has_file_id())
            .map(|image| {
                let mut dst = [0u8; 20];
                dst.clone_from_slice(image.get_file_id());
                FileId(dst)
            })
            .collect::<Vec<_>>();

        Show {
            id: SpotifyId::from_raw(msg.get_gid()).unwrap(),
            name: msg.get_name().to_owned(),
            publisher: msg.get_publisher().to_owned(),
            episodes,
            covers,
        }
    }
}

struct StrChunks<'s>(&'s str, usize);

trait StrChunksExt {
    fn chunks(&self, size: usize) -> StrChunks;
}

impl StrChunksExt for str {
    fn chunks(&self, size: usize) -> StrChunks {
        StrChunks(self, size)
    }
}

impl<'s> Iterator for StrChunks<'s> {
    type Item = &'s str;
    fn next(&mut self) -> Option<&'s str> {
        let &mut StrChunks(data, size) = self;
        if data.is_empty() {
            None
        } else {
            let ret = Some(&data[..size]);
            self.0 = &data[size..];
            ret
        }
    }
}