squeezelite-esp32/components/spotify/cspot/src/TrackProvider.cpp

#include "TrackProvider.h"
#include <memory>
#include "AccessKeyFetcher.h"
#include "CDNTrackStream.h"
#include "Logger.h"
#include "MercurySession.h"
#include "TrackReference.h"
#include "Utils.h"
#include "protobuf/metadata.pb.h"

using namespace cspot;

TrackProvider::TrackProvider(std::shared_ptr<cspot::Context> ctx) {
  this->accessKeyFetcher = std::make_shared<cspot::AccessKeyFetcher>(ctx);
  this->ctx = ctx;
  this->cdnStream =
      std::make_unique<cspot::CDNTrackStream>(this->accessKeyFetcher);

  this->trackInfo = {};
}

TrackProvider::~TrackProvider() {
  pb_release(Track_fields, &trackInfo);
}

std::shared_ptr<cspot::CDNTrackStream> TrackProvider::loadFromTrackRef(TrackReference& trackRef) {
  auto track = std::make_shared<cspot::CDNTrackStream>(this->accessKeyFetcher);
  this->currentTrackReference = track;
  this->trackIdInfo = trackRef;

  queryMetadata();
  return track;
}

void TrackProvider::queryMetadata() {
  std::string requestUrl = string_format(
      "hm://metadata/3/%s/%s", trackIdInfo.type == TrackReference::Type::TRACK ? "track" : "episode",
      bytesToHexString(trackIdInfo.gid).c_str());
  CSPOT_LOG(debug, "Requesting track metadata from %s", requestUrl.c_str());

  auto responseHandler = [this](MercurySession::Response& res) {
    this->onMetadataResponse(res);
  };

  // Execute the request
  ctx->session->execute(MercurySession::RequestType::GET, requestUrl,
                        responseHandler);
}

void TrackProvider::onMetadataResponse(MercurySession::Response& res) {
  CSPOT_LOG(debug, "Got track metadata response");

  pb_release(Track_fields, &trackInfo);
  pbDecode(trackInfo, Track_fields, res.parts[0]);

  CSPOT_LOG(info, "Track name: %s", trackInfo.name);
  CSPOT_LOG(info, "Track duration: %d", trackInfo.duration);

  CSPOT_LOG(debug, "trackInfo.restriction.size() = %d",
            trackInfo.restriction_count);

  int altIndex = -1;
  while (!canPlayTrack(altIndex)) {
    altIndex++;
    CSPOT_LOG(info, "Trying alternative %d", altIndex);

    if (altIndex >= trackInfo.alternative_count) {
      // no alternatives for song
      if (!this->currentTrackReference.expired()) {
        auto trackRef = this->currentTrackReference.lock();
        trackRef->status = CDNTrackStream::Status::FAILED;
        trackRef->trackReady->give();
      }
      return;
    }
  }

  std::vector<uint8_t> trackId;
  std::vector<uint8_t> fileId;
  
  if (altIndex < 0) {
    trackId = pbArrayToVector(trackInfo.gid);
    for (int x = 0; x < trackInfo.file_count; x++) {
      if (trackInfo.file[x].format == ctx->config.audioFormat) {
        fileId = pbArrayToVector(trackInfo.file[x].file_id);
        break;  // If file found stop searching
      }
    }
  } else {
    trackId = pbArrayToVector(trackInfo.alternative[altIndex].gid);
    for (int x = 0; x < trackInfo.alternative[altIndex].file_count; x++) {
      if (trackInfo.alternative[altIndex].file[x].format == ctx->config.audioFormat) {
        fileId =
            pbArrayToVector(trackInfo.alternative[altIndex].file[x].file_id);
        break;  // If file found stop searching
      }
    }
  }

  if (!this->currentTrackReference.expired()) {
    auto trackRef = this->currentTrackReference.lock();

    auto imageId =
        pbArrayToVector(trackInfo.album.cover_group.image[0].file_id);

    trackRef->trackInfo.trackId = bytesToHexString(trackIdInfo.gid);
    trackRef->trackInfo.name = std::string(trackInfo.name);
    trackRef->trackInfo.album = std::string(trackInfo.album.name);
    trackRef->trackInfo.artist = std::string(trackInfo.artist[0].name);
    trackRef->trackInfo.imageUrl =
        "https://i.scdn.co/image/" + bytesToHexString(imageId);
    trackRef->trackInfo.duration = trackInfo.duration;
  }

  this->fetchFile(fileId, trackId);
}

void TrackProvider::fetchFile(const std::vector<uint8_t>& fileId,
                              const std::vector<uint8_t>& trackId) {
  ctx->session->requestAudioKey(
      trackId, fileId,
      [this, fileId](bool success, const std::vector<uint8_t>& audioKey) {
        if (success) {
          CSPOT_LOG(info, "Got audio key");
          if (!this->currentTrackReference.expired()) {
            auto ref = this->currentTrackReference.lock();
            ref->fetchFile(fileId, audioKey);
          }

        } else {
          CSPOT_LOG(error, "Failed to get audio key");
          if (!this->currentTrackReference.expired()) {
            auto ref = this->currentTrackReference.lock();
            ref->fail();
          }
        }
      });
}

bool countryListContains(char* countryList, char* country) {
  uint16_t countryList_length = strlen(countryList);
  for (int x = 0; x < countryList_length; x += 2) {
    if (countryList[x] == country[0] && countryList[x + 1] == country[1]) {
      return true;
    }
  }
  return false;
}

bool TrackProvider::canPlayTrack(int altIndex) {
  if (altIndex < 0) {
    for (int x = 0; x < trackInfo.restriction_count; x++) {
      if (trackInfo.restriction[x].countries_allowed != nullptr) {
        return countryListContains(trackInfo.restriction[x].countries_allowed,
                                   (char*)ctx->config.countryCode.c_str());
      }

      if (trackInfo.restriction[x].countries_forbidden != nullptr) {
        return !countryListContains(
            trackInfo.restriction[x].countries_forbidden,
            (char*)ctx->config.countryCode.c_str());
      }
    }
  } else {
    for (int x = 0; x < trackInfo.alternative[altIndex].restriction_count;
         x++) {
      if (trackInfo.alternative[altIndex].restriction[x].countries_allowed !=
          nullptr) {
        return countryListContains(
            trackInfo.alternative[altIndex].restriction[x].countries_allowed,
            (char*)ctx->config.countryCode.c_str());
      }

      if (trackInfo.alternative[altIndex].restriction[x].countries_forbidden !=
          nullptr) {
        return !countryListContains(
            trackInfo.alternative[altIndex].restriction[x].countries_forbidden,
            (char*)ctx->config.countryCode.c_str());
      }
    }
  }
  return true;
}