/*
 * Strawberry Music Player
 * This file was part of Clementine.
 * Copyright 2010, David Sansome <me@davidsansome.com>
 *
 * Strawberry 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 3 of the License, or
 * (at your option) any later version.
 *
 * Strawberry 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 Strawberry.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef M3UPARSER_H
#define M3UPARSER_H

#include "config.h"

#include <QtGlobal>
#include <QObject>
#include <QByteArray>
#include <QSet>
#include <QHash>
#include <QString>
#include <QStringList>
#include <QDir>

#include "includes/shared_ptr.h"
#include "constants/playlistsettings.h"
#include "core/song.h"
#include "parserbase.h"

class QIODevice;
class TagReaderClient;
class CollectionBackendInterface;

class M3UParser : public ParserBase {
  Q_OBJECT

 public:
  explicit M3UParser(const SharedPtr<TagReaderClient> tagreader_client, const SharedPtr<CollectionBackendInterface> collection_backend, QObject *parent = nullptr);

  QString name() const override { return QStringLiteral("M3U"); }
  QStringList file_extensions() const override { return QStringList() << QStringLiteral("m3u") << QStringLiteral("m3u8"); }
  QString mime_type() const override { return QStringLiteral("text/uri-list"); }
  bool load_supported() const override { return true; }
  bool save_supported() const override { return true; }

  bool TryMagic(const QByteArray &data) const override;

  LoadResult Load(QIODevice *device, const QString &playlist_path = QLatin1String(""), const QDir &dir = QDir(), const bool collection_lookup = true) const override;
  void Save(const QString &playlist_name, const SongList &songs, QIODevice *device, const QDir &dir = QDir(), const PlaylistSettings::PathType path_type = PlaylistSettings::PathType::Automatic) const override;

  static constexpr int kMaxNestingDepth = 5;

 private:
  enum class M3UType {
    STANDARD = 0,
    EXTENDED,  // Includes extended info (track, artist, etc.)
    LINK,      // Points to a directory.
  };

  struct Metadata {
    Metadata() : length(-1) {}
    QString artist;
    QString title;
    qint64 length;
  };

  static bool ParseMetadata(const QString &line, Metadata *metadata);

  // Returns true when a playlist entry is a local (non-URL) reference to another .m3u/.m3u8 file, which must be expanded rather than loaded as a track.
  // Remote or stream URLs (those carrying a URL scheme, such as an HLS http .m3u8) are left for LoadSong to turn into a stream, matching its own URL-scheme detection.
  static bool IsNestedPlaylistReference(const QString &line);

  // Parses playlist data read from device, appending resolved tracks to ret.
  // Local nested .m3u/.m3u8 references are expanded via LoadNested while every other entry loads as a track.
  // Shared by the top-level Load and each nested descent so entry detection lives in one place.
  void ParsePlaylistData(QIODevice *device, const QDir &dir, QSet<QString> &ancestors, QHash<QString, SongList> &expanded, int depth, bool collection_lookup, SongList &ret) const;

  // Expands a single nested .m3u/.m3u8 reference into ret.
  // ancestors holds the canonical paths currently on the recursion path and detects true cycles, while expanded memoizes each file's parsed tracks keyed by remaining depth budget so a repeated or diamond reference is not parsed again.
  // Recursion depth is bounded by kMaxNestingDepth.
  void LoadNested(const QString &filename, const QDir &dir, QSet<QString> &ancestors, QHash<QString, SongList> &expanded, int depth, bool collection_lookup, SongList &ret) const;
};

#endif  // M3UPARSER_H
