persistence

type Database interface {
	Engine() databaseEngine
	DoesTorrentExist(infoHash []byte) (bool, error)
	AddNewTorrent(infoHash []byte, name string, files []File) error
	Close() error

	// GetNumberOfTorrents returns the number of torrents saved in the database. Might be an
	// approximation.
	GetNumberOfTorrents() (uint, error)
	GetTotalSizeOfTorrents() (uint64, error)
	// QueryTorrents returns @pageSize amount of torrents,
	// * that are discovered before @discoveredOnBefore
	// * that match the @query if it's not empty, else all torrents
	// * ordered by the @orderBy in ascending order if @ascending is true, else in descending order
	// after skipping (@page * @pageSize) torrents that also fits the criteria above.
	QueryTorrents(
		query string,
		epoch int64,
		orderBy OrderingCriteria,
		ascending bool,
		limit uint,
		lastOrderedValue uint64,
		lastID uint64,
		backward bool,
	) ([]TorrentMetadata, error)
	// GetTorrents returns the TorrentExtMetadata for the torrent of the given InfoHash. Will return
	// nil, nil if the torrent does not exist in the database.
	GetTorrent(infoHash []byte) (*TorrentMetadata, error)
	GetFiles(infoHash []byte) ([]File, error)
	GetStatistics(n uint, from string) (*Statistics, error)
	GenerateStatisticData(from time.Time) error
	GetFirstTorrentDate() (*time.Time, error)
	GetLastTorrentDate() (*time.Time, error)
	GetLatestStatisticsDate() (*time.Time, error)
}

type File struct {
	Size uint64
	Path string
}

type Granularity int

type OrderingCriteria uint8

type Statistics struct {
	N uint

	// All these slices below have the exact length equal to the Period.
	NTorrents []uint64
	NFiles    []uint64
	TotalSize []uint64
}

type TorrentMetadata struct {
	InfoHash     []byte
	Name         string
	Size         uint64
	DiscoveredOn int64
	NFiles       uint
	ID           uint
}