block

type AppendCallback = func(seqs []int64, err error)

type AppendContext interface {
	WriteOffset() int64
	Archived() bool
}

type Appender interface {
	Append(ctx context.Context, entries []Entry, cb AppendCallback)
}

type ArchivedCallback func(stat Statistics)

type ArchivedListener interface {
	OnArchived(stat Statistics)
}

type Block interface {
	Seeker
	Reader
	Appender

	ID() vanus.ID
}

type BytesValue []byte

type CommitAppendCallback = func()

type EmptyEntry struct{}

type EmptyEntryExt struct {
	EmptyEntry
}

type Entry interface {
	Get(ordinal int) interface{}
	GetBytes(ordinal int) []byte
	GetString(ordinal int) string
	GetUint16(ordinal int) uint16
	GetUint64(ordinal int) uint64
	GetInt64(ordinal int) int64
	GetTime(ordinal int) time.Time

	GetExtensionAttribute([]byte) []byte
	RangeExtensionAttributes(cb ExtensionAttributeCallback)
}

type EntryExt interface {
	Entry

	OptionalAttributeCount() int
	ExtensionAttributeCount() int

	RangeOptionalAttributes(cb OptionalAttributeCallback)
}

type EntryExtWrapper struct {
	E EntryExt
}

type ExtensionAttributeCallback interface {
	OnAttribute(attr []byte, val Value)
}

type Fragment interface {
	Payload() []byte
	Size() int
	StartOffset() int64
	EndOffset() int64
}

type FragmentMarshaler interface {
	MarshalFragment() ([]byte, error)
}

type OnExtensionAttributeFunc func(attr []byte, val Value)

type OnOptionalAttributeFunc func(ordinal int, val interface{})

type OptionalAttributeCallback interface {
	OnBytes(ordinal int, val []byte)
	OnString(ordinal int, val string)
	OnUint16(ordinal int, val uint16)
	OnUint64(ordinal int, val uint64)
	OnInt64(ordinal int, val int64)
	OnTime(ordinal int, val time.Time)
	// TODO(james.yin): more types
	OnAttribute(ordinal int, val interface{})
}

type Raw interface {
	Seeker
	Reader
	TwoPCAppender
	Snapshoter

	ID() vanus.ID

	Open(context.Context) error
	Close(context.Context) error
	Delete(context.Context) error
	Status() Statistics
}

type Reader interface {
	Read(ctx context.Context, seq int64, num int) ([]Entry, error)
}

type SeekKeyFlag uint64

type Seeker interface {
	Seek(ctx context.Context, index int64, key Entry, flag SeekKeyFlag) (int64, error)
}

type Snapshoter interface {
	Snapshot(ctx context.Context) (Fragment, error)
	ApplySnapshot(ctx context.Context, snap Fragment) error
}

type Statistics struct {
	ID        vanus.ID
	Capacity  uint64
	Archived  bool
	EntryNum  uint32
	EntrySize uint64
	// FirstEntryStime is the millisecond timestamp when the first Entry will be written to Block.
	FirstEntryStime int64
	// LastEntryStime is the millisecond timestamp when the last Entry will be written to Block.
	LastEntryStime int64
}

type TwoPCAppender interface {
	NewAppendContext(last Fragment) AppendContext
	PrepareAppend(ctx context.Context, appendCtx AppendContext, entries ...Entry) ([]int64, Fragment, bool, error)
	PrepareArchive(ctx context.Context, appendCtx AppendContext) (Fragment, error)
	CommitAppend(ctx context.Context, frag Fragment, cb CommitAppendCallback)
}

type Value interface {
	Size() int
	Value() []byte
}

type ValueMarshaler interface {
	Value

	MarshalTo(buf []byte) int
}