format

type CompressionType uint8

type Entry struct {
	// Length is the total size of the entry including header and CRC (excludes the length field itself)
	Length uint32

	// Type indicates the entry type (Data, Tombstone, Checkpoint)
	Type uint8

	// Flags contains entry flags (compressed, encrypted, TTL, headers, priority, etc.)
	Flags uint8

	// MsgID is the unique message identifier
	MsgID uint64

	// Timestamp is the Unix time in nanoseconds when the entry was created
	Timestamp int64

	// Priority is the message priority level (Low/Medium/High) (v1.1.0+)
	// Only serialized if EntryFlagPriority is set
	// Defaults to PriorityLow for backward compatibility
	Priority uint8

	// ExpiresAt is the Unix time in nanoseconds when the message expires (0 = no expiration)
	// Only serialized if EntryFlagTTL is set
	ExpiresAt int64

	// Headers contains key-value metadata for the message
	// Only serialized if EntryFlagHeaders is set
	Headers map[string]string

	// Compression is the compression algorithm used for the payload (v1.3.0+)
	// Only serialized if EntryFlagCompressed is set
	// Defaults to CompressionNone for backward compatibility
	Compression CompressionType

	// Payload is the message data (may be compressed if Compression != CompressionNone)
	Payload []byte
}

type Index struct {
	Header  *IndexHeader
	Entries []*IndexEntry
}

type IndexEntry struct {
	// MessageID is the message identifier
	MessageID uint64

	// FileOffset is the byte position in the segment file
	FileOffset uint64

	// Timestamp is the Unix time in nanoseconds
	Timestamp int64
}

type IndexHeader struct {
	// Magic is the file format identifier (0x4C445149 for indexes)
	Magic uint32

	// Version is the format version
	Version uint16

	// BaseID is the base message ID for this index
	BaseID uint64

	// EntryCount is the number of index entries
	EntryCount uint64

	// Reserved is space for future extensions (4 bytes)
	Reserved uint32

	// HeaderCRC is the checksum of the header (excluding this field)
	HeaderCRC uint32
	// contains filtered or unexported fields
}

type MetadataFile struct {
	// contains filtered or unexported fields
}

type PriorityIndex struct {
	// contains filtered or unexported fields
}

type PriorityIndexEntry struct {
	Offset    uint64 // Message offset
	Position  uint32 // Position in segment file
	Priority  uint8  // Priority level
	Timestamp int64  // For starvation prevention
}

type QueueMetadata struct {
	// Version is the metadata format version
	Version uint16 `json:"version"`

	// WriteOffset is the next offset to write to (monotonically increasing)
	WriteOffset uint64 `json:"write_offset"`

	// ReadOffset is the next offset to read from
	ReadOffset uint64 `json:"read_offset"`

	// AckOffset is the highest contiguously acknowledged offset
	AckOffset uint64 `json:"ack_offset"`

	// ActiveSegmentID is the ID of the current write segment
	ActiveSegmentID uint64 `json:"active_segment_id"`

	// OldestSegmentID is the ID of the oldest segment (for cleanup)
	OldestSegmentID uint64 `json:"oldest_segment_id"`

	// MessageCount is the total number of messages written
	MessageCount uint64 `json:"message_count"`

	// AckCount is the total number of messages acknowledged
	AckCount uint64 `json:"ack_count"`

	// LastWriteTime is the Unix timestamp (nanoseconds) of the last write
	LastWriteTime int64 `json:"last_write_time"`

	// LastAckTime is the Unix timestamp (nanoseconds) of the last acknowledgment
	LastAckTime int64 `json:"last_ack_time"`

	// LastCompactTime is the Unix timestamp (nanoseconds) of the last compaction
	LastCompactTime int64 `json:"last_compact_time,omitempty"`
}

type SegmentHeader struct {
	// Magic is the file format identifier (0x4C445151 for segments)
	Magic uint32

	// Version is the format version
	Version uint16

	// Flags contains segment properties (compressed, encrypted, etc.)
	Flags uint16

	// BaseOffset is the starting offset of this segment in the queue
	BaseOffset uint64

	// CreatedAt is the Unix timestamp (nanoseconds) when segment was created
	CreatedAt int64

	// MinMsgID is the smallest message ID in this segment
	MinMsgID uint64

	// MaxMsgID is the largest message ID in this segment
	MaxMsgID uint64

	// Reserved is space for future extensions (20 bytes)
	Reserved [20]byte

	// HeaderCRC is the checksum of the header (excluding this field)
	HeaderCRC uint32
}