package notify

const (
	recordStreamMetadataCapBatchAckKey = "_notify.record_cap_batch_ack"
	recordStreamMetadataUseBatchAckKey = "_notify.record_use_batch_ack"
	recordStreamMetadataEnabledValue   = "1"
)

func advertiseRecordStreamOpenMetadata(metadata StreamMetadata) StreamMetadata {
	metadata = cloneStreamMetadata(metadata)
	if metadata == nil {
		metadata = make(StreamMetadata, 1)
	}
	metadata[recordStreamMetadataCapBatchAckKey] = recordStreamMetadataEnabledValue
	return metadata
}

func negotiateRecordStreamOpenMetadata(channel StreamChannel, metadata StreamMetadata) (StreamMetadata, StreamMetadata) {
	metadata = cloneStreamMetadata(metadata)
	if normalizeStreamChannel(channel) != StreamRecordChannel {
		return metadata, nil
	}
	if metadata[recordStreamMetadataCapBatchAckKey] != recordStreamMetadataEnabledValue {
		return metadata, nil
	}
	metadata[recordStreamMetadataUseBatchAckKey] = recordStreamMetadataEnabledValue
	return metadata, StreamMetadata{
		recordStreamMetadataUseBatchAckKey: recordStreamMetadataEnabledValue,
	}
}

func mergeStreamMetadata(base StreamMetadata, overlay StreamMetadata) StreamMetadata {
	if len(base) == 0 && len(overlay) == 0 {
		return nil
	}
	merged := cloneStreamMetadata(base)
	if merged == nil {
		merged = make(StreamMetadata, len(overlay))
	}
	for key, value := range overlay {
		merged[key] = value
	}
	return merged
}

func recordStreamUseBatchAck(metadata StreamMetadata) bool {
	return metadata[recordStreamMetadataUseBatchAckKey] == recordStreamMetadataEnabledValue
}