package endee

import (

"regexp"

"time"

)

// Precision types for vector indices (quantization levels).

// Defines the data types available for storing vector embeddings.

const (

PrecisionBinary = "binary" // Binary vectors (1 bit per dimension)

PrecisionFloat16 = "float16" // 16-bit floating point

PrecisionFloat32 = "float32" // 32-bit floating point

PrecisionInt16 = "int16" // 16-bit integer

PrecisionInt8 = "int8" // 8-bit integer

)

// PrecisionTypesSupported lists all supported precision types.

var PrecisionTypesSupported = []string{

PrecisionBinary,

PrecisionFloat16,

PrecisionFloat32,

PrecisionInt16,

PrecisionInt8,

}

// Checksum value while creating an index.

const Checksum = -1

// HTTP Configuration.

const (

HTTPSProtocol = "https://"

HTTPProtocol = "http://"

)

// HTTPMethodsAllowed defines allowed HTTP methods for API requests.

var HTTPMethodsAllowed = []string{"GET", "POST", "PUT", "DELETE", "PATCH"}

// HTTPStatusCodes defines status codes that trigger automatic retries.

var HTTPStatusCodes = []int{429, 500, 502, 503, 504}

// API Endpoints.

const (

LocalBaseURL = "http://127.0.0.1:8080/api/v1"

CloudURLTemplate = "https://%s.endee.io/api/v1"

LocalRegion = "local"

)

// Vector Index Limits.

const (

MaxDimensionAllowed = 8000 // Maximum vector dimensionality allowed

MaxVectorsPerBatch = 1000 // Maximum number of vectors in a single batch operation

MaxTopKAllowed = 4096 // Maximum number of nearest neighbors (top-k) that can be retrieved

MaxEfSearchAllowed = 1024 // Maximum ef_search parameter for HNSW query accuracy

MaxIndexNameLenAllowed = 48 // Maximum length for index names (alphanumeric + underscores)

// Filter key/value size limits.

MaxKeyBytes = 128 // Maximum bytes for a filter key name

MaxValueBytes = 1024 // Maximum bytes for a string filter value

)

// Distance metric types.

const (

Cosine = "cosine" // Cosine similarity (normalized dot product)

L2 = "l2" // Euclidean distance (L2 norm)

InnerProduct = "ip" // Inner product (dot product)

)

// SpaceTypesSupported lists all supported distance/space types.

var SpaceTypesSupported = []string{Cosine, L2, InnerProduct}

// Sparse model types.

const (

SparseModelDefault = "default" // Sparse search without server-side IDF

SparseModelEndEeBM25 = "endee_bm25" // BM25 scoring with server-side IDF

)

// API Field Names.

// Common field names used in API requests/responses.

const (

AuthorizationHeader = "Authorization"

NameField = "name"

SpaceTypeField = "space_type"

DimensionField = "dimension"

SparseModelField = "sparse_model"

IsHybridField = "is_hybrid"

CountField = "count"

PrecisionField = "precision"

MaxConnectionsField = "M"

)

// Session Configuration (for HTTP clients).

const (

// Requests Library Session Configuration.

SessionPoolConnections = 1 // Number of connection pools to cache (one per unique host)

SessionPoolMaxSize = 10 // Maximum number of connections to save in each pool for reuse

SessionMaxRetries = 3 // Maximum number of retry attempts for failed requests

// HTTPX Library Client Configuration.

HTTPXMaxConnections = 1 // Maximum total connections across all hosts

HTTPXMaxKeepaliveConnections = 10 // Maximum idle connections to keep alive for reuse

HTTPXMaxRetries = 3 // Maximum number of retry attempts for failed requests

HTTPXTimeoutSec = 30.0 // Request timeout in seconds (prevents hanging requests)

)

// HNSW Algorithm Defaults.

const (

DefaultM = 16 // Default M parameter: number of bi-directional links per node in HNSW graph

DefaultEfConstruction = 128 // Default ef_construction: size of dynamic candidate list during index construction

DefaultTopK = 10 // Default number of nearest neighbors to return in search queries

DefaultEfSearch = 128 // Default ef_search: size of dynamic candidate list during search

DefaultTimeout = 30 * time.Second

DefaultPrefilterCardinalityThreshold = 10000 // Switches from HNSW to brute-force for filtered queries

DefaultFilterBoostPercentage = 0 // Expands HNSW candidate pool by this percentage

DefaultDenseRRFWeight float64 = 0.5 // RRF weight for the dense component in hybrid search

DefaultRRFRankConstant = 60 // RRF rank constant in hybrid search

)

// NameRegex is a pre-compiled regex for validating index names.

var NameRegex = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)