decoder.go

// Package abn provides automatic detection and decoding capabilities for various encoding formats
package abn

import "errors"

// Common errors
var (
	ErrEmptyInput      = errors.New("empty input provided")
	ErrUnknownEncoding = errors.New("unknown or unsupported encoding format")
	ErrInvalidFormat   = errors.New("invalid format for detected encoding")
	ErrDecodeFailed    = errors.New("decoding failed for detected format")
)

// EncodingType represents the type of encoding detected
type EncodingType int

const (
	Unknown EncodingType = iota
	Base64
	Base58
	Base52
	// Future encoding types can be added here// Base32
	// Hex
)

// String returns the string representation of the encoding type
func (et EncodingType) String() string {
	switch et {
	case Base64:
		return "Base64"
	case Base58:
		return "Base58"
	case Base52:
		return "Base52"
	default:
		return "Unknown"
	}
}

// DecodeResult contains the result of a decode operation
type DecodeResult struct {
	EncodingType EncodingType `json:"encoding_type"`
	DecodedData  []byte       `json:"decoded_data"`
	DecodedText  string       `json:"decoded_text"`
	Confidence   float64      `json:"confidence"` // Detection confidence (0.0-1.0)
	Error        error        `json:"error,omitempty"`
}

// IsValid returns true if the decode operation was successful
func (dr *DecodeResult) IsValid() bool {
	return dr.Error == nil && dr.EncodingType != Unknown
}

// EncodingDetector defines the interface for encoding detection
type EncodingDetector interface {
	// Detect analyzes the input and returns possible encoding types with confidence scores
	Detect(input string) []DetectionResult

	// CanDetect returns true if this detector can handle the given encoding type
	CanDetect(encodingType EncodingType) bool
}

// DetectionResult represents a detection result with confidence
type DetectionResult struct {
	EncodingType EncodingType
	Confidence   float64 // 0.0 to 1.0, higher is more confident
}

// Decoder defines the interface for decoding operations
type Decoder interface {
	// Decode attempts to decode the input using this decoder's format
	Decode(input string) ([]byte, error)

	// GetEncodingType returns the encoding type this decoder handles
	GetEncodingType() EncodingType

	// Validate checks if the input format is valid for this decoder
	Validate(input string) error
}

// DecoderRegistry manages available decoders and detectors
type DecoderRegistry interface {
	// RegisterDecoder adds a new decoder to the registry
	RegisterDecoder(decoder Decoder) error

	// RegisterDetector adds a new detector to the registry
	RegisterDetector(detector EncodingDetector) error

	// GetDecoder returns a decoder for the specified encoding type
	GetDecoder(encodingType EncodingType) (Decoder, bool)

	// GetDetectors returns all registered detectors
	GetDetectors() []EncodingDetector

	// ListSupportedTypes returns all supported encoding types
	ListSupportedTypes() []EncodingType
}

// AutoDecoder defines the main interface for automatic decoding
type AutoDecoder interface {
	// AutoDecode automatically detects and decodes the input
	AutoDecode(input string) *DecodeResult

	// DecodeWithType attempts to decode using a specific encoding type
	DecodeWithType(input string, encodingType EncodingType) *DecodeResult

	// DetectEncoding only detects the encoding type without decoding
	DetectEncoding(input string) []DetectionResult
}