package ids

import (
	"crypto/rand"
	"encoding/hex"
	"fmt"
)

// StableID is a transport-neutral opaque identifier primitive. Domain packages
// wrap it in strong semantic ID types; do not pass bare StableID across
// semantic boundaries.
type StableID string

// ID is retained as a compatibility name for the V1 primitive.
type ID = StableID

// Revision is the optimistic version of a versioned semantic record.
type Revision uint64

const InitialRevision Revision = 1

func (r Revision) Valid() bool { return r >= InitialRevision }

// SemanticRef is a technical cross-owner reference envelope. It identifies a
// record but does not grant storage ownership or provide generic CRUD.
type SemanticRef struct {
	OwnerNamespace string
	SemanticKind   string
	StableID       StableID
	Revision       *Revision
}

func (r SemanticRef) Valid() bool {
	return r.OwnerNamespace != "" && r.SemanticKind != "" && r.StableID != "" &&
		(r.Revision == nil || r.Revision.Valid())
}

func NewStableID() (StableID, error) {
	var b [16]byte
	if _, err := rand.Read(b[:]); err != nil {
		return "", fmt.Errorf("generate id: %w", err)
	}
	return StableID(hex.EncodeToString(b[:])), nil
}

func New() (ID, error) {
	return NewStableID()
}