package actor

import (
	"encoding/json"
	"fmt"

	"git.k6n.net/mats/platform/uid"
)

// GrainId is a 64-bit grain identifier with a compact base62 string form.
type GrainId uid.ID

// String returns the canonical base62 encoding.
func (id GrainId) String() string { return uid.ID(id).String() }

// MarshalJSON encodes the id as a JSON string.
func (id GrainId) MarshalJSON() ([]byte, error) {
	return json.Marshal(uid.ID(id).String())
}

// UnmarshalJSON decodes from a base62 JSON string.
func (id *GrainId) UnmarshalJSON(data []byte) error {
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		return err
	}
	parsed, ok := ParseGrainId(s)
	if !ok {
		return fmt.Errorf("invalid grain id: %q", s)
	}
	*id = parsed
	return nil
}

// NewGrainId generates a new cryptographically random non-zero 64-bit id.
func NewGrainId() (GrainId, error) {
	id, err := uid.New()
	if err != nil {
		return 0, fmt.Errorf("NewGrainId: %w", err)
	}
	return GrainId(id), nil
}

// MustNewGrainId panics if generation fails.
func MustNewGrainId() GrainId {
	id, err := NewGrainId()
	if err != nil {
		panic(err)
	}
	return id
}

// ParseGrainId parses a base62 string into a GrainId.
func ParseGrainId(s string) (GrainId, bool) {
	id, ok := uid.Parse(s)
	return GrainId(id), ok
}

// MustParseGrainId panics on invalid base62 input.
func MustParseGrainId(s string) GrainId {
	id, ok := ParseGrainId(s)
	if !ok {
		panic(fmt.Sprintf("invalid grain id: %q", s))
	}
	return id
}