package local

import (
	"fmt"
	"strings"

	"galaxy/user/internal/domain/account"
	"galaxy/user/internal/domain/common"
	"galaxy/user/internal/ports"

	confusables "github.com/disciplinedware/go-confusables"
	"golang.org/x/text/cases"
)

type confusableSkeletoner interface {
	Skeleton(string) string
}

type raceNamePolicy struct {
	caseFolder cases.Caser
	skeletoner confusableSkeletoner
}

var raceNameAntiFraudReplacer = strings.NewReplacer(
	"1", "i",
	"0", "o",
	"8", "b",
)

// NewRaceNamePolicy returns the local Stage 06 race-name canonicalization
// policy backed by Unicode case folding, explicit ASCII anti-fraud mappings,
// and a TR39 confusable skeleton.
func NewRaceNamePolicy() (ports.RaceNamePolicy, error) {
	policy := &raceNamePolicy{
		caseFolder: cases.Fold(),
		skeletoner: confusables.Default(),
	}
	if policy.skeletoner == nil {
		return nil, fmt.Errorf("new race-name policy: nil confusable skeletoner")
	}

	return policy, nil
}

// CanonicalKey returns the stable uniqueness key for raceName.
func (policy *raceNamePolicy) CanonicalKey(raceName common.RaceName) (account.RaceNameCanonicalKey, error) {
	switch {
	case policy == nil:
		return "", fmt.Errorf("canonicalize race name: nil policy")
	case policy.skeletoner == nil:
		return "", fmt.Errorf("canonicalize race name: nil confusable skeletoner")
	}
	if err := raceName.Validate(); err != nil {
		return "", fmt.Errorf("canonicalize race name: %w", err)
	}

	folded := policy.caseFolder.String(raceName.String())
	antiFraudMapped := raceNameAntiFraudReplacer.Replace(folded)
	key := account.RaceNameCanonicalKey(policy.skeletoner.Skeleton(antiFraudMapped))
	if err := key.Validate(); err != nil {
		return "", fmt.Errorf("canonicalize race name: %w", err)
	}

	return key, nil
}