package repository

import (
	"context"
	"fmt"
	"strconv"
	"strings"

	redislib "gateway/internal/library/redis"
	member "gateway/internal/model/member/domain"
	domrepo "gateway/internal/model/member/domain/repository"
)

type uidGenerator struct {
	redis *redislib.Client
}

// NewRedisUIDGenerator allocates readable UIDs using Redis INCR.
func NewRedisUIDGenerator(rds *redislib.Client) domrepo.UIDGenerator {
	return &uidGenerator{redis: rds}
}

func (g *uidGenerator) Next(ctx context.Context, tenantID, uidPrefix string) (string, error) {
	if tenantID == "" || uidPrefix == "" {
		return "", fmt.Errorf("member: tenant_id and uid_prefix are required")
	}
	key := member.GetMemberSeqRedisKey(tenantID)
	seq, err := g.redis.Zero().IncrCtx(ctx, key)
	if err != nil {
		return "", err
	}
	if seq == 1 {
		seq, err = g.redis.Zero().IncrbyCtx(ctx, key, member.UIDSequenceStart-1)
		if err != nil {
			return "", err
		}
	}
	return strings.ToUpper(uidPrefix) + "-" + strconv.FormatInt(seq, 10), nil
}

var _ domrepo.UIDGenerator = (*uidGenerator)(nil)