feat: add otp redis repo

internal/repository/cache/otp_repo.go

@@ -0,0 +1,53 @@
+package cache
+
+import (
+	"backend/internal/domain"
+	"backend/pkg/cache"
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+type OTPRepository struct {
+	redis *cache.Redis
+}
+
+func NewOTPRepository(redis *cache.Redis) domain.OTPRepo {
+	return &OTPRepository{
+		redis: redis,
+	}
+}
+
+func (r *OTPRepository) Create(ctx context.Context, phone string, otp *domain.OTP) error {
+	key := r.getOTPKey(phone)
+
+	otpData, err := json.Marshal(otp)
+	if err != nil {
+		return fmt.Errorf("failed to marshal otp: %w", err)
+	}
+
+	ttl := time.Until(otp.ExpiredAt)
+	if ttl <= 0 {
+		return fmt.Errorf("OTP expired already")
+	}
+
+	if err := r.redis.Client().Set(ctx, key, otpData, ttl).Err(); err != nil {
+		return fmt.Errorf("failed to store otp in redis: %w", err)
+	}
+	return nil
+}
+
+func (r *OTPRepository) Delete(ctx context.Context, phone string) error {
+	key := r.getOTPKey(phone)
+
+	if err := r.redis.Client().Del(ctx, key).Err(); err != nil {
+		return fmt.Errorf("failed to del otp from redis")
+	}
+
+	return nil
+}
+
+func (r *OTPRepository) getOTPKey(phone string) string {
+	return fmt.Sprintf("challenge:%s", phone)
+}