coupon

type Application struct {
	ID             id.CouponApplicationID `json:"id"`
	CouponID       id.CouponID            `json:"coupon_id"`
	SubscriptionID id.SubscriptionID      `json:"subscription_id"`
	AppliedAt      time.Time              `json:"applied_at"`
}

type Coupon struct {
	types.Entity
	ID             id.CouponID       `json:"id"`
	Code           string            `json:"code"`
	Name           string            `json:"name"`
	Type           CouponType        `json:"type"`
	Amount         types.Money       `json:"amount,omitempty"`
	Percentage     int               `json:"percentage,omitempty"`
	Currency       string            `json:"currency"`
	MaxRedemptions int               `json:"max_redemptions"`
	TimesRedeemed  int               `json:"times_redeemed"`
	ValidFrom      *time.Time        `json:"valid_from,omitempty"`
	ValidUntil     *time.Time        `json:"valid_until,omitempty"`
	AppID          string            `json:"app_id"`
	Metadata       map[string]string `json:"metadata,omitempty"`
}

type CouponType string

type ListOpts struct {
	Active bool
	Limit  int
	Offset int
}

type Store interface {
	Create(ctx context.Context, c *Coupon) error
	Get(ctx context.Context, code string, appID string) (*Coupon, error)
	GetByID(ctx context.Context, couponID id.CouponID) (*Coupon, error)
	List(ctx context.Context, appID string, opts ListOpts) ([]*Coupon, error)
	Update(ctx context.Context, c *Coupon) error
	Delete(ctx context.Context, couponID id.CouponID) error

	// Apply and IncrementRedemptions are low-level operations kept for
	// backends and tests that need them separately. Engine code redeems
	// through Redeem, which performs both as one unit.
	Apply(ctx context.Context, subID id.SubscriptionID, couponID id.CouponID) error
	ListApplied(ctx context.Context, subID id.SubscriptionID) ([]*Coupon, error)
	IncrementRedemptions(ctx context.Context, couponID id.CouponID) error
	// Redeem records a coupon's application and increments its redemption
	// count as a single unit, enforcing the redemption cap with a
	// conditional increment rather than a read followed by a write.
	Redeem(ctx context.Context, subID id.SubscriptionID, couponID id.CouponID) error
}