func (payment *Payment) advance(targetState PaymentStatus) error {
if !targetState.canAdvance {
return fmt.Errorf("Won't advance payment to %v", targetState)
}
for payment.status.order < targetState.order {
previousStatus := payment.status
var err error
switch previousStatus {
case PaymentCreated:
err = payment.advanceToPending()
case PaymentPending:
err = payment.advanceToCommitted()
default:
return services.Conflictf("Cannot advance %v payment", previousStatus)
}
if err != nil {
return fmt.Errorf("Failed to advance %v payment: %v", previousStatus, err)
}
if previousStatus.order == payment.status.order {
// Avoid infinite loop
return fmt.Errorf("Status of %v payment did not change", previousStatus)
}
}
return nil
}
func (shipment *Shipment) doDeliver() error {
return shipment.modifyItem("delivering",
func(item *Item) error {
if item.Reserved < shipment.Quantity {
return services.Conflictf("Cannot deliver %v %v: Only %v reserved", shipment.Quantity, item.Name, item.Reserved)
}
item.Reserved -= shipment.Quantity
item.Shipped += shipment.Quantity
shipment.Status = catalogApi.ShipmentDelivered
return nil
})
}
func (shipment *Shipment) doCommit() error {
return shipment.modifyItem("committing",
func(item *Item) error {
if item.Stock < shipment.Quantity {
return services.Conflictf("Cannot commit %v %v: Only %v in stock", shipment.Quantity, item.Name, item.Stock)
}
item.Stock -= shipment.Quantity
item.Reserved += shipment.Quantity
shipment.Status = catalogApi.ShipmentCommitted
return nil
})
}
func (shipment *Shipment) Commit() error {
if err := shipment.lock.Lock(); err != nil {
return fmt.Errorf("Failed to lock shipment: %v", err)
}
defer shipment.unlock()
switch shipment.Status {
case catalogApi.ShipmentCreated:
return shipment.doCommit()
case catalogApi.ShipmentCommitted, catalogApi.ShipmentDelivered:
return nil
default:
return services.Conflictf("Cannot commit %v shipment", shipment.Status)
}
}
func (shipment *Shipment) Deliver() error {
if err := shipment.lock.Lock(); err != nil {
return fmt.Errorf("Failed to lock shipment: %v", err)
}
defer shipment.unlock()
switch shipment.Status {
case catalogApi.ShipmentCreated:
if err := shipment.doCommit(); err != nil {
return err
}
if shipment.Status != catalogApi.ShipmentCommitted {
return fmt.Errorf("Shipment did not change to %v status", catalogApi.ShipmentCommitted)
}
return shipment.doDeliver()
case catalogApi.ShipmentCommitted:
return shipment.doDeliver()
case catalogApi.ShipmentDelivered:
return nil
default:
return services.Conflictf("Cannot deliver %v shipment", shipment.Status)
}
}
func (payment *Payment) Cancel() error {
defer payment.unlock()
switch payment.status {
case PaymentCreated, PaymentCancelled:
// Transaction has not been created yet, or already cancelled
return nil
case PaymentPending, PaymentCommitted:
trans, err := payment.getTransaction()
if err != nil {
return err
}
return trans.Cancel()
case PaymentProcessed:
trans, err := payment.getTransaction()
if err != nil {
return err
}
return trans.Revert()
default:
return services.Conflictf("Cannot cancel a %v payment", payment.status)
}
}