task

type Event struct {
	Message  *string
	Progress *float32
}

type EventFunc func(p *Event)

type Factory func(id ID, payload []byte) (Task, error)

type Handler interface {
	Handle(ctx context.Context, task Task, events chan Event) error
}

type HandlerFunc func(ctx context.Context, task Task, events chan Event) error

type ID string

type PersistentRunner interface {
	RegisterFactory(taskType Type, factory Factory)
}

type Runner interface {
	ScheduleTask(ctx context.Context, task Task) error
	GetTaskState(ctx context.Context, id ID) (*State, error)
	GetTask(ctx context.Context, id ID) (Task, error)
	ListTasks(ctx context.Context) ([]StateHeader, error)
	RegisterTask(taskType Type, handler Handler)
	// CancelTask cancels a scheduled or running task
	// A canceled task should return the error ErrCanceled
	CancelTask(ctx context.Context, id ID) error
	Run(ctx context.Context) error
}

type State struct {
	StateHeader
	FinishedAt time.Time
	Progress   float32
	Error      error
	Message    string
}

type StateHeader struct {
	ID          ID
	Type        Type
	ScheduledAt time.Time
	Status      Status
}

type Status string

type Task interface {
	json.Marshaler
	json.Unmarshaler

	ID() ID
	Type() Type
}

type Type string