package stanza

// FIFO queue for string contents
// Implementations have no guarantee regarding thread safety !
type FifoQueue interface {
	// Pop returns the first inserted element still in queue and deletes it from queue. If queue is empty, returns nil
	// No guarantee regarding thread safety !
	Pop() Queueable

	// PopN returns the N first inserted elements still in queue and deletes them from queue. If queue is empty or i<=0, returns nil
	// If number to pop is greater than queue length, returns all queue elements
	// No guarantee regarding thread safety !
	PopN(i int) []Queueable

	// Peek returns a copy of the first inserted element in queue without deleting it. If queue is empty, returns nil
	// No guarantee regarding thread safety !
	Peek() Queueable

	// Peek returns a copy of the first inserted element in queue without deleting it. If queue is empty or i<=0, returns nil.
	// If number to peek is greater than queue length, returns all queue elements
	// No guarantee regarding thread safety !
	PeekN() []Queueable
	// Push adds an element to the queue
	// No guarantee regarding thread safety !
	Push(s Queueable) error

	// Empty returns true if queue is empty
	// No guarantee regarding thread safety !
	Empty() bool
}

type Queueable interface {
	QueueableName() string
}