package dsUtils

// ICBuf is a basic Circular buffer interface
type ICBuf[T any] interface {
	Push(item T)
	Get() []T
}

// CBuf is the implementation of ICBuf interface
// Simplest circular buffer implementation
// If thread safety is needed -- use CBufSync
//
// WARNING: It's not thread-safe by default,
// use it with a lock
type CBuf[T any] struct {
	ICBuf[T]
	Buffer   []T
	Cursor   int
	Capacity int
}

// NewCBuf creates a new CBuf instance
func NewCBuf[T any](capacity int) *CBuf[T] {
	return &CBuf[T]{
		Buffer:   make([]T, capacity),
		Capacity: capacity,
	}
}

func (cbuf *CBuf[T]) Push(item T) {
	cbuf.Buffer[cbuf.Cursor] = item
	cbuf.Cursor++
	if cbuf.Cursor >= cbuf.Capacity {
		cbuf.Cursor = 0
	}
	println(cbuf.Cursor)
}

// This method isn't a part of ICBuf interface
//
// It pushes item to the "buffer start"
// (Right before the cursor)
// removing item from back
func (cbuf *CBuf[T]) PushFront(item T) {
	cbuf.Buffer = append(
		append(cbuf.Buffer[cbuf.Cursor+1:], cbuf.Buffer[:cbuf.Cursor]...),
		item,
	)
	cbuf.Cursor = 0
}

// Get returns the whole buffer in the correct order
func (cbuf *CBuf[T]) Get() []T {
	out := make([]T, 0, cbuf.Capacity)
	copy(out, cbuf.Buffer[cbuf.Cursor:])
	out = append(out, cbuf.Buffer[:cbuf.Cursor]...)
	return out
}