package generics

import (
	"fmt"
	"io"
	"os"
)

type LinkedList[T any] struct {
	Head *LinkedListElement[T]
	Tail *LinkedListElement[T]
}

type LinkedListElement[T any] struct {
	Next  *LinkedListElement[T]
	Value T
}

func NewLinkedList[T any]() *LinkedList[T] {
	return &LinkedList[T]{}
}

func (lst *LinkedList[T]) Push(value T) *LinkedListElement[T] {
	node := &LinkedListElement[T]{
		Value: value,
	}

	if lst.Head == nil {
		lst.Head = node
		lst.Tail = node
	}

	lst.Tail.Next = node
	lst.Tail = lst.Tail.Next

	return lst.Tail
}

func (lst *LinkedList[T]) Print(out io.Writer) {
	curr := lst.Head

	for curr != nil {
		fmt.Fprint(out, curr.Value)

		if curr.Next != nil {
			fmt.Fprint(out, " → ")
		}

		curr = curr.Next
	}

	fmt.Fprintln(out)
}

func Generics() {
	lst := NewLinkedList[int]()

	for i := range 5 {
		lst.Push(i)
	}

	lst.Print(os.Stdout)
}