using System;

namespace LinkedList
{
    public static class Helpers
    {
        public static void InsertItem<T>(ref Item<T> start, T val, Func<T, Item<T>, bool> insertBefore)
        {
            Console.WriteLine($"Creating item: {val}");
            Item<T> current = start, previous = null;

            while (current != null && !insertBefore(val, current))
            {
                previous = current;
                current = current.next;
            }
            Item<T> item = new Item<T>(val, current);

            if (previous == null)
            {
                start = item;
            }
            else
            {
                previous.next = item;
            }
        }

        public static void RemoveItem<T>(ref Item<T> start, T val, Func<Item<T>, T, bool> valueEquals)
        {
            Item<T> current = start, previous = null;

            while (current != null && !valueEquals(current, val))
            {
                previous = current;
                current = current.next;
            }

            if (current == null)
            {
                Console.WriteLine($"Item {val} does not exist!");
            }
            else
            {
                if (previous == null)
                {
                    start = current.next;
                }
                else
                {
                    previous.next = current.next;
                }
                Console.WriteLine($"Removed item: {val}");
            }
        }

        public static void RemoveAll<T>(ref Item<T> start) => start = null;

        public static void PrintList<T>(Item<T> start)
        {
            while (start != null)
            {
                start = start.PrintGetNext();
            }
        }

        public static void PrintIterator<T>(Item<T> start)
        {
            if (start != null)
            {
                foreach (var item in start.GetIterator())
                {
                    item.PrintGetNext();
                }
            }
        }

        public static void PrintArray<T>(Item<T> start)
        {
            var item = start;
            for (int i = 0; item != null; ++i)
            {
                item = start[i].PrintGetNext();
            }
        }

        public static void PrintRecursive<T>(Item<T> start)
        {
            if (start != null)
            {
                PrintRecursive(start.PrintGetNext());
            }
        }
    }
}