using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine.Assertions;

namespace RosettaUI
{
    public readonly partial struct ListBinder
    {
        public static Type GetItemBinderType(Type type)
        {
            var listType = IsIList(type)
                ? type
                : type.GetInterfaces().FirstOrDefault(IsIList);
            Assert.IsNotNull(listType, $"{type} does not Inherit from IList<>.");
            
            var itemType =  listType.GetGenericArguments()[0];
            return typeof(ListItemBinder<>).MakeGenericType(itemType);

            static bool IsIList(Type type) => type.IsGenericType && type.GetGenericTypeDefinition() == typeof(IList<>);
        }

        public static IListItemBinder CreateItemBinderAt(IBinder listBinder, int index)
        {
            var itemBinderType = GetItemBinderType(listBinder.ValueType);
            return CreateItemBinderAt(listBinder, index, itemBinderType);
        }

        private static IListItemBinder CreateItemBinderAt(IBinder listBinder, int index, Type itemBinderType)
            => Activator.CreateInstance(itemBinderType, listBinder, index) as IListItemBinder;

        public static IList GetIList(IBinder binder) => binder.GetObject() as IList;
        
        public static int GetCount(IBinder binder)
        {
            return GetIList(binder)?.Count ?? 0;
        }

        public static void SetCount(IBinder binder, int count)
        {
            var current = GetCount(binder);
            var diff = count - current;
            for (var i = 0; i < diff; ++i)
            {
                AddItemAtLast(binder);
            }

            for (var i = 0; i < -diff; ++i)
            {
                RemoveItemAtLast(binder);
            }
        }

        public static bool IsListBinder(IBinder binder)
        {
            var type = binder.ValueType;
            return typeof(IList).IsAssignableFrom(type)
                && type.GetInterfaces()
                    .Where(t => t.IsGenericType)
                    .Select(t => t.GetGenericTypeDefinition())
                    .Contains(typeof(IList<>));
        }

        public static bool IsReadOnly(IBinder binder) => binder.IsReadOnly || (GetIList(binder)?.IsReadOnly ?? false);


        public static void DuplicateItem(IBinder binder, int index)
        {
            var list = GetIList(binder);
            
            var itemType = ListUtility.GetItemType(binder.ValueType);
            var newItem = ListUtility.CreateNewItem(list[index], itemType);
            list = ListUtility.AddItem(list, itemType, newItem, index + 1);
            binder.SetObject(list);
        }

        public static void AddItem(IBinder binder, int index)
        {
            var list = GetIList(binder);
            
            var itemType = ListUtility.GetItemType(binder.ValueType);
            var newItem = ListUtility.CreateNewItem(null, itemType);
            
            list = ListUtility.AddItem(list, itemType, newItem, index);
            binder.SetObject(list);
        }
        
        public static void AddNullItem(IBinder binder, int index)
        {
            var list = GetIList(binder);
            
            var itemType = ListUtility.GetItemType(binder.ValueType);
            
            list = ListUtility.AddNullItem(list, itemType, index);
            binder.SetObject(list);
        }

        public static void RemoveItem(IBinder binder, int index)
            => RemoveItems(binder, index..(index + 1));
        
        public static void RemoveItems(IBinder binder, Range range)
        {
            var list = GetIList(binder);
            
            var itemType = ListUtility.GetItemType(binder.ValueType);
            
            list = ListUtility.RemoveItems(list, itemType, range);
            binder.SetObject(list);
        }
        
        public static void MoveItem(IBinder binder, int fromIndex, int toIndex)
        {
            var list = GetIList(binder);
            ListUtility.MoveItem(list, fromIndex, toIndex);
            binder.SetObject(list);
        }

        public static void AddItemAtLast(IBinder binder)
        {
            var list = GetIList(binder);
            
            var listType = binder.ValueType;
            var itemType = ListUtility.GetItemType(binder.ValueType);

            list = ListUtility.AddItemAtLast(list, listType, itemType);
            binder.SetObject(list);
        }

        public static void RemoveItemAtLast(IBinder binder)
        {
            var list = GetIList(binder);
            
            var itemType = ListUtility.GetItemType(binder.ValueType);
            list = ListUtility.RemoveItemAtLast(list, itemType);
            binder.SetObject(list);
        }
    }
}