using GongSolutions.Wpf.DragDrop;
using GongSolutions.Wpf.DragDrop.Utilities;
using OpenTap;
using System.Windows;

namespace OpenTapEditor.Util
{
    public class StepTreeDragHandler: DefaultDropHandler
    {
        public bool CanConvert(IDropInfo dropInfo)
        {
            if (!(dropInfo.TargetItem is TestStep target))
            {
                return false;
            }

            if (!(dropInfo.Data is TestStep source))
            {
                return false;
            }

            if (source == target)
            {
                return false;
            }
            var tType = target.GetType();
            var sType = source.GetType();
            if (!dropInfo.InsertPosition.HasFlag(RelativeInsertPosition.TargetItemCenter))
            {
                return true;
            }

            if (!TestStepList.AllowChild(tType, sType))
            {
                return false;
            }

            //if(source.)

            //if (target.sequence != source.sequence)
            //{
            //    return false;
            //}
            return true;
        }

        public override void DragOver(IDropInfo dropInfo)
        {
            if (CanConvert(dropInfo))
            {
                dropInfo.Effects = DragDropEffects.Move;

                if (dropInfo.InsertPosition.HasFlag(RelativeInsertPosition.TargetItemCenter))
                {
                    dropInfo.DropTargetAdorner = null;
                }
                else
                {
                    dropInfo.DropTargetAdorner = DropTargetAdorners.Insert;
                }

                //if (dropInfo.DropTargetAdorner == DropTargetAdorners.Highlight) { 

                //}
                //dropInfo.DropTargetAdorner = DropTargetAdorners.Insert;
                dropInfo.DropTargetHintState = DropHintState.Active;
                dropInfo.DropTargetHintAdorner = DropTargetAdorners.Hint;
            }
            else
            {
                dropInfo.Effects = DragDropEffects.None;
                dropInfo.DropTargetHintAdorner = DropTargetAdorners.Hint;
                dropInfo.DropTargetHintState = DropHintState.Error;
            }
        }

        public override void Drop(IDropInfo dropInfo)
        {
            if (dropInfo?.DragInfo == null)
            {
                return;
            }

            if (!CanConvert(dropInfo))
            {
                return;
            }

            ITestStep target = dropInfo.TargetItem as ITestStep;

            var insertIndex = GetInsertIndex(dropInfo);
            var destinationList = dropInfo.TargetCollection.TryGetList();
            var data = ExtractData(dropInfo.Data).OfType<object>().ToList();
            bool isSameCollection = false;

            var copyData = ShouldCopyData(dropInfo);
            if (!copyData)
            {
                var sourceList = dropInfo.DragInfo.SourceCollection.TryGetList();
                if (sourceList != null)
                {
                    isSameCollection = sourceList.IsSameObservableCollection(destinationList);
                    if (!isSameCollection)
                    {
                        foreach (var o in data)
                        {
                            var index = sourceList.IndexOf(o);
                            if (index != -1)
                            {
                                sourceList.RemoveAt(index);

                                // If source is destination too fix the insertion index
                                if (destinationList != null && ReferenceEquals(sourceList, destinationList) && index < insertIndex)
                                {
                                    --insertIndex;
                                }
                            }
                        }
                    }
                }
            }

            if (destinationList != null)
            {
                var objects2Insert = new List<object>();

                // check for cloning
                var cloneData = dropInfo.Effects.HasFlag(DragDropEffects.Copy) || dropInfo.Effects.HasFlag(DragDropEffects.Link);

                foreach (var o in data)
                {
                    var obj2Insert = o;
                    if (cloneData)
                    {
                        if (o is ICloneableDragItem cloneableItem)
                        {
                            obj2Insert = cloneableItem.CloneItem(dropInfo);
                        }
                        else if (o is ICloneable cloneable)
                        {
                            obj2Insert = cloneable.Clone();
                        }
                    }

                    objects2Insert.Add(obj2Insert);

                    if (!cloneData && isSameCollection)
                    {
                        var index = destinationList.IndexOf(o);
                        if (index != -1)
                        {
                            if (insertIndex > index)
                            {
                                insertIndex--;
                            }

                            Move(destinationList, index, insertIndex++);
                        }
                    }
                    else
                    {
                        destinationList.Insert(insertIndex++, obj2Insert);
                    }

                    if (obj2Insert is IDragItemSource dragItemSource)
                    {
                        dragItemSource.ItemDropped(dropInfo);
                    }
                }

                SelectDroppedItems(dropInfo, objects2Insert);
            }
        }
    }
}