PixiEditor/src/PixiEditor.ChangeableDocument/Changes/Structure/CreateStructureMember_Change.cs

using PixiEditor.ChangeableDocument.Changeables;
using PixiEditor.ChangeableDocument.ChangeInfos;
using PixiEditor.ChangeableDocument.ChangeInfos.Structure;
using PixiEditor.ChangeableDocument.Enums;

namespace PixiEditor.ChangeableDocument.Changes.Structure;

internal class CreateStructureMember_Change : Change
{
    private Guid newMemberGuid;

    private Guid parentFolderGuid;
    private int parentFolderIndex;
    private StructureMemberType type;

    [GenerateMakeChangeAction]
    public CreateStructureMember_Change(Guid parentFolder, Guid newGuid, int parentFolderIndex, StructureMemberType type)
    {
        this.parentFolderGuid = parentFolder;
        this.parentFolderIndex = parentFolderIndex;
        this.type = type;
        newMemberGuid = newGuid;
    }

    public override void Initialize(Document target) { }

    public override IChangeInfo Apply(Document document, out bool ignoreInUndo)
    {
        var folder = (Folder)document.FindMemberOrThrow(parentFolderGuid);

        StructureMember member = type switch
        {
            StructureMemberType.Layer => new Layer(document.Size) { GuidValue = newMemberGuid },
            StructureMemberType.Folder => new Folder() { GuidValue = newMemberGuid },
            _ => throw new InvalidOperationException("Cannon create member of type " + type.ToString())
        };

        folder.Children.Insert(parentFolderIndex, member);

        ignoreInUndo = false;
        return new CreateStructureMember_ChangeInfo() { GuidValue = newMemberGuid };
    }

    public override IChangeInfo Revert(Document document)
    {
        var folder = (Folder)document.FindMemberOrThrow(parentFolderGuid);
        var child = document.FindMemberOrThrow(newMemberGuid);
        child.Dispose();
        folder.Children.RemoveAt(folder.Children.FindIndex(child => child.GuidValue == newMemberGuid));

        return new DeleteStructureMember_ChangeInfo() { GuidValue = newMemberGuid, ParentGuid = parentFolderGuid };
    }
}