import SwiftUI
import UniformTypeIdentifiers

struct ContentView: View {
    @State var items = ["1", "2", "3"]
    @State var draggedItem : String?
    @State var isHovering: Bool = false

    var body: some View {
        VStack {
            ForEach(items, id:\.self) { item in
                HStack {
                    Image(systemName: "line.horizontal.3")
                    Text(item)
                }
                .frame(minWidth: 0, maxWidth: .infinity, minHeight: 50)
                .border(Color.black).background(Color.teal)
                .onDrag({
                    self.draggedItem = item
                    return NSItemProvider(item: nil, typeIdentifier: item)
                })
                .onDrop(of: [UTType.text], delegate: MyDropDelegate(item: item, items: $items, draggedItem: $draggedItem))
            }
            .onMove { indices, newOffset in
                self.items.move(
                    fromOffsets: indices,
                    toOffset: newOffset
                )
            }
        }
    }
}

struct MyDropDelegate : DropDelegate {
    let item : String
    @Binding var items : [String]
    @Binding var draggedItem : String?

    func validateDrop(info: DropInfo) -> Bool {
        return true
    }

    func dropUpdated(info: DropInfo) -> DropProposal? {
        return DropProposal(operation: .move)
    }

    func performDrop(info: DropInfo) -> Bool {
        return true
    }

    func dropEntered(info: DropInfo) {
        guard let draggedItem = self.draggedItem else {
            return
        }

        if draggedItem != item {
            let from = items.firstIndex(of: draggedItem)!
            let to = items.firstIndex(of: item)!
            withAnimation(.default) {
                self.items.move(fromOffsets: IndexSet(integer: from), toOffset: to > from ? to + 1 : to)
            }
        }
    }
}