Enable favorites reordering on New Tab Page (#3169)

Task/Issue URL:
https://app.asana.com/0/1206226850447395/1207932325145653/f
Tech Design URL:
CC:

**Description**:

Adds reordering capability for Favorites on New Tab Page.

**Steps to test this PR**:
1. Reorder Favorites in different ways (to last, to first etc.)
2. Verify if the order is preserved across launches and NTP instances.
3. Check if the order is reflected in the Bookmakrs/Favorites list

DuckDuckGo/Favorite.swift

@@ -20,7 +20,7 @@
 import Bookmarks
 import SwiftUI
 
-struct Favorite: Identifiable, Equatable {
+struct Favorite: Identifiable, Equatable, Hashable {
     let id: String
     let title: String
     let domain: String

DuckDuckGo/FavoritesDefaultModel.swift

@@ -114,6 +114,19 @@ final class FavoritesDefaultModel: FavoritesModel {
         onFavoriteEdit?(entity)
     }
 
+    func moveFavorites(from indexSet: IndexSet, to index: Int) {
+        guard indexSet.count == 1,
+              let fromIndex = indexSet.first else { return }
+
+        let favorite = allFavorites[fromIndex]
+        guard let entity = lookupEntity(for: favorite) else { return }
+
+        // adjust for different target index handling
+        let toIndex = index > fromIndex ? index - 1 : index
+        interactionModel.moveFavorite(entity, fromIndex: fromIndex, toIndex: toIndex)
+        allFavorites.move(fromOffsets: IndexSet(integer: fromIndex), toOffset: index)
+    }
+
     private func lookupEntity(for favorite: Favorite) -> BookmarkEntity? {
         interactionModel.favorites.first {
             $0.uuid == favorite.id

DuckDuckGo/FavoritesModel.swift

@@ -37,6 +37,7 @@ protocol FavoritesModel: AnyObject, ObservableObject {
     func favoriteSelected(_ favorite: Favorite)
     func editFavorite(_ favorite: Favorite)
     func deleteFavorite(_ favorite: Favorite)
+    func moveFavorites(from indexSet: IndexSet, to index: Int)
 }
 
 struct FavoritesSlice {

DuckDuckGo/FavoritesPreviewModel.swift

@@ -71,6 +71,10 @@ final class FavoritesPreviewModel: FavoritesModel {
 
     }
 
+    func moveFavorites(from indexSet: IndexSet, to index: Int) {
+        allFavorites.move(fromOffsets: indexSet, toOffset: index)
+    }
+
     func loadFavicon(for favorite: Favorite, size: CGFloat) async {
 
     }

DuckDuckGo/FavoritesView.swift

@@ -19,6 +19,7 @@
 
 import Bookmarks
 import SwiftUI
+import UniformTypeIdentifiers
 
 struct FavoritesView<Model: FavoritesModel>: View {
     @Environment(\.horizontalSizeClass) var horizontalSizeClass
@@ -35,7 +36,7 @@ struct FavoritesView<Model: FavoritesModel>: View {
             let result = model.prefixedFavorites(for: columns)
 
             NewTabPageGridView { _ in
-                ForEach(result.items) { item in
+                ReorderableForEach(result.items) { item in
                     Button(action: {
                         model.favoriteSelected(item)
                         selectionFeedback.selectionChanged()
@@ -52,6 +53,15 @@ struct FavoritesView<Model: FavoritesModel>: View {
                         .background(.clear)
                         .frame(width: NewTabPageGrid.Item.edgeSize)
                     })
+                    .previewShape()
+                } preview: { favorite in
+                    FavoriteIconView(favorite: favorite, faviconLoading: model.faviconLoader)
+                        .frame(width: NewTabPageGrid.Item.edgeSize)
+                        .previewShape()
+                } onMove: { from, to in
+                    withAnimation {
+                        model.moveFavorites(from: from, to: to)
+                    }
                 }
             }
 
@@ -70,6 +80,22 @@ struct FavoritesView<Model: FavoritesModel>: View {
     }
 }
 
+private extension View {
+    func previewShape() -> some View {
+        contentShape(.dragPreview, RoundedRectangle(cornerRadius: 8))
+    }
+}
+
+extension Favorite: Reorderable {
+    var dropItemProvider: NSItemProvider {
+        NSItemProvider(object: (urlObject?.absoluteString ?? "") as NSString)
+    }
+
+    var dropType: UTType {
+        .plainText
+    }
+}
+
 #Preview {
     FavoritesView(model: FavoritesPreviewModel())
 }