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//
// LocationDiffableDataSourceProtocol.swift
// MullvadVPNUITests
//
// Created by Jon Petersson on 2024-03-27.
// Copyright © 2025 Mullvad VPN AB. All rights reserved.
//
import MullvadTypes
import UIKit
protocol LocationDiffableDataSourceProtocol: UITableViewDiffableDataSource<LocationSection, LocationCellViewModel> {
var tableView: UITableView { get }
var sections: [LocationSection] { get }
func nodeShowsChildren(_ node: LocationNode) -> Bool
func nodeShouldBeSelected(_ node: LocationNode) -> Bool
}
extension LocationDiffableDataSourceProtocol {
func scroll(to item: LocationCellViewModel, animated: Bool) {
guard
let visibleIndexPaths = tableView.indexPathsForVisibleRows,
let indexPath = indexPath(for: item)
else { return }
if item.node.children.count > visibleIndexPaths.count {
tableView.scrollToRow(at: indexPath, at: .top, animated: animated)
} else {
if let last = item.node.children.last {
if let lastInsertedIndexPath = self.indexPath(
for: LocationCellViewModel(
section: sections[indexPath.section],
node: last
)),
let lastVisibleIndexPath = visibleIndexPaths.last,
lastInsertedIndexPath >= lastVisibleIndexPath
{
tableView.scrollToRow(at: lastInsertedIndexPath, at: .bottom, animated: animated)
}
}
}
}
func toggleItems(for cell: LocationCell, completion: (() -> Void)? = nil) {
guard let indexPath = tableView.indexPath(for: cell),
let item = itemIdentifier(for: indexPath)
else { return }
let snapshot = snapshot()
let section = sections[indexPath.section]
let isExpanded = item.node.showsChildren
var locationList = snapshot.itemIdentifiers(inSection: section)
item.node.showsChildren = !isExpanded
if !isExpanded {
locationList.addSubNodes(from: item, at: indexPath)
addItem(locationList, toSection: section, index: indexPath.row, completion: completion)
} else {
locationList.removeSubNodes(from: item.node)
updateSnapshotRetainingOnly(locationList, toSection: section, completion: completion)
}
}
private func addItem(
_ items: [LocationCellViewModel],
toSection section: LocationSection,
index: Int,
completion: (() -> Void)? = nil
) {
var snapshot = snapshot()
let existingItems = snapshot.itemIdentifiers(inSection: section)
// Filter itemsToAdd to only include items not already in the section
let uniqueItems = items.filter { item in
existingItems.firstIndex(where: { $0 == item }) == nil
}
// Insert unique items at the specified index
if index < existingItems.count {
snapshot.insertItems(uniqueItems, afterItem: existingItems[index])
} else {
// If the index is beyond bounds, append to the end
snapshot.appendItems(uniqueItems, toSection: section)
}
applyAndReconfigureSnapshot(snapshot, in: section, completion: completion)
}
private func updateSnapshotRetainingOnly(
_ itemsToKeep: [LocationCellViewModel],
toSection section: LocationSection,
completion: (() -> Void)? = nil
) {
var snapshot = snapshot()
// Ensure the section exists in the snapshot
guard snapshot.sectionIdentifiers.contains(section) else { return }
// Get the current items in the section
let currentItems = snapshot.itemIdentifiers(inSection: section)
// Determine the items that should be deleted
let itemsToDelete = currentItems.filter { !itemsToKeep.contains($0) }
snapshot.deleteItems(itemsToDelete)
// Apply the updated snapshot
applyAndReconfigureSnapshot(snapshot, in: section, completion: completion)
}
private func applyAndReconfigureSnapshot(
_ snapshot: NSDiffableDataSourceSnapshot<LocationSection, LocationCellViewModel>,
in section: LocationSection,
completion: (() -> Void)? = nil
) {
self.apply(snapshot, animatingDifferences: true) {
// After adding, reconfigure specified items to update their content
var updatedSnapshot = self.snapshot()
// Ensure the items exist in the snapshot before attempting to reconfigure
let existingItems = updatedSnapshot.itemIdentifiers(inSection: section)
// Reconfigure the specified items
updatedSnapshot.reconfigureItems(existingItems)
// Apply the reconfigured snapshot without animations to avoid any flickering
self.apply(updatedSnapshot, animatingDifferences: false)
}
}
func reloadDataSnapshot(
with list: [[LocationCellViewModel]],
animated: Bool = false,
completion: (() -> Void)? = nil
) {
var snapshot = NSDiffableDataSourceSnapshot<LocationSection, LocationCellViewModel>()
snapshot.appendSections(sections)
for (index, section) in sections.enumerated() {
let items = list[index]
snapshot.appendItems(items, toSection: section)
}
self.apply(snapshot, animatingDifferences: animated, completion: completion)
}
func recursivelyCreateCellViewModelTree(
for node: LocationNode,
in section: LocationSection,
indentationLevel: Int
) -> [LocationCellViewModel] {
var viewModels = [LocationCellViewModel]()
for childNode in node.children where !childNode.isHiddenFromSearch {
viewModels.append(
LocationCellViewModel(
section: section,
node: childNode,
indentationLevel: indentationLevel,
isSelected: nodeShouldBeSelected(childNode)
)
)
if nodeShowsChildren(childNode) {
viewModels.append(
contentsOf: recursivelyCreateCellViewModelTree(
for: childNode,
in: section,
indentationLevel: indentationLevel + 1
)
)
}
}
return viewModels
}
}
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