Add search operators UI on Mastodon 4.2

Closes #433

Packages/InstanceFeatures/Sources/InstanceFeatures/InstanceFeatures.swift

@@ -167,6 +167,10 @@ public class InstanceFeatures: ObservableObject {
         }
     }
     
+    public var searchOperators: Bool {
+        hasMastodonVersion(4, 2, 0)
+    }
+    
     public init() {
     }
     

Packages/Pachyderm/Sources/Pachyderm/Model/SearchOperatorType.swift

@@ -0,0 +1,19 @@
+//
+//  SearchOperatorType.swift
+//  Pachyderm
+//
+//  Created by Shadowfacts on 10/1/23.
+//
+
+import Foundation
+
+public enum SearchOperatorType: String, CaseIterable, Equatable {
+    case has
+    case `is`
+    case language
+    case from
+    case before
+    case during
+    case after
+    case `in`
+}

Tusker.xcodeproj/project.pbxproj

@@ -288,6 +288,7 @@
 		D6CA8CDE296387310050C433 /* SaveToPhotosActivity.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6CA8CDD296387310050C433 /* SaveToPhotosActivity.swift */; };
 		D6CF5B832AC65DDF00F15D83 /* NSCollectionLayoutSection+Readable.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6CF5B822AC65DDF00F15D83 /* NSCollectionLayoutSection+Readable.swift */; };
 		D6CF5B852AC7C56F00F15D83 /* MultiColumnCollectionViewLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6CF5B842AC7C56F00F15D83 /* MultiColumnCollectionViewLayout.swift */; };
+		D6CF5B892AC9BA6E00F15D83 /* MastodonSearchController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6CF5B882AC9BA6E00F15D83 /* MastodonSearchController.swift */; };
 		D6D12B2F2925D66500D528E1 /* TimelineGapCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6D12B2E2925D66500D528E1 /* TimelineGapCollectionViewCell.swift */; };
 		D6D12B56292D57E800D528E1 /* AccountCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6D12B55292D57E800D528E1 /* AccountCollectionViewCell.swift */; };
 		D6D12B58292D5B2C00D528E1 /* StatusActionAccountListCollectionViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6D12B57292D5B2C00D528E1 /* StatusActionAccountListCollectionViewController.swift */; };
@@ -339,6 +340,7 @@
 		D6EE63FB2551F7F60065485C /* StatusCollapseButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6EE63FA2551F7F60065485C /* StatusCollapseButton.swift */; };
 		D6F0B12B24A3071C001E48C3 /* MainSplitViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F0B12A24A3071C001E48C3 /* MainSplitViewController.swift */; };
 		D6F0B17524A3A1AA001E48C3 /* MainSidebarViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F0B17424A3A1AA001E48C3 /* MainSidebarViewController.swift */; };
+		D6F253CF2AC9F86300806D83 /* SearchTokenSuggestionCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F253CE2AC9F86300806D83 /* SearchTokenSuggestionCollectionViewCell.swift */; };
 		D6F2E965249E8BFD005846BB /* IssueReporterViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F2E963249E8BFD005846BB /* IssueReporterViewController.swift */; };
 		D6F2E966249E8BFD005846BB /* IssueReporterViewController.xib in Resources */ = {isa = PBXBuildFile; fileRef = D6F2E964249E8BFD005846BB /* IssueReporterViewController.xib */; };
 		D6F4D79429ECB0AF00351B87 /* UIBackgroundConfiguration+AppColors.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F4D79329ECB0AF00351B87 /* UIBackgroundConfiguration+AppColors.swift */; };
@@ -689,6 +691,7 @@
 		D6CA8CDD296387310050C433 /* SaveToPhotosActivity.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SaveToPhotosActivity.swift; sourceTree = "<group>"; };
 		D6CF5B822AC65DDF00F15D83 /* NSCollectionLayoutSection+Readable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NSCollectionLayoutSection+Readable.swift"; sourceTree = "<group>"; };
 		D6CF5B842AC7C56F00F15D83 /* MultiColumnCollectionViewLayout.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MultiColumnCollectionViewLayout.swift; sourceTree = "<group>"; };
+		D6CF5B882AC9BA6E00F15D83 /* MastodonSearchController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MastodonSearchController.swift; sourceTree = "<group>"; };
 		D6D12B2E2925D66500D528E1 /* TimelineGapCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineGapCollectionViewCell.swift; sourceTree = "<group>"; };
 		D6D12B55292D57E800D528E1 /* AccountCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AccountCollectionViewCell.swift; sourceTree = "<group>"; };
 		D6D12B57292D5B2C00D528E1 /* StatusActionAccountListCollectionViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StatusActionAccountListCollectionViewController.swift; sourceTree = "<group>"; };
@@ -750,6 +753,7 @@
 		D6EE63FA2551F7F60065485C /* StatusCollapseButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StatusCollapseButton.swift; sourceTree = "<group>"; };
 		D6F0B12A24A3071C001E48C3 /* MainSplitViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainSplitViewController.swift; sourceTree = "<group>"; };
 		D6F0B17424A3A1AA001E48C3 /* MainSidebarViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainSidebarViewController.swift; sourceTree = "<group>"; };
+		D6F253CE2AC9F86300806D83 /* SearchTokenSuggestionCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchTokenSuggestionCollectionViewCell.swift; sourceTree = "<group>"; };
 		D6F2E963249E8BFD005846BB /* IssueReporterViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IssueReporterViewController.swift; sourceTree = "<group>"; };
 		D6F2E964249E8BFD005846BB /* IssueReporterViewController.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = IssueReporterViewController.xib; sourceTree = "<group>"; };
 		D6F4D79329ECB0AF00351B87 /* UIBackgroundConfiguration+AppColors.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIBackgroundConfiguration+AppColors.swift"; sourceTree = "<group>"; };
@@ -1364,6 +1368,8 @@
 			isa = PBXGroup;
 			children = (
 				D6BC9DD9232D8BE5002CA326 /* SearchResultsViewController.swift */,
+				D6F253CE2AC9F86300806D83 /* SearchTokenSuggestionCollectionViewCell.swift */,
+				D6CF5B882AC9BA6E00F15D83 /* MastodonSearchController.swift */,
 			);
 			path = Search;
 			sourceTree = "<group>";
@@ -2130,6 +2136,7 @@
 				D620483423D3801D008A63EF /* LinkTextView.swift in Sources */,
 				D61F75882932DB6000C0B37F /* StatusSwipeActions.swift in Sources */,
 				D68A76EA295285D0001DA1B3 /* AddHashtagPinnedTimelineView.swift in Sources */,
+				D6F253CF2AC9F86300806D83 /* SearchTokenSuggestionCollectionViewCell.swift in Sources */,
 				D6D12B58292D5B2C00D528E1 /* StatusActionAccountListCollectionViewController.swift in Sources */,
 				D6412B0D24B0D4CF00F5412E /* ProfileHeaderView.swift in Sources */,
 				D641C77F213DC78A004B4513 /* InlineTextAttachment.swift in Sources */,
@@ -2212,6 +2219,7 @@
 				D6F0B12B24A3071C001E48C3 /* MainSplitViewController.swift in Sources */,
 				D6AEBB3E2321638100E5038B /* UIActivity+Types.swift in Sources */,
 				D61AC1D5232E9FA600C54D2D /* InstanceSelectorTableViewController.swift in Sources */,
+				D6CF5B892AC9BA6E00F15D83 /* MastodonSearchController.swift in Sources */,
 				D681E4D9246E346E0053414F /* AccountActivityItemSource.swift in Sources */,
 				D68015422401A74600D6103B /* MediaPrefsView.swift in Sources */,
 				D6093F9B25BDD4B9004811E6 /* HashtagSearchResultsViewController.swift in Sources */,

Tusker/Screens/Explore/ExploreViewController.swift

@@ -59,14 +59,7 @@ class ExploreViewController: UIViewController, UICollectionViewDelegate, Collect
         
         resultsController = SearchResultsViewController(mastodonController: mastodonController)
         resultsController.exploreNavigationController = self.navigationController!
-        searchController = UISearchController(searchResultsController: resultsController)
+        searchController = MastodonSearchController(searchResultsController: resultsController)
-        searchController.searchResultsUpdater = resultsController
-        if #available(iOS 16.0, *) {
-            searchController.scopeBarActivation = .onSearchActivation
-        }
-        searchController.searchBar.autocapitalizationType = .none
-        searchController.searchBar.delegate = resultsController
-        searchController.searchBar.scopeButtonTitles = SearchResultsViewController.Scope.allCases.map(\.title)
         definesPresentationContext = true
         
         navigationItem.searchController = searchController
@@ -88,13 +81,6 @@ class ExploreViewController: UIViewController, UICollectionViewDelegate, Collect
             )
             .sink { [unowned self] in self.updateHashtagsSection(followed: $0) }
             .store(in: &cancellables)
-        
-        let a = PassthroughSubject<Int, Never>()
-        let b = PassthroughSubject<Int, Never>()
-        
-        a.merge(with: b)
-            .sink(receiveValue: { print($0) })
-            .store(in: &cancellables)
     }
     
     override func viewWillAppear(_ animated: Bool) {

Tusker/Screens/Explore/InlineTrendsViewController.swift

@@ -34,14 +34,8 @@ class InlineTrendsViewController: UIViewController {
 
         resultsController = SearchResultsViewController(mastodonController: mastodonController)
         resultsController.exploreNavigationController = self.navigationController
-        searchController = UISearchController(searchResultsController: resultsController)
+        searchController = MastodonSearchController(searchResultsController: resultsController)
         searchController.obscuresBackgroundDuringPresentation = true
-        if #available(iOS 16.0, *) {
-            searchController.scopeBarActivation = .onSearchActivation
-        }
-        searchController.searchBar.autocapitalizationType = .none
-        searchController.searchBar.delegate = resultsController
-        searchController.searchBar.scopeButtonTitles = SearchResultsViewController.Scope.allCases.map(\.title)
         searchController.hidesNavigationBarDuringPresentation = false
         definesPresentationContext = true
 

Tusker/Screens/Search/MastodonSearchController.swift

@@ -0,0 +1,174 @@
+//
+//  MastodonSearchController.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 10/1/23.
+//  Copyright © 2023 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+import Pachyderm
+
+private let acctRegex = try! NSRegularExpression(pattern: "[a-z0-9_]+(@[a-z0-9\\-\\.]+[a-z0-9]+)?$", options: .caseInsensitive)
+private let dateLikeRegex = try! NSRegularExpression(pattern: "\\d{4}(-\\d{2}(-\\d{2})?)?$")
+private let languageRegex = try! NSRegularExpression(pattern: "(?:language:)?(\\w{2,3})$", options: .caseInsensitive)
+
+class MastodonSearchController: UISearchController {
+    override var delegate: UISearchControllerDelegate? {
+        willSet {
+            precondition(newValue === self)
+        }
+    }
+    
+    override var searchResultsController: SearchResultsViewController {
+        super.searchResultsController as! SearchResultsViewController
+    }
+    
+    init(searchResultsController: SearchResultsViewController) {
+        super.init(searchResultsController: searchResultsController)
+        
+        searchResultsController.tokenHandler = { [unowned self] token, op in
+            self.addToken(token, operator: op)
+        }
+        
+        delegate = self
+        searchResultsUpdater = searchResultsController
+        automaticallyShowsSearchResultsController = false
+        showsSearchResultsController = true
+        if #available(iOS 16.0, *) {
+            scopeBarActivation = .onSearchActivation
+        }
+        
+        searchBar.autocapitalizationType = .none
+        searchBar.delegate = self
+        searchBar.scopeButtonTitles = SearchResultsViewController.Scope.allCases.map(\.title)
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    private func updateTokenSuggestions(searchText: String, animated: Bool) {
+        guard searchResultsController.mastodonController.instanceFeatures.searchOperators else {
+            return
+        }
+        
+        let searchText = searchText.trimmingCharacters(in: .whitespaces)
+        
+        var suggestions: [(SearchOperatorType, [String])] = []
+        
+        suggestions.append((.has, ["has:media", "has:poll", "has:embed"].filter {
+            searchText.isEmpty || $0.contains(searchText)
+        }))
+        
+        suggestions.append((.is, ["is:reply", "is:sensitive"].filter {
+            searchText.isEmpty || $0.contains(searchText)
+        }))
+        
+        // TODO: use default language from preferences
+        var langSuggestions = [String]()
+        if searchText.isEmpty || "language:en".contains(searchText) {
+            langSuggestions.append("language:en")
+        }
+        if searchText != "en",
+           let match = languageRegex.firstMatch(in: searchText, range: NSRange(location: 0, length: searchText.utf16.count)) {
+            let identifier = (searchText as NSString).substring(with: match.range(at: 1))
+            if #available(iOS 16.0, *) {
+                if Locale.LanguageCode.isoLanguageCodes.contains(where: { $0.identifier == identifier }) {
+                    langSuggestions.append("language:\(identifier)")
+                }
+            } else if searchText != "en" {
+                langSuggestions.append("language:\(searchText)")
+            }
+        }
+        suggestions.append((.language, langSuggestions))
+        
+        var fromSuggestions = [String]()
+        if searchText.isEmpty || "from:me".contains(searchText) {
+            fromSuggestions.append("from:me")
+        }
+        if searchText != "me",
+           let match = acctRegex.firstMatch(in: searchText, range: NSRange(location: 0, length: searchText.utf16.count)) {
+            let matched = (searchText as NSString).substring(with: match.range)
+            fromSuggestions.append("from:\(matched)")
+        }
+        suggestions.append((.from, fromSuggestions))
+        
+        let components = Calendar.current.dateComponents([.year, .month], from: Date())
+        for op in [SearchOperatorType.before, .during, .after] {
+            if searchText.isEmpty {
+                suggestions.append((op, ["\(op.rawValue):\(components.year!)-\(components.month!)"]))
+            } else if let match = dateLikeRegex.firstMatch(in: searchText, range: NSRange(location: 0, length: searchText.utf16.count)) {
+                let matched = (searchText as NSString).substring(with: match.range)
+                suggestions.append((op, ["\(op.rawValue):\(matched)"]))
+            }
+        }
+        
+        suggestions.append((.in, ["in:all", "in:library"].filter {
+            searchText.isEmpty || $0.contains(searchText)
+        }))
+        
+        searchResultsController.updateTokenSuggestions(suggestions, animated: animated)
+    }
+    
+    private func addToken(_ token: String, operator: SearchOperatorType) {
+        let field = searchBar.searchTextField
+        if field.tokens.contains(where: { ($0.representedObject as? String) == token }) {
+            return
+        }
+        let searchToken = UISearchToken(icon: nil, text: token)
+        searchToken.representedObject = token
+        field.insertToken(searchToken, at: field.tokens.count)
+        field.text = ""
+        let tokenPos = field.positionOfToken(at: field.tokens.count - 1)
+        field.selectedTextRange = field.textRange(from: tokenPos, to: field.endOfDocument)
+        
+        if let requiredScope = `operator`.requiredScope,
+           let index = searchBar.scopeButtonTitles?.firstIndex(of: requiredScope.title) {
+            searchBar.selectedScopeButtonIndex = index
+            searchBar(searchBar, selectedScopeButtonIndexDidChange: index)
+        }
+    }
+}
+
+extension MastodonSearchController: UISearchControllerDelegate {
+    func willPresentSearchController(_ searchController: UISearchController) {
+        updateTokenSuggestions(searchText: "", animated: false)
+    }
+}
+
+extension MastodonSearchController: UISearchBarDelegate {
+    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
+        updateTokenSuggestions(searchText: searchText, animated: true)
+    }
+    
+    func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
+        searchResultsController.searchBarTextDidEndEditing(searchBar)
+    }
+    
+    func searchBar(_ searchBar: UISearchBar, selectedScopeButtonIndexDidChange selectedScope: Int) {
+        searchResultsController.searchBar(searchBar, selectedScopeButtonIndexDidChange: selectedScope)
+    }
+}
+
+extension UISearchBar {
+    var searchQueryWithOperators: String {
+        var parts = searchTextField.tokens.compactMap { $0.representedObject as? String }
+        let query = text?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
+        if !query.isEmpty {
+            parts.append(query)
+        }
+        return parts.joined(separator: " ")
+    }
+}
+
+private extension SearchOperatorType {
+    var requiredScope: SearchResultsViewController.Scope? {
+        switch self {
+        case .is, .from, .in:
+            return .posts
+        default:
+            return nil
+        }
+    }
+}

Tusker/Screens/Search/SearchResultsViewController.swift

@@ -33,6 +33,7 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
     
     weak var exploreNavigationController: UINavigationController?
     weak var delegate: SearchResultsViewControllerDelegate?
+    var tokenHandler: ((String, SearchOperatorType) -> Void)?
     
     var collectionView: UICollectionView! { view as? UICollectionView }
     private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
@@ -42,8 +43,9 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
     /// Whether to limit results to accounts the users is following.
     var following: Bool? = nil
     
-    let searchSubject = PassthroughSubject<String?, Never>()
+    private let searchSubject = PassthroughSubject<String?, Never>()
-    var currentQuery: String?
+    private var searchCancellable: AnyCancellable?
+    private var currentQuery: String?
     
     init(mastodonController: MastodonController, scope: Scope = .all) {
         self.mastodonController = mastodonController
@@ -60,29 +62,43 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
     
     override func loadView() {
         let layout = UICollectionViewCompositionalLayout { [unowned self] sectionIndex, environment in
-            var config = UICollectionLayoutListConfiguration(appearance: .grouped)
+            let sectionIdentifier = self.dataSource.sectionIdentifier(for: sectionIndex)!
-            config.backgroundColor = .appGroupedBackground
+            switch sectionIdentifier {
-            config.headerMode = .supplementary
+            case .tokenSuggestions(_):
-            switch self.dataSource.sectionIdentifier(for: sectionIndex) {
+                let itemSize = NSCollectionLayoutSize(widthDimension: .estimated(100), heightDimension: .absolute(30))
+                let item = NSCollectionLayoutItem(layoutSize: itemSize)
+                let group = NSCollectionLayoutGroup.horizontal(layoutSize: itemSize, subitems: [item])
+                let section = NSCollectionLayoutSection(group: group)
+                section.orthogonalScrollingBehavior = .continuousGroupLeadingBoundary
+                section.interGroupSpacing = 8
+                section.contentInsets = NSDirectionalEdgeInsets(top: sectionIndex == 0 ? 16 : 4, leading: 16, bottom: 4, trailing: 16)
+                return section
+                
             case .loadingIndicator:
+                var config = UICollectionLayoutListConfiguration(appearance: .grouped)
+                config.backgroundColor = .appGroupedBackground
                 config.showsSeparators = false
                 config.headerMode = .none
-            case .statuses:
+                return .list(using: config, layoutEnvironment: environment)
+                
+            case .accounts, .hashtags, .statuses:
+                var config = UICollectionLayoutListConfiguration(appearance: .grouped)
+                config.backgroundColor = .appGroupedBackground
+                config.headerMode = .supplementary
                 config.leadingSwipeActionsConfigurationProvider = { [unowned self] in
                     (self.collectionView.cellForItem(at: $0) as? TimelineStatusCollectionViewCell)?.leadingSwipeActions()
                 }
                 config.trailingSwipeActionsConfigurationProvider = { [unowned self] in
                     (self.collectionView.cellForItem(at: $0) as? TimelineStatusCollectionViewCell)?.trailingSwipeActions()
                 }
-                config.separatorConfiguration.topSeparatorInsets = TimelineStatusCollectionViewCell.separatorInsets
+                if sectionIdentifier == .statuses {
-                config.separatorConfiguration.bottomSeparatorInsets = TimelineStatusCollectionViewCell.separatorInsets
+                    config.separatorConfiguration.topSeparatorInsets = TimelineStatusCollectionViewCell.separatorInsets
-            default:
+                    config.separatorConfiguration.bottomSeparatorInsets = TimelineStatusCollectionViewCell.separatorInsets
-                break
+                }
+                // we don't use the readable content inset here, because it insets the entire cell, rather than just the content
+                // so the cell backgrounds not being full width looks weird
+                return .list(using: config, layoutEnvironment: environment)
             }
-            let section = NSCollectionLayoutSection.list(using: config, layoutEnvironment: environment)
-            // we don't use the readable content inset here, because it insets the entire cell, rather than just the content
-            // so the cell backgrounds not being full width looks weird
-            return section
         }
         view = UICollectionView(frame: .zero, collectionViewLayout: layout)
         collectionView.delegate = self
@@ -97,11 +113,10 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
         
-        _ = searchSubject
+        searchCancellable = searchSubject
-            .debounce(for: .milliseconds(500), scheduler: RunLoop.main)
+            .debounce(for: .seconds(1), scheduler: RunLoop.main)
             .map { $0?.trimmingCharacters(in: .whitespacesAndNewlines) }
-            .filter { $0 != self.currentQuery }
+            .sink { [unowned self] in self.performSearch(query: $0) }
-            .sink(receiveValue: performSearch(query:))
 
         userActivity = UserActivityManager.searchActivity(query: nil, accountID: mastodonController.accountInfo!.id)
         
@@ -115,6 +130,9 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
             config.text = section.displayName
             supplementaryView.contentConfiguration = config
         }
+        let tokenSuggestionCell = UICollectionView.CellRegistration<SearchTokenSuggestionCollectionViewCell, String> { cell, indexPath, itemIdentifier in
+            cell.setText(itemIdentifier)
+        }
         let loadingCell = UICollectionView.CellRegistration<LoadingCollectionViewCell, Void> { cell, indexPath, itemIdentifier in
             cell.indicator.startAnimating()
         }
@@ -132,6 +150,8 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
         let dataSource = UICollectionViewDiffableDataSource<Section, Item>(collectionView: collectionView) { collectionView, indexPath, itemIdentifier in
             let cell: UICollectionViewCell
             switch itemIdentifier {
+            case .tokenSuggestion(let value):
+                return collectionView.dequeueConfiguredReusableCell(using: tokenSuggestionCell, for: indexPath, item: value)
             case .loadingIndicator:
                 return collectionView.dequeueConfiguredReusableCell(using: loadingCell, for: indexPath, item: ())
             case .account(let accountID):
@@ -172,6 +192,45 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
         return super.targetViewController(forAction: action, sender: sender)
     }
     
+    func updateTokenSuggestions(_ suggestions: [(SearchOperatorType, [String])], animated: Bool) {
+        var snapshot = dataSource.snapshot()
+        var prev: Section?
+        for (op, values) in suggestions {
+            let section = Section.tokenSuggestions(op)
+            if values.isEmpty {
+                if snapshot.sectionIdentifiers.contains(section) {
+                    snapshot.deleteSections([section])
+                }
+            } else {
+                if !snapshot.sectionIdentifiers.contains(section) {
+                    if let prev {
+                        snapshot.insertSections([section], afterSection: prev)
+                    } else if let first = snapshot.sectionIdentifiers.first {
+                        snapshot.insertSections([section], beforeSection: first)
+                    } else {
+                        snapshot.appendSections([section])
+                    }
+                } else {
+                    snapshot.deleteItems(snapshot.itemIdentifiers(inSection: section))
+                }
+                snapshot.appendItems(values.map { .tokenSuggestion($0) }, toSection: section)
+                prev = section
+            }
+        }
+        
+        dataSource.apply(snapshot, animatingDifferences: animated)
+    }
+    
+    func removeResults() {
+        var snapshot = dataSource.snapshot()
+        removeResults(from: &snapshot)
+        dataSource.apply(snapshot, animatingDifferences: false)
+    }
+    
+    private func removeResults(from snapshot: inout NSDiffableDataSourceSnapshot<Section, Item>) {
+        snapshot.deleteSections([Section.loadingIndicator, .accounts, .hashtags, .statuses].filter { snapshot.sectionIdentifiers.contains($0) })
+    }
+    
     func loadResults(from source: SearchResultsViewController) {
         currentQuery = source.currentQuery
         if let sourceDataSource = source.dataSource {
@@ -180,16 +239,18 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
     }
     
     func performSearch(query: String?) {
-        guard isViewLoaded else {
+        guard isViewLoaded,
+              query != currentQuery else {
             return
         }
         guard let query = query, !query.isEmpty else {
-            self.dataSource.apply(NSDiffableDataSourceSnapshot<Section, Item>())
+            removeResults()
             return
         }
         self.currentQuery = query
 
-        var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
+        var snapshot = dataSource.snapshot()
+        removeResults(from: &snapshot)
         snapshot.appendSections([.loadingIndicator])
         snapshot.appendItems([.loadingIndicator])
         dataSource.apply(snapshot)
@@ -209,7 +270,8 @@ class SearchResultsViewController: UIViewController, CollectionViewController {
     }
     
     private func showSearchResults(_ results: SearchResults) {
-        var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
+        var snapshot = dataSource.snapshot()
+        snapshot.deleteSections([.loadingIndicator])
         
         self.mastodonController.persistentContainer.performBatchUpdates({ (context, addAccounts, addStatuses) in
             let resultTypes = self.scope.resultTypes
@@ -304,7 +366,8 @@ extension SearchResultsViewController {
 }
 
 extension SearchResultsViewController {
-    enum Section: CaseIterable {
+    enum Section: Hashable {
+        case tokenSuggestions(SearchOperatorType)
         case loadingIndicator
         case accounts
         case hashtags
@@ -312,6 +375,8 @@ extension SearchResultsViewController {
 
         var displayName: String? {
             switch self {
+            case .tokenSuggestions:
+                return nil
             case .loadingIndicator:
                 return nil
             case .accounts:
@@ -324,6 +389,7 @@ extension SearchResultsViewController {
         }
     }
     enum Item: Hashable {
+        case tokenSuggestion(String)
         case loadingIndicator
         case account(String)
         case hashtag(Hashtag)
@@ -331,6 +397,9 @@ extension SearchResultsViewController {
         
         func hash(into hasher: inout Hasher) {
             switch self {
+            case let .tokenSuggestion(value):
+                hasher.combine("tokenSuggestion")
+                hasher.combine(value)
             case .loadingIndicator:
                 hasher.combine("loadingIndicator")
             case let .account(id):
@@ -347,6 +416,8 @@ extension SearchResultsViewController {
         
         static func ==(lhs: Item, rhs: Item) -> Bool {
             switch (lhs, rhs) {
+            case (.tokenSuggestion(let a), .tokenSuggestion(let b)):
+                return a == b
             case (.loadingIndicator, .loadingIndicator):
                 return true
             case (.account(let a), .account(let b)):
@@ -376,6 +447,12 @@ extension SearchResultsViewController: UICollectionViewDelegate {
         switch dataSource.itemIdentifier(for: indexPath) {
         case nil, .loadingIndicator:
             return
+        case .tokenSuggestion(let value):
+            guard case .tokenSuggestions(let op) = dataSource.sectionIdentifier(for: indexPath.section) else {
+                return
+            }
+            tokenHandler?(value, op)
+            collectionView.deselectItem(at: indexPath, animated: true)
         case let .account(id):
             if let delegate {
                 delegate.selectedSearchResult(account: id)
@@ -403,7 +480,7 @@ extension SearchResultsViewController: UICollectionViewDelegate {
             return nil
         }
         switch item {
-        case .loadingIndicator:
+        case .loadingIndicator, .tokenSuggestion(_):
             return nil
         case .account(let id):
             return UIContextMenuConfiguration {
@@ -436,7 +513,7 @@ extension SearchResultsViewController: UICollectionViewDragDelegate {
         let url: URL
         let activity: NSUserActivity
         switch item {
-        case .loadingIndicator:
+        case .loadingIndicator, .tokenSuggestion(_):
             return []
         case .account(let id):
             guard let account = mastodonController.persistentContainer.account(for: id) else {
@@ -464,18 +541,29 @@ extension SearchResultsViewController: UICollectionViewDragDelegate {
 
 extension SearchResultsViewController: UISearchResultsUpdating {
     func updateSearchResults(for searchController: UISearchController) {
-        searchSubject.send(searchController.searchBar.text)
+        searchSubject.send(searchController.searchBar.searchQueryWithOperators)
     }
 }
 
 extension SearchResultsViewController: UISearchBarDelegate {
     func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
+        var snapshot = dataSource.snapshot()
+        let allSuggestionSections = snapshot.sectionIdentifiers.filter {
+            if case .tokenSuggestions(_) = $0 {
+                return true
+            } else {
+                return false
+            }
+        }
+        snapshot.deleteSections(allSuggestionSections)
+        dataSource.apply(snapshot, animatingDifferences: true)
+        
         // perform a search immedaitely when the search button is pressed
-        performSearch(query: searchBar.text?.trimmingCharacters(in: .whitespacesAndNewlines))
+        performSearch(query: searchBar.searchQueryWithOperators)
     }
     
     func searchBar(_ searchBar: UISearchBar, selectedScopeButtonIndexDidChange selectedScope: Int) {
-        let newQuery = searchBar.text?.trimmingCharacters(in: .whitespacesAndNewlines)
+        let newQuery = searchBar.searchQueryWithOperators
         let newScope = Scope.allCases[selectedScope]
         if self.scope == .all && currentQuery == newQuery {
             self.scope = newScope

Tusker/Screens/Search/SearchTokenSuggestionCollectionViewCell.swift

@@ -0,0 +1,42 @@
+//
+//  SearchTokenSuggestionCollectionViewCell.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 10/1/23.
+//  Copyright © 2023 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+import Pachyderm
+
+class SearchTokenSuggestionCollectionViewCell: UICollectionViewCell {
+    private let label = UILabel()
+    
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        
+        label.textColor = .tintColor
+        
+        contentView.backgroundColor = .tintColor.withAlphaComponent(0.2)
+        contentView.layer.masksToBounds = true
+        contentView.layer.cornerRadius = 6
+        contentView.layer.cornerCurve = .continuous
+        
+        label.translatesAutoresizingMaskIntoConstraints = false
+        contentView.addSubview(label)
+        NSLayoutConstraint.activate([
+            label.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 8),
+            label.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -8),
+            label.topAnchor.constraint(equalTo: contentView.topAnchor),
+            label.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
+        ])
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    func setText(_ text: String) {
+        label.text = text
+    }
+}