make ItemFilter injectable

Author: DivineDominion

Sources/FloatingFilter/FilterInteractor.swift

@@ -12,14 +12,19 @@ class FilterInteractor {
 
     private var state: State {
         didSet {
-            self.view.showItems(state.filteredItems)
+            self.view.showItems(state.filteredItems(filter: filter))
         }
     }
 
     let view: FilteredItemView
+    let filter: ItemFilter
 
-    init(view: FilteredItemView) {
+    init(
+        view: FilteredItemView,
+        filter: @escaping ItemFilter
+    ) {
         self.view = view
+        self.filter = filter
         self.state = State(allItems: [], filterPhrase: "")
     }
 }
@@ -41,28 +46,8 @@ extension FilterInteractor: FilterChangeDelegate {
 }
 
 extension FilterInteractor.State {
-    fileprivate var filteredItems: [Item] {
+    fileprivate func filteredItems(filter: ItemFilter) -> [Item] {
         guard !filterPhrase.isEmpty else { return allItems }
-        return allItems.sortedByNormalizedFuzzyMatch(pattern: self.filterPhrase)
-    }
-}
-
-extension Sequence where Iterator.Element == Item {
-    fileprivate func sortedByNormalizedFuzzyMatch(pattern: String) -> [Element] {
-        // These magic numbers are totally experimental
-        let fuzziness = 0.3
-        let threshold = 0.4
-        
-        return self
-            .map { (element: $0, score: $0.title.score(word: pattern, fuzziness: fuzziness)) }
-            .filter { $0.score > threshold }
-            .sorted(by: { $0.score > $1.score })
-            .map { $0.element }
-    }
-}
-
-extension Item {
-    fileprivate var normalizedTitle: String {
-        return self.title.lowercased()
+        return filter(filterPhrase, allItems)
     }
 }

Sources/FloatingFilter/FloatingFilterModule.swift

@@ -6,15 +6,44 @@ import AppKit
 private var windowHoldingService = WindowHoldingService()
 
 public typealias SelectionCallback = (_ selectedItems: [Item]) -> Void
+public typealias ItemFilter = (_ needle: String, _ haystack: [Item]) -> [Item]
 
 public struct FloatingFilterModule {
+    /// Uses the default filter that scores all ``Item``s by `pattern` fuzzily, discards matches below a certain
+    /// threshold, and sorts by score.
+    public static func defaultFuzzyFilter(
+        fuzziness: Double = 0.3,
+        threshold: Double = 0.4
+    ) -> ItemFilter {
+        return { needle, haystack in
+            let needle = needle.localizedLowercase
+
+            return haystack
+                .map { (element: $0, score: $0.title.localizedLowercase.score(word: needle, fuzziness: fuzziness)) }
+                .filter { $0.score > threshold }
+                .sorted(by: { $0.score > $1.score })
+                .map { $0.element }
+        }
+    }
+
     private init() { }
 
+    /// - Parameters:
+    ///   - items: Filter-able items, sorted, to show in the floating filter window.
+    ///   - filterPlaceholderText: Placeholder for the FloatingFilter text field
+    ///   - windowLevel: Level to show the filter window  on. Default `.floating` is intended for use
+    ///     as a utility panel.
+    ///   - closeWhenLosingFocus: Whether the filter should disappear when users e.g. activate another app
+    ///     before completing the operation. Defaults to `true` to be used as a temporary utility.
+    ///   - filter: Narrows down all filterable `items` to find `needle`. The default uses a fuzzy string
+    ///     matching algorithm.
+    ///   - selectionCallback: Output port for confirmed selections in the filter window.
     public static func showFilterWindow(
         items: [Item],
         filterPlaceholderText: String = NSLocalizedString("Filter Items", comment: "Placeholder for the FloatingFilter text field"),
         windowLevel: NSWindow.Level = .floating,
         closeWhenLosingFocus: Bool = true,
+        filter: @escaping ItemFilter = FloatingFilterModule.defaultFuzzyFilter(),
         selection selectionCallback: @escaping SelectionCallback
     ) {
         let windowController = FilterWindowController()
@@ -34,7 +63,10 @@ public struct FloatingFilterModule {
             window.makeKeyAndOrderFront(nil)
         }
 
-        let interactor = FilterInteractor(view: windowController)
+        let interactor = FilterInteractor(
+            view: windowController,
+            filter: filter
+        )
         interactor.showItems(items)
 
         windowController.filterChangeDelegate = interactor