Somewhat working file tray

DynamicIsland/components/Shelf/ViewModels/ShelfSelectionModel.swift

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+//
+//  ShelfSelectionModel.swift
+//  boringNotch
+//
+//  Created by Alexander on 2025-09-26.
+//
+
+import Foundation
+import Combine
+
+private let _shelfTypeAnchor: Bool = {
+    _ = String(describing: ShelfItem.self)
+    return true
+}()
+
+@MainActor
+final class ShelfSelectionModel: ObservableObject {
+    static let shared = ShelfSelectionModel()
+
+    @Published private(set) var selectedIDs: Set<UUID> = []
+
+    // Anchor for shift-range selection
+    private var lastAnchorID: UUID? = nil
+
+    func isSelected(_ id: UUID) -> Bool { selectedIDs.contains(id) }
+
+    var hasSelection: Bool { !selectedIDs.isEmpty }
+
+    var firstSelectedItem: ShelfItem? {
+        guard let firstID = selectedIDs.first else { return nil }
+        return ShelfStateViewModel.shared.items.first(where: { $0.id == firstID })
+    }
+
+    func selectedItems(in allItems: [ShelfItem]) -> [ShelfItem] {
+        allItems.filter { selectedIDs.contains($0.id) }
+    }
+
+    func selectSingle(_ item: ShelfItem) {
+        selectedIDs = [item.id]
+        lastAnchorID = item.id
+    }
+
+    func toggle(_ item: ShelfItem) {
+        if selectedIDs.contains(item.id) {
+            selectedIDs.remove(item.id)
+        } else {
+            selectedIDs.insert(item.id)
+        }
+        lastAnchorID = item.id
+    }
+
+    func shiftSelect(to item: ShelfItem, in allItems: [ShelfItem]) {
+        // Determine anchor
+        let anchorID = lastAnchorID ?? selectedIDs.first ?? item.id
+        guard let startIndex = allItems.firstIndex(where: { $0.id == anchorID }),
+              let endIndex = allItems.firstIndex(where: { $0.id == item.id }) else {
+            // Fallback to single select if indices not found
+            return selectSingle(item)
+        }
+        let lower = min(startIndex, endIndex)
+        let upper = max(startIndex, endIndex)
+        let rangeIDs = allItems[lower...upper].map { $0.id }
+        selectedIDs = Set(rangeIDs)
+    }
+
+    func clear() {
+        selectedIDs.removeAll()
+        lastAnchorID = nil
+    }
+
+    // Keep anchor sane if items array changed drastically (optional helper)
+    func ensureValidAnchor(in allItems: [ShelfItem]) {
+        if let anchor = lastAnchorID, !allItems.contains(where: { $0.id == anchor }) {
+            lastAnchorID = selectedIDs.first
+        }
+    }
+
+    @Published private(set) var isDragging: Bool = false
+
+    func beginDrag() {
+        isDragging = true
+    }
+
+    func endDrag() {
+        isDragging = false
+    }
+}