Stuff…

TagTunes/ContentViewController.swift

@@ -0,0 +1,124 @@
+//
+//  ContentViewController.swift
+//  TagTunes
+//
+//  Created by Kim Wittenburg on 21.01.16.
+//  Copyright © 2016 Kim Wittenburg. All rights reserved.
+//
+
+import Cocoa
+import SearchAPI
+
+/// A `ContentViewController` displays a set of `TagTunesItem`s. It is
+/// responsible for allowing the user to associate `TagTunesTrack`s with
+/// `TagTunesEntityItem`s.
+///
+/// The expected structure of the content view controller is a tree structure in
+/// the following form:
+///
+/// 1. At the root level there are `TagTunesGroupItem`s (groups) and
+///    `TagTunesEntityItem`s (entities).
+/// 2. Groups can contain other entities (children).
+/// 3. Entities can have tracks associated with them. A track should not be
+///    associated with multiple entities.
+public class ContentViewController: NSViewController {
+
+    override public func viewDidLoad() {
+        super.viewDidLoad()
+        
+        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ContentViewController.itemDidChangeState(_:)), name: TagTunesGroupItem.StateChangedNotificationName, object: nil)
+    }
+    
+    /// Called when the `TagTunesGroupItem.StateChangedNotification` is posted.
+    private dynamic func itemDidChangeState(notification: NSNotification) {
+        if let item = notification.object as? TagTunesItem {
+            updateItem(item)
+        }
+    }
+    
+    deinit {
+        NSNotificationCenter.defaultCenter().removeObserver(self)
+    }
+
+    /// Returns all selected items. This property should remove duplicate items
+    /// from the selection following these three rules:
+    ///
+    /// 1. If an entity is selected (and thus contained in the returned array)
+    ///    none of its `associatedTracks` should be contained in the returned
+    ///    array.
+    /// 2. If a group is selected none of its children should be contained in the
+    ///    returned array.
+    /// 3. If a track is selected and (1) and (2) do not appy it should be
+    ///    contained in the returned array.
+    ///
+    /// This value is not cached. If you need to access this multiple times in a
+    /// row, you should consider caching it yourself in a local variable. The
+    /// order in which the selected objects occur in the returned array may be
+    /// different from the order in which they are displayed.
+    ///
+    /// This method must be implemented by subclasses.
+    public var selectedItems: [AnyObject] {
+        fatalError("Must override property selectedItems")
+    }
+
+    /// Returns the item the user clicked on. This property should be used
+    /// instead of the `selectedItems` for any context menu related actions. This
+    /// property should behave the same way that `selectedItems` does.
+    ///
+    /// This method must be implemented by subclasses.
+    public var clickedItems: [AnyObject] {
+        fatalError("Must override property clickedItem")
+    }
+
+    /// Returns the item that represents the specified `entity`. If no such item
+    /// exists in the content view controller `nil` is returned.
+    ///
+    /// This method must be implemented by subclasses.
+    public func itemForEntity(entity: SearchAPIEntity) -> TagTunesItem? {
+        fatalError("Must override itemForEntity(_:)")
+    }
+
+    /// Adds the specified `item` to the view controller. This should insert the
+    /// `item` at the root level of the controller. If the controller already
+    /// contains an item that represents the same entity as the specified `item`
+    /// this method should do nothing.
+    ///
+    /// This method must be implemented by subclasses.
+    public func addItem(item: TagTunesItem) {
+        fatalError("Must override addItem(_:)")
+    }
+    
+    /// Updates the specified `item`. This method should be called if the
+    /// properties of the `item` changed in any way and the view should be
+    /// notified about it. If the `item` has not previously been added to the
+    /// view controller this method should do nothing.
+    ///
+    /// This method must be implemented by subclasses.
+    public func updateItem(item: TagTunesItem) {
+        fatalError("Must override updateItem(_:)")
+    }
+    
+    /// Updates all items. If many items in the view controller changed it may be
+    /// more efficient to use this method instead of `updateItem(_:)`.
+    ///
+    /// This method must be implemented by subclasses.
+    public func updateAllItems() {
+        fatalError("Must override updateAllItems()")
+    }
+
+    /// Removes the selected items from the view controller. By default the
+    /// implementation just calls `removeItems(selectedItems` but subclasses may
+    /// override this method to optimize the behavior.
+    public func removeSelectedItems() {
+        removeItems(selectedItems)
+    }
+    
+    /// Removes the specified items from the view controller and updates the view
+    /// accordingly.
+    ///
+    /// This method must be implemented by subclasses.
+    public func removeItems(items: [AnyObject]) {
+        fatalError("Must override removeItems(_:)")
+    }
+    
+}