From e809a0a013824988734f832226d4e80fa730429a Mon Sep 17 00:00:00 2001
From: Chris Engelhardt <chris.engelhardt@me.com>
Date: Tue, 7 Jan 2020 00:29:19 +0100
Subject: [PATCH] rearrange the list of layouts #887

---
 .../GeneralPreferencesViewController.swift    | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/Amethyst/Preferences/GeneralPreferencesViewController.swift b/Amethyst/Preferences/GeneralPreferencesViewController.swift
index 52dc7a47..f6e38a6f 100644
--- a/Amethyst/Preferences/GeneralPreferencesViewController.swift
+++ b/Amethyst/Preferences/GeneralPreferencesViewController.swift
@@ -20,6 +20,8 @@ class GeneralPreferencesViewController: NSViewController, NSTableViewDataSource,
 
         layoutsTableView?.dataSource = self
         layoutsTableView?.delegate = self
+        layoutsTableView?.registerForDraggedTypes([.string])
+
     }
 
     override func viewWillAppear() {
@@ -93,4 +95,43 @@ class GeneralPreferencesViewController: NSViewController, NSTableViewDataSource,
 
         return LayoutManager<AXWindow>.layoutNameForKey(layoutKeys[row])
     }
+    
+    
+
+    func tableView(_ tableView: NSTableView, acceptDrop info: NSDraggingInfo, row: Int, dropOperation: NSTableView.DropOperation) -> Bool {
+        if let dragData = info.draggingPasteboard.data(forType: .string),
+            let rowString = String(bytes: dragData, encoding: .utf8),
+            let oldRow = Int(rowString){
+
+            layoutKeys.move(from: oldRow, to: oldRow < row ? row-1 : row)
+            UserConfiguration.shared.setLayoutKeys(self.layoutKeys)
+            layoutsTableView?.reloadData()
+            return true
+        }
+        return false
+    }
+    
+    
+    
+    func tableView(_ tableView: NSTableView, validateDrop info: NSDraggingInfo, proposedRow row: Int, proposedDropOperation dropOperation: NSTableView.DropOperation) -> NSDragOperation {
+        if dropOperation == .above {
+            return .move
+        }
+        return []
+       
+    }
+    
+    func tableView(_ tableView: NSTableView, pasteboardWriterForRow row: Int) -> NSPasteboardWriting? {
+        let item = NSPasteboardItem()
+        item.setString(String(row), forType: .string)
+        return item
+    }
+}
+
+extension Array{
+    mutating func move(from oldIndex: Index, to newIndex: Index) {
+        if oldIndex == newIndex { return }
+        if abs(newIndex - oldIndex) == 1 { return self.swapAt(oldIndex, newIndex) }
+        self.insert(self.remove(at: oldIndex), at: newIndex)
+    }
 }