naturally orders files and folders #1714 (#1774)

Author: hkarmoush

CodeEdit/Utils/Extensions/Array/Array+SortURLs.swift

@@ -18,19 +18,39 @@ extension Array where Element == URL {
     /// Sorts the elements in alphabetical order.
     /// - Parameter foldersOnTop: if set to `true` folders will always be on top of files.
     /// - Returns: A sorted array of `URL`
-    func sortItems(foldersOnTop: Bool) -> Self {
-        var alphabetically = sorted { $0.lastPathComponent < $1.lastPathComponent }
+    func sortItems(foldersOnTop: Bool) -> [URL] {
+        return self.sorted { lhs, rhs in
+            let lhsIsDir = (try? lhs.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) ?? false
+            let rhsIsDir = (try? rhs.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) ?? false
 
-        if foldersOnTop {
-            var foldersOnTop = alphabetically.filter { $0.isFolder }
-            alphabetically.removeAll { $0.isFolder }
+            if foldersOnTop {
+                if lhsIsDir != rhsIsDir {
+                    return lhsIsDir
+                }
+            }
 
-            foldersOnTop.append(contentsOf: alphabetically)
+            return compareNaturally(lhs.lastPathComponent, rhs.lastPathComponent)
+        }
+    }
 
-            return foldersOnTop
-        } else {
-            return alphabetically
+    /// Compare two strings using natural sorting.
+    /// - Parameters:
+    ///   - lhs: The left-hand string.
+    ///   - rhs: The right-hand string.
+    /// - Returns: `true` if `lhs` should be ordered before `rhs`.
+    private func compareNaturally(_ lhs: String, _ rhs: String) -> Bool {
+        let lhsComponents = lhs.components(separatedBy: CharacterSet.decimalDigits.inverted)
+        let rhsComponents = rhs.components(separatedBy: CharacterSet.decimalDigits.inverted)
+
+        for (lhsPart, rhsPart) in zip(lhsComponents, rhsComponents) where lhsPart != rhsPart {
+            if let lhsNum = Int(lhsPart), let rhsNum = Int(rhsPart) {
+                return lhsNum < rhsNum
+            } else {
+                return lhsPart < rhsPart
+            }
         }
+
+        return lhs < rhs
     }
 }