Add native file dialogs (#6)

* Add SwiftNFD package

* Add dialogs

* Fix foundation import in package

* Fix submodule compile failure

* Update SwiftNFD

Package.resolved

@@ -10,6 +10,15 @@
           "version": "0.11.0"
         }
       },
+      {
+        "package": "SwiftNFD",
+        "repositoryURL": "https://github.com/ctreffs/SwiftNFD.git",
+        "state": {
+          "branch": null,
+          "revision": "6c9e4666649f70920775e25d187d5a2c05df5fd2",
+          "version": "1.0.2"
+        }
+      },
       {
         "package": "SDL2",
         "repositoryURL": "https://github.com/ctreffs/SwiftSDL2.git",

Package.swift

@@ -111,6 +111,7 @@ let package = Package(
         .firebladeTime,
         .vulkan,
         .sdl2,
+        .nfd,
     ],
     targets: [
         .target(
@@ -120,6 +121,7 @@ let package = Package(
                 .firebladeTime,
                 .sdl2,
                 .vulkan,
+                .nfd,
             ],
             swiftSettings: swiftSettings
         ),
@@ -142,13 +144,15 @@ extension Package.Dependency {
     static let firebladeTime = Package.Dependency.package(name: "FirebladeTime", url: "https://github.com/fireblade-engine/time.git", from: "0.2.0")
     static let sdl2 = Package.Dependency.package(name: "SDL2", url: "https://github.com/ctreffs/SwiftSDL2.git", from: "1.3.1")
     static let vulkan = Package.Dependency.package(name: "Vulkan", url: "https://github.com/ctreffs/SwiftVulkan", from: "0.1.2")
+    static let nfd = Package.Dependency.package(name: "SwiftNFD", url: "https://github.com/ctreffs/SwiftNFD.git", from: "1.0.2")
 }
 
 extension Target.Dependency {
     static let firebladeTime = byName(name: "FirebladeTime")
     static let firebladeMath = product(name: "FirebladeMath", package: "FirebladeMath")
     static let sdl2 = product(name: "SDL2", package: "SDL2")
     static let vulkan = product(name: "Vulkan", package: "Vulkan")
+    static let nfd = product(name: "NFD", package: "SwiftNFD")
 }
 
 extension Env {

Sources/FirebladePAL/Window.swift

@@ -6,6 +6,7 @@
 // Licensed under MIT License. See LICENSE file for details.
 
 import FirebladeMath
+@_implementationOnly import NFD
 
 #if FRB_PLATFORM_SDL
     public typealias Window = SDLWindow
@@ -48,6 +49,66 @@ public protocol WindowBase: AnyObject {
     func centerOnScreen()
 }
 
+// MARK: - Dialogs
+
+public extension WindowBase {
+    /// Single file open dialog
+    /// - Parameters:
+    ///   - startPath: The current directory shown in the dialog.
+    ///   - fileExtensions: An array of filename extensions or UTIs that represent the allowed file types for the dialog.
+    /// - Returns: Selected file path or `nil` if user canceled.
+    static func openDialog(at startPath: String? = nil, filterFor fileExtensions: [String]? = nil) throws -> String? {
+        switch NFD.OpenDialog(filter: fileExtensions, defaultPath: startPath) {
+        case let .success(path):
+            return path
+        case let .failure(error):
+            throw error
+        }
+    }
+
+    /// Multiple file open dialog
+    /// - Parameters:
+    ///   - startPath: The current directory shown in the dialog.
+    ///   - fileExtensions: An array of filename extensions or UTIs that represent the allowed file types for the dialog.
+    /// - Returns: Array of selected file paths or `nil` if user canceled.
+    static func openDialogMultiple(at startPath: String? = nil, filterFor fileExtensions: [String]? = nil) throws -> [String]? {
+        switch NFD.OpenDialogMultiple(filter: fileExtensions, defaultPath: startPath) {
+        case let .success(path):
+            return path
+        case let .failure(error):
+            throw error
+        }
+    }
+
+    /// Save dialog
+    /// - Parameters:
+    ///   - startPath: The current directory shown in the dialog.
+    ///   - fileExtensions: An array of filename extensions or UTIs that represent the allowed file types for the dialog.
+    /// - Returns: Selected file path or `nil` if user canceled.
+    static func saveDialog(at startPath: String? = nil, filterFor fileExtensions: [String]? = nil) throws -> String? {
+        switch NFD.SaveDialog(filter: fileExtensions, defaultPath: startPath) {
+        case let .success(path):
+            return path
+        case let .failure(error):
+            throw error
+        }
+    }
+
+    /// Select folder dialog
+    /// - Parameter startPath: The current directory shown in the dialog.
+    /// - Returns: Selected folder path or `nil` if user canceled.
+    static func pickFolder(at startPath: String? = nil) throws -> String? {
+        switch NFD.PickFolder(defaultPath: startPath) {
+        case let .success(path):
+            return path
+        case let .failure(error):
+            throw error
+        }
+    }
+}
+
+// MARK: - Window properties
+
 public struct WindowProperties {
     public var title: String
     public var frame: Rect<Int>