Implement "open file" delegate

Author: dteoh

devdocs-macos/DocumentationViewController.swift

@@ -18,6 +18,7 @@ class DocumentationViewController: NSViewController {
         case ready
     }
 
+    weak var delegate: DocumentationViewDelegate?
     private var webView: WKWebView!
     private var searchCVC: SearchControlViewController?
 
@@ -203,6 +204,11 @@ class DocumentationViewController: NSViewController {
     }
 }
 
+protocol DocumentationViewDelegate: class {
+    typealias OpenPanelParameters = WKOpenPanelParameters
+    func selectFileToOpen(_ parameters: OpenPanelParameters, completionHandler: @escaping ([URL]?) -> Void)
+}
+
 // MARK:- WKUIDelegate
 extension DocumentationViewController: WKUIDelegate {
     func webView(_ webView: WKWebView,
@@ -229,6 +235,13 @@ extension DocumentationViewController: WKUIDelegate {
 
         return nil
     }
+
+    func webView(_ webView: WKWebView,
+                 runOpenPanelWith parameters: WKOpenPanelParameters,
+                 initiatedByFrame frame: WKFrameInfo,
+                 completionHandler: @escaping ([URL]?) -> Void) {
+        delegate?.selectFileToOpen(parameters, completionHandler: completionHandler)
+    }
 }
 
 // MARK:- WKNavigationDelegate

devdocs-macos/DocumentationWindowController.swift

@@ -14,6 +14,7 @@ class DocumentationWindowController: NSWindowController {
 
     override func awakeFromNib() {
         guard let dvc = documentationViewController else { return }
+        dvc.delegate = self
         dvc.documentURL = documentation.url
     }
 
@@ -110,3 +111,22 @@ class DocumentationWindowController: NSWindowController {
         )
     }
 }
+
+// MARK:- DocumentationViewDelegate
+extension DocumentationWindowController: DocumentationViewDelegate {
+    func selectFileToOpen(_ parameters: OpenPanelParameters, completionHandler: @escaping ([URL]?) -> Void) {
+        let panel = NSOpenPanel()
+        panel.canChooseFiles = true
+        panel.canChooseDirectories = parameters.allowsDirectories
+        panel.allowsMultipleSelection = parameters.allowsMultipleSelection
+        panel.allowedFileTypes = ["json"]
+        panel.allowsOtherFileTypes = false
+        panel.resolvesAliases = true
+
+        panel.beginSheetModal(for: self.window!) { modalResponse in
+            if modalResponse == NSApplication.ModalResponse.OK, let url = panel.url {
+                completionHandler([url])
+            }
+        }
+    }
+}