[iOS] Handle non-passbook attachment downloads correctly

ios/brave-ios/Sources/Brave/Frontend/Browser/BrowserViewController/BVC+WKDownloadDelegate.swift

@@ -33,6 +33,12 @@ extension BrowserViewController: WKDownloadDelegate {
     let temporaryDir = NSTemporaryDirectory()
     let fileName = temporaryDir + "/" + suggestedFilename
     let url = URL(fileURLWithPath: fileName)
+
+    // WKDownload will fail with a -3000 error code if the file already exists at the given path
+    if await AsyncFileManager.default.fileExists(atPath: url.path(percentEncoded: false)) {
+      try? await AsyncFileManager.default.removeItem(at: url)
+    }
+
     let pendingDownload = WebKitDownload(
       fileURL: url,
       response: response,
@@ -70,8 +76,6 @@ extension BrowserViewController: WKDownloadDelegate {
       return
     }
 
-    downloadQueue.download(downloadInfo, didFinishDownloadingTo: downloadInfo.fileURL)
-
     let response = URLResponse(
       url: downloadInfo.fileURL,
       mimeType: downloadInfo.response.mimeType,
@@ -80,6 +84,7 @@ extension BrowserViewController: WKDownloadDelegate {
     )
 
     if downloadInfo.response.mimeType == MIMEType.passbook {
+      downloadQueue.download(downloadInfo, didFinishDownloadingTo: downloadInfo.fileURL)
       if let passbookHelper = OpenPassBookHelper(
         request: nil,
         response: response,
@@ -89,12 +94,26 @@ extension BrowserViewController: WKDownloadDelegate {
       ) {
         Task {
           await passbookHelper.open()
+          try await AsyncFileManager.default.removeItem(at: downloadInfo.fileURL)
         }
       }
+      return
     }
 
+    // Handle non-passbook downloads the same as HTTPDownload
+    let filename = downloadInfo.filename
+    let location = downloadInfo.fileURL
+    let temporaryLocation = FileManager.default.temporaryDirectory
+      .appending(component: "\(filename)-\(location.lastPathComponent)")
+    try? FileManager.default.moveItem(at: location, to: temporaryLocation)
     Task {
-      try await AsyncFileManager.default.removeItem(at: downloadInfo.fileURL)
+      do {
+        let destination = try await downloadInfo.uniqueDownloadPathForFilename(filename)
+        try await AsyncFileManager.default.moveItem(at: temporaryLocation, to: destination)
+        downloadQueue.download(downloadInfo, didFinishDownloadingTo: destination)
+      } catch {
+        downloadQueue.download(downloadInfo, didCompleteWithError: error)
+      }
     }
   }
 

ios/brave-ios/Sources/Brave/Frontend/Browser/BrowserViewController/BVC+WKNavigationDelegate.swift

@@ -756,13 +756,14 @@ extension BrowserViewController: WKNavigationDelegate {
       return .download
     }
 
+    if response.mimeType == MIMEType.passbook {
+      return .download
+    }
+
     // Check if this response should be handed off to Passbook.
     if shouldDownloadNavigationResponse {
       shouldDownloadNavigationResponse = false
-
-      if response.mimeType == MIMEType.passbook {
-        return .download
-      }
+      return .download
     }
 
     // If the content type is not HTML, create a temporary document so it can be downloaded and

ios/brave-ios/Sources/Brave/Frontend/Browser/DownloadQueue.swift

@@ -38,7 +38,7 @@ class Download: NSObject {
   func pause() {}
   func resume() {}
 
-  fileprivate func uniqueDownloadPathForFilename(_ filename: String) async throws -> URL {
+  func uniqueDownloadPathForFilename(_ filename: String) async throws -> URL {
     let downloadsPath = try await AsyncFileManager.default.downloadsPath()
     let basePath = downloadsPath.appending(path: filename)
     let fileExtension = basePath.pathExtension