Plan cloud browse decisions in app core

src/app_core/document_cloud.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <string_view>
+
 namespace pp::app {
 
 enum class CloudUploadAction {
@@ -8,6 +10,16 @@ enum class CloudUploadAction {
     prompt_publish,
 };
 
+enum class CloudBrowseAction {
+    unavailable_no_canvas,
+    show_browser,
+};
+
+enum class CloudDownloadSelectionAction {
+    wait_for_selection,
+    start_download,
+};
+
 struct CloudUploadPlan {
     CloudUploadAction action = CloudUploadAction::unavailable_no_canvas;
     bool save_before_upload = false;
@@ -29,4 +41,19 @@ struct CloudUploadPlan {
     return { CloudUploadAction::prompt_publish, has_unsaved_changes };
 }
 
+[[nodiscard]] constexpr CloudBrowseAction plan_cloud_browse(bool has_canvas) noexcept
+{
+    return has_canvas
+        ? CloudBrowseAction::show_browser
+        : CloudBrowseAction::unavailable_no_canvas;
+}
+
+[[nodiscard]] constexpr CloudDownloadSelectionAction plan_cloud_download_selection(
+    std::string_view selected_file) noexcept
+{
+    return selected_file.empty()
+        ? CloudDownloadSelectionAction::wait_for_selection
+        : CloudDownloadSelectionAction::start_download;
+}
+
 }