Plan new document creation in app core

src/app_core/document_session.h

@@ -3,6 +3,7 @@
 #include "app_core/document_route.h"
 #include "foundation/result.h"
 
+#include <array>
 #include <cctype>
 #include <cstdio>
 #include <string>
@@ -65,6 +66,12 @@ struct DocumentVersionTarget {
     std::string path;
 };
 
+struct NewDocumentPlan {
+    DocumentFileTarget target;
+    int resolution = 0;
+    DocumentFileWriteDecision write_decision = DocumentFileWriteDecision::save_now;
+};
+
 [[nodiscard]] constexpr ProjectOpenDecision plan_project_open(bool has_unsaved_changes) noexcept
 {
     return has_unsaved_changes
@@ -175,6 +182,41 @@ struct DocumentVersionTarget {
         : DocumentFileWriteDecision::save_now;
 }
 
+[[nodiscard]] constexpr pp::foundation::Result<int> document_resolution_from_index(int index) noexcept
+{
+    constexpr std::array<int, 6> resolutions{ 512, 1024, 1536, 2048, 4096, 8192 };
+    if (index < 0 || static_cast<std::size_t>(index) >= resolutions.size()) {
+        return pp::foundation::Result<int>::failure(
+            pp::foundation::Status::out_of_range("document resolution index is out of range"));
+    }
+
+    return pp::foundation::Result<int>::success(resolutions[static_cast<std::size_t>(index)]);
+}
+
+template <typename ExistsPredicate>
+[[nodiscard]] pp::foundation::Result<NewDocumentPlan> plan_new_document(
+    std::string_view work_directory,
+    std::string_view document_name,
+    int resolution_index,
+    ExistsPredicate&& exists)
+{
+    const auto resolution = document_resolution_from_index(resolution_index);
+    if (!resolution) {
+        return pp::foundation::Result<NewDocumentPlan>::failure(resolution.status());
+    }
+
+    auto target = make_document_file_target(work_directory, document_name);
+    if (!target) {
+        return pp::foundation::Result<NewDocumentPlan>::failure(target.status());
+    }
+
+    NewDocumentPlan plan;
+    plan.target = std::move(target.value());
+    plan.resolution = resolution.value();
+    plan.write_decision = plan_document_file_write(exists(plan.target.path));
+    return pp::foundation::Result<NewDocumentPlan>::success(std::move(plan));
+}
+
 [[nodiscard]] inline bool has_legacy_two_character_version_suffix(std::string_view document_name) noexcept
 {
     const auto dot = document_name.rfind('.');

src/app_dialogs.cpp

@@ -2,6 +2,7 @@
 #include "app.h"
 #include "action.h"
 #include "app_core/document_export.h"
+#include "app_core/document_session.h"
 #include "settings.h"
 #include "node_dialog_open.h"
 #include "node_dialog_browse.h"
@@ -158,24 +159,32 @@ void App::dialog_newdoc()
         dialog->btn_ok->on_click = [this, dialog](Node*)
         {
             std::string name = dialog->input->m_text;
-            const auto target = pp::app::make_document_file_target(work_path, name);
-            if (!target)
+            const auto plan = pp::app::plan_new_document(
+                work_path,
+                name,
+                dialog->m_resolution->m_current_index,
+                [](const std::string& path) {
+                    return Asset::exist(path);
+                });
+            if (!plan)
             {
-                message_box("Warning", "You need to specify a name to file.");
+                const bool missing_name =
+                    plan.status().code == pp::foundation::StatusCode::invalid_argument;
+                message_box(
+                    "Warning",
+                    missing_name ? "You need to specify a name to file." : plan.status().message);
                 return;
             }
 
-            auto action = [this, dialog, target = target.value()] {
-                std::array<int, 6> resolutions{ 512, 1024, 1536, 2048, 4096, 8192 };
-                int res = resolutions[dialog->m_resolution->m_current_index];
-                doc_name = target.name;
-                doc_path = target.path;
-                doc_filename = target.name + ".ppi";
-                doc_dir = target.directory;
+            auto action = [this, dialog, plan = plan.value()] {
+                doc_name = plan.target.name;
+                doc_path = plan.target.path;
+                doc_filename = plan.target.name + ".ppi";
+                doc_dir = plan.target.directory;
 
                 layers->clear();
                 canvas->m_canvas->m_layers.clear();
-                canvas->m_canvas->resize(res, res);
+                canvas->m_canvas->resize(plan.resolution, plan.resolution);
                 canvas->reset_camera();
                 ActionManager::clear();
 
@@ -189,8 +198,7 @@ void App::dialog_newdoc()
                 App::I->hideKeyboard();
             };
 
-            const auto write_decision = pp::app::plan_document_file_write(Asset::exist(target.value().path));
-            if (write_decision == pp::app::DocumentFileWriteDecision::prompt_overwrite)
+            if (plan.value().write_decision == pp::app::DocumentFileWriteDecision::prompt_overwrite)
             {
                 // ask confirm is file already exist
                 auto msgbox = new NodeMessageBox();