fix: write default settings file, if none is present

Author: Totto16

src/libs/core/helper/parse_json.hpp

@@ -5,9 +5,10 @@
 // better json error messages, see https://json.nlohmann.me/api/macros/json_diagnostics/
 #define JSON_DIAGNOSTICS 1 // NOLINT(cppcoreguidelines-macro-usage)
 #endif
-
 #include <nlohmann/json.hpp>
 
+#include <core/helper/types.hpp>
+
 #include "./expected.hpp"
 #include "./windows.hpp"
 
@@ -49,6 +50,12 @@ NLOHMANN_JSON_NAMESPACE_END
 
 namespace json {
 
+    enum class ParseError : u8 {
+        OpenError,
+        ReadError,
+        FormatError,
+    };
+
     template<typename T>
     [[nodiscard]] helper::expected<T, std::string> try_parse_json(const std::string& content) noexcept {
 
@@ -68,22 +75,43 @@ namespace json {
     }
 
     template<typename T>
-    [[nodiscard]] helper::expected<T, std::string> try_parse_json_file(const std::filesystem::path& file) noexcept {
+    [[nodiscard]] helper::expected<T, std::pair<std::string, ParseError>> try_parse_json_file(
+            const std::filesystem::path& file
+    ) noexcept {
 
         if (not std::filesystem::exists(file)) {
-            return helper::unexpected<std::string>{ fmt::format("File '{}' doesn't exist", file.string()) };
+            return helper::unexpected<std::pair<std::string, ParseError>>{ std::make_pair<std::string, ParseError>(
+                    fmt::format("File '{}' doesn't exist", file.string()), ParseError::OpenError
+            ) };
         }
 
         std::ifstream file_stream{ file };
 
         if (not file_stream.is_open()) {
-            return helper::unexpected<std::string>{ fmt::format("File '{}' couldn't be opened!", file.string()) };
+            return helper::unexpected<std::pair<std::string, ParseError>>{ std::make_pair<std::string, ParseError>(
+                    fmt::format("File '{}' couldn't be opened!", file.string()), ParseError::OpenError
+            ) };
         }
 
         std::stringstream result;
         result << file_stream.rdbuf();
 
-        return try_parse_json<T>(result.str());
+        file_stream.close();
+
+        if (file_stream.fail()) {
+            return helper::unexpected<std::pair<std::string, ParseError>>{ std::make_pair<std::string, ParseError>(
+                    fmt::format("Couldn't read from file '{}'", file.string()), ParseError::ReadError
+            ) };
+        }
+
+        auto parse_result = try_parse_json<T>(result.str());
+        if (not parse_result.has_value()) {
+            return helper::unexpected<std::pair<std::string, ParseError>>{
+                std::make_pair<std::string, ParseError>(std::move(parse_result.error()), ParseError::FormatError)
+            };
+        }
+
+        return parse_result.value();
     }
 
     template<typename T>

src/manager/settings_manager.cpp

@@ -17,7 +17,9 @@ SettingsManager::SettingsManager() {
     if (result.has_value()) {
         m_settings = result.value();
     } else {
-        spdlog::error("unable to load settings from \"{}\": {}", settings_filename, result.error());
+        auto [error, error_type] = result.error();
+
+        spdlog::error("unable to load settings from \"{}\": {}", settings_filename, error);
         spdlog::warn("applying default settings");
 
         m_settings = {
@@ -28,7 +30,10 @@ SettingsManager::SettingsManager() {
                                .api_url = std::nullopt }
         };
 
-        //TODO(Totto): save the file, if it doesn't exist, if it has an error, just leave it there
+        //save the default file, only if it doesn't exist, if it has an error, just leave it there
+        if (error_type == json::ParseError::OpenError) {
+            this->save();
+        }
     }
 }