Configuration to preserve device being offline

Refs: #57

src/app.cc

@@ -10,6 +10,8 @@
 
 namespace taranis {
 
+bool config_already_loaded{false};
+
 int App::process_event(int event_type, int param_one, int param_two) {
   BOOST_LOG_TRIVIAL(debug) << "Processing event of type "
                            << format_event_type(event_type);
@@ -82,10 +84,7 @@ void App::setup() {
     current_location.country = "FR";
     current_location.state = "Ile-de-France";
   }
-
-  BOOST_LOG_TRIVIAL(info)
-      << "First load of configuration asked to trigger a data refresh";
-  this->load_config(true);
+  this->load_config();
 }
 
 void App::show() {
@@ -111,11 +110,20 @@ void App::initialize_language() {
   this->language = currentLang();
   initialize_translations();
 }
-void App::load_config(bool force_data_refresh) {
-  BOOST_LOG_TRIVIAL(debug) << "Loading config";
+
+void App::load_config() {
+  if (not config_already_loaded) {
+    BOOST_LOG_TRIVIAL(debug) << "Loading configuration";
+  } else {
+    BOOST_LOG_TRIVIAL(debug) << "Rereading configuration";
+  }
 
   Config config;
 
+  const auto preserve_offline_from_config =
+      config.read_bool("preserve_offline", false);
+  this->model->preserve_offline = preserve_offline_from_config;
+
   const auto api_key_from_config = config.read_string("api_key", "");
   const auto is_api_key_obsolete =
       (not api_key_from_config.empty() and
@@ -148,19 +156,22 @@ void App::load_config(bool force_data_refresh) {
     initialize_translations();
   }
 
-  const bool is_data_obsolete = force_data_refresh or is_api_key_obsolete or
-                                is_unit_system_obsolete or is_language_obsolete;
+  const bool is_data_obsolete =
+      (not config_already_loaded and not this->model->preserve_offline) or
+      is_api_key_obsolete or is_unit_system_obsolete or is_language_obsolete;
   // temperatures, wind speed and weather description are computed
   // by the backend thus unit system or language change implies that
   // data are obsolete
 
   const auto event_handler = GetEventHandler();
   if (is_data_obsolete) {
-    SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data, 0);
+    SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data,
+              CustomEventParam::triggered_by_configuration_change);
   } else if (is_display_daily_forecast_obsolete) {
     SendEvent(event_handler, EVT_CUSTOM,
               CustomEvent::model_daily_forecast_display_changed, 0);
   }
+  config_already_loaded = true;
 }
 
 int App::handle_custom_event(int param_one, int param_two) {
@@ -186,7 +197,11 @@ int App::handle_custom_event(int param_one, int param_two) {
       return 1;
     }
   } else if (param_one == CustomEvent::refresh_data) {
-    this->refresh_data();
+    const bool force_refresh =
+        (param_two == CustomEventParam::triggered_by_configuration_change or
+         param_two == CustomEventParam::triggered_by_user or
+         param_two == CustomEventParam::triggered_by_configuration_change);
+    this->refresh_data(force_refresh);
     return 1;
   } else if (param_one == CustomEvent::select_location_from_history) {
     const size_t history_index = param_two;
@@ -252,9 +267,26 @@ void App::clear_model_weather_conditions() {
   this->model->refresh_date = 0;
 }
 
-void App::refresh_data() {
+bool App::must_skip_data_refresh() const {
+  const auto *const netinfo = NetInfo();
+  if (netinfo == nullptr or not netinfo->connected) {
+    BOOST_LOG_TRIVIAL(debug) << "Device is offline";
+
+    if (this->model->preserve_offline) {
+      BOOST_LOG_TRIVIAL(info)
+          << "Won't refresh data since configured to preserve offline";
+      return true;
+    }
+  }
+  return false;
+}
+
+void App::refresh_data(bool force) {
   BOOST_LOG_TRIVIAL(debug) << "Refreshing data";
 
+  if (not force and this->must_skip_data_refresh()) {
+    return;
+  }
   ShowHourglassForce();
 
   ClearTimerByName(App::refresh_timer_name);
@@ -372,7 +404,8 @@ void App::set_model_location(const Location &location) const {
   this->model->location = location;
 
   const auto event_handler = GetEventHandler();
-  SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data, 0);
+  SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data,
+            CustomEventParam::triggered_by_model_change);
 }
 
 void App::update_configured_unit_system(UnitSystem unit_system) {
@@ -416,7 +449,8 @@ void App::refresh_data_maybe() {
     return;
   }
   const auto event_handler = GetEventHandler();
-  SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data, 0);
+  SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data,
+            CustomEventParam::triggered_by_timer);
 }
 
 void App::handle_about_dialog_button_clicked(int button_index) {

src/app.h

@@ -56,13 +56,15 @@ class App {
 
   void initialize_language();
 
-  void load_config(bool force_data_refresh = false);
+  void load_config();
 
   int handle_custom_event(int param_one, int param_two);
 
   void clear_model_weather_conditions();
 
-  void refresh_data();
+  bool must_skip_data_refresh() const;
+
+  void refresh_data(bool force);
 
   void open_about_dialog();
 

src/events.h

@@ -25,6 +25,10 @@ enum CustomEvent {
 
 enum CustomEventParam {
   invalid_location,
+  triggered_by_configuration_change,
+  triggered_by_model_change,
+  triggered_by_timer,
+  triggered_by_user,
 };
 
 std::string format_custom_event_param(int param);

src/http.cc

@@ -1,6 +1,7 @@
 #include "http.h"
 
 #include <boost/log/trivial.hpp>
+#include <memory>
 #include <sstream>
 
 #include "errors.h"
@@ -90,7 +91,7 @@ std::unique_ptr<CURL, void (*)(CURL *)> HttpClient::prepare_curl() {
 }
 
 void HttpClient::ensure_network() const {
-  iv_netinfo *netinfo = NetInfo();
+  const auto *netinfo = NetInfo();
   if (netinfo == nullptr or not netinfo->connected) {
     BOOST_LOG_TRIVIAL(debug) << "Will try to establish connection";
 

src/model.h

@@ -202,5 +202,7 @@ struct Model {
   std::list<HistoryItem> location_history;
 
   bool display_daily_forecast{false};
+
+  bool preserve_offline{false};
 };
 } // namespace taranis

src/ui.cc

@@ -194,7 +194,8 @@ void Ui::handle_menu_item_selected(int item_index) {
 
   const auto event_handler = GetEventHandler();
   if (item_index == MENU_ITEM_REFRESH) {
-    SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data, 0);
+    SendEvent(event_handler, EVT_CUSTOM, CustomEvent::refresh_data,
+              CustomEventParam::triggered_by_user);
   } else if (item_index == MENU_ITEM_TOGGLE_FAVORITE_LOCATION) {
     SendEvent(event_handler, EVT_CUSTOM,
               CustomEvent::toggle_current_location_favorite, 0);