From af22a4f2cda86a7667578281a51ea1ec08a49af6 Mon Sep 17 00:00:00 2001
From: Patric Stout <truebrain@openttd.org>
Date: Thu, 7 Jan 2021 23:06:23 +0100
Subject: [PATCH] Add: show in the tooltip of disabled toolbar buttons why they
 are disabled

---
 src/airport_gui.cpp  |  5 +++++
 src/dock_gui.cpp     |  9 +++++++++
 src/lang/english.txt |  3 +++
 src/road_gui.cpp     | 12 +++++++++++-
 src/widget.cpp       |  9 +++++++++
 src/widget_type.h    |  1 +
 6 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/airport_gui.cpp b/src/airport_gui.cpp
index 62eca78f9f..e12b8dccbd 100644
--- a/src/airport_gui.cpp
+++ b/src/airport_gui.cpp
@@ -97,6 +97,11 @@ struct BuildAirToolbarWindow : Window {
 			WIDGET_LIST_END);
 		if (!can_build) {
 			DeleteWindowById(WC_BUILD_STATION, TRANSPORT_AIR);
+
+			/* Show in the tooltip why this button is disabled. */
+			this->GetWidget<NWidgetCore>(WID_AT_AIRPORT)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+		} else {
+			this->GetWidget<NWidgetCore>(WID_AT_AIRPORT)->SetToolTip(STR_TOOLBAR_AIRCRAFT_BUILD_AIRPORT_TOOLTIP);
 		}
 	}
 
diff --git a/src/dock_gui.cpp b/src/dock_gui.cpp
index 7e2d618572..39237f5ca1 100644
--- a/src/dock_gui.cpp
+++ b/src/dock_gui.cpp
@@ -125,6 +125,15 @@ struct BuildDocksToolbarWindow : Window {
 		if (!can_build) {
 			DeleteWindowById(WC_BUILD_STATION, TRANSPORT_WATER);
 			DeleteWindowById(WC_BUILD_DEPOT, TRANSPORT_WATER);
+
+			/* Show in the tooltip why this button is disabled. */
+			this->GetWidget<NWidgetCore>(WID_DT_DEPOT)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+			this->GetWidget<NWidgetCore>(WID_DT_STATION)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+			this->GetWidget<NWidgetCore>(WID_DT_BUOY)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+		} else {
+			this->GetWidget<NWidgetCore>(WID_DT_DEPOT)->SetToolTip(STR_WATERWAYS_TOOLBAR_BUILD_DEPOT_TOOLTIP);
+			this->GetWidget<NWidgetCore>(WID_DT_STATION)->SetToolTip(STR_WATERWAYS_TOOLBAR_BUILD_DOCK_TOOLTIP);
+			this->GetWidget<NWidgetCore>(WID_DT_BUOY)->SetToolTip(STR_WATERWAYS_TOOLBAR_BUOY_TOOLTIP);
 		}
 	}
 
diff --git a/src/lang/english.txt b/src/lang/english.txt
index 52b75f413f..a0cf2b9a0f 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -2353,6 +2353,9 @@ STR_JOIN_STATION_CREATE_SPLITTED_STATION                        :{YELLOW}Build a
 STR_JOIN_WAYPOINT_CAPTION                                       :{WHITE}Join waypoint
 STR_JOIN_WAYPOINT_CREATE_SPLITTED_WAYPOINT                      :{YELLOW}Build a separate waypoint
 
+# Generic toolbar
+STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE                       :{BLACK}Disabled as currently no vehicles are available for this infrastructure
+
 # Rail construction toolbar
 STR_RAIL_TOOLBAR_RAILROAD_CONSTRUCTION_CAPTION                  :Railway Construction
 STR_RAIL_TOOLBAR_ELRAIL_CONSTRUCTION_CAPTION                    :Electrified Railway Construction
diff --git a/src/road_gui.cpp b/src/road_gui.cpp
index dff4d2bc10..b9f59333d4 100644
--- a/src/road_gui.cpp
+++ b/src/road_gui.cpp
@@ -303,8 +303,9 @@ struct BuildRoadToolbarWindow : Window {
 	void OnInvalidateData(int data = 0, bool gui_scope = true) override
 	{
 		if (!gui_scope) return;
+		RoadTramType rtt = GetRoadTramType(this->roadtype);
 
-		bool can_build = CanBuildVehicleInfrastructure(VEH_ROAD, GetRoadTramType(this->roadtype));
+		bool can_build = CanBuildVehicleInfrastructure(VEH_ROAD, rtt);
 		this->SetWidgetsDisabledState(!can_build,
 			WID_ROT_DEPOT,
 			WID_ROT_BUS_STATION,
@@ -314,6 +315,15 @@ struct BuildRoadToolbarWindow : Window {
 			DeleteWindowById(WC_BUS_STATION, TRANSPORT_ROAD);
 			DeleteWindowById(WC_TRUCK_STATION, TRANSPORT_ROAD);
 			DeleteWindowById(WC_BUILD_DEPOT, TRANSPORT_ROAD);
+
+			/* Show in the tooltip why this button is disabled. */
+			this->GetWidget<NWidgetCore>(WID_ROT_DEPOT)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+			this->GetWidget<NWidgetCore>(WID_ROT_BUS_STATION)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+			this->GetWidget<NWidgetCore>(WID_ROT_TRUCK_STATION)->SetToolTip(STR_TOOLBAR_DISABLED_NO_VEHICLE_AVAILABLE);
+		} else {
+			this->GetWidget<NWidgetCore>(WID_ROT_DEPOT)->SetToolTip(rtt == RTT_ROAD ? STR_ROAD_TOOLBAR_TOOLTIP_BUILD_ROAD_VEHICLE_DEPOT : STR_ROAD_TOOLBAR_TOOLTIP_BUILD_TRAM_VEHICLE_DEPOT);
+			this->GetWidget<NWidgetCore>(WID_ROT_BUS_STATION)->SetToolTip(rtt == RTT_ROAD ? STR_ROAD_TOOLBAR_TOOLTIP_BUILD_BUS_STATION : STR_ROAD_TOOLBAR_TOOLTIP_BUILD_PASSENGER_TRAM_STATION);
+			this->GetWidget<NWidgetCore>(WID_ROT_TRUCK_STATION)->SetToolTip(rtt == RTT_ROAD ? STR_ROAD_TOOLBAR_TOOLTIP_BUILD_TRUCK_LOADING_BAY : STR_ROAD_TOOLBAR_TOOLTIP_BUILD_CARGO_TRAM_STATION);
 		}
 	}
 
diff --git a/src/widget.cpp b/src/widget.cpp
index 2be2f2b85d..d1ba44679b 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -895,6 +895,15 @@ void NWidgetCore::SetDataTip(uint32 widget_data, StringID tool_tip)
 	this->tool_tip = tool_tip;
 }
 
+/**
+ * Set the tool tip of the nested widget.
+ * @param tool_tip Tool tip string to use.
+ */
+void NWidgetCore::SetToolTip(StringID tool_tip)
+{
+	this->tool_tip = tool_tip;
+}
+
 void NWidgetCore::FillNestedArray(NWidgetBase **array, uint length)
 {
 	if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
diff --git a/src/widget_type.h b/src/widget_type.h
index 1b16770391..d8841f9bd2 100644
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -285,6 +285,7 @@ public:
 
 	void SetIndex(int index);
 	void SetDataTip(uint32 widget_data, StringID tool_tip);
+	void SetToolTip(StringID tool_tip);
 
 	inline void SetLowered(bool lowered);
 	inline bool IsLowered() const;