Fix Philosophy's free tech being auto-spent, and the Science Advisor picker

C7/Game.cs

@@ -4,6 +4,7 @@
 using C7Engine;
 using C7GameData;
 using Serilog;
+using C7.UIElements;
 using C7Engine.Pathing;
 using System.Collections.Generic;
 using System.Linq;
@@ -178,6 +179,8 @@ public override async void _Ready() {
 		FileDialog.Canceled += OnResolved;
 		FileDialog.FileSelected += path => OnResolved();
 
+		advisor.VisibilityChanged += OnAdvisorVisibilityChanged;
+
 		try {
 			await InitializeGame();
 			await StartGame();
@@ -380,6 +383,9 @@ public void HandleEngineMessage(MessageToUI msg) {
 			case MsgShowScienceAdvisor mSSA:
 				EmitSignal(SignalName.ShowSpecificAdvisor, C7Action.ShowScienceAdvisor);
 				break;
+			case MsgPromptResearch:
+				PromptForResearchIfNeeded();
+				break;
 			case MsgUpdateUiAfterDomesticChange mUUASC:
 				// Ensure the citizen moods are correct before displaying them.
 				foreach (City c in controller.cities) {
@@ -501,6 +507,40 @@ private void _onEndTurnButtonPressed() {
 		}
 	}
 
+	// Runs any action a popup deferred until an advisor screen was closed.
+	private void OnAdvisorVisibilityChanged() {
+		if (!advisor.Visible) {
+			popupOverlay.OnAdvisorClosed();
+		}
+	}
+
+	// Prompts for a tech to research, or auto-picks one if prompts are disabled.
+	private void PromptForResearchIfNeeded() {
+		if (controller.cities.Count == 0 || popupOverlay.ShowingPopup) {
+			return;
+		}
+		if (controller.GetAvailableTechsToResearch(EngineStorage.gameData.techs).Count == 0) {
+			return;
+		}
+
+		if (controller.freeTechsRemaining > 0) {
+			popupOverlay.ShowPopup(new ScienceSelection(controller, claimingFreeTech: true), PopupOverlay.PopupCategory.Info);
+			return;
+		}
+
+		if (controller.currentlyResearchedTech != null) {
+			return;
+		}
+
+		bool promptForResearch = PreferencesSettings.GetPromptForResearch();
+
+		if (promptForResearch) {
+			popupOverlay.ShowPopup(new ScienceSelection(controller), PopupOverlay.PopupCategory.Info);
+		} else {
+			PlayerAI.MaybePickTechToResearch(controller, EngineStorage.gameData.techs);
+		}
+	}
+
 	private void OnPlayerStartTurn() {
 		EngineStorage.ReadGameData((GameData gameData) => {
 			log.Information("Starting player turn");
@@ -520,17 +560,7 @@ private void OnPlayerStartTurn() {
 
 			// If the player can pick a new tech to research, prompt them to do so
 			// once they have a city.
-			if (controller.cities.Count > 0
-					&& controller.currentlyResearchedTech == null
-					&& controller.GetAvailableTechsToResearch(gameData.techs).Count > 0) {
-				popupOverlay.ShowPopup(
-						new ScienceSelection(controller),
-						PopupOverlay.PopupCategory.Info);
-
-				if (controller.currentlyResearchedTech == null && controller.GetAvailableTechsToResearch(gameData.techs).Count > 0) {
-					PlayerAI.MaybePickTechToResearch(controller, gameData.techs);
-				}
-			}
+			PromptForResearchIfNeeded();
 
 			// Allow fast forwarding in observer mode.
 			if (gameData.observerMode && turnsLeftToFastForward > 0) {

C7/UIElements/Advisors/ScienceAdvisor.cs

@@ -106,7 +106,7 @@ private void LoadTechTree() {
 		});
 	}
 
-	void DrawTechTree(string eraName, Player player, List<Tech> allTechs, HashSet<Tech> availableTechsToResearch) {
+	void DrawTechTree(string eraName, Player player, List<Tech> allTechs, List<Tech> availableTechsToResearch) {
 		// clear all tech-box items so we don't draw new ones over the old ones
 		foreach (TechBox tb in techBoxes) {
 			background.RemoveChild(tb);

C7/UIElements/Popups/Popup.cs

@@ -48,8 +48,8 @@ protected void AddButton(string label, int verticalPosition, Action action) {
 		button.SetPosition(new Vector2(HORIZONTAL_POSITION, verticalPosition));
 		AddChild(button);
 		button.Pressed += () => {
-			action();
 			ReleaseFocus();
+			action();
 		};
 	}
 

C7/UIElements/Popups/PopupOverlay.cs

@@ -1,6 +1,7 @@
 using Godot;
 using C7GameData;
 using Serilog;
+using System;
 
 [GlobalClass]
 [Tool]
@@ -26,6 +27,9 @@ public partial class PopupOverlay : HBoxContainer {
 
 	Control currentChild = null;
 
+	// Set when a popup defers its decision until an advisor screen is closed.
+	private Action advisorCloseAction;
+
 	[Export]
 	private Control control;
 
@@ -47,6 +51,16 @@ public void OnHidePopup() {
 
 	public bool ShowingPopup => currentChild is not null;
 
+	public void SetAdvisorCloseAction(Action action) {
+		advisorCloseAction = action;
+	}
+
+	public void OnAdvisorClosed() {
+		Action action = advisorCloseAction;
+		advisorCloseAction = null;
+		action?.Invoke();
+	}
+
 	public void PlaySound(AudioStream stream) {
 		AudioStreamPlayer player = GetNode<AudioStreamPlayer>("PopupSound");
 		player.Stream = stream;

C7/UIElements/Popups/ScienceSelection.cs

@@ -7,11 +7,14 @@
 public partial class ScienceSelection : Popup {
 	Player player;
 	List<Tech> options = new();
+	bool claimingFreeTech;
+	OptionButton optionButton;
 
-	public ScienceSelection(Player player) {
+	public ScienceSelection(Player player, bool claimingFreeTech = false) {
 		alignment = BoxContainer.AlignmentMode.End;
 		margins = new Margins(right: 10);
 		this.player = player;
+		this.claimingFreeTech = claimingFreeTech;
 	}
 
 	public override void _Ready() {
@@ -30,26 +33,29 @@ public override void _Ready() {
 		AddHeader("Science Advisor", 120);
 
 		Label messageLabel = new();
-		messageLabel.Text = "What shall we explore now?";
+		messageLabel.Text = claimingFreeTech
+			? "You have earned a free advance. Choose a technology:"
+			: "What shall we explore now?";
 		messageLabel.SetPosition(new Vector2(25, 160));
 		AddChild(messageLabel);
 
-		OptionButton optionButton = MakeStyledOptionButton();
+		optionButton = MakeStyledOptionButton();
 		AddChild(optionButton);
 		optionButton.SetPosition(new Vector2(25, 190));
 
 		AddButton("OK. Sounds good.", 235, () => {
-			new MsgChooseResearch(options[optionButton.Selected], AdvisorState.DontShow).send();
-			GetParent().EmitSignal(PopupOverlay.SignalName.HidePopup);
+			Choose(SelectedTech);
 		});
 		AddButton("What's the big picture?", 265, () => {
+			if (claimingFreeTech) {
+				GetParent<PopupOverlay>().SetAdvisorCloseAction(ClaimFreeTechFromCurrentResearch);
+			}
 			new MsgShowScienceAdvisor().send();
 			GetParent().EmitSignal(PopupOverlay.SignalName.HidePopup);
 		});
 
 		AddConfirmButton(new Vector2(width - 40, height - 40), () => {
-			new MsgChooseResearch(options[optionButton.Selected], AdvisorState.DontShow).send();
-			GetParent().EmitSignal(PopupOverlay.SignalName.HidePopup);
+			Choose(SelectedTech);
 		});
 	}
 
@@ -95,9 +101,43 @@ private OptionButton MakeStyledOptionButton() {
 	}
 
 	private void AddItem(GameData gameData, Tech tech, OptionButton optionButton) {
-		int turns = player.EstimateTurnsToResearch(gameData, tech);
-		string turnsStr = turns == int.MaxValue ? "--" : $"{turns}";
-		optionButton.AddItem($"{tech.Name} ({turnsStr} turns)");
+		if (claimingFreeTech) {
+			optionButton.AddItem(tech.Name);
+		} else {
+			int turns = player.EstimateTurnsToResearch(gameData, tech);
+			string turnsStr = turns == int.MaxValue ? "--" : $"{turns}";
+			optionButton.AddItem($"{tech.Name} ({turnsStr} turns)");
+		}
 		options.Add(tech);
 	}
+
+	private void Choose(Tech tech) {
+		if (tech == null) {
+			return;
+		}
+		if (claimingFreeTech) {
+			new MsgClaimFreeTech(tech).send();
+		} else {
+			new MsgChooseResearch(tech, AdvisorState.DontShow).send();
+		}
+		GetParent().EmitSignal(PopupOverlay.SignalName.HidePopup);
+	}
+
+	// Spends the free advance on the queued tech, matching Civ3.
+	private void ClaimFreeTechFromCurrentResearch() {
+		Tech selected = player.ResearchQueue.Count > 0 ? player.ResearchQueue.Peek() : SelectedTech;
+		if (selected != null) {
+			new MsgClaimFreeTech(selected).send();
+		}
+	}
+
+	private Tech SelectedTech {
+		get {
+			int selected = optionButton.Selected;
+			if (selected < 0 || selected >= options.Count) {
+				return null;
+			}
+			return options[selected];
+		}
+	}
 }

C7Engine/AI/PlayerAI.cs

@@ -76,6 +76,14 @@ private static void MaybeDoPriorityReevaluation(Player player) {
 		}
 
 		public static void MaybePickTechToResearch(Player player, List<Tech> techs) {
+			// AI players get no prompt, so they spend any free advances immediately.
+			while (!player.isHuman && player.freeTechsRemaining > 0) {
+				Tech freeTech = player.GetAvailableTechsToResearch(techs).FirstOrDefault();
+				if (freeTech == null || !player.ClaimFreeTech(EngineStorage.gameData, freeTech)) {
+					break;
+				}
+			}
+
 			while (player.currentlyResearchedTech == null || player.knownTechs.Contains(player.currentlyResearchedTech)) {
 				Tech toResearch = player.GetAvailableTechsToResearch(techs).FirstOrDefault();
 				if (toResearch == null) {