Re-add missing icons to Classic tooltips (#864)

* Re-add missing icons to Classic tooltips

* Comment clarifications

totalRP3/Core/Globals.lua

@@ -71,17 +71,12 @@ TRP3_API.globals = {
 	PSYCHO_MAX_VALUE_V2 = 20,
 };
 
--- TODO: Expansion constants are temporary and can be cleaned up once the next
---       Classic Era patch (1.14.4+/1.15.0) goes live.
-
-local TRP3_EXPANSION_CATACLYSM = LE_EXPANSION_CATACLYSM or 3;
-local TRP3_EXPANSION_BATTLE_FOR_AZEROTH = LE_EXPANSION_BATTLE_FOR_AZEROTH or 7;
-
 TRP3_ClientFeatures = {
 	ChannelBroadcasts = (WOW_PROJECT_ID == WOW_PROJECT_MAINLINE),
-	WarMode = (LE_EXPANSION_LEVEL_CURRENT >= TRP3_EXPANSION_BATTLE_FOR_AZEROTH),
-	Transmogrification = (LE_EXPANSION_LEVEL_CURRENT >= TRP3_EXPANSION_CATACLYSM),
+	WarMode = (LE_EXPANSION_LEVEL_CURRENT >= LE_EXPANSION_BATTLE_FOR_AZEROTH),
+	Transmogrification = (LE_EXPANSION_LEVEL_CURRENT >= LE_EXPANSION_CATACLYSM),
 	WaterElementalWorkaround = (WOW_PROJECT_ID ~= WOW_PROJECT_MAINLINE),
+	OldTooltipAPI = (WOW_PROJECT_ID ~= WOW_PROJECT_MAINLINE),
 };
 
 TRP3_OOCIndicatorStyle = {

totalRP3/Modules/Register/Main/RegisterTooltip.lua

@@ -365,7 +365,24 @@ end
 ---@param texture TextureAssetDisk
 ---@param options TooltipTextureInfo
 function TooltipBuilder:AddTexture(texture, options)
-	self.tooltip:AddTexture(texture, options);
+	if not TRP3_ClientFeatures.OldTooltipAPI then
+		self.tooltip:AddTexture(texture, options);
+	else
+		-- In Classic, AddTexture won't work on the first line of the tooltip,
+		-- which is also coincidentally the only line that we actually care
+		-- to stick icons on currently.
+		--
+		-- Fall back to a legacy |T string prefix approach for this case. Note
+		-- that we can't use the size values in the options table either, as
+		-- for some reason they aren't equivalent.
+
+		local line = self.tooltip:NumLines();
+		local leftFontString = TRP3_TooltipUtil.GetLineFontStrings(self.tooltip, line);
+		local leftText = leftFontString:GetText();
+		local iconText = string.format("|T%s:%d:%d|t ", texture, 24, 24);
+
+		leftFontString:SetText(iconText .. leftText);
+	end
 end
 
 function TooltipBuilder:Build()