minimap: a tooltip for the tracking button, and no 3.x icon on a 1.12 interface

Two faults on the same button, either of which was enough to make hovering it
do nothing useful.

GameTooltip:SetTrackingSpell was in neither the method table nor the no-op
allowlist, so the lookup answered nil. 1.12's Minimap.xml opens the tracking
frame's OnEnter with SetOwner and that call, so the handler raised on its second
line with the tooltip already owned by a frame that then wrote nothing into it.
It is the spell's own tooltip now, through SetSpellByID, because "Track
Humanoids" is a title with nothing under it saying what that does.

And GetTrackingTexture answered Interface\Minimap\Tracking\None for nothing
tracked, which is 3.x's art. A 1.12 client has no Interface\Minimap\Tracking
folder at all - interface.MPQ, patch.MPQ and patch-2.MPQ hold nothing under that
path - and its Minimap.xml hides the tracking frame outright when this answers
nil. So the frame was shown with a missing texture in it rather than hidden.
Only 1.12 changes: the dropdown and its None entry are 2.x's.

The spell id the tooltip needs comes from __WoweeActiveTrackingSpell rather than
from a fifth value on GetTrackingInfo, which is 4.x's own - it says whether an
entry nests under the one above it, and a spell id would have been read as that.

Reported in #132

Author: Kelsidavis

src/addons/lua_engine.cpp

@@ -7108,6 +7108,27 @@ void LuaEngine::registerCoreAPI() {
         "        self:AddLine(string.format('%.0f sec remaining', duration), 1, 1, 1)\n"
         "    end\n"
         "end\n"
+        // What the minimap's tracking button is showing. 1.12's Minimap.xml
+        // opens the tracking frame's OnEnter with SetOwner and this, and it was
+        // in neither the method table nor the no-op allowlist - so the lookup
+        // answered nil, the call raised, and the OnEnter it was the second line
+        // of took the tooltip's owner with it. Reported in #132.
+        //
+        // The spell's own tooltip where SetSpellByID can render one, because
+        // "Track Humanoids" is a title without the line under it saying what
+        // that does. The id comes from this client rather than from
+        // GetTrackingInfo, whose fifth value is 4.x's own.
+        "function __WoweeFrameMT:SetTrackingSpell()\n"
+        "    self:ClearLines()\n"
+        "    local spellId = __WoweeActiveTrackingSpell()\n"
+        "    if spellId and self.SetSpellByID then\n"
+        "        return self:SetSpellByID(spellId)\n"
+        "    end\n"
+        "    for i = 1, GetNumTrackingTypes() do\n"
+        "        local name, _, active = GetTrackingInfo(i)\n"
+        "        if active and name then return self:SetText(name, 1, 1, 1) end\n"
+        "    end\n"
+        "end\n"
         "function __WoweeFrameMT:SetTrainerService(index)\n"
         "    self:ClearLines()\n"
         "    if not index then return end\n"

src/addons/lua_system_api.cpp

@@ -2288,6 +2288,19 @@ static int lua_GetTrackingTexture(lua_State* L) {
         const std::string icon = gh->getSpellIconPath(sid);
         if (!icon.empty()) { lua_pushstring(L, icon.c_str()); return 1; }
     }
+    // Nothing tracked, and what a stock client shows for that is not the same
+    // picture in every expansion. 3.x has a button whose art is empty in the
+    // XML and a magnifying glass to fill it with. 1.12 has neither: its
+    // Minimap.xml hides the tracking frame outright when this answers nil, and
+    // the 1.12 archives carry no Interface\Minimap\Tracking folder at all -
+    // interface.MPQ, patch.MPQ and patch-2.MPQ hold nothing under that path. So
+    // on turtle the answer named a file that does not exist, and the frame was
+    // shown with an empty icon in it rather than hidden.
+    //
+    // Only 1.12 changes. The tracking dropdown and its None entry are 2.x's and
+    // nothing here has been checked against a 2.4.3 tree, so every other
+    // interface keeps the answer it already had.
+    if (interfaceVersion(L) < 20000) return luaReturnNil(L);
     lua_pushstring(L, "Interface\\Minimap\\Tracking\\None");
     return 1;
 }
@@ -2302,6 +2315,12 @@ static int lua_GetNumTrackingTypes(lua_State* L) {
 ///
 /// "spell" for the category, because these are spell icons and the menu uses
 /// that to crop the icon's border - the same trim the action bar gives them.
+///
+/// Four values and not five. The spell id would have been useful to
+/// GameTooltip:SetTrackingSpell and belongs in none of them: 4.x defines a
+/// fifth of its own - whether the entry nests under the one above it - and a
+/// number in that position would be read as that. __WoweeActiveTrackingSpell
+/// carries it instead, under a name no interface will ever call.
 static int lua_GetTrackingInfo(lua_State* L) {
     auto* gh = getGameHandler(L);
     const int index = static_cast<int>(luaL_optnumber(L, 1, 0));
@@ -2315,6 +2334,21 @@ static int lua_GetTrackingInfo(lua_State* L) {
     return 4;
 }
 
+/// __WoweeActiveTrackingSpell() → the spell id of the tracking now running.
+///
+/// This client's own and not an interface function: GameTooltip:SetTrackingSpell
+/// needs the id to render the spell's own tooltip, and every real API that
+/// could have carried it is a shape some expansion has already defined.
+static int lua_ActiveTrackingSpell(lua_State* L) {
+    auto* gh = getGameHandler(L);
+    for (uint32_t sid : trackingSpells(gh)) {
+        if (!trackingActive(gh, sid)) continue;
+        lua_pushnumber(L, static_cast<lua_Number>(sid));
+        return 1;
+    }
+    return luaReturnNil(L);
+}
+
 /// SetTracking(index) - casting the spell is how tracking is turned on; there
 /// is no separate message for it. A nil index is the menu's "None" entry,
 /// which in a stock client cancels the running tracking aura. Cancelling a
@@ -6433,6 +6467,7 @@ void registerSystemLuaAPI(lua_State* L) {
                 {"GetTrackingTexture",  lua_GetTrackingTexture},
                 {"GetNumTrackingTypes", lua_GetNumTrackingTypes},
                 {"GetTrackingInfo",     lua_GetTrackingInfo},
+                {"__WoweeActiveTrackingSpell", lua_ActiveTrackingSpell},
                 {"SetTracking",         lua_SetTracking},
                 {"GetZoneText",          lua_GetZoneText},
                 {"GetRealZoneText",      lua_GetZoneText},