spell: CastAtUnit casts unit-target spells directly at the unit

Previously CastAtUnit only handled ground-target spells (placement at the
unit's feet); a non-ground spell fired with no implicit target (fell to
current selection). Now it resolves the unit once to its object, reads
position AND GUID, and dispatches the cast WITH that GUID -- the engine's
FUN_SPELL_CAST_DISPATCH substitutes it exactly where it would the current
selection (verified: passing 0 substitutes VAR_CURRENT_SELECTION_GUID), so
a unit-target/normal spell fires straight at that unit regardless of
current target.

Branch on placement state after dispatch: no placement -> cast went out
(unit-target); ground placement -> commit at the unit's feet (existing);
other placement -> unit not accepted as target, cancel + false.

AtCursor gains an optional targetGuid on DispatchSpellCast[ByName] (0 =
prior behavior, so CastAtCursor is unchanged) and IsPlacementActive().

Verified in-game: ground spells still land at the unit's feet; Frostbolt/
Renew/PW:Fortitude cast on the named unit while another unit stays targeted.

AddOns/!!!ClassicAPI/!!!ClassicAPI.toc

@@ -42,3 +42,4 @@ Util\Rectangle.lua
 Util\Vector2D.lua
 Util\Vector3D.lua
 Util\Vector4D.lua
+Util\UIParent.lua

AddOns/!!!ClassicAPI/Util/UIParent.lua

@@ -0,0 +1,3 @@
+function MouseIsOver(region, topOffset, bottomOffset, leftOffset, rightOffset)
+	return region:IsMouseOver(topOffset, bottomOffset, leftOffset, rightOffset);
+end

AddOns/DebugTools/DebugTools.lua

@@ -155,25 +155,6 @@ _initFrame:SetScript("OnEvent", function()
     end
 end);
 
--- Vanilla has no Frame:IsMouseOver(); do it ourselves from cursor + bounds.
-local function DebugTools_IsMouseOver(frame)
-    if (not frame) then return false; end
-    local visOK, visible = pcall(frame.IsVisible, frame);
-    if (not visOK or not visible) then return false; end
-    local sOK, scale = pcall(frame.GetEffectiveScale, frame);
-    if (not sOK or not scale or scale == 0) then return false; end
-    local cx, cy = GetCursorPosition();
-    cx = cx / scale;
-    cy = cy / scale;
-    local lOK, left   = pcall(frame.GetLeft,   frame);
-    local rOK, right  = pcall(frame.GetRight,  frame);
-    local tOK, top    = pcall(frame.GetTop,    frame);
-    local bOK, bottom = pcall(frame.GetBottom, frame);
-    if (not (lOK and rOK and tOK and bOK)) then return false; end
-    if (not (left and right and top and bottom)) then return false; end
-    return cx >= left and cx <= right and cy >= bottom and cy <= top;
-end
-
 local _EventTraceFrame;
 
 _framesSinceLast = 0;
@@ -566,7 +547,7 @@ function EventTraceFrame_Update()
                         button:GetHighlightTexture():SetVertexColor(.8, .8, 1, .15);
                         button:UnlockHighlight();
                     end
-                    if (DebugTools_IsMouseOver(button)) then
+                    if (button:IsMouseOver()) then
                         EventTraceFrameEvent_OnEnter(button);
                     end
                 end
@@ -1016,8 +997,8 @@ local function _CollectFramesUnderMouse(showHidden)
     local frame = EnumerateFrames(nil);
     while (frame) do
         local visOK, visible = pcall(frame.IsVisible, frame);
-        local mouseOver = DebugTools_IsMouseOver(frame);
-        if (mouseOver and (showHidden or (visOK and visible))) then
+        local overOK, mouseOver = pcall(frame.IsMouseOver, frame);
+        if (overOK and mouseOver and (showHidden or (visOK and visible))) then
             local nameOK, name = pcall(frame.GetName, frame);
             if (not nameOK or not name) then name = "<anonymous>"; end
             table.insert(matches, { name = name, frame = frame });

README.md

@@ -35,9 +35,10 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | [Expansion](docs/API.md#expansion) | `ClassicExpansionAtLeast`, `ClassicExpansionAtMost`, `GetClassicExpansionLevel` |
 | [Faction](docs/API.md#faction) | `C_Reputation.GetFactionDataByIndex`, `C_Reputation.GetFactionStandings`, `C_Reputation.GetLastStandingChange`, `C_Reputation.GetWatchedFactionData`, `C_Reputation.SetWatchedFactionByID`, `GetFactionIDByIndex`, `GetFactionInfoByID`, `GetFactionParentID` |
 | [Focus](docs/API.md#focus) | `ClearFocus`, `FocusUnit` |
-| [Frame](docs/API.md#frame) | `region:SetPoint("point")` (one-arg form), `region:SetSize`, `region:GetSize`, `frame:SetShown`, `frame:SetResizeBounds`, `frame:HookScript`, `frame:IsEventRegistered` |
+| [Frame](docs/API.md#frame) | `region:SetPoint("point")` (one-arg form), `region:SetSize`, `region:GetSize`, `region:IsMouseOver`, `region:GetRect`, `region:IsDragging`, `frame:SetShown`, `frame:SetResizeBounds`, `frame:HookScript`, `frame:IsEventRegistered`, `frame:GetEffectiveAlpha` |
 | [FriendList](docs/API.md#friendlist) | `C_FriendList.IsWhoQueryPending`, `C_FriendList.SendWhoQueryByName` |
 | [GameObject](docs/API.md#gameobject) | `C_GameObjectInfo.GetGameObjectInfoByID`, `C_GameObjectInfo.RequestLoadGameObjectByID`, `ClosestGameObjectPosition` |
+| [Glue](docs/API.md#glue) | `C_Glue.IsOnGlueScreen` |
 | [Gossip](docs/API.md#gossip) | `C_GossipInfo.CloseGossip`, `C_GossipInfo.GetActiveQuests`, `C_GossipInfo.GetAvailableQuests`, `C_GossipInfo.GetNumActiveQuests`, `C_GossipInfo.GetNumAvailableQuests`, `C_GossipInfo.GetNumOptions`, `C_GossipInfo.GetOptions`, `C_GossipInfo.GetText`, `C_GossipInfo.SelectActiveQuest`, `C_GossipInfo.SelectAvailableQuest`, `C_GossipInfo.SelectOption`, `C_GossipInfo.SelectOptionByIndex` |
 | [GameTooltip](docs/API.md#gametooltip) | `GameTooltip:AddSpellByID`, `GameTooltip:GetGameObject`, `GameTooltip:GetItem`, `GameTooltip:GetOwner`, `GameTooltip:GetSpell`, `GameTooltip:GetUnitGUID`, `GameTooltip:HasGameObject`, `GameTooltip:HasItem`, `GameTooltip:HasSpell`, `GameTooltip:HasUnit`, `GameTooltip:IsEquippedItem`, `GameTooltip:SetEquipmentSet`, `GameTooltip:SetHyperlinkCompareItem`, `GameTooltip:SetInventoryItemByID`, `GameTooltip:SetItemByGUID`, `GameTooltip:SetItemByID`, `GameTooltip:SetSpellByID`, `GameTooltip:SetTalentByID`, `GameTooltip:SetTotem`, `GameTooltip:SetUnitAura`, `OnTooltipSetItem`, `OnTooltipSetSpell`, `OnTooltipSetUnit`, `OnTooltipSetGameObject` (scripts) |
 | [Hooks](docs/API.md#hooks) | `hooksecurefunc` |
@@ -69,7 +70,7 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | [Totem](docs/API.md#totem) | `GetTotemInfo`, `GetTotemTimeLeft`, `GetTotemDuration`, `TargetTotem` |
 | [TradeSkillUI](docs/API.md#tradeskillui) | `C_TradeSkillUI.GetTradeSkillListLink`, `C_TradeSkillUI.GetCraftListLink`, `C_TradeSkillUI.GetTradeSkillListRecipes` |
 | [UIColor](docs/API.md#uicolor) | `C_UIColor.GetColors` |
-| [Unit](docs/API.md#unit) | `ClosestUnitPosition`, `GetUnitSpeed`, `UnitClassBase`, `UnitCreatureFamilyID`, `UnitCreatureTypeID`, `UnitDistanceSquared`, `UnitGUID`, `UnitHealthMissing`, `UnitInLineOfSight`, `UnitInRange`, `UnitIsAFK`, `UnitIsDND`, `UnitIsFeignDeath`, `UnitIsInMyGuild`, `UnitIsMinion`, `UnitIsOtherPlayersPet`, `UnitIsPet`, `UnitIsPossessed`, `UnitOwnerGUID`, `UnitPower`, `UnitPowerMax`, `UnitPowerMissing`, `UnitPowerType`, `UnitRaceBase`, `UnitSpellHaste`, `UnitStandState`, `UnitSubName`, `UnitTokenFromGUID` |
+| [Unit](docs/API.md#unit) | `ClosestUnitPosition`, `GetUnitSpeed`, `UnitClassBase`, `UnitCreatureFamilyID`, `UnitCreatureTypeID`, `UnitDistanceSquared`, `UnitGUID`, `UnitHealthMissing`, `UnitInLineOfSight`, `UnitInRange`, `UnitIsAFK`, `UnitIsDND`, `UnitIsFeignDeath`, `UnitIsInMyGuild`, `UnitIsMinion`, `UnitIsOtherPlayersPet`, `UnitIsPet`, `UnitIsPossessed`, `UnitOwnerGUID`, `UnitPosition`, `UnitPower`, `UnitPowerMax`, `UnitPowerMissing`, `UnitPowerType`, `UnitRaceBase`, `UnitSpellHaste`, `UnitStandState`, `UnitSubName`, `UnitTokenFromGUID` |
 | [UnitAuras](docs/API.md#unitauras) | `C_UnitAuras.GetAuraDataByIndex`, `C_UnitAuras.GetAuraDataBySpellName`, `C_UnitAuras.GetAuraDispelTypeColor`, `C_UnitAuras.GetBuffDataByIndex`, `C_UnitAuras.GetDebuffDataByIndex`, `C_UnitAuras.GetPlayerAuraBySpellID`, `C_UnitAuras.GetUnitAuraBySpellID`, `C_UnitAuras.GetUnitAuras`, `C_UnitAuras.RegisterComboDuration` |
 | [VoiceChat](docs/API.md#voicechat) | `C_VoiceChat.GetTtsVoices`, `C_VoiceChat.GetRemoteTtsVoices`, `C_VoiceChat.SpeakText`, `C_VoiceChat.StopSpeakingText`, `C_TTSSettings.GetSpeechRate`, `C_TTSSettings.GetSpeechVolume`, `C_TTSSettings.GetSpeechVoiceID`, `C_TTSSettings.GetVoiceOptionName`, `C_TTSSettings.SetSpeechRate`, `C_TTSSettings.SetSpeechVolume`, `C_TTSSettings.SetVoiceOption`, `C_TTSSettings.SetVoiceOptionByName`, `C_TTSSettings.SetDefaultSettings`, `C_TTSSettings.RefreshVoices` |
 | [XMLUtil](docs/API.md#xmlutil) | `C_XMLUtil.DoesTemplateExist`, `C_XMLUtil.GetTemplateInfo`, `C_XMLUtil.GetTemplates` |
@@ -90,6 +91,7 @@ the glue state because GlueXML had no way to reach them otherwise.
 | [Account](docs/API.md#account) | `SaveAccount`, `DeleteAccount`, `GetSavedAccounts`, `LoginWithSavedAccount` (passwords encrypted in Windows Credential Manager, scoped per realmlist; plaintext never returned to Lua) |
 | [CharacterList](docs/API.md#characterlist) | `GetSavedCharacterOrder`, `SetSavedCharacterOrder` (persist to `WTF\Account\...\ClassicAPI.txt`) |
 | CVar | `GetCVar`, `SetCVar`, `RegisterCVar`, `GetCVarDefault`, `C_CVar.GetCVarBool` (storage is process-global — writes from glue are visible in-world and vice versa) |
+| [Glue](docs/API.md#glue) | `C_Glue.IsFirstLoadThisSession`, `C_Glue.IsOnGlueScreen` |
 | Script | `RunScript` (compile and run a Lua chunk in the glue state's globals — useful for slash-command-style helpers in GlueXML) |
 | State | `IsLoggedIn` |
 

docs/API.md

@@ -155,10 +155,14 @@ build instructions.
 - [Frame](#frame)
   - [`region:SetPoint("point")` (one-argument form)](#regionsetpointpoint-one-argument-form)
   - [`region:SetSize(width, height)` / `region:GetSize()`](#regionsetsizewidth-height--regiongetsize)
+  - [`region:IsMouseOver([topOffset, bottomOffset, leftOffset, rightOffset])`](#regionismouseovertopoffset-bottomoffset-leftoffset-rightoffset)
+  - [`region:GetRect()`](#regiongetrect)
+  - [`region:IsDragging()`](#regionisdragging)
   - [`frame:SetShown(shown)`](#framesetshownshown)
   - [`frame:SetResizeBounds(minWidth, minHeight [, maxWidth, maxHeight])`](#framesetresizeboundsminwidth-minheight--maxwidth-maxheight)
   - [`frame:HookScript(scriptType, handler)`](#framehookscriptscripttype-handler)
   - [`frame:IsEventRegistered(event)`](#frameiseventregisteredevent)
+  - [`frame:GetEffectiveAlpha()`](#framegeteffectivealpha)
 
 - [FriendList](#friendlist)
   - [`C_FriendList.SendWhoQueryByName(name)`](#c_friendlistsendwhoquerybynamename)
@@ -198,6 +202,10 @@ build instructions.
   - [`Enum.ItemQuality`](#enumitemquality)
   - [`Enum.PowerType`](#enumpowertype)
 
+- [Glue](#glue)
+  - [`C_Glue.IsFirstLoadThisSession()`](#c_glueisfirstloadthissession)
+  - [`C_Glue.IsOnGlueScreen()`](#c_glueisongluescreen)
+
 - [Gossip](#gossip)
   - [`C_GossipInfo.GetText()`](#c_gossipinfogettext)
   - [`C_GossipInfo.GetOptions()`](#c_gossipinfogetoptions)
@@ -529,6 +537,7 @@ build instructions.
   - [`UnitStandState(unit)`](#unitstandstateunit)
   - [`UnitInRange(unit)`](#unitinrangeunit)
   - [`UnitDistanceSquared(unit)`](#unitdistancesquaredunit)
+  - [`UnitPosition(unit)`](#unitpositionunit)
   - [`UnitInLineOfSight(unit)`](#unitinlineofsightunit)
   - [`ClosestUnitPosition(creatureID)`](#closestunitpositioncreatureid)
   - [`UnitHealthMissing(unit)`](#unithealthmissingunit)
@@ -3593,6 +3602,52 @@ The modern combined setter/getter for `SetWidth`+`SetHeight` /
 textures (including engine-created ones like
 `button:GetNormalTexture()`), fontstrings.
 
+### `region:IsMouseOver([topOffset, bottomOffset, leftOffset, rightOffset])`
+
+`true` when the mouse cursor is within the region's rectangle, `false`
+otherwise. The four optional offsets shift the corresponding edge before
+the test (added to that edge, matching modern semantics: positive
+`topOffset` / `rightOffset` and negative `bottomOffset` / `leftOffset`
+enlarge the hit area). Registered on the Region base, so it works on any
+region type — frames, buttons, textures, fontstrings.
+
+Uses the engine's own rect getters and cursor position, dividing the
+cursor by the region's effective scale — the exact computation vanilla
+addons have long open-coded as `MouseIsOver()`. Returns `false` for a
+region with no resolved rect (unpositioned / zero-size).
+
+```lua
+ItemRefTooltip:IsMouseOver()                 -- true while hovering the tooltip
+Minimap:IsMouseOver(20, -20, -20, 20)        -- true within a 20px halo around it
+```
+
+### `region:GetRect()`
+
+Returns the region's `left, bottom, width, height` in one call (the
+modern combined form of `GetLeft`+`GetBottom`+`GetWidth`+`GetHeight`).
+Composed from the engine's own getters, so all UI-scale conversion is its
+code. On the Region base — works on any region type. Returns nothing for
+a region with no resolved rect (unpositioned), matching retail.
+
+```lua
+UIParent:GetRect()   -- 0, 0, <screenWidth>, <screenHeight>
+Minimap:GetRect()    -- <left>, <bottom>, 140, 140
+```
+
+### `region:IsDragging()`
+
+`true` while the region is the frame currently being moved or resized by
+the mouse — i.e. after `StartMoving`/`StartSizing` and before
+`StopMovingOrSizing` — `false` otherwise. Reads the engine's single global
+drag target (the same slot `StopMovingOrSizing` checks to decide whether
+it owns the active drag). On the Region base; non-frame regions (textures,
+fontstrings) always report `false`, since only frames can be dragged.
+
+```lua
+-- in a frame's OnUpdate while the user drags it:
+if self:IsDragging() then ... end
+```
+
 ### `frame:SetShown(shown)`
 
 `Show()` if `shown` is truthy, `Hide()` otherwise. Registered for
@@ -3641,6 +3696,22 @@ f:IsEventRegistered("PLAYER_LOGIN")   -- true
 f:IsEventRegistered("PLAYER_LOGOUT")  -- false
 ```
 
+### `frame:GetEffectiveAlpha()`
+
+Returns the frame's **effective** alpha — its own `GetAlpha()` multiplied
+by every ancestor's, i.e. the opacity WoW actually composites at render
+time (fading `UIParent` fades all of its children). Vanilla exposes only
+`GetAlpha` (a frame's own alpha); this walks `self → parent → …` via the
+engine's own `GetAlpha`/`GetParent`, so it sees exactly what the engine
+does — including the 8-bit quantization of alpha (`SetAlpha(0.5)` stores
+`127/255 ≈ 0.498`, and effective alpha is the product of those).
+
+```lua
+UIParent:GetEffectiveAlpha()   -- 1
+-- with UIParent at 0.5 and Minimap's own alpha 1:
+Minimap:GetEffectiveAlpha()    -- ~0.498 (0.5 truncates to 127/255)
+```
+
 ## FriendList
 
 ### `C_FriendList.SendWhoQueryByName(name)`
@@ -4641,6 +4712,47 @@ not modern's `ComboPoints` reuse of the same number.
 local rage = UnitPower("player", Enum.PowerType.Rage)
 ```
 
+## Glue
+
+Backports of two `C_Glue` session helpers. `C_Glue` is registered on the glue
+(login / character-select) Lua state; `IsOnGlueScreen` is *also* registered
+in-game, so code that runs in either environment can branch on it. Neither
+needs an engine flag — both answers fall out of which glue boot / Lua state
+is asking.
+
+### `C_Glue.IsFirstLoadThisSession()`
+
+Returns `true` only while the **first** glue screen since the process
+launched is showing, `false` on every later return to the glue screen. Login
+↔ character-select transitions stay within the first glue session (they never
+enter the world), so it stays `true` across them — it flips `false` only once
+you've entered the world and logged back out. Glue state only.
+
+```lua
+if C_Glue.IsFirstLoadThisSession() then
+    -- one-time-per-launch startup (intro cinematic, news, …)
+end
+```
+
+Backed by a process-static count of glue boots (the glue script-registration
+pass fires once per boot: initial launch + each world→glue logout); boot 1 is
+the first load.
+
+### `C_Glue.IsOnGlueScreen()`
+
+Returns `true` when a GlueXML screen is showing (login or character select —
+no character in the world), `false` in the world. Registered on **both** Lua
+states, so it's callable from glue and in-game code alike. The two states are
+mutually exclusive (the glue state exists only when no character is in the
+world), so the answer is fixed per state — `true` from the glue registration,
+`false` from the in-game one.
+
+```lua
+if C_Glue.IsOnGlueScreen() then
+    -- at login / character select
+end
+```
+
 ## Gossip
 
 Retail-shaped wrappers around vanilla's flat `GetGossipText` /
@@ -10474,34 +10586,47 @@ the item-use path for grenades / on-use ground-target items.
 
 ### `C_Spell.CastAtUnit(spellIDOrName, unit)`
 
-Casts a ground-target spell at `unit`'s feet, bypassing the AoE
-reticle click. ClassicAPI's analog of modern's
-`/cast [@unit] Flamestrike` — `CastAtUnit(spell, "player")` drops it
-at the player's position, `"target"` at the target's, and so on for
-any unit token (`"mouseover"`, `"party1"`, `"raid7"`, …). Returns
-`true` when the placement landed at the unit; `false` for
-non-ground-target spells (cast still fires normally), unknown
-spells, or a unit with no resolvable position.
+Casts a spell **at `unit`, whatever its target type** — ClassicAPI's
+analog of modern's `/cast [@unit] Spell`:
+
+- **Ground-target spells** (Flamestrike, Blizzard, Rain of Fire, …) are
+  placed at the unit's feet, bypassing the AoE reticle click.
+- **Unit-target / normal spells** (Frostbolt, Renew, a buff, …) fire
+  directly on the unit — regardless of your current selection, so you can
+  buff `"party1"` or heal `"player"` while an enemy stays targeted.
+
+Works with any unit token (`"target"`, `"player"`, `"mouseover"`,
+`"party1"`, `"raid7"`, …). Returns `true` when the spell was cast at the
+unit (fired or placed); `false` for a spell not in your spellbook, a unit
+with no resolvable position, or a unit the engine won't accept as a target
+for that spell (wrong faction, out of range).
 
 The first argument takes a spellID or a spell name, with the same
 exact-rank / `(Rank N)` semantics as `CastAtCursor`.
 
 ```lua
+-- ground-target: dropped at the unit's feet
 C_Spell.CastAtUnit(2120, "target")            -- Flamestrike at the target's feet
-C_Spell.CastAtUnit(10, "player")              -- Blizzard Rank 1 on yourself
 C_Spell.CastAtUnit("Blizzard(Rank 6)", "target")
+
+-- unit-target / normal: cast straight on the unit, ignoring current target
+C_Spell.CastAtUnit("Frostbolt", "target")
+C_Spell.CastAtUnit("Renew", "player")         -- heal yourself mid-fight
+C_Spell.CastAtUnit("Power Word: Fortitude", "party1")
 ```
 
-Same two-stage shape as
-[`C_Spell.CastAtCursor`](#c_spellcastatcursorspellidorname), but instead of
-the cursor raycast, step 2 reads the unit's world position from its
-`GetPosition` virtual (the same one `CheckInteractDistance` /
-`UnitInRange` use) and commits placement there via
-`FUN_COMMIT_PLACEMENT_COORDS`. The unit is resolved *before* the cast
-is dispatched, so an absent/invalid unit fails cleanly without
-leaving the engine armed in placement mode. A genuinely unrecognized
-unit-token string raises the engine's standard "Unknown unit" error,
-matching `UnitHealth("garbage")`.
+The unit is resolved once to its object; the cast is dispatched with the
+unit's **GUID** as the implicit target (the engine substitutes it exactly
+where it would the current selection), so a unit-target spell fires
+immediately at that unit. A ground spell ignores the GUID and enters
+placement mode instead, which is then committed at the unit's world
+position (read from its `GetPosition` virtual — the same one
+`CheckInteractDistance` / `UnitInRange` use) via
+`FUN_COMMIT_PLACEMENT_COORDS`. The engine can't be left armed in placement
+mode on failure: if no placement is active after dispatch the cast already
+went out, and a non-ground placement (an unaccepted unit target) is
+cancelled. A genuinely unrecognized unit-token string raises the engine's
+standard "Unknown unit" error, matching `UnitHealth("garbage")`.
 
 The companion item version is
 [`C_Item.UseAtUnit`](#c_itemuseatunititeminfo-unit).
@@ -12484,17 +12609,58 @@ human.
 
 Reads world positions via the `CGObject::GetPosition` vtable virtual
 (slot 5, offset `+0x14`) — the same path `UnitInRange` /
-`CheckInteractDistance` use. **Center-to-center**, not reach-aware (that
-edge-to-edge nicety is UnitXP_SP3's niche); the value equals what you'd
-compute from SuperWoW's `UnitPosition`, but it's self-contained (no
-sibling-DLL dependency, and no clash with SuperWoW's own `UnitPosition`,
-which is left untouched).
+`CheckInteractDistance` and our own [`UnitPosition`](#unitpositionunit)
+use. **Center-to-center**, not reach-aware (that edge-to-edge nicety is
+UnitXP_SP3's niche); the value equals what you'd compute from the raw
+`UnitPosition` coordinates, and it's self-contained (no sibling-DLL
+dependency).
 
 > No self-quirk (unlike `UnitInRange`): `UnitDistanceSquared("player")`
 > returns a legitimate `(0, true)`. Because a real `0` (self, or two
 > exactly co-located units) is indistinguishable by value from the miss
 > placeholder, always branch on `checkedPosition`.
 
+### `UnitPosition(unit)`
+
+Returns `posY, posX, posZ, instanceID` — the unit's world position, in
+the modern (WoD+) `UnitPosition` shape. `nil` when the unit has no known
+position.
+
+```lua
+local posY, posX, posZ, instanceID = UnitPosition("player")
+```
+
+| Return | Meaning |
+|--------|---------|
+| `posY` | World Y coordinate (the west axis). |
+| `posX` | World X coordinate (the north axis). |
+| `posZ` | World Z coordinate (height). |
+| `instanceID` | Currently-loaded map id (`Map.dbc` row — e.g. `0` Eastern Kingdoms, `1` Kalimdor). Every visible unit shares the player's instance. |
+
+**Order matches retail** — `posY` (west) first, then `posX` (north), then
+`posZ`, mirroring Blizzard's own `UnitPosition`. So an addon written for
+retail that does `local py, px = UnitPosition(u)` gets its coordinates
+labelled as expected. (World X is north/south, Y is west/east — WoW's
+long-standing convention.)
+
+**Not group-restricted.** Retail returns `nil` for units outside your
+party/raid (a privacy guard that doesn't exist in 1.12). This backport
+reads any *visible* unit — `"target"`, `"mouseover"`, nameplate tokens,
+arbitrary party/raid members in sync range — so it's strictly more
+permissive, closer to SuperWoW's unit-position access. Units the client
+can't currently see (out of range, another zone) have no position → `nil`.
+
+Reads through the same `CGObject::GetPosition` virtual as
+[`UnitDistanceSquared`](#unitdistancesquaredunit); the two are consistent
+(the squared delta of two `UnitPosition` reads equals
+`UnitDistanceSquared`).
+
+> **SuperWoW interaction.** SuperWoW also defines a global `UnitPosition`
+> with a different return shape. Both register on the same Lua state, so
+> if SuperWoW is loaded the last registrant wins — install order decides
+> which shape is live. Without SuperWoW, this retail-shaped version is the
+> one you get.
+
 ### `UnitInLineOfSight(unit)`
 
 Returns `true` if the player has clear line of sight to `unit`, `false`

src/Offsets.h

@@ -1314,12 +1314,42 @@ enum Offsets {
     FUN_SCRIPT_REGION_SETHEIGHT = 0x007A2150,
     FUN_SCRIPT_REGION_GETWIDTH = 0x007A1E00,
     FUN_SCRIPT_REGION_GETHEIGHT = 0x007A2030,
+    // Region rect getters (return a number, or nil when the region has no
+    // resolved rect). All on the REGION base registry → callable on any
+    // region type. Used by Frame::Modern's IsMouseOver.
+    FUN_SCRIPT_REGION_GETLEFT = 0x007A1980,
+    FUN_SCRIPT_REGION_GETRIGHT = 0x007A1AA0,
+    FUN_SCRIPT_REGION_GETTOP = 0x007A1BC0,
+    FUN_SCRIPT_REGION_GETBOTTOM = 0x007A1CE0,
+    // In-game GetCursorPosition (0x0046DAD0 is the glue-state copy). Pushes
+    // (x, y) in the same k = FUN_0041ad70()*DAT_007ffd68 space the region
+    // rect getters use — so dividing by the region's effective scale puts
+    // the cursor in the region's logical coordinate space.
+    FUN_SCRIPT_GETCURSORPOSITION = 0x0048B820,
+    // Region effective-scale field: `piVar[0x1f]` (float) read by both
+    // GetEffectiveScale (0x00774FC0) and internally by GetLeft/Top/etc. —
+    // present on every region object, so it's the all-region way to get the
+    // effective scale without the Frame-only GetEffectiveScale method.
+    OFF_REGION_EFFECTIVE_SCALE = 0x7C,
+
+    // Global UI/screen context pointer (every frame's +0xA0 field mirrors
+    // it; GetCursorPosition reads the cursor from *ptr + 0x1118). Its
+    // +0xCFC slot holds the frame currently being moved/sized via
+    // StartMoving/StartSizing (0 when idle) — the drag target. Backs
+    // Frame::Modern's IsDragging: StopMovingOrSizing (0x00776990) gates its
+    // clear on `*(context+0xCFC) == self`, i.e. the IsDragging predicate.
+    VAR_UI_CONTEXT_PTR = 0x00CF0BD8,
+    OFF_UI_CONTEXT_DRAG_TARGET = 0xCFC,
     FUN_SCRIPT_FRAME_SHOW = 0x00775750,
     FUN_SCRIPT_FRAME_HIDE = 0x00775810,
     FUN_SCRIPT_FRAME_SETMINRESIZE = 0x00776020,
     FUN_SCRIPT_FRAME_SETMAXRESIZE = 0x007762A0,
     FUN_SCRIPT_FRAME_GETSCRIPT = 0x00774780,
     FUN_SCRIPT_FRAME_SETSCRIPT = 0x007748D0,
+    // Frame GetAlpha (own alpha, 0..1) + Region GetParent — walked by
+    // Frame::Modern's GetEffectiveAlpha up the parent chain.
+    FUN_SCRIPT_FRAME_GETALPHA = 0x00774DC0,
+    FUN_SCRIPT_REGION_GETPARENT = 0x007A1460,
     FUN_SCRIPT_TEXTURE_SHOW = 0x0079B770,
     FUN_SCRIPT_TEXTURE_HIDE = 0x0079B830,
     FUN_SCRIPT_FONTSTRING_SHOW = 0x0079CDB0,

src/baselib/StringLib.cpp

@@ -265,6 +265,7 @@ void RegisterFns() {
     Game::Lua::RegisterTableFunction("string", "match", &Script_string_match);
     Game::Lua::RegisterTableFunction("string", "gmatch", Script_string_gmatch);
     Game::Lua::RegisterTableFunction("string", "reverse", &Script_string_reverse);
+    Game::Lua::RegisterTableFunction("string", "split", &Script_strsplit);
     Game::Lua::RegisterGlobalFunction("strsplit", &Script_strsplit);
     Game::Lua::RegisterGlobalFunction("strjoin", &Script_strjoin);
     Game::Lua::RegisterGlobalFunction("strtrim", &Script_strtrim);

src/frame/Modern.cpp

@@ -26,6 +26,12 @@
 //   - `region:SetSize(w, h)` / `region:GetSize()` — registered on the
 //     REGION base method registry, so they resolve on frames, buttons,
 //     textures, fontstrings — everything.
+//   - `region:IsMouseOver([top, bottom, left, right])` — cursor-in-rect
+//     test with optional per-edge offsets, also on the REGION registry.
+//   - `region:GetRect()` — left, bottom, width, height, composed from the
+//     engine's Region getters. Also on the REGION registry.
+//   - `region:IsDragging()` — true while the region is the frame currently
+//     being moved/sized. Reads the engine's global drag target.
 //   - `frame:SetShown(shown)` — Show/Hide are per-branch script functions
 //     (each with its own object typecheck), so SetShown is registered
 //     separately on Frame / Texture / FontString with matching delegates.
@@ -34,6 +40,9 @@
 //   - `frame:HookScript(scriptType, handler)` — absent in vanilla
 //     entirely. Chains after any existing handler and invokes `handler`
 //     with modern positional args (see the implementation comment).
+//   - `frame:GetEffectiveAlpha()` — own alpha × the parent chain's, the
+//     product WoW composites at render time. Frame-scoped (matches
+//     GetAlpha); walks the parents via the engine's own getters.
 //
 // Implementation style: each new method delegates to the ENGINE's own
 // Script_* implementations by reshaping the Lua stack and calling them
@@ -83,6 +92,119 @@ int __fastcall Script_GetSize(void *L) {
     return 2;
 }
 
+// ---- IsMouseOver (Region base — all region types) --------------------------
+
+// `region:IsMouseOver([topOffset, bottomOffset, leftOffset, rightOffset])` —
+// true when the cursor is within the region's rect, each edge optionally
+// shifted by the matching offset (added to that edge, modern semantics:
+// +top/-bottom/-left/+right enlarges). Vanilla addons have always done this
+// in Lua as MouseIsOver(); we register it as the native Region method later
+// clients expose.
+//
+// The math mirrors the engine exactly: GetLeft/Right/Top/Bottom (Region
+// registry, all types) and GetCursorPosition both return values scaled by the
+// same k = FUN_0041ad70()*DAT_007ffd68 factor, but the rect getters also
+// divide by the region's effective scale — so dividing the cursor by that same
+// effective scale (read from obj+0x7C, the field GetLeft/GetEffectiveScale
+// themselves read) puts both in the region's logical space. A getter returns
+// nil for an unpositioned region → we report false.
+
+// Calls a Region getter that returns one number; false if it pushed nil/none.
+bool CallRegionNumber(void *L, uintptr_t fn, double *out) {
+    Game::Lua::SetTop(L, 1); // (self)
+    CallScript(fn, L);       // (self, value | nil)
+    if (!Game::Lua::IsNumber(L, 2))
+        return false;
+    *out = Game::Lua::ToNumber(L, 2);
+    return true;
+}
+
+int __fastcall Script_IsMouseOver(void *L) {
+    // Offsets first — the stack gets reshaped by the delegated getters.
+    const double offTop = Game::Lua::IsNumber(L, 2) ? Game::Lua::ToNumber(L, 2) : 0.0;
+    const double offBottom = Game::Lua::IsNumber(L, 3) ? Game::Lua::ToNumber(L, 3) : 0.0;
+    const double offLeft = Game::Lua::IsNumber(L, 4) ? Game::Lua::ToNumber(L, 4) : 0.0;
+    const double offRight = Game::Lua::IsNumber(L, 5) ? Game::Lua::ToNumber(L, 5) : 0.0;
+
+    void *obj = Game::Lua::ResolveObject(L, 1);
+    if (obj == nullptr) {
+        Game::Lua::PushBool(L, false);
+        return 1;
+    }
+    const float effScale = *reinterpret_cast<const float *>(
+        reinterpret_cast<const uint8_t *>(obj) + Offsets::OFF_REGION_EFFECTIVE_SCALE);
+
+    double left, right, top, bottom;
+    if (effScale == 0.0f ||
+        !CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETLEFT, &left) ||
+        !CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETRIGHT, &right) ||
+        !CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETTOP, &top) ||
+        !CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETBOTTOM, &bottom)) {
+        Game::Lua::PushBool(L, false); // no resolved rect
+        return 1;
+    }
+
+    Game::Lua::SetTop(L, 0);
+    CallScript(Offsets::FUN_SCRIPT_GETCURSORPOSITION, L); // (x, y)
+    const double x = Game::Lua::ToNumber(L, 1) / effScale;
+    const double y = Game::Lua::ToNumber(L, 2) / effScale;
+
+    left += offLeft;
+    right += offRight;
+    top += offTop;
+    bottom += offBottom;
+
+    const bool inside = x >= left && x <= right && y >= bottom && y <= top;
+    Game::Lua::PushBool(L, inside);
+    return 1;
+}
+
+// ---- GetRect (Region base — all region types) ------------------------------
+
+// `region:GetRect()` → left, bottom, width, height. Composed from the
+// engine's own Region getters (so all UI-scale conversion is its code).
+// Matches retail: returns nothing for a region with no resolved rect —
+// gated on GetLeft, which pushes nil when the position isn't resolved (a
+// size-only region with no anchor has width/height but no rect).
+int __fastcall Script_GetRect(void *L) {
+    double left, bottom, width, height;
+    if (!CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETLEFT, &left))
+        return 0;
+    CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETBOTTOM, &bottom);
+    CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETWIDTH, &width);
+    CallRegionNumber(L, Offsets::FUN_SCRIPT_REGION_GETHEIGHT, &height);
+    Game::Lua::SetTop(L, 1);
+    Game::Lua::PushNumber(L, left);
+    Game::Lua::PushNumber(L, bottom);
+    Game::Lua::PushNumber(L, width);
+    Game::Lua::PushNumber(L, height);
+    return 4;
+}
+
+// ---- IsDragging (Region base — all region types) ---------------------------
+
+// `region:IsDragging()` — true while this region is the frame currently
+// being moved/sized (StartMoving/StartSizing active, before
+// StopMovingOrSizing). The engine tracks a single drag target in the global
+// UI context at +0xCFC; StopMovingOrSizing itself gates on
+// `context+0xCFC == self`, which is exactly this predicate. Reading the
+// global context (rather than self+0xA0) keeps it correct for non-frame
+// regions — a texture/fontstring self can never match the frame stored
+// there, so it reports false, as it should.
+int __fastcall Script_IsDragging(void *L) {
+    void *self = Game::Lua::ResolveObject(L, 1);
+    void *ctx = *reinterpret_cast<void *const *>(
+        static_cast<uintptr_t>(Offsets::VAR_UI_CONTEXT_PTR));
+    void *dragTarget =
+        ctx != nullptr
+            ? *reinterpret_cast<void *const *>(
+                  reinterpret_cast<const uint8_t *>(ctx) +
+                  Offsets::OFF_UI_CONTEXT_DRAG_TARGET)
+            : nullptr;
+    Game::Lua::PushBool(L, self != nullptr && self == dragTarget);
+    return 1;
+}
+
 // ---- SetShown (per-branch Show/Hide delegates) -----------------------------
 
 // `object:SetShown(shown)` — any falsy value hides, truthy shows,
@@ -95,6 +217,33 @@ int __fastcall Script_SetShown(void *L) {
     return 0;
 }
 
+// ---- GetEffectiveAlpha (Frame) ---------------------------------------------
+
+// `frame:GetEffectiveAlpha()` — the frame's own alpha times every
+// ancestor's alpha, i.e. the product WoW composites at render time (fading
+// UIParent fades all children). Vanilla exposes only GetAlpha (own alpha);
+// we walk self → parent → … via the engine's own GetAlpha (Frame) and
+// GetParent (Region), so no field offsets or scale math are re-derived. The
+// iteration cap is a defensive guard against a pathological chain (WoW frame
+// trees are shallow; the loop normally ends when GetParent returns nil at
+// the top of the tree).
+int __fastcall Script_GetEffectiveAlpha(void *L) {
+    Game::Lua::SetTop(L, 1); // (obj) = self
+    double eff = 1.0;
+    for (int guard = 0; guard < 128; ++guard) {
+        CallScript(Offsets::FUN_SCRIPT_FRAME_GETALPHA, L); // (obj, alpha)
+        eff *= Game::Lua::ToNumber(L, 2);
+        Game::Lua::SetTop(L, 1);                             // (obj)
+        CallScript(Offsets::FUN_SCRIPT_REGION_GETPARENT, L); // (obj, parent|nil)
+        if (Game::Lua::Type(L, 2) == Game::Lua::TYPE_NIL)
+            break;
+        Game::Lua::Remove(L, 1); // drop obj → (parent) becomes index 1
+    }
+    Game::Lua::SetTop(L, 0);
+    Game::Lua::PushNumber(L, eff);
+    return 1;
+}
+
 // ---- SetResizeBounds (Frame) -----------------------------------------------
 
 // `frame:SetResizeBounds(minWidth, minHeight [, maxWidth, maxHeight])` —
@@ -274,6 +423,9 @@ const Game::HookAutoRegister _setPointHook{
 const Game::Lua::FrameMethodEntry g_regionMethods[] = {
     {"SetSize", &Script_SetSize},
     {"GetSize", &Script_GetSize},
+    {"IsMouseOver", &Script_IsMouseOver},
+    {"GetRect", &Script_GetRect},
+    {"IsDragging", &Script_IsDragging},
 };
 
 const Game::Lua::FrameMethodEntry g_frameMethods[] = {
@@ -282,6 +434,7 @@ const Game::Lua::FrameMethodEntry g_frameMethods[] = {
     {"SetResizeBounds", &Script_SetResizeBounds},
     {"HookScript", &Script_HookScript},
     {"IsEventRegistered", &Script_IsEventRegistered},
+    {"GetEffectiveAlpha", &Script_GetEffectiveAlpha},
 };
 
 const Game::Lua::FrameMethodEntry g_textureMethods[] = {

src/glue/Session.cpp

@@ -0,0 +1,82 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software Foundation, either
+// version 3 of the License, or (at your option) any later version.
+//
+// ClassicAPI is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+// PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// `C_Glue` session helpers.
+//
+// `C_Glue.IsFirstLoadThisSession()` — glue-only. Returns true only while the
+// FIRST glue screen since the process launched is showing, and false on
+// every return to glue after a world login (a genuine world→glue logout;
+// login↔character-select stays within the first glue session). Retail uses
+// it so the login UI runs one-time startup (intro cinematic, news) only on
+// the initial launch, not on each relog.
+//
+// Backed by a process-static boot counter, no engine state needed: the glue
+// registration callback fires exactly once per glue boot
+// (FUN_LOAD_GLUE_SCRIPT_FUNCTIONS — initial launch + each world→glue return),
+// so the counter equals "how many glue screens this session" and the first
+// one is boot #1. The glue Lua state is recreated per boot, so C_Glue is
+// re-registered each time; the counter is process-static and survives that.
+//
+// `C_Glue.IsOnGlueScreen()` — true when a GlueXML screen is showing (no
+// character logged in), false in the world. Registered on BOTH Lua states,
+// and the answer is a compile-time constant per state: the glue and in-game
+// Lua states are mutually exclusive (glue exists only when no character is in
+// the world), so the glue registration returns true and the in-game one
+// returns false — no runtime flag to consult. Available in both states so
+// shared code that runs in either environment can branch on it.
+
+#include "Game.h"
+
+namespace Glue::Session {
+
+namespace {
+
+// Glue-screen boots since process start. 1 during the very first glue screen.
+int g_glueBootCount = 0;
+
+int __fastcall Script_IsFirstLoadThisSession(void *L) {
+    Game::Lua::PushBool(L, g_glueBootCount <= 1);
+    return 1;
+}
+
+int __fastcall Script_IsOnGlueScreen_True(void *L) {
+    Game::Lua::PushBool(L, true);
+    return 1;
+}
+
+int __fastcall Script_IsOnGlueScreen_False(void *L) {
+    Game::Lua::PushBool(L, false);
+    return 1;
+}
+
+void RegisterGlue() {
+    ++g_glueBootCount; // one glue boot per callback invocation
+    Game::Lua::RegisterTableFunction("C_Glue", "IsFirstLoadThisSession",
+                                     &Script_IsFirstLoadThisSession);
+    Game::Lua::RegisterTableFunction("C_Glue", "IsOnGlueScreen",
+                                     &Script_IsOnGlueScreen_True);
+}
+
+void RegisterInGame() {
+    // In-world: only IsOnGlueScreen makes sense (and it's always false).
+    // IsFirstLoadThisSession is a glue concept, so it's not registered here.
+    Game::Lua::RegisterTableFunction("C_Glue", "IsOnGlueScreen",
+                                     &Script_IsOnGlueScreen_False);
+}
+
+const Game::GlueModuleAutoRegister _autoregGlue{&RegisterGlue};
+const Game::ModuleAutoRegister _autoreg{&RegisterInGame};
+
+} // namespace
+
+} // namespace Glue::Session

src/item/NewItems.cpp

@@ -30,11 +30,23 @@
 //
 // The feed is event-driven, not polled: it hangs off `Bag::UpdateDelayed`,
 // which co-hooks the engine's three `BAG_UPDATE` fire sites and signals once
-// per frame in which a bag actually changed. On that signal we scan bags
-// 0..4, diff the resident item GUIDs against the previous scan, flag anything
-// newly acquired, and prune flags for items that left. `BAG_NEW_ITEMS_UPDATED`
-// (no payload — matching retail) fires whenever the new-item set changes. So
-// nothing runs on quiet frames.
+// per frame in which a bag actually changed. On that signal we scan bags 0..4,
+// flag any resident GUID that isn't in the owned "seen-set", reconcile the
+// seen-set against everything owned now, and prune flags for items that have
+// genuinely left. `BAG_NEW_ITEMS_UPDATED` (no payload — matching retail) fires
+// whenever the new-item set changes. Nothing runs on quiet frames.
+//
+// The seen-set is deliberately NOT rebuilt from each scan: a bag update in
+// progress transiently drops items from the read — sometimes the entire
+// backpack at once, for a frame or two — and a naive "seen = this scan"
+// approach would then re-flag the momentarily-missing item as new when it
+// reappears (the exact bug this system had). Instead each entry carries a
+// consecutive-absent-scan counter (`SeenReconcile`): present items reset it to
+// 0, absent ones age by one, and only items absent `kMaxMissStreak` scans
+// running are evicted. Counting scans (not wall-clock) means a pause with no
+// bag activity never ages an owned item; any reappearance resets the streak.
+// This keeps the set BOUNDED to ~currently-owned items — genuinely-removed
+// items age out — while absorbing the transient reads.
 //
 // The one exception is establishing the login baseline: a lightweight
 // WorldTick handler waits ~1.5s after the player is first resolvable (long
@@ -47,7 +59,7 @@
 // — even though only *bag* items are ever flagged new. That's what stops a
 // move INTO a bag from any of those (unequip, or a pull from the bank) from
 // looking like a fresh loot: the item's GUID was already in the owned set, so
-// the bag diff treats it as a move. The bank is reachable without the bank
+// the seen-set treats it as already-owned, not new. The bank is reachable without the bank
 // window open because its GUIDs are read straight from the invMgr array (the
 // same gate-bypass `C_Item.GetItemCount` uses; the array is server-populated
 // at login).
@@ -88,7 +100,23 @@ constexpr int kMaxItems = 512;
 // engine ms counter) so it's independent of frame rate.
 constexpr uint32_t kSettleMs = 1500;
 
-uint64_t g_seen[kMaxItems]; // all owned GUIDs (bags + equipment + bank) at the last scan
+// Consecutive bag-change scans an item may be absent from the read before it's
+// dropped from the seen-set. A bag update in progress transiently drops items
+// from the scan — sometimes the whole backpack at once — for a frame or two;
+// counting SCANS (not wall-clock) means a pause with no bag activity never ages
+// an owned item, and any reappearance resets the streak to 0, so a transient
+// miss never reaches the threshold. Genuinely-removed items hit it within a few
+// subsequent bag changes and age out — that's what keeps the set BOUNDED to
+// ~currently-owned items rather than everything ever owned.
+constexpr int kMaxMissStreak = 4;
+
+// One seen-set entry: an owned item's GUID and how many consecutive scans it
+// has been absent from the read (0 = present this scan).
+struct SeenEntry {
+    uint64_t guid;
+    int miss;
+};
+SeenEntry g_seen[kMaxItems];
 int g_seenCount = 0;
 uint64_t g_new[kMaxItems]; // subset currently flagged "new"
 int g_newCount = 0;
@@ -115,6 +143,44 @@ bool AddUnique(uint64_t *arr, int *count, uint64_t guid) {
     return true;
 }
 
+// --- seen-set (bounded, absent-scan-count evicted) -----------------------
+
+bool SeenContains(uint64_t guid) {
+    for (int i = 0; i < g_seenCount; ++i)
+        if (g_seen[i].guid == guid)
+            return true;
+    return false;
+}
+
+// One scan's reconcile: age every entry by one missed scan, then reset the
+// streak (and insert) for everything owned right now, then evict entries that
+// have been absent `kMaxMissStreak` scans running. `owned` is the union of the
+// current bag scan and non-bag owned items (equipment + bank).
+void SeenReconcile(const uint64_t *owned, int ownedCount) {
+    for (int i = 0; i < g_seenCount; ++i)
+        ++g_seen[i].miss;
+    for (int j = 0; j < ownedCount; ++j) {
+        const uint64_t guid = owned[j];
+        if (guid == 0)
+            continue;
+        bool found = false;
+        for (int i = 0; i < g_seenCount; ++i)
+            if (g_seen[i].guid == guid) {
+                g_seen[i].miss = 0;
+                found = true;
+                break;
+            }
+        if (!found && g_seenCount < kMaxItems)
+            g_seen[g_seenCount++] = {guid, 0};
+    }
+    for (int i = 0; i < g_seenCount;) {
+        if (g_seen[i].miss >= kMaxMissStreak)
+            g_seen[i] = g_seen[--g_seenCount];
+        else
+            ++i;
+    }
+}
+
 bool RemoveFrom(uint64_t *arr, int *count, uint64_t guid) {
     for (int i = 0; i < *count; ++i) {
         if (arr[i] == guid) {
@@ -257,12 +323,6 @@ void FireChanged() {
     Event::Custom::Fire(Event::Custom::Lookup(kEvtNewItems), "");
 }
 
-void CopyToSeen(const uint64_t *current, int count) {
-    for (int i = 0; i < count; ++i)
-        g_seen[i] = current[i];
-    g_seenCount = count;
-}
-
 // Login-baseline handler. Runs every frame but does no work once the
 // baseline is taken — it only watches for (re)login and, after a short
 // settle, takes the single authoritative baseline scan. Steady state is just
@@ -290,11 +350,14 @@ void OnTick() {
     if (player == nullptr)
         return; // not resolvable yet — retry next tick
 
-    // Everything currently owned — bags AND worn equipment — becomes the
+    // Everything currently owned — bags AND worn equipment + bank — becomes the
     // baseline; nothing owned at login is "new". Including equipment means a
     // later unequip (paperdoll → bag) is recognized as a move, not a loot.
-    g_seenCount = ScanBags(player, g_seen);
-    AppendNonBagOwned(g_seen, &g_seenCount);
+    uint64_t owned[kMaxItems];
+    int ownedCount = ScanBags(player, owned);
+    AppendNonBagOwned(owned, &ownedCount);
+    g_seenCount = 0;
+    SeenReconcile(owned, ownedCount);
     g_newCount = 0;
     g_seeded = true;
 }
@@ -316,21 +379,35 @@ void OnBagChanged() {
     const int bagCount = ScanBags(player, currentBags);
 
     bool changed = false;
-    // Drop flags for items no longer in the bags (used, sold, equipped, banked).
+    // Flag bag items we've never owned. An item merely dropped from a recent
+    // scan (bag update mid-swap) is still in the seen-set (its miss streak is
+    // below the threshold), so it is NOT re-flagged when it reappears — that
+    // was the false-"new" bug. Checked before the reconcile so a genuinely new
+    // item isn't inserted first.
+    for (int i = 0; i < bagCount; ++i) {
+        if (!SeenContains(currentBags[i]))
+            changed |= AddUnique(g_new, &g_newCount, currentBags[i]);
+    }
+
+    // Reconcile the seen-set against everything owned now (bags + equipment +
+    // bank): resets present items, ages absent ones, evicts long-gone ones.
+    uint64_t owned[kMaxItems];
+    int ownedCount = 0;
+    for (int i = 0; i < bagCount; ++i)
+        AddUnique(owned, &ownedCount, currentBags[i]);
+    AppendNonBagOwned(owned, &ownedCount);
+    SeenReconcile(owned, ownedCount);
+
+    // Drop flags only for items that have genuinely left (fallen out of the
+    // seen-set entirely), not ones merely missing from this one scan.
     for (int i = 0; i < g_newCount;) {
-        if (!Contains(currentBags, bagCount, g_new[i])) {
+        if (!SeenContains(g_new[i])) {
             g_new[i] = g_new[--g_newCount];
             changed = true;
         } else {
             ++i;
         }
     }
-    for (int i = 0; i < bagCount; ++i) {
-        if (!Contains(g_seen, g_seenCount, currentBags[i]))
-            changed |= AddUnique(g_new, &g_newCount, currentBags[i]);
-    }
-    CopyToSeen(currentBags, bagCount);
-    AppendNonBagOwned(g_seen, &g_seenCount);
 
     if (changed)
         FireChanged();

src/spell/AtCursor.cpp

@@ -140,20 +140,31 @@ bool Resolve() {
 
 namespace {
 
+// 4th arg is the GUID high dword. Ghidra types it `float` from usage, but
+// it's a plain dword on the stack (the engine assigns it the current
+// selection's high dword when 0); `unsigned` puts the correct 4 bytes there.
 using CastDispatch_t = void(__fastcall *)(unsigned slot, int bookType,
-                                           unsigned targetGuidLo, float targetGuidHi);
+                                           unsigned targetGuidLo, unsigned targetGuidHi);
 using NameToSlot_t = int(__fastcall *)(const char *name, void *out);
 
-void DispatchSlot(int slot0Based, int bookType) {
+void DispatchSlot(int slot0Based, int bookType, uint64_t targetGuid) {
     auto dispatch = reinterpret_cast<CastDispatch_t>(
         Offsets::FUN_SPELL_CAST_DISPATCH);
-    // (0, 0) GUID = no implicit target; the engine handles placement.
-    dispatch(static_cast<unsigned>(slot0Based), bookType, 0, 0.0f);
+    // GUID 0 = no implicit target (engine uses current selection / placement).
+    // A real GUID casts a unit-target spell straight at that unit.
+    dispatch(static_cast<unsigned>(slot0Based), bookType,
+             static_cast<unsigned>(targetGuid),
+             static_cast<unsigned>(targetGuid >> 32));
 }
 
 } // namespace
 
-bool DispatchSpellCast(int spellID) {
+bool IsPlacementActive() {
+    return *reinterpret_cast<const uint32_t *>(
+               Offsets::VAR_SPELL_PLACEMENT_STATE) != 0;
+}
+
+bool DispatchSpellCast(int spellID, uint64_t targetGuid) {
     if (spellID <= 0)
         return false;
 
@@ -167,11 +178,11 @@ bool DispatchSpellCast(int spellID) {
     if (slot1 <= 0)
         return false; // not in the player's spellbook
 
-    DispatchSlot(slot1 - 1, bookType);
+    DispatchSlot(slot1 - 1, bookType, targetGuid);
     return true;
 }
 
-bool DispatchSpellCastByName(const char *name) {
+bool DispatchSpellCastByName(const char *name, uint64_t targetGuid) {
     if (name == nullptr || *name == '\0')
         return false;
 
@@ -185,7 +196,7 @@ bool DispatchSpellCastByName(const char *name) {
     if (slot < 0)
         return false; // not in the player's spellbook
 
-    DispatchSlot(slot, bookType);
+    DispatchSlot(slot, bookType, targetGuid);
     return true;
 }
 

src/spell/AtCursor.h

@@ -13,8 +13,16 @@
 
 #pragma once
 
+#include <cstdint>
+
 namespace Spell::AtCursor {
 
+// True while the engine has an in-flight targeting placement of any kind
+// (ground reticle, unit/item/corpse select). `VAR_SPELL_PLACEMENT_STATE != 0`.
+// Used by `CastAtUnit` to tell a unit-target spell that fired immediately
+// (no placement) from a ground spell that's waiting for a location.
+bool IsPlacementActive();
+
 // Resolves the engine's in-flight ground-target placement at the
 // player's current cursor world position. Intended to be called
 // immediately after initiating a ground-target cast (spell or item)
@@ -51,7 +59,14 @@ bool CommitAtCoords(const float coords[3]);
 // name form defers to the engine's own resolver, which parses a
 // trailing `(Rank N)` — `"Blizzard"` casts the highest known rank,
 // `"Blizzard(Rank 6)"` casts that rank.
-bool DispatchSpellCast(int spellID);
-bool DispatchSpellCastByName(const char *name);
+//
+// `targetGuid` is the implicit cast target: `0` = the engine's default
+// (current selection, or ground placement for AoE); a unit's GUID makes
+// a unit-target/normal spell fire directly on that unit (the engine
+// substitutes it exactly where it would the current target). Ground
+// spells ignore it and still enter placement. `CastAtUnit` passes the
+// resolved unit's GUID; `CastAtCursor` leaves it 0.
+bool DispatchSpellCast(int spellID, uint64_t targetGuid = 0);
+bool DispatchSpellCastByName(const char *name, uint64_t targetGuid = 0);
 
 } // namespace Spell::AtCursor

src/spell/AtUnit.cpp

@@ -11,33 +11,46 @@
 // You should have received a copy of the GNU General Public License along with
 // ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
 
-// `C_Spell.CastAtUnit(spellID, unit)` — cast a ground-target spell at
-// the given unit's feet, bypassing the manual click on the AoE
-// reticle. `CastAtUnit(spellID, "player")` drops it at the player's
-// position, `"target"` at the target's, etc.
+// `C_Spell.CastAtUnit(spellIDOrName, unit)` — cast a spell at the given
+// unit, whatever its target type. One primitive covering both:
 //
-// Same two-step shape as `C_Spell.CastAtCursor`, but the placement is
-// committed at the unit's world position instead of the cursor
-// raycast:
+//   - **Ground-target spells** (Blizzard, Flamestrike, Rain of Fire…) are
+//     placed at the unit's feet — the reticle is committed at the unit's
+//     world position, no manual click.
+//   - **Unit-target / normal spells** (Frostbolt, Healing Touch, a buff…)
+//     fire directly on the unit — its GUID is fed to the engine's cast
+//     dispatcher as the implicit target, so no current-target juggling and
+//     no "select target" reticle.
 //
-//   1. `Spell::AtCursor::DispatchSpellCast(spellID)` initiates the
-//      cast; the engine enters placement mode for a ground-target
-//      spell.
-//   2. Read the unit's world position (vtable `GetPosition`) and
-//      `Spell::AtCursor::CommitAtCoords()` commits the placement
-//      there.
+// Mechanism: resolve the token once to the unit object, read its position
+// and GUID, then dispatch the cast WITH that GUID
+// (`Spell::AtCursor::DispatchSpellCast(spell, guid)`). The engine's
+// dispatcher substitutes the GUID exactly where it would the current
+// selection, so a unit-target spell fires immediately at that unit. A
+// ground spell ignores the GUID and enters placement mode instead — so we
+// branch on `IsPlacementActive()`:
 //
-// Returns `true` when the placement was committed at the unit; `false`
-// when the spell isn't ground-target (placement cancelled), the spell
-// isn't in the spellbook, or the unit has no resolvable position. The
-// cast itself still proceeds for non-ground spells, just with no
-// implicit target — matching `CastAtCursor`'s semantics.
+//   - No placement after dispatch → the cast already went out on the unit
+//     (unit-target / normal). Success.
+//   - Ground placement active     → commit at the unit's feet. Success.
+//   - Other placement still active → the engine didn't accept the unit as a
+//     target (e.g. wrong faction / out of range); `CommitAtCoords` cancels
+//     it. Failure.
+//
+// Returns `true` when the spell was cast at the unit; `false` when the
+// spell isn't in the spellbook, the unit has no resolvable position, or the
+// unit wasn't a valid target. A genuinely unrecognized token string raises
+// the engine's standard "Unknown unit" error inside the resolver, same as
+// `UnitHealth("garbage")`.
 
 #include "Game.h"
 #include "spell/AtCursor.h"
 #include "spell/MacroPrimarySpell.h"
+#include "unit/Identity.h"
 #include "unit/Position.h"
 
+#include <cstdint>
+
 namespace Spell::AtUnit {
 
 namespace {
@@ -53,27 +66,35 @@ int __fastcall Script_C_Spell_CastAtUnit(void *L) {
     }
     const char *token = Game::Lua::ToString(L, 2);
 
-    // Resolve the unit's position before dispatching — fail fast so a
-    // bad/absent unit doesn't leave the engine sitting in placement
-    // mode. (A genuinely unrecognized token string raises the engine's
-    // standard "Unknown unit" error inside the resolver, same as
-    // `UnitHealth("garbage")`.)
+    // Resolve the unit once → object, then read position + GUID from it.
+    // Fail fast so a bad/absent unit doesn't leave the engine mid-cast.
+    void *unitObj = Unit::Position::ResolveToken(token);
     float pos[3];
-    if (!Unit::Position::ReadToken(token, pos)) {
+    if (unitObj == nullptr || !Unit::Position::Read(unitObj, pos)) {
         Game::Lua::PushBool(L, false);
         return 1;
     }
+    const uint64_t targetGuid = Unit::Identity::GuidForObject(unitObj);
 
     const bool dispatched =
         byNumber
             ? Spell::AtCursor::DispatchSpellCast(
-                  static_cast<int>(Game::Lua::ToNumber(L, 1)))
-            : Spell::AtCursor::DispatchSpellCastByName(Game::Lua::ToString(L, 1));
+                  static_cast<int>(Game::Lua::ToNumber(L, 1)), targetGuid)
+            : Spell::AtCursor::DispatchSpellCastByName(Game::Lua::ToString(L, 1),
+                                                       targetGuid);
     if (!dispatched) {
         Game::Lua::PushBool(L, false);
         return 1;
     }
 
+    // Unit-target / normal spells fired straight at the GUID — no placement.
+    // Ground spells are now sitting in placement mode; commit at the unit's
+    // feet (CommitAtCoords cancels + fails for a non-ground placement, i.e.
+    // an unaccepted unit target).
+    if (!Spell::AtCursor::IsPlacementActive()) {
+        Game::Lua::PushBool(L, true);
+        return 1;
+    }
     const bool placed = Spell::AtCursor::CommitAtCoords(pos);
     Game::Lua::PushBool(L, placed);
     return 1;

src/unit/Position.cpp

@@ -0,0 +1,87 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software Foundation, either
+// version 3 of the License, or (at your option) any later version.
+//
+// ClassicAPI is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+// PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// UnitPosition backport.
+//
+// `UnitPosition("unit") → posY, posX, posZ, instanceID` — the modern
+// (WoD+) world-position accessor, ported to 1.12. The world position of
+// any visible unit already lives on its CGObject; we read it through the
+// shared `Unit::Position` helper (the object's GetPosition virtual, vtable
+// slot 5 — the same path UnitDistanceSquared / UnitInRange use).
+//
+// Two semantic notes:
+//
+//  - **Order matches retail.** The engine's C3Vector is {x, y, z} with the
+//    standard WoW convention (x = north, y = west, z = up). Retail's
+//    UnitPosition returns (posY, posX, posZ) — west, north, up — so we push
+//    the engine's y, then x, then z. An addon ported from retail that reads
+//    `posY, posX = UnitPosition(u)` gets coordinates labelled exactly as it
+//    expects.
+//  - **No group restriction.** Retail returns nil for units outside your
+//    party/raid (a taint/privacy guard that doesn't exist in 1.12). We can
+//    read any *visible* unit, so this is strictly more permissive — closer
+//    to SuperWoW's unit-position access than to retail's restricted form.
+//    Units the client can't see (out of range, different zone) have no
+//    known position → nil.
+//
+// `instanceID` is the currently-loaded Map.dbc id (VAR_CURRENT_MAP_ID) —
+// every visible unit shares the player's instance, so the player's map id
+// is the unit's instance id.
+
+#include "Game.h"
+#include "Offsets.h"
+#include "unit/Position.h"
+
+#include <cstdint>
+
+namespace Unit::PositionApi {
+
+namespace {
+
+// `UnitPosition("unit") → posY, posX, posZ, instanceID`. nil when the unit
+// has no known position (recognized-but-absent token, or a visible-object
+// miss). Genuinely unrecognized token strings raise a Lua error, same as
+// UnitHealth("garbage") — the engine's resolver owns that contract.
+int __fastcall Script_UnitPosition(void *L) {
+    if (!Game::Lua::IsString(L, 1)) {
+        Game::Lua::Error(L, "Usage: UnitPosition(\"unit\")");
+        return 0;
+    }
+    const char *token = Game::Lua::ToString(L, 1);
+
+    float pos[3];
+    if (!Unit::Position::ReadToken(token, pos)) {
+        Game::Lua::PushNil(L);
+        return 1;
+    }
+
+    Game::Lua::PushNumber(L, static_cast<double>(pos[1])); // posY (world Y, west)
+    Game::Lua::PushNumber(L, static_cast<double>(pos[0])); // posX (world X, north)
+    Game::Lua::PushNumber(L, static_cast<double>(pos[2])); // posZ (up)
+    const int mapId = *reinterpret_cast<const int *>(
+        static_cast<uintptr_t>(Offsets::VAR_CURRENT_MAP_ID));
+    Game::Lua::PushNumber(L, static_cast<double>(mapId));
+    return 4;
+}
+
+void RegisterLuaFunctions() {
+    Game::Lua::RegisterGlobalFunction("UnitPosition", &Script_UnitPosition);
+    Game::Lua::RegisterTableFunction("C_PlayerInfo", "UnitPosition",
+                                     &Script_UnitPosition);
+}
+
+const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
+
+} // namespace
+
+} // namespace Unit::PositionApi