Add support for scouts to grid brain (FAForever#4961)

lua/AI/GridBrain.lua

@@ -1,5 +1,7 @@
 local Grid = import("/lua/ai/grid.lua").Grid
 
+local WeakValue = { __mode = 'v' }
+
 local Debug = false
 function EnableDebugging()
     if ScenarioInfo.GameHasAIs or CheatsEnabled() then
@@ -15,6 +17,11 @@ end
 
 ---@class AIGridBrainCell : AIGridCell
 ---@field EngineersReclaiming table<EntityId, Unit>
+---@field AssignedScouts { LAND: table<EntityId, Unit>, AIR: table<EntityId, Unit> } 
+---@field LastScouted number
+---@field ScoutPriority number
+---@field MustScout boolean
+---@field IntelCoverage boolean
 
 ---@class AIGridBrain : AIGrid
 ---@field Cells AIGridBrainCell[][]
@@ -30,7 +37,17 @@ GridBrain = Class(Grid) {
         for k = 1, cellCount do
             for l = 1, cellCount do
                 local cell = cells[k][l]
-                cell.EngineersReclaiming = { }
+                cell.EngineersReclaiming = setmetatable({}, WeakValue)
+                cell.AssignedScouts =  {
+                    OTHER = setmetatable({}, WeakValue),
+                    AIR = setmetatable({}, WeakValue),
+                }
+
+                cell.AssignedAirScouts = setmetatable({}, WeakValue)
+                cell.LastScouted = 0
+                cell.ScoutPriority = 0
+                cell.MustScout = false
+                cell.IntelCoverage = false
             end
         end
 
@@ -79,6 +96,56 @@ GridBrain = Class(Grid) {
     CountReclaimingEngineers = function(self, cell)
         return table.getsize(cell.EngineersReclaiming)
     end,
+
+    --- Registers a scout in a given cell
+    ---@param self AIGridBrain
+    ---@param scout Unit
+    AddAssignedScout = function(self, scout)
+        -- determine cell
+        local px, _, pz = scout:GetPositionXYZ()
+        local cell = self:ToCellFromWorldSpace(px, pz)
+
+        -- determine layer
+        local layer = scout.Blueprint.LayerCategory
+        if layer != 'AIR' then
+            layer = 'LAND'
+        end
+
+        cell.AssignedScouts[layer][scout.EntityId] = scout
+    end,
+
+    --- Unregisters a scout in a given cell
+    ---@param self AIGridBrain
+    ---@param scout Unit
+    RemoveAssignedScout = function(self, scout)
+        -- determine cell
+        local px, _, pz = scout:GetPositionXYZ()
+        local cell = self:ToCellFromWorldSpace(px, pz)
+
+        -- determine layer
+        local layer = scout.Blueprint.LayerCategory
+        if layer != 'AIR' then
+            layer = 'LAND'
+        end
+
+        cell.AssignedScouts[layer][scout.EntityId] = nil
+    end,
+
+    --- Counts the number of scouts assigned to a cell
+    ---@param self AIGridBrain
+    ---@param layer 'LAND' | 'AIR'
+    ---@return number | nil
+    CountAssignedScouts = function(self, position, layer)
+        if not (layer == 'LAND' or layer == 'AIR') then 
+            WARN('GridBrain: unable to get scout count, invalid layer')
+            return
+        end
+
+        -- determine cell
+        local cell = self:ToCellFromWorldSpace(position[1], position[3])
+
+        return table.getsize(cell.AssignedScouts[layer])
+    end,
 }
 
 ---@return AIGridBrain