feat: implement auto-discard feature for excess stock management

manager/operations.lua

@@ -765,6 +765,92 @@ function O.autoCompost()
     return didWork
 end
 
+-------------------------------------------------
+-- Auto-discard excess stock
+-------------------------------------------------
+
+function O.discardExcess()
+    if #cfg.TRASH_DROPPERS == 0 then return false end
+
+    local catalogue = cache.catalogue
+    local didWork = false
+
+    -- Build a flat list of dropper handles + free capacity
+    local droppers = {}
+    for _, dName in ipairs(cfg.TRASH_DROPPERS) do
+        local d = O.wrapCached(dName)
+        if d then
+            local used = 0
+            local contents = d.list()
+            if contents then
+                for _, item in pairs(contents) do used = used + item.count end
+            end
+            local free = (d.size() * 64) - used
+            if free > 0 then
+                table.insert(droppers, { name = dName, handle = d, free = free })
+            end
+        end
+    end
+    if #droppers == 0 then return false end
+
+    -- Round-robin index across droppers
+    local dIdx = 1
+
+    for itemName, maxCount in pairs(cfg.STOCK_LIMITS) do
+        if catalogue[itemName] then
+            local totalInStorage = 0
+            for _, src in ipairs(catalogue[itemName]) do
+                totalInStorage = totalInStorage + src.total
+            end
+
+            local excess = totalInStorage - maxCount
+            if excess > 0 then
+                log.info("DISCARD", "%s: %d in stock, limit %d, discarding %d",
+                    itemName, totalInStorage, maxCount, excess)
+                local discarded = 0
+                local srcSnapshot = { table.unpack(catalogue[itemName]) }
+                for _, source in ipairs(srcSnapshot) do
+                    if discarded >= excess then break end
+                    if source.total > 0 then
+                        local chest = O.wrapCached(source.chest)
+                        if chest then
+                            for slot, slotItem in pairs(chest.list()) do
+                                if slotItem.name == itemName then
+                                    -- Find a dropper with free space (round-robin)
+                                    local startIdx = dIdx
+                                    local dropper = nil
+                                    repeat
+                                        if droppers[dIdx].free > 0 then
+                                            dropper = droppers[dIdx]
+                                        end
+                                        dIdx = (dIdx % #droppers) + 1
+                                    until dropper or dIdx == startIdx
+                                    if not dropper then break end  -- all droppers full
+
+                                    local batch = math.min(slotItem.count, excess - discarded, dropper.free)
+                                    local n = chest.pushItems(dropper.name, slot, batch)
+                                    if n and n > 0 then
+                                        state.adjustCache(itemName, source.chest, -n)
+                                        dropper.free = dropper.free - n
+                                        discarded = discarded + n
+                                        didWork = true
+                                    end
+                                    if discarded >= excess then break end
+                                end
+                            end
+                        end
+                    end
+                end
+                if discarded > 0 then
+                    log.info("DISCARD", "Discarded %s x%d", itemName, discarded)
+                end
+            end
+        end
+    end
+
+    return didWork
+end
+
 -------------------------------------------------
 -- Low-stock alert checker
 -------------------------------------------------