Implement cache persistence for inventory data and enhance loading mechanism

inventoryManager.lua

@@ -8,6 +8,7 @@ local MONITOR_SIDE  = "left"
 local SCAN_INTERVAL = 3    -- seconds between background scans
 local SMELT_INTERVAL = 3   -- seconds between furnace checks
 local SMELT_RESERVE  = 64  -- keep at least 1 stack of each raw material
+local CACHE_FILE     = ".inventory_cache"  -- persistent cache file
 
 -------------------------------------------------
 -- Furnace types to manage
@@ -239,6 +240,58 @@ local function refreshCache(onProgress)
     cache.furnaceCount = furnaceCount
 
     activity.scanning = false
+
+    -- Persist cache to disk
+    pcall(function()
+        local data = {
+            catalogue  = cache.catalogue,
+            itemList   = cache.itemList,
+            grandTotal = cache.grandTotal,
+            chestCount = cache.chestCount,
+            totalSlots = cache.totalSlots,
+            usedSlots  = cache.usedSlots,
+            freeSlots  = cache.freeSlots,
+            usedRatio  = cache.usedRatio,
+            dropperOk  = cache.dropperOk,
+            barrelOk   = cache.barrelOk,
+            furnaceCount = cache.furnaceCount,
+            savedAt    = os.epoch("utc"),
+        }
+        local f = fs.open(CACHE_FILE, "w")
+        f.write(textutils.serialise(data))
+        f.close()
+    end)
+end
+
+-- Load cache from disk (returns true if loaded)
+local function loadCacheFromDisk()
+    if not fs.exists(CACHE_FILE) then return false end
+    local ok, err = pcall(function()
+        local f = fs.open(CACHE_FILE, "r")
+        local raw = f.readAll()
+        f.close()
+        local data = textutils.unserialise(raw)
+        if data and data.catalogue and data.itemList then
+            cache.catalogue    = data.catalogue
+            cache.itemList     = data.itemList
+            cache.grandTotal   = data.grandTotal   or 0
+            cache.chestCount   = data.chestCount   or 0
+            cache.totalSlots   = data.totalSlots   or 0
+            cache.usedSlots    = data.usedSlots    or 0
+            cache.freeSlots    = data.freeSlots    or 0
+            cache.usedRatio    = data.usedRatio    or 0
+            cache.dropperOk    = data.dropperOk    or false
+            cache.barrelOk     = data.barrelOk     or false
+            cache.furnaceCount = data.furnaceCount or 0
+        else
+            error("invalid cache data")
+        end
+    end)
+    if not ok then
+        print("[WARN] Could not load cache: " .. tostring(err))
+        return false
+    end
+    return true
 end
 
 -------------------------------------------------
@@ -1079,78 +1132,91 @@ local function main()
     print("Console shows log. Use the monitor to interact.")
     print("")
 
-    -- Initial scan with progress bar on monitor
+    -- Try loading cached inventory from disk for instant startup
-    print("[INIT] Scanning inventories...")
+    local cacheLoaded = loadCacheFromDisk()
-    if mon then
+    if cacheLoaded then
-        local w, h = mon.getSize()
+        print("[INIT] Loaded cached inventory (" .. #cache.itemList .. " types)")
-        local buf = window.create(mon, 1, 1, w, h, false)
+        print("[INIT] Background refresh starting...")
-
-        local function drawBoot(current, total, chestName)
-            buf.setBackgroundColor(colors.black)
-            buf.clear()
-
-            -- Title
-            buf.setBackgroundColor(colors.blue)
-            buf.setCursorPos(1, 1)
-            buf.write(string.rep(" ", w))
-            local title = " INVENTORY MANAGER "
-            buf.setCursorPos(math.floor((w - #title) / 2) + 1, 1)
-            buf.setTextColor(colors.white)
-            buf.write(title)
-
-            -- Scanning label
-            local midY = math.floor(h / 2)
-            buf.setBackgroundColor(colors.black)
-            buf.setTextColor(colors.lightGray)
-            local label = "Scanning inventories..."
-            buf.setCursorPos(math.floor((w - #label) / 2) + 1, midY - 2)
-            buf.write(label)
-
-            -- Chest name
-            local short = chestName or ""
-            if #short > w - 4 then short = ".." .. short:sub(-(w - 6)) end
-            buf.setTextColor(colors.gray)
-            buf.setCursorPos(math.floor((w - #short) / 2) + 1, midY - 1)
-            buf.write(short)
-
-            -- Progress bar
-            local barW = math.min(w - 8, 40)
-            local barX = math.floor((w - barW) / 2) + 1
-            local ratio = total > 0 and (current / total) or 0
-            local filled = math.floor(ratio * barW)
-
-            buf.setCursorPos(barX, midY + 1)
-            buf.setBackgroundColor(colors.lime)
-            buf.write(string.rep(" ", filled))
-            buf.setBackgroundColor(colors.gray)
-            buf.write(string.rep(" ", barW - filled))
-
-            -- Percentage + count
-            buf.setBackgroundColor(colors.black)
-            buf.setTextColor(colors.white)
-            local pct = string.format("%d/%d  (%d%%)", current, total, math.floor(ratio * 100))
-            buf.setCursorPos(math.floor((w - #pct) / 2) + 1, midY + 3)
-            buf.write(pct)
-
-            -- Bottom accent
-            buf.setCursorPos(1, h)
-            buf.setBackgroundColor(colors.blue)
-            buf.write(string.rep(" ", w))
-
-            buf.setVisible(true)
-            buf.setVisible(false)
-        end
-
-        refreshCache(drawBoot)
     else
-        refreshCache()
+        -- No cache: do full scan with progress bar
+        print("[INIT] No cache found. Scanning inventories...")
+        if mon then
+            local w, h = mon.getSize()
+            local buf = window.create(mon, 1, 1, w, h, false)
+
+            local function drawBoot(current, total, chestName)
+                buf.setBackgroundColor(colors.black)
+                buf.clear()
+
+                -- Title
+                buf.setBackgroundColor(colors.blue)
+                buf.setCursorPos(1, 1)
+                buf.write(string.rep(" ", w))
+                local title = " INVENTORY MANAGER "
+                buf.setCursorPos(math.floor((w - #title) / 2) + 1, 1)
+                buf.setTextColor(colors.white)
+                buf.write(title)
+
+                -- Scanning label
+                local midY = math.floor(h / 2)
+                buf.setBackgroundColor(colors.black)
+                buf.setTextColor(colors.lightGray)
+                local label = "Scanning inventories..."
+                buf.setCursorPos(math.floor((w - #label) / 2) + 1, midY - 2)
+                buf.write(label)
+
+                -- Chest name
+                local short = chestName or ""
+                if #short > w - 4 then short = ".." .. short:sub(-(w - 6)) end
+                buf.setTextColor(colors.gray)
+                buf.setCursorPos(math.floor((w - #short) / 2) + 1, midY - 1)
+                buf.write(short)
+
+                -- Progress bar
+                local barW = math.min(w - 8, 40)
+                local barX = math.floor((w - barW) / 2) + 1
+                local ratio = total > 0 and (current / total) or 0
+                local filled = math.floor(ratio * barW)
+
+                buf.setCursorPos(barX, midY + 1)
+                buf.setBackgroundColor(colors.lime)
+                buf.write(string.rep(" ", filled))
+                buf.setBackgroundColor(colors.gray)
+                buf.write(string.rep(" ", barW - filled))
+
+                -- Percentage + count
+                buf.setBackgroundColor(colors.black)
+                buf.setTextColor(colors.white)
+                local pct = string.format("%d/%d  (%d%%)", current, total, math.floor(ratio * 100))
+                buf.setCursorPos(math.floor((w - #pct) / 2) + 1, midY + 3)
+                buf.write(pct)
+
+                -- Bottom accent
+                buf.setCursorPos(1, h)
+                buf.setBackgroundColor(colors.blue)
+                buf.write(string.rep(" ", w))
+
+                buf.setVisible(true)
+                buf.setVisible(false)
+            end
+
+            refreshCache(drawBoot)
+        else
+            refreshCache()
+        end
+        print("[INIT] Done. Found " .. #cache.itemList .. " item types.")
     end
-    print("[INIT] Done. Found " .. #cache.itemList .. " item types.")
     print("")
 
     parallel.waitForAny(
         -- Task 1: Background inventory scanner
         function()
+            -- If we loaded from disk cache, refresh immediately in background
+            if cacheLoaded then
+                pcall(refreshCache)
+                needsRedraw = true
+                print("[INIT] Background refresh complete. " .. #cache.itemList .. " types.")
+            end
             while true do
                 sleep(SCAN_INTERVAL)
                 pcall(refreshCache)