-- manager/operations.lua — Peripheral helpers + all inventory operations
-- Usage: local ops = dofile("manager/operations.lua")(ctx)

return function(ctx)

local cfg   = ctx.cfg
local state = ctx.state
local log   = ctx.log
local ui    = ctx.ui

local cache    = state.cache
local activity = state.activity

local O = {}

-------------------------------------------------
-- Peripheral caching
-------------------------------------------------

local cachedChests = nil
local cachedChestsTime = 0
local cachedFurnaces = nil
local cachedFurnacesTime = 0
local wrapCache = {}

function O.invalidatePeripheralCaches()
    cachedChests = nil
    cachedFurnaces = nil
end

function O.wrapCached(name)
    local handle = wrapCache[name]
    if handle then return handle end
    handle = peripheral.wrap(name)
    if handle then
        wrapCache[name] = handle
    end
    return handle
end

function O.invalidateWrapCache(name)
    if name then
        wrapCache[name] = nil
    else
        wrapCache = {}
    end
end

function O.getChests()
    local now = os.clock()
    if cachedChests and (now - cachedChestsTime) < cfg.PERIPHERAL_CACHE_TTL then
        return cachedChests
    end
    local chests = {}
    for _, name in ipairs(peripheral.getNames()) do
        if peripheral.getType(name) == "minecraft:chest" then
            table.insert(chests, name)
        end
    end
    cachedChests = chests
    cachedChestsTime = now
    return chests
end

function O.getFurnaces()
    local now = os.clock()
    if cachedFurnaces and (now - cachedFurnacesTime) < cfg.PERIPHERAL_CACHE_TTL then
        return cachedFurnaces
    end
    local furnaces = {}
    for _, ftype in ipairs(cfg.FURNACE_TYPES) do
        for _, name in ipairs(peripheral.getNames()) do
            if peripheral.getType(name) == ftype then
                table.insert(furnaces, name)
            end
        end
    end
    cachedFurnaces = furnaces
    cachedFurnacesTime = now
    return furnaces
end

function O.refreshFurnaceStatus()
    local furnaces = O.getFurnaces()
    local status = {}
    for _, fname in ipairs(furnaces) do
        local furnace = O.wrapCached(fname)
        if furnace then
            local contents = furnace.list()
            local entry = {
                name   = fname,
                type   = peripheral.getType(fname),
                input  = contents[cfg.SLOT_INPUT] or nil,
                fuel   = contents[cfg.SLOT_FUEL] or nil,
                output = contents[cfg.SLOT_OUTPUT] or nil,
                active = (contents[cfg.SLOT_INPUT] ~= nil and contents[cfg.SLOT_FUEL] ~= nil),
            }
            table.insert(status, entry)
        end
    end
    cache.furnaceStatus = status
    state.bumpStateVersion()
end

function O.scanInventory(deviceName)
    local inv = O.wrapCached(deviceName)
    if not inv then return {} end
    local result = {}
    for slot, item in pairs(inv.list()) do
        if not result[item.name] then
            result[item.name] = { total = 0, slots = {} }
        end
        result[item.name].total = result[item.name].total + item.count
        result[item.name].slots[slot] = { name = item.name, count = item.count }
    end
    return result
end

-------------------------------------------------
-- Full cache refresh
-------------------------------------------------

function O.refreshCache(onProgress)
    activity.scanning = true
    O.invalidateWrapCache()

    local chests = {}
    local furnaces = {}
    local furnaceTypeSet = {}
    for _, ft in ipairs(cfg.FURNACE_TYPES) do furnaceTypeSet[ft] = true end

    for _, name in ipairs(peripheral.getNames()) do
        local ptype = peripheral.getType(name)
        if ptype == "minecraft:chest" then
            table.insert(chests, name)
        elseif furnaceTypeSet[ptype] then
            table.insert(furnaces, name)
        end
    end

    local now = os.clock()
    cachedChests = chests
    cachedChestsTime = now
    cachedFurnaces = furnaces
    cachedFurnacesTime = now

    local catalogue = {}
    local totalSlots = 0
    local usedSlots = 0

    -- Parallel inventory scanning (chunked)
    local CHUNK = cfg.PARALLEL_SCAN_CHUNKS or 8
    local scanData = {}
    local scanFns = {}
    for _, chest in ipairs(chests) do
        table.insert(scanFns, function()
            local inv = O.wrapCached(chest)
            if inv then
                scanData[chest] = {
                    size     = inv.size(),
                    contents = inv.list(),
                }
            end
        end)
    end

    for i = 1, #scanFns, CHUNK do
        local chunk = {}
        local chunkEnd = math.min(i + CHUNK - 1, #scanFns)
        for j = i, chunkEnd do
            chunk[#chunk + 1] = scanFns[j]
        end
        if onProgress then
            onProgress(chunkEnd, #chests, chests[chunkEnd] or "scanning...")
        end
        parallel.waitForAll(table.unpack(chunk))
    end

    for _, chest in ipairs(chests) do
        local data = scanData[chest]
        if data then
            totalSlots = totalSlots + data.size
            for slot, item in pairs(data.contents) do
                usedSlots = usedSlots + 1
                if not catalogue[item.name] then
                    catalogue[item.name] = {}
                end
                local found = false
                for _, entry in ipairs(catalogue[item.name]) do
                    if entry.chest == chest then
                        entry.total = entry.total + item.count
                        found = true
                        break
                    end
                end
                if not found then
                    table.insert(catalogue[item.name], { chest = chest, total = item.count })
                end
            end
        end
    end

    local itemList = {}
    local grandTotal = 0
    for itemName, sources in pairs(catalogue) do
        local total = 0
        for _, s in ipairs(sources) do total = total + s.total end
        grandTotal = grandTotal + total
        table.insert(itemList, { name = itemName, total = total })
    end
    table.sort(itemList, function(a, b) return a.total > b.total end)

    cache.catalogue  = catalogue
    cache.itemList   = itemList
    cache.itemListDirty = false
    cache.grandTotal = grandTotal
    cache.chestCount = #chests
    cache.totalSlots = totalSlots
    cache.usedSlots  = usedSlots
    cache.freeSlots  = totalSlots - usedSlots
    cache.usedRatio  = totalSlots > 0 and (usedSlots / totalSlots) or 0
    cache.dropperOk  = peripheral.isPresent(cfg.DROPPER_NAME)
    cache.barrelOk   = peripheral.isPresent(cfg.BARREL_NAME)

    -- Discover droppers
    local droppers = {}
    for _, name in ipairs(peripheral.getNames()) do
        local isDropper = name:match("^minecraft:dropper_")
        if not isDropper and peripheral.hasType then
            isDropper = peripheral.hasType(name, "minecraft:dropper")
        end
        if not isDropper then
            isDropper = peripheral.getType(name) == "minecraft:dropper"
        end
        if isDropper and name ~= cfg.COMPOST_DROPPER then
            local isDefault = (name == cfg.DROPPER_NAME)
            table.insert(droppers, { name = name, isDefault = isDefault })
        end
    end
    table.sort(droppers, function(a, b)
        if a.isDefault ~= b.isDefault then return a.isDefault end
        return a.name < b.name
    end)

    local seenNames = {}
    for _, d in ipairs(droppers) do seenNames[d.name] = true end
    for clientId, clientList in pairs(state.clientDroppers) do
        for _, d in ipairs(clientList) do
            if not seenNames[d.name] then
                table.insert(droppers, { name = d.name, isDefault = false, clientId = clientId })
                seenNames[d.name] = true
            end
        end
    end
    cache.droppers = droppers
    cache.furnaceCount = #furnaces

    O.refreshFurnaceStatus()
    activity.scanning = false
    state.bumpStateVersion()

    -- 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,
            furnaceStatus = cache.furnaceStatus,
            droppers     = cache.droppers,
            savedAt      = os.epoch("utc"),
        }
        local f = fs.open(cfg.CACHE_FILE, "w")
        f.write(textutils.serialise(data))
        f.close()
    end)
end

function O.loadCacheFromDisk()
    if not fs.exists(cfg.CACHE_FILE) then return false end
    local ok, err = pcall(function()
        local f = fs.open(cfg.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
            cache.furnaceStatus = data.furnaceStatus or {}
            cache.droppers     = data.droppers     or {}
        else
            error("invalid cache data")
        end
    end)
    if not ok then
        log.warn("INIT", "Could not load cache: %s", tostring(err))
        return false
    end
    return true
end

-------------------------------------------------
-- Barrel auto-sort
-------------------------------------------------

--- Get chests sorted by priority (highest first).
-- Falls back to name order if no priority is configured.
function O.getChestsByPriority()
    local chests = O.getChests()
    local priority = cfg.CHEST_PRIORITY
    if not priority or not next(priority) then return chests end
    local sorted = { table.unpack(chests) }
    table.sort(sorted, function(a, b)
        local pa = priority[a] or 0
        local pb = priority[b] or 0
        if pa ~= pb then return pa > pb end
        return a < b
    end)
    return sorted
end

function O.sortBarrel(barrelOverride)
    local barrelTarget = (barrelOverride and barrelOverride ~= "") and barrelOverride or cfg.BARREL_NAME
    local barrel = O.wrapCached(barrelTarget)
    if not barrel then return end

    local contents = barrel.list()
    if not contents or not next(contents) then return end

    activity.sorting = true
    state.needsRedraw = true

    local catalogue = cache.catalogue
    local chests = O.getChestsByPriority()

    for slot, item in pairs(contents) do
        local moved = 0
        local triedChests = {}

        if catalogue[item.name] then
            for _, entry in ipairs(catalogue[item.name]) do
                triedChests[entry.chest] = true
                local n = barrel.pushItems(entry.chest, slot)
                if n and n > 0 then
                    moved = moved + n
                    state.adjustCache(item.name, entry.chest, n)
                    state.needsRedraw = true
                    state.smelterNeedsRedraw = true
                    log.info("SORT", "%s x%d -> %s", item.name, n, entry.chest)
                end
                if moved >= item.count then break end
            end
        end

        if moved < item.count then
            for _, chest in ipairs(chests) do
                if not triedChests[chest] then
                    local n = barrel.pushItems(chest, slot)
                    if n and n > 0 then
                        moved = moved + n
                        state.adjustCache(item.name, chest, n)
                        state.needsRedraw = true
                        state.smelterNeedsRedraw = true
                        log.info("SORT", "%s x%d -> %s", item.name, n, chest)
                    end
                    if moved >= item.count then break end
                end
            end
        end

        if moved < item.count then
            log.warn("SORT", "Could not sort %d remaining %s", item.count - moved, item.name)
        end
    end

    activity.sorting = false
    state.needsRedraw = true
end

-------------------------------------------------
-- Auto-smelt
-------------------------------------------------

function O.autoSmelt()
    if state.smeltingPaused then return false end

    local furnaces = O.getFurnaces()
    if #furnaces == 0 then return false end

    local chests = O.getChests()
    local catalogue = cache.catalogue
    local didWork = false
    local emptyInputFurnaces = {}

    for _, fname in ipairs(furnaces) do
        local furnace = O.wrapCached(fname)
        if furnace then
            local contents = furnace.list()

            -- 1) Pull finished output
            if contents[cfg.SLOT_OUTPUT] then
                local outputItem = contents[cfg.SLOT_OUTPUT]
                local remaining = outputItem.count
                for _, chest in ipairs(chests) do
                    local n = furnace.pushItems(chest, cfg.SLOT_OUTPUT)
                    if n and n > 0 then
                        state.adjustCache(outputItem.name, chest, n)
                        remaining = remaining - n
                        log.info("SMELT", "Output %s x%d -> %s", outputItem.name, n, chest)
                        didWork = true
                        if remaining <= 0 then break end
                    end
                end
                if remaining > 0 then
                    log.warn("SMELT", "Could not move %d %s from %s output (chests full?)",
                        remaining, outputItem.name, fname)
                end
            end

            -- Check extra slots
            for slot, item in pairs(contents) do
                if slot ~= cfg.SLOT_INPUT and slot ~= cfg.SLOT_FUEL and slot ~= cfg.SLOT_OUTPUT then
                    for _, chest in ipairs(chests) do
                        local n = furnace.pushItems(chest, slot)
                        if n and n > 0 then
                            state.adjustCache(item.name, chest, n)
                            log.info("SMELT", "Extra slot %d: %s x%d -> %s", slot, item.name, n, chest)
                            didWork = true
                            break
                        end
                    end
                end
            end

            contents = furnace.list()

            -- 2) Remove incompatible items from input
            local furnaceType = peripheral.getType(fname)
            local inputItem = contents[cfg.SLOT_INPUT]
            if inputItem then
                local recipe = cfg.SMELTABLE[inputItem.name]
                local validHere = recipe and recipe.furnaceSet[furnaceType] or false
                if not validHere then
                    for _, chest in ipairs(chests) do
                        local n = furnace.pushItems(chest, cfg.SLOT_INPUT)
                        if n and n > 0 then
                            state.adjustCache(inputItem.name, chest, n)
                            log.info("SMELT", "Removed incompatible %s x%d from %s -> %s",
                                inputItem.name, n, fname, chest)
                            didWork = true
                            break
                        end
                    end
                    contents = furnace.list()
                end
            end

            -- 3) Refuel
            local fuelItem = contents[cfg.SLOT_FUEL]
            local needFuel = not fuelItem or fuelItem.count < 8

            if needFuel then
                for _, fuel in ipairs(cfg.FUEL_LIST) do
                    if catalogue[fuel.name] then
                        for _, source in ipairs(catalogue[fuel.name]) do
                            local chest = O.wrapCached(source.chest)
                            if chest then
                                for slot, slotItem in pairs(chest.list()) do
                                    if slotItem.name == fuel.name then
                                        local toMove = math.min(16, slotItem.count)
                                        local n = chest.pushItems(fname, slot, toMove, cfg.SLOT_FUEL)
                                        if n and n > 0 then
                                            state.adjustCache(fuel.name, source.chest, -n)
                                            log.info("SMELT", "Fuel %s x%d -> %s", fuel.name, n, fname)
                                            didWork = true
                                            needFuel = false
                                            break
                                        end
                                    end
                                end
                            end
                            if not needFuel then break end
                        end
                    end
                    if not needFuel then break end
                end
            end

            -- 4) Collect empty-input furnaces
            inputItem = contents[cfg.SLOT_INPUT]
            if not inputItem then
                table.insert(emptyInputFurnaces, { name = fname, type = furnaceType })
            end
        end
    end

    -- 5) Balanced distribution
    if #emptyInputFurnaces > 0 then
        local typesSeen = {}
        for _, ef in ipairs(emptyInputFurnaces) do typesSeen[ef.type] = true end

        local allCandidates = {}
        local candSeen = {}
        for ftype in pairs(typesSeen) do
            for _, cand in ipairs(cfg.smeltCandidatesByType[ftype] or {}) do
                if not candSeen[cand.name] then
                    candSeen[cand.name] = true
                    table.insert(allCandidates, cand)
                end
            end
        end
        table.sort(allCandidates, function(a, b)
            if a.food ~= b.food then return a.food end
            return a.name < b.name
        end)

        local usedFurnaces = {}

        for _, cand in ipairs(allCandidates) do
            local itemName = cand.name
            if not state.disabledRecipes[itemName] and catalogue[itemName] then
                local compatFurnaces = {}
                for _, ef in ipairs(emptyInputFurnaces) do
                    if not usedFurnaces[ef.name] and cand.recipe.furnaceSet[ef.type] then
                        table.insert(compatFurnaces, ef)
                    end
                end

                if #compatFurnaces > 0 then
                    local totalInStorage = 0
                    for _, src in ipairs(catalogue[itemName]) do
                        totalInStorage = totalInStorage + src.total
                    end
                    local available = totalInStorage - cfg.SMELT_RESERVE
                    if available > 0 then
                        local perFurnace = math.min(64, math.ceil(available / #compatFurnaces))

                        for _, ef in ipairs(compatFurnaces) do
                            if available <= 0 then break end
                            local toLoad = math.min(perFurnace, available)
                            local remaining = toLoad
                            local loaded = false

                            local srcSnapshot = { table.unpack(catalogue[itemName]) }
                            for _, source in ipairs(srcSnapshot) do
                                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
                                            local toMove = math.min(slotItem.count, remaining)
                                            local n = chest.pushItems(ef.name, slot, toMove, cfg.SLOT_INPUT)
                                            if n and n > 0 then
                                                state.adjustCache(itemName, source.chest, -n)
                                                log.info("SMELT", "Input %s x%d -> %s (balanced %d/furnace)",
                                                    itemName, n, ef.name, perFurnace)
                                                didWork = true
                                                remaining = remaining - n
                                                available = available - n
                                                if remaining <= 0 then
                                                    loaded = true
                                                    break
                                                end
                                            end
                                        end
                                    end
                                end
                                end
                                if loaded then break end
                            end

                            if loaded or remaining < toLoad then
                                usedFurnaces[ef.name] = true
                            end
                        end
                    end
                end
            end
        end
    end

    return didWork
end

-------------------------------------------------
-- Defrag (consolidate partial stacks)
-------------------------------------------------

function O.defragInventory()
    local chests = O.getChests()
    if #chests == 0 then return end

    activity.defragging = true
    state.needsRedraw = true

    local itemSlots = {}
    for _, chestName in ipairs(chests) do
        local inv = O.wrapCached(chestName)
        if inv then
            local contents = inv.list()
            for slot, item in pairs(contents) do
                if not itemSlots[item.name] then
                    itemSlots[item.name] = {}
                end
                local maxCount = 64
                local ok, detail = pcall(inv.getItemDetail, slot)
                if ok and detail and detail.maxCount then
                    maxCount = detail.maxCount
                end
                table.insert(itemSlots[item.name], {
                    chest = chestName,
                    slot  = slot,
                    count = item.count,
                    max   = maxCount,
                })
            end
        end
    end

    local totalMerged = 0
    for itemName, slots in pairs(itemSlots) do
        table.sort(slots, function(a, b) return a.count < b.count end)

        local i = 1
        local j = #slots

        while i < j do
            local donor = slots[i]
            local recv  = slots[j]

            if donor.chest == recv.chest and donor.slot == recv.slot then
                i = i + 1
            elseif donor.count == 0 then
                i = i + 1
            elseif recv.count >= recv.max then
                j = j - 1
            else
                local space = recv.max - recv.count
                local toMove = math.min(donor.count, space)
                local donorInv = O.wrapCached(donor.chest)
                if donorInv then
                    local n = donorInv.pushItems(recv.chest, donor.slot, toMove, recv.slot)
                    if n and n > 0 then
                        donor.count = donor.count - n
                        recv.count  = recv.count + n
                        totalMerged = totalMerged + n
                        if donor.chest ~= recv.chest then
                            state.adjustCache(itemName, donor.chest, -n)
                            state.adjustCache(itemName, recv.chest, n)
                        end
                    end
                end
                if donor.count <= 0 then i = i + 1 end
                if recv.count >= recv.max then j = j - 1 end
            end
        end
    end

    if totalMerged > 0 then
        log.info("DEFRAG", "Consolidated %d items", totalMerged)
    end

    activity.defragging = false
    state.needsRedraw = true
end

-------------------------------------------------
-- Auto-compost
-------------------------------------------------

function O.autoCompost()
    local catalogue = cache.catalogue
    local chests = O.getChests()
    local didWork = false

    local hopper = O.wrapCached(cfg.COMPOST_HOPPER)
    if hopper then
        local contents = hopper.list()
        if contents then
            for slot, item in pairs(contents) do
                for _, chest in ipairs(chests) do
                    local n = hopper.pushItems(chest, slot)
                    if n and n > 0 then
                        state.adjustCache(item.name, chest, n)
                        log.info("COMPOST", "%s x%d -> %s", item.name, n, chest)
                        didWork = true
                        break
                    end
                end
            end
        end
    end

    local dropper = O.wrapCached(cfg.COMPOST_DROPPER)
    if not dropper then return didWork end

    local dropperContents = dropper.list()
    local dropperUsedItems = 0
    if dropperContents then
        for _, item in pairs(dropperContents) do
            dropperUsedItems = dropperUsedItems + item.count
        end
    end
    local dropperSize = dropper.size()
    local dropperFreeItems = (dropperSize * 64) - dropperUsedItems

    if dropperFreeItems <= 0 then return didWork end

    for _, itemName in ipairs(cfg.COMPOSTABLE) do
        if dropperFreeItems <= 0 then break end
        if catalogue[itemName] then
            local totalInStorage = 0
            for _, src in ipairs(catalogue[itemName]) do
                totalInStorage = totalInStorage + src.total
            end

            local reserve = cfg.COMPOST_TRASH[itemName] and 0 or cfg.COMPOST_RESERVE
            local available = totalInStorage - reserve
            if available > 0 then
                local toFeed = math.min(available, dropperFreeItems)
                local fed = 0
                local srcSnapshot = { table.unpack(catalogue[itemName]) }
                for _, source in ipairs(srcSnapshot) do
                    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
                                local batch = math.min(slotItem.count, toFeed - fed)
                                local n = chest.pushItems(cfg.COMPOST_DROPPER, slot, batch)
                                if n and n > 0 then
                                    state.adjustCache(itemName, source.chest, -n)
                                    fed = fed + n
                                    didWork = true
                                    log.info("COMPOST", "Fed %s x%d -> dropper", itemName, n)
                                    if fed >= toFeed then break end
                                end
                            end
                        end
                    end
                    end
                    if fed >= toFeed then break end
                end
                dropperFreeItems = dropperFreeItems - fed
            end
        end
    end

    return didWork
end

-------------------------------------------------
-- Collection hopper emptying (egg spawner, mob farm, etc.)
-------------------------------------------------

function O.collectHoppers()
    if #cfg.COLLECTION_HOPPERS == 0 then return false end

    local didWork = false
    local chests = O.getChestsByPriority()
    local catalogue = cache.catalogue

    for _, hopperName in ipairs(cfg.COLLECTION_HOPPERS) do
        local hopper = O.wrapCached(hopperName)
        if hopper then
            local contents = hopper.list()
            if contents and next(contents) then
                for slot, item in pairs(contents) do
                    local moved = 0
                    local triedChests = {}

                    -- Prefer chests where item already exists
                    if catalogue[item.name] then
                        for _, entry in ipairs(catalogue[item.name]) do
                            triedChests[entry.chest] = true
                            local n = hopper.pushItems(entry.chest, slot)
                            if n and n > 0 then
                                moved = moved + n
                                state.adjustCache(item.name, entry.chest, n)
                                didWork = true
                                log.info("COLLECT", "%s x%d -> %s (from %s)", item.name, n, entry.chest, hopperName)
                            end
                            if moved >= item.count then break end
                        end
                    end

                    -- Overflow to any chest with space
                    if moved < item.count then
                        for _, chest in ipairs(chests) do
                            if not triedChests[chest] then
                                local n = hopper.pushItems(chest, slot)
                                if n and n > 0 then
                                    moved = moved + n
                                    state.adjustCache(item.name, chest, n)
                                    didWork = true
                                    log.info("COLLECT", "%s x%d -> %s (from %s)", item.name, n, chest, hopperName)
                                end
                                if moved >= item.count then break end
                            end
                        end
                    end
                end
            end
        end
    end

    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 })
            else
                log.debug("DISCARD", "Dropper %s is full, skipping", dName)
            end
        end
    end
    if #droppers == 0 then
        log.debug("DISCARD", "All trash droppers full or offline, cannot discard")
        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

-------------------------------------------------
-- Auto-craft excess stock into target items
-------------------------------------------------

function O.autoCraft()
    if not ctx.craftEngine then return false end
    if not ctx.craftTurtleName then return false end

    local catalogue = cache.catalogue
    local didWork = false

    -- Phase 1: Explicit rules from auto_craft.lua
    for _, rule in ipairs(cfg.AUTO_CRAFT_RULES) do
        local inputName = rule.input
        local reserve   = rule.reserve or 0
        local outputName = rule.output

        if catalogue[inputName] then
            local totalInStorage = 0
            for _, src in ipairs(catalogue[inputName]) do
                totalInStorage = totalInStorage + src.total
            end

            local excess = totalInStorage - reserve
            if excess > 0 then
                local recipe = cfg.recipeBook.getCraftingRecipe(outputName)
                if recipe then
                    local ingredients = cfg.recipeBook.getIngredients(recipe)
                    local inputPerCraft = ingredients[inputName] or 0
                    if inputPerCraft > 0 then
                        local batches = math.floor(excess / inputPerCraft)
                        batches = math.min(batches, 64)
                        if batches > 0 then
                            local craftCount = batches * recipe.count
                            log.info("AUTOCRAFT", "%s: %d excess (reserve %d), crafting %d x %s",
                                inputName, excess, reserve, craftCount, outputName)
                            local ok, err = O.recursiveCraft(outputName, craftCount)
                            if ok then
                                didWork = true
                                log.info("AUTOCRAFT", "Crafted %s x%d", outputName, craftCount)
                            else
                                log.warn("AUTOCRAFT", "Failed to craft %s: %s", outputName, tostring(err))
                            end
                        end
                    end
                else
                    log.warn("AUTOCRAFT", "No recipe found for output: %s", outputName)
                end
            end
        end
    end

    -- Phase 2: Smart excess-to-craft — auto-discover recipes for over-stocked items
    if cfg.AUTO_CRAFT_FROM_EXCESS then
        -- Track outputs we've already handled via explicit rules to avoid duplicates
        local handledOutputs = {}
        for _, rule in ipairs(cfg.AUTO_CRAFT_RULES) do
            handledOutputs[rule.output] = true
        end

        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
                    -- Find all crafting recipes that use this item
                    local usingRecipes = cfg.recipeBook.findRecipesUsing(itemName)
                    for _, recipe in ipairs(usingRecipes) do
                        if not handledOutputs[recipe.output] then
                            -- Check how much of the output we already have
                            local outputTotal = O.getItemTotal(recipe.output)
                            if outputTotal < cfg.AUTO_CRAFT_OUTPUT_CAP then
                                local ingredients = cfg.recipeBook.getIngredients(recipe)
                                local inputPerCraft = ingredients[itemName] or 0
                                if inputPerCraft > 0 then
                                    -- Only craft up to the output cap
                                    local outputRoom = cfg.AUTO_CRAFT_OUTPUT_CAP - outputTotal
                                    local maxBatches = math.floor(excess / inputPerCraft)
                                    local batchesByRoom = math.ceil(outputRoom / recipe.count)
                                    local batches = math.min(maxBatches, batchesByRoom, 64)
                                    if batches > 0 then
                                        -- Check all other ingredients are available
                                        local canCraft = true
                                        for ingr, needed in pairs(ingredients) do
                                            if ingr ~= itemName then
                                                local have = O.getItemTotal(ingr)
                                                if have < needed * batches then
                                                    canCraft = false
                                                    break
                                                end
                                            end
                                        end
                                        if canCraft then
                                            local craftCount = batches * recipe.count
                                            log.info("AUTOCRAFT", "Smart: %s over limit, crafting %d x %s",
                                                itemName, craftCount, recipe.output)
                                            local ok, err = O.recursiveCraft(recipe.output, craftCount)
                                            if ok then
                                                didWork = true
                                                handledOutputs[recipe.output] = true
                                                log.info("AUTOCRAFT", "Smart-crafted %s x%d", recipe.output, craftCount)
                                                -- Recalculate excess after crafting
                                                break
                                            else
                                                log.warn("AUTOCRAFT", "Smart craft failed %s: %s", recipe.output, tostring(err))
                                            end
                                        end
                                    end
                                end
                            end
                        end
                    end
                end
            end
        end
    end

    return didWork
end

-------------------------------------------------
-- Low-stock alert checker
-------------------------------------------------

function O.checkAlerts()
    local alerts = {}
    for _, alert in ipairs(cfg.LOW_STOCK_ALERTS) do
        local total = 0
        if cache.catalogue[alert.name] then
            for _, src in ipairs(cache.catalogue[alert.name]) do
                total = total + src.total
            end
        end
        if total < alert.min then
            table.insert(alerts, {
                label   = alert.label,
                current = total,
                min     = alert.min,
            })
        end
    end
    state.activeAlerts = alerts
    if #alerts > 0 then
        state.needsRedraw = true
        state.smelterNeedsRedraw = true
    end
end

-------------------------------------------------
-- Supply chest (builder / manifest-based stocking)
-------------------------------------------------

function O.supplyChest()
    if cfg.SUPPLY_CHEST == "" or #cfg.SUPPLY_MANIFEST == 0 then return false end

    local supply = O.wrapCached(cfg.SUPPLY_CHEST)
    if not supply then return false end

    -- Scan what's already in the supply chest
    local existing = {}
    local contents = supply.list()
    if contents then
        for _, item in pairs(contents) do
            existing[item.name] = (existing[item.name] or 0) + item.count
        end
    end

    local catalogue = cache.catalogue
    local didWork = false

    for _, manifest in ipairs(cfg.SUPPLY_MANIFEST) do
        local have = existing[manifest.name] or 0
        local want = manifest.count or 0
        local deficit = want - have

        if deficit > 0 and catalogue[manifest.name] then
            local remaining = deficit
            local srcSnapshot = { table.unpack(catalogue[manifest.name]) }
            for _, source in ipairs(srcSnapshot) do
                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 == manifest.name then
                                local toMove = math.min(slotItem.count, remaining)
                                local n = chest.pushItems(cfg.SUPPLY_CHEST, slot, toMove)
                                if n and n > 0 then
                                    state.adjustCache(manifest.name, source.chest, -n)
                                    remaining = remaining - n
                                    didWork = true
                                    log.info("SUPPLY", "%s x%d -> %s", manifest.name, n, cfg.SUPPLY_CHEST)
                                    if remaining <= 0 then break end
                                end
                            end
                        end
                    end
                end
                if remaining <= 0 then break end
            end
        end
    end

    return didWork
end

-------------------------------------------------
-- Order / Dispense
-------------------------------------------------

function O.orderItem(itemName, amount, dropperOverride)
    activity.dispensing = true
    state.needsRedraw = true

    local dropperTarget = (dropperOverride and dropperOverride ~= "") and dropperOverride or cfg.DROPPER_NAME
    local catalogue = cache.catalogue

    if not catalogue[itemName] then
        state.statusMessage = "Not found: " .. itemName:gsub("^minecraft:", "")
        state.statusColor = colors.red
        state.statusTimer = 5
        activity.dispensing = false
        state.needsRedraw = true
        return false
    end

    local dropper = O.wrapCached(dropperTarget)
    if not dropper then
        state.statusMessage = "Dropper offline: " .. dropperTarget
        state.statusColor = colors.red
        state.statusTimer = 5
        activity.dispensing = false
        state.needsRedraw = true
        return false
    end

    local remaining = amount
    local srcSnapshot = { table.unpack(catalogue[itemName]) }
    for _, entry in ipairs(srcSnapshot) do
        if entry.total > 0 then
        local chest = O.wrapCached(entry.chest)
        if chest then
            for slot, slotItem in pairs(chest.list()) do
                if slotItem.name == itemName then
                    local toMove = math.min(remaining, slotItem.count)
                    local moved = chest.pushItems(dropperTarget, slot, toMove)
                    if moved and moved > 0 then
                        remaining = remaining - moved
                        state.adjustCache(itemName, entry.chest, -moved)
                        state.needsRedraw = true
                        state.smelterNeedsRedraw = true
                        log.info("ORDER", "%s x%d from %s", itemName, moved, entry.chest)
                    end
                    if remaining <= 0 then break end
                end
            end
        end
        end
        if remaining <= 0 then break end
    end

    local sent = amount - remaining
    local short = itemName:gsub("^minecraft:", ""):gsub("_", " ")
    if sent > 0 then
        state.statusMessage = string.format("Dispensing %s x%d", short, sent)
        state.statusColor = colors.lime
        log.info("ORDER", "Ordered %s x%d", short, sent)
    else
        state.statusMessage = "Could not order " .. short
        state.statusColor = colors.red
    end
    state.statusTimer = 5

    activity.dispensing = false
    state.needsRedraw = true
    return sent > 0
end

-------------------------------------------------
-- Crafting
-------------------------------------------------

function O.getItemTotal(itemName)
    local have = 0
    if cache.catalogue[itemName] then
        for _, src in ipairs(cache.catalogue[itemName]) do
            have = have + src.total
        end
    end
    return have
end

function O.getRecipeIngredients(recipe)
    return ui.getRecipeIngredients(recipe)
end

function O.canCraftRecipe(recipe)
    return ui.canCraftRecipe(recipe, O.getItemTotal)
end

function O.maxCraftBatches(recipe)
    return ui.maxCraftBatches(recipe, O.getItemTotal)
end

function O.getMissingIngredients(recipe)
    return ui.getMissingIngredients(recipe, O.getItemTotal)
end

function O.craftItem(recipeIdx, batches)
    batches = batches or 1
    local recipe = cfg.CRAFTABLE[recipeIdx]
    if not recipe then
        log.error("CRAFT", "Invalid recipe index: %s", tostring(recipeIdx))
        return false, "Invalid recipe"
    end
    if not ctx.craftTurtleName then
        log.error("CRAFT", "No turtle detected on network")
        return false, "No turtle"
    end
    if not ctx.networkModem then
        log.error("CRAFT", "No modem available for craft commands")
        return false, "No modem"
    end
    if not peripheral.isPresent(ctx.craftTurtleName) then
        log.error("CRAFT", "Turtle offline: %s", ctx.craftTurtleName)
        return false, "Turtle offline"
    end

    -- Clamp batches to 64 (max stack size per slot)
    batches = math.min(batches, 64)

    log.info("CRAFT", "Starting craft: %s x%d (%d batches, turtle: %s)",
        recipe.output, batches * recipe.count, batches, ctx.craftTurtleName)

    activity.crafting = true
    state.needsRedraw = true
    state.smelterNeedsRedraw = true

    local chests = O.getChests()
    local slotMap = {}
    local reservedSlots = {}

    -- Sum how many of each ingredient we need total
    local ingredientTotals = {}
    for gridPos = 1, 9 do
        local itemName = recipe.grid[gridPos]
        if itemName then
            ingredientTotals[itemName] = (ingredientTotals[itemName] or 0) + batches
        end
    end

    -- Check we have enough of each ingredient
    for itemName, needed in pairs(ingredientTotals) do
        local have = O.getItemTotal(itemName)
        if have < needed then
            log.error("CRAFT", "Not enough %s: have %d, need %d", itemName, have, needed)
            activity.crafting = false
            state.needsRedraw = true
            state.smelterNeedsRedraw = true
            return false, string.format("Need %d %s, have %d", needed, itemName, have)
        end
    end

    for gridPos = 1, 9 do
        local itemName = recipe.grid[gridPos]
        if itemName then
            local turtleSlot = cfg.GRID_TO_SLOT[gridPos]
            local found = false

            if cache.catalogue[itemName] then
                for _, source in ipairs(cache.catalogue[itemName]) do
                    local chest = O.wrapCached(source.chest)
                    if chest then
                        for slot, slotItem in pairs(chest.list()) do
                            local key = source.chest .. ":" .. slot
                            if slotItem.name == itemName and not reservedSlots[key] then
                                local pullCount = math.min(batches, slotItem.count)
                                slotMap[tostring(turtleSlot)] = {
                                    chestName = source.chest,
                                    chestSlot = slot,
                                    itemName  = itemName,
                                    count     = pullCount,
                                }
                                reservedSlots[key] = true
                                found = true
                                break
                            end
                        end
                    end
                    if found then break end
                end
            end

            if not found then
                log.error("CRAFT", "Cannot find %s in storage, aborting", itemName)
                activity.crafting = false
                state.needsRedraw = true
                state.smelterNeedsRedraw = true
                return false, "Missing ingredient: " .. itemName
            end
        end
    end

    local craftMessage = {
        type         = "craft_request",
        recipeIdx    = recipeIdx,
        output       = recipe.output,
        slots        = slotMap,
        returnChests = chests,
    }

    log.info("CRAFT", "Sending craft request to turtle on channel %d", cfg.CRAFT_CHANNEL)
    ctx.networkModem.transmit(cfg.CRAFT_CHANNEL, cfg.CRAFT_REPLY_CHANNEL, craftMessage)

    for _, info in pairs(slotMap) do
        state.adjustCache(info.itemName, info.chestName, -info.count)
    end

    log.info("CRAFT", "Waiting for turtle reply (timeout: %ds)...", cfg.CRAFT_TIMEOUT)
    local deadline = os.clock() + cfg.CRAFT_TIMEOUT
    local result = nil

    while os.clock() < deadline do
        local timerId = os.startTimer(math.max(0.1, deadline - os.clock()))
        local event, p1, p2, p3, p4, p5 = os.pullEvent()

        if event == "modem_message" then
            local channel = p2
            local message = p4
            if channel == cfg.CRAFT_REPLY_CHANNEL and type(message) == "table" and message.type == "craft_result" then
                result = message
                break
            end
            -- ORDER_CHANNEL messages are captured by the Network-capture task
        elseif event == "timer" and p1 == timerId then
            -- Timeout tick
        end
    end

    activity.crafting = false
    state.needsRedraw = true
    state.smelterNeedsRedraw = true

    if not result then
        log.error("CRAFT", "TIMEOUT: No reply from turtle within %ds", cfg.CRAFT_TIMEOUT)
        log.error("CRAFT", "Items may be stuck in turtle. Run a manual scan to reconcile.")
        return false, "Turtle timeout"
    end

    if result.success then
        local totalOutput = result.totalOutput or recipe.count
        if result.results then
            for _, r in ipairs(result.results) do
                for _, ch in ipairs(chests) do
                    local chest = O.wrapCached(ch)
                    if chest then
                        for slot, slotItem in pairs(chest.list()) do
                            if slotItem.name == r.name then
                                state.adjustCache(r.name, ch, r.count)
                                goto credited
                            end
                        end
                    end
                end
                if #chests > 0 then
                    state.adjustCache(r.name, chests[1], r.count)
                end
                ::credited::
            end
        else
            if #chests > 0 then
                state.adjustCache(recipe.output, chests[1], totalOutput)
            end
        end

        local short = recipe.output:gsub("^minecraft:", ""):gsub("_", " ")
        log.info("CRAFT", "OK: %s x%d", short, totalOutput)
        return true
    else
        for turtleSlotStr, info in pairs(slotMap) do
            state.adjustCache(info.itemName, info.chestName, info.count)
        end
        local errMsg = result.error or "Craft failed"
        log.error("CRAFT", "Failed: %s", errMsg)
        return false, errMsg
    end
end

-------------------------------------------------
-- Recursive crafting (multi-step chains)
-------------------------------------------------

function O.recursiveCraft(outputName, count)
    if not ctx.craftEngine then
        return false, "Craft engine not initialized"
    end
    activity.crafting = true
    state.needsRedraw = true
    state.smelterNeedsRedraw = true
    local ok, err = ctx.craftEngine.executeChain(outputName, count, ctx)
    activity.crafting = false
    state.needsRedraw = true
    state.smelterNeedsRedraw = true
    return ok, err
end

-------------------------------------------------
-- Smelting recipe persistence
-------------------------------------------------

function O.loadDisabledRecipes()
    if not fs.exists(cfg.DISABLED_RECIPES_FILE) then return end
    pcall(function()
        local f = fs.open(cfg.DISABLED_RECIPES_FILE, "r")
        local raw = f.readAll()
        f.close()
        local data = textutils.unserialise(raw)
        if type(data) == "table" then
            if data.disabled then state.disabledRecipes = data.disabled end
            if data.paused ~= nil then state.smeltingPaused = data.paused end
        end
    end)
end

function O.saveDisabledRecipes()
    pcall(function()
        local f = fs.open(cfg.DISABLED_RECIPES_FILE, "w")
        f.write(textutils.serialise({ disabled = state.disabledRecipes, paused = state.smeltingPaused }))
        f.close()
    end)
end

return O

end