-- manager/state.lua — Shared mutable state, cache, and coordination flags
-- Usage: local state = dofile("manager/state.lua")()

return function()

local S = {}

-------------------------------------------------
-- Cached data (updated by background scanner)
-------------------------------------------------

S.cache = {
    catalogue   = {},
    itemList    = {},
    itemListDirty = false,
    grandTotal  = 0,
    chestCount  = 0,
    totalSlots  = 0,
    usedSlots   = 0,
    freeSlots   = 0,
    usedRatio   = 0,
    dropperOk   = false,
    barrelOk    = false,
    furnaceCount    = 0,
    furnaceStatus   = {},
    droppers        = {},
}

-- Client-registered droppers, keyed by clientId
S.clientDroppers = {}

-------------------------------------------------
-- Activity flags (shown on monitor)
-------------------------------------------------

S.activity = {
    sorting    = false,
    dispensing = false,
    scanning   = false,
    smelting   = false,
    defragging = false,
    composting = false,
    crafting   = false,
    discarding = false,
    autocrafting = false,
}

-------------------------------------------------
-- State version tracking (for delta broadcasting)
-------------------------------------------------

S.stateVersion = 0
S.lastBroadcastVersion = -1
S.configDirty = true

function S.bumpStateVersion()
    S.stateVersion = S.stateVersion + 1
    S.billboardNeedsRedraw = true
end

-------------------------------------------------
-- UI coordination flags
-------------------------------------------------

S.needsRedraw = true
S.smelterNeedsRedraw = true
S.billboardNeedsRedraw = true
S.statusMessage = ""
S.statusColor = colors.white
S.statusTimer = 0

-------------------------------------------------
-- Alerts and smelting control
-------------------------------------------------

S.activeAlerts = {}
S.smeltingPaused = false
S.disabledRecipes = {}

-------------------------------------------------
-- Instant cache adjustment (no scan needed)
-------------------------------------------------

function S.adjustCache(itemName, chestName, delta)
    if delta == 0 then return end

    local cat = S.cache.catalogue
    if delta > 0 then
        if not cat[itemName] then cat[itemName] = {} end
        local found = false
        for _, entry in ipairs(cat[itemName]) do
            if entry.chest == chestName then
                entry.total = entry.total + delta
                found = true
                break
            end
        end
        if not found then
            table.insert(cat[itemName], { chest = chestName, total = delta })
        end
    else
        if cat[itemName] then
            for idx, entry in ipairs(cat[itemName]) do
                if entry.chest == chestName then
                    entry.total = entry.total + delta
                    if entry.total <= 0 then
                        table.remove(cat[itemName], idx)
                    end
                    break
                end
            end
            if #cat[itemName] == 0 then
                cat[itemName] = nil
            end
        end
    end

    S.cache.itemListDirty = true
    S.cache.grandTotal = S.cache.grandTotal + delta
    S.bumpStateVersion()
end

function S.ensureItemList()
    if not S.cache.itemListDirty then return end
    local itemList = {}
    local grandTotal = 0
    for name, sources in pairs(S.cache.catalogue) do
        local total = 0
        for _, s in ipairs(sources) do total = total + s.total end
        grandTotal = grandTotal + total
        table.insert(itemList, { name = name, total = total })
    end
    table.sort(itemList, function(a, b) return a.total > b.total end)
    S.cache.itemList   = itemList
    S.cache.grandTotal = grandTotal
    S.cache.itemListDirty = false
end

return S

end