simple storage network

local chest_list = { peripheral.find("minecraft:chest") }
local chest_main = ""
local item_list = {}
local ssn = {}

local function index_item(item, slot, chest)
    if item_list[item.name] == nil then item_list[item.name] = {} end
    local list_ = item_list[item.name]
    list_[#list_+1] = {item=item, slot=slot, chest=chest}
end

function ssn.init(chest_name)
    chest_main = chest_name
    for index, chest in pairs(chest_list) do
        if peripheral.getName(chest) == chest_main then
            table.remove(chest_list, index)
            chest_main = chest
        else
            for slot, item in pairs(chest.list()) do
                index_item(item, slot, chest)
            end
        end
    end
end

function ssn.sum(item_id)
    if item_list[item_id] == nil then return 0 end
    local sum = 0

    for index, info in pairs(item_list[item_id]) do
        sum = sum + info.item.count
    end
    return sum
end

function ssn.pull(item_id)
    if item_list[item_id] == nil then return false end
    if #item_list[item_id] == 0 then return false end
    local item = item_list[item_id]
    item[#item].chest.pushItems( peripheral.getName(chest_main), item[#item].slot)
    table.remove(item #item)
end

function ssn.free_capacity(chest)
    local cap = 0
    for i = 1, chest.size() do
        if chest.getItemDetail(i) == nil then
            cap = cap + 1
        end
    end
    return cap
end

function ssn.exist(item_id)
    return item_list[item_id] ~= nil
end

return ssn