-- program to manage a cargo elevator
-- yes, i am aware i could just use the computer to transfer packages at this
-- point, but where's the fun in that?

local FLOORS = {
    {
        match = function (input)
            local first_char = string.sub(input, 1, 1)
            return first_char == "A" or first_char == "W"
        end,
        detect = function ()
            -- TODO
        end,
        call = function ()
            -- TODO
        end
        storage = "",
        elevator_storage = "",
    }
}

local SLEEP_T = 5

local PKG_STACK = {
    transfer_all = function (self, src, dest)
        -- TODO
    end,
    transfer_matching = function (self, src, dest, match_f)
        -- TODO
    end,
    get_next_floor = function (self)
        -- TODO
    end
    stack = {},
}

function run (floors, stack)
    local next_addr = nil
    for _, floor in pairs(floors) do
        if floor.detect() then
            stack:transfer_all(floor.storage, floor.elevator_storage)
            stack:transfer_matching(
                floor.elevator_storage, floor.storage, floor.match
            )
            next_addr = stack:get_next_floor()
        end
    end
    if next_addr ~= nil then
        for _, floor in pairs(floors) do
            if floor.match(next_addr) then
                floor.call()
                break
            end
        end
    end
end

while true do
    run(FLOORS)
    os.sleep(SLEEP_T)
end