Spot farm

-- Spot farm, please don't ask why
local robot_api = require("robot")
local computer = require("computer")
local event = require("event")

fsm = {}

-- flags
inventory_used = false
inventory_overflowed = false

function checkInventory()
    if inventory_used then
        for i=1,16 do
            if robot_api.space(i) > 0 then
                return true
            end
        end
        return false
    end
    return nil
end

function checkInstrument()
    if robot_api.durability() > 0 then
        return true
    end
    return false
end

function configureTest()
    inv_size = robot_api.inventorySize()
    if inv_size > 0 then
        inventory_used = true
        print("inventory founded...\n")
    end
end


function fsm.storeItemsState()
    robot_api.turnLeft()
    for i=1,16 do
        robot_api.select(i)
        robot_api.drop()
    end
    robot_api.turnRight()
    print("store all items from inventory")
    inventory_overflowed = false
end

function fsm:instrumentIssueEvent()
    while not checkInstrument() do
        computer.beep()
        os.sleep(1)
    end
end

function killEntity()
    robot_api.swing()
    if not checkInstrument() then
        print("instrument broken")
        fsm:instrumentIssueEvent()
    end
end

-- function fsm.chargeState() end

-- function checkEnergy() end

timerID = nil

function fsm.farmState()
    if inventory_overflowed then
        return
    end
    if checkInventory() ~= nil then
        if not checkInventory() then
            print("inventory overflowed...")
            inventory_overflowed = true
            fsm.storeItemsState()
        end
    end
    _, name = robot_api.detect()
    while name == "entity" do
        killEntity()
    end
end

function start()
    print("initialize...\n")
    configureTest()
    timerID = event.timer(1, fsm.farmState, math.huge)
end

start()