NanoShop Sellbot

local mainFrame=24

local sensor=peripheral.wrap("right")
local range=4
rednet.open("left")

function getNearbyUser()
    local players=sensor.getPlayers()
    for i,d in pairs(players) do
        local playerFunctions=sensor.getPlayerByName(d.name)
        local playerData=playerFunctions.select(1)
        local pos=playerData.position
        if pos.x<range and pos.x>-range and pos.y<range and pos.y>-range and pos.z<range and pos.z>-range  then
            return d.name
        end
    end
end

function checkForItems()
    turtle.suck()
    turtle.select(1)
    local detail=turtle.getItemDetail(1)
    if detail==nil then return end
    local id=detail.name
    local value=value
    local user=getNearbyUser()
    repeat
        rednet.send(mainFrame,"getValue,"..id,"NanoShop")
        local i,value=rednet.receive(5)
        if i==mainFrame then
            if value=="false" then
                turtle.select(1)
                turtle.drop()
                os.setComputerLabel("This item is worthless")
                sleep(5)
                os.setComputerLabel("Earn NanoCredits")
            elseif user==nil then
                turtle.select(1)
                turtle.drop()
                os.setComputerLabel("Could not identify any users.")
                sleep(5)
                os.setComputerLabel("Earn NanoCredits")
            else
                redstone.setOutput("bottom",true)
                repeat
                    rednet.send(mainFrame,"addCredit,"..user..","..value,"NanoShop")
                    local i,added=rednet.receive(5)
                until added=="true" and i==mainFrame
                os.setComputerLabel(value.." has been added to your account.")
                redstone.setOutput("bottom",false)
                sleep(3)
                os.setComputerLabel("Earn NanoCredits")
            end
        end
    until i==mainFrame
end

function setup()
    term.clear()
    term.setCursorPos(1,1)
    print([[Welcome to the NanoTech shop!

I will assist you by exchanging your items for NanoCredits.

Place an item on the ground in front of me and I will exchange it for NanoCredits.]])
end
setup()


while true do
    checkForItems()
    sleep(2)
end