Repair Drone Controller

local repairDrone = -1
local status = {}

term.setCursorPos(1,1)
term.clear()

print("Repair Drone Command Terminal V1.3")
print("(C) 1989 KillaVanilla Industries")
print("Subcomponents initalizing...")
textutils.slowWrite("Checking: Redstone-Based Communications...")
os.sleep(1)
local modems = 0
for i,v in ipairs(rs.getSides()) do
    if peripheral.getType(v) == "modem" then
        rednet.open(v)
        modems = modems+1
    end
end
if modems > 0 then
    term.setTextColor(colors.lime)
    print("good")
else
    term.setTextColor(colors.red)
    print("failed")
    term.setTextColor(colors.white)
    print("System check failed: No modem found.")
    return
end
term.setTextColor(colors.white)
textutils.slowPrint("Enter the ID of the drone you wish to control: ")
textutils.slowWrite(">")
while true do
    local input = tonumber(read())
    if input then
        repairDrone = input
        break
    end
end
term.setTextColor(colors.white)
textutils.slowWrite("Checking: Remote Repair Unit...")
os.sleep(1)
rednet.send(repairDrone, "PING")
local id, msg = rednet.receive(5)
if id == nil then
    term.setTextColor(colors.red)
    print("failed")
    term.setTextColor(colors.white)
    print("System check failed: Could not contact drone.")
    os.reboot()
else
    status = textutils.unserialize(msg)
    term.setTextColor(colors.lime)
    print("good")
end
term.setTextColor(colors.white)
textutils.slowWrite("Checking: Robotics Supply Unit...")
os.sleep(1)
if (status[1] == "unlimited" or status[1] > 0) and (status[2] > 0) then
    term.setTextColor(colors.lime)
    print("good")
else
    term.setTextColor(colors.red)
    print("failed")
    term.setTextColor(colors.white)
    print("System check failed: Not enough materials/fuel.")
    return
end
term.setTextColor(colors.white)
os.sleep(1)
textutils.slowWrite("Checking: Robotics Interpreter Unit...")
os.sleep(1)
term.setTextColor(colors.lime)
print("good")
term.setTextColor(colors.white)
textutils.slowWrite("Checking: Secondary Communications Link...")
os.sleep(1)
term.setTextColor(colors.lime)
print("good")
term.setTextColor(colors.white)
textutils.slowWrite("Beginning communications...")
os.sleep(1)
print("Ready.")
os.sleep(2)
local cmdHistory = {}
while true do
    term.clear()
    term.setCursorPos(1,1)
    print("DRONE CONTROL UNIT:")
    write("Connected to repair drone ")
    term.setTextColor(colors.lime)
    write(repairDrone)
    term.setTextColor(colors.white)
    print(".")
    write("Fuel Level: ")
    term.setTextColor(colors.lime)
    print(status[1])
    term.setTextColor(colors.white)
    write("Materials Level: ")
    term.setTextColor(colors.lime)
    print(status[2])
    term.setTextColor(colors.white)
    write("drone"..repairDrone..">")
    local cmd = read(nil, cmdHistory)
    if string.lower(cmd) == "help" then
        term.clear()
        term.setCursorPos(1,1)
        print("Commands:")
        print("forward - Moves the drone forward 1 meter.")
        print("back - Moves the drone back 1 meter.")
        print("turnleft - Turns the drone to the left.")
        print("turnright - Turns the drone to the right.")
        print("up - Moves the drone up 1 meter.")
        print("down - Moves the drone down 1 meter.")
        print("place - Places materials directly beneath the drone.")
        os.pullEvent("key")
    else
        table.insert(cmdHistory, cmd)
        cmd = string.upper(cmd)
        os.sleep(0.5)
        rednet.send(repairDrone, cmd)
        local id, msg = rednet.receive(5)
        if id ~= nil then
            status = textutils.unserialize(msg)
        else
            printError("Error: Communications timeout.")
            return
        end
        if status[1] ~= "unlimited" then
            if status[1] == 0 then
                printError("Error: Drone is entering low-fuel mode...")
                return
            end
        end
        if status[2] == 0 then
            printError("Warning: Drone is out of repair materials!")
        end
        os.sleep(0.5)
    end
end