CC Tweaked Train Station Ticket Kiosk

--this script allows the purchase and reactivation of National Train Line Credit Cards, which are used for payment of tickets and allows entrence innmost Train stations
local w, h = term.getSize()
local Credit = 0
local User = "guest"

local AvailableLines = {"Northern Outpost"}

local function Clear()
term.clear()
term.setCursorPos(1,1)
end

function CUI(m) --declare function
n=1
local l = #m
while true do
term.setCursorPos(1,5)

for i=1, #m, 1 do --traverse the table of options
if i==n then term.clearLine() print(i, " ["..m[i].."]") else term.clearLine() print(i, " ", m[i]) end --print them
end
a, b= os.pullEvent("key") --wait for keypress
if b==keys.w and n>1 then n=n-1 end
if b==keys.s and n<l then n=n+1 end
if b==keys.enter then break end
end
return n --return the value
end

local function PageDraw(page)
if page == "Login" then
    term.setBackgroundColor(colors.cyan)
    Clear()
    print("Central Rail Network Kiosk")
    print("Please Login")
    term.write("Code = ")
elseif page == "Menu" then
    term.setBackgroundColor(colors.green)
    Clear()
    print("Central Rail Network Kiosk")
    print("Hello, "..User)
elseif page == "Swipe" then

elseif page == "Lines" then
    term.setBackgroundColor(colors.black)
    Clear()
    print("Central Rail Network Kiosk")
elseif page == "Line Details" then

end
end

local function AccountPage()

end

local function LinesPage()

end

local function LineDetails(LineName)

end

local function TicketsPage()
local Options = AvailableLines
Options[#Options +1] = "exit"
local n = CUI(Options)
if Options[n] == "exit" then
    MainMenu()
else
    LineDetails(Options[n])
end
end

local function MainMenu()
PageDraw("Menu")
local Options = {"Account","Lines","Buy Ticket","Logout"}
local n = CUI(Options)
if Options[n] == "Account" then
    AccountPage()
elseif Options[n] == "Lines" then
    LinesPage()
elseif Options[n] == "Buy Ticket" then
    TicketsPage()
elseif Options[n] == "Logout" then
    Logout()
end
end

local function Login()
PageDraw("Login")
local input
while true do
    input = read
    if string.len(input) == 6 then
        break
    end
end
local file = fs.open("Users","r")
local Contents = file.readAll()
if Contents.find(input) == true then
    User = input
    MainMenu()
else
    Login()
end
end

local function Logout()
User = "guest"
PageDraw("Login")
end