GraviMail Server Installer

local w, h = term.getSize()

function printCentered(text, y)
    term.setCursorPos(w/2 - #text/2, y)
    term.write(text)
end

term.clear()

term.setCursorPos(1,1)
print(string.rep("-", w))
printCentered("Welcome to the GraviMail server wizard.", 2)
printCentered("This will lead you through", 3)
printCentered("installing the GraviMail server.", 4)
print(string.rep("-", w))
os.sleep(0.5)
print("\n")
print("Which side is your modem on?")
print("[top, bottom, back, front, left, right]")
local side = read()
print("Modem at side: "..side)
os.sleep(0.5)

function askForMaster()
    print("What is the master server ID?")
    local master = read()
    if not tonumber(master) then
        print("Master ID not a number.")
        os.sleep(0.2)
        askForMaster()
    else
        return master
    end
end

local master = askForMaster()
os.sleep(0.5)
print("Creating preference file...")
os.sleep(0.2)
file = fs.open("gravimail/server/pref", "w")
file.write(textutils.serialise({side=side,master=master}))
file.close()
print("Preference file created in gravimail/server/pref. Do not delete this file!")
os.sleep(0.5)
print("Removing old startup files...")
if fs.exists("startup") then
    fs.delete("startup")
end
print("Downloading GraviMail server files...")
shell.run("pastebin","get","https://pastebin.com/4cEztaWS","startup")
os.sleep(0.5)
print("Rebooting...")
os.sleep(0.5)
os.reboot()