[GraviBank] ATM UI

-- Variables
local COMPUTER_ID = os.getComputerID()
local TURTLE_ID = 130

local diskDrive = peripheral.wrap("right")

rednet.open("back")

w,h = term.getSize()
local select = 1
local selectedAmount = 1
local menustate = "start"

-- Functions

function printCentered(str, ypos)
    term.setCursorPos(w/2 - #str/2, ypos)
    term.write(str)
end

function printRight(str, ypos)
    term.setCursorPos(w - #str, ypos)
    term.write(str)
end

function printLeft(str, ypos)
    term.setCursorPos(#str, ypos)
    term.write(str)
end

function readTable(dir)
    local file = fs.open(dir, "r")
    local data = file.readAll()
    file.close()
    return textutils.unserialize(data)
end

function checkPassword(password)
    if password == nil then
        return "false"
    end
    local data = readTable("disk/userData.txt")
    local username = data.username
    rednet.broadcast({"request", {"checkPassword", username, password}}, "graviBank")
    local senderID, message = rednet.receive("graviBank")
    return message
end

function hasEnoughMoney(amount)
    local data = readTable("disk/userData.txt")
    local username = data.username
    rednet.broadcast({"request", {"getBalance", username}}, "graviBank")
    local senderID, message = rednet.receive("graviBank")
    if message[1] >= amount then
        return true
    else
        return false
    end
end

-- Menus

---- Drawing Menus

function drawStart()
    printCentered("Start", h/2)
    printCentered("Get Balance", h/2+2)

    local ypos = h/2 + 1
    if select == 2 then
        ypos = h/2+3
    end

    printCentered("-----------", ypos)
end

function drawMain()
    printLeft(" 1", 4)
    printLeft(" 4", 9)
    printLeft(" 8", 14)

    printRight("16 ", 4)
    printRight("32 ", 9)
    printRight("64 ", 14)

    printCentered("Go Back", h - 2)

    if select == 1 then
        printLeft(">", 4)
        selectedAmount = 1
    elseif select == 2 then
        printLeft(">", 9)
        selectedAmount = 4
    elseif select == 3 then
        printLeft(">", 14)
        selectedAmount = 8
    elseif select == 4 then
        printRight("<", 4)
        selectedAmount = 16
    elseif select == 5 then
        printRight("<", 9)
        selectedAmount = 32
    elseif select == 6 then
        printRight("<", 14)
        selectedAmount = 64
    elseif select == 7 then
        printCentered("-----------", h - 1)
    end
end

function drawPay()
    printCentered("Getting "..selectedAmount.." diamonds ready..", 4)
    rednet.send(TURTLE_ID, {"request", {"diamond", selectedAmount}}, "gATM")
    local senderID, receivedMessage = rednet.receive("gATM")
    printCentered("Getting diamonds ready was "..receivedMessage[1], 6)
    if receivedMessage[1] == "unsuccesful" then
        printCentered("Stopping program...", 8)
        os.sleep(0.5)
        os.reboot()
        return
    end
    local data = readTable("disk/userData.txt")
    local username = data.username
    rednet.broadcast({"post", {"changeBalance", username, -selectedAmount}}, "graviBank")

    printCentered("Diamonds should be received", 8)
    printCentered("Thanks for using this Gravibank ATM", 10)
    os.sleep(0.5)
    os.reboot()
end

function drawPassword()
    if not diskDrive.isDiskPresent() then
        printCentered("No card in the system.", h/2-1)
        printCentered("Returning to start menu.", h/2)
        os.sleep(0.5)
        os.reboot()
        return
    end

    if not hasEnoughMoney(selectedAmount) then
        printCentered("Not enough balance.", h/2)
        os.sleep(0.5)
        os.reboot()
    end

    printCentered("Password:", h/2-1)
    printCentered("__________", h/2+1)

    term.setCursorPos(w/2 - 10/2, h/2)
    local password = read("*")
    local isCorrect = checkPassword(password)

    if isCorrect[1] == "false" then
        return
    else
        menustate = "pay"
    end
end

function drawBalance()
    if not diskDrive.isDiskPresent() then
        printCentered("No card in the system.", h/2)
        os.sleep(0.5)
        os.reboot()
    end
    printCentered("Balance on your account:", h/2 - 2)

    local data = readTable("disk/userData.txt")
    local username = data.username
    rednet.broadcast({"request", {"getBalance", username}}, "graviBank")
    local senderID, message = rednet.receive("graviBank")

    printCentered("$"..message[1], h/2)

    printCentered("Go Back", h-2)
    printCentered("-----------", h - 1)
end

function drawHeader()
    printCentered("GRAVIBANK ATM", 1)
    printCentered(string.rep("-", w + 1), 2)
    printRight("GraviBank system made by gravitowl.", h)
end

---- Menu State
local mopt = {
    ["start"] = {
        options = {"main", "balance"},
        draw = drawStart
    },
    ["main"] = {
        options = {"password", "password", "password", "password", "password", "password", "start"},
        draw = drawMain
    },
    ["password"] = {
        options = {},
        draw = drawPassword
    },
    ["check"] = {
        options = {},
        draw = drawCheck
    },
    ["pay"] = {
        options = {},
        draw = drawPay
    },
    ["balance"] = {
        options = {"start"},
        draw = drawBalance
    }
}

---- Run Functions

function runMenu()
    while true do
        term.clear()
        drawHeader()
        mopt[menustate].draw()
        if #mopt[menustate].options > 0 then
            local id, key = os.pullEvent("key")
            if key == keys.up and select > 1 then select = select-1
            elseif key == keys.down and select < #mopt[menustate].options then select = select + 1
            elseif key == keys.enter then
                if mopt[menustate].options[select] == "quit" then break end
                menustate = mopt[menustate].options[select]
                select = 1
            end
        end
    end
end

runMenu()