TodoList Gui

  local args = {...}
local tasks = {}
local currentTask = "tasks"
local running = true
local state = "list"
local timer

if #args > 0 then
    currentTask = args[1]
end

function loadTasks(fileName)
  if fs.exists(fileName) then
    local file = fs.open(fileName,"r")
    local i = 1
    local tmpTasks = {}
    while true do
        tmpTasks[i] = file.readLine()
        if tmpTasks[i] == nil then
            break
        end
        i = i + 1
    end
    file.close()
    return tmpTasks
  end
  return {}
end
function saveTasks(fileName, taskTable)
    local file = fs.open(fileName,"w")
    for i = 1, #taskTable, 1 do
         file.writeLine(taskTable[i])
    end
    file.close()
end

local selectedMenuItem= 1
function printTasks(taskTable)
    local padding = 2
    local w, h = term.getSize()
    term.clear()
    if #taskTable > 0 then
    for i=1, #taskTable do
        if i == selectedMenuItem then
            term.setBackgroundColor(colors.white)
            term.setTextColor(colors.black)
        else
            term.setBackgroundColor(colors.black)
            term.setTextColor(colors.white)
end
        term.setCursorPos(padding, padding+i-1)
        local completed = false
        if i == 2 then
            completed = true
        end
        if completed then
        term.write("[X] "..taskTable[i])
else
        term.write("[_] "..taskTable[i])
end
            term.setBackgroundColor(colors.black)
            term.setTextColor(colors.white)
end
else
        term.setCursorPos(padding, padding)
        term.write("No tasks found.")
end
    term.setCursorPos(2, h - 1)
    term.write("Up/Down/Enter - [A]dd - [D]elete - [Q]uit")
end

local currentMessage = {}
function showMessage(messageTable)
    state = "msg"
currentMessage = messageTable
end
function displayMsg(messageTable)
    local padding = 6
    local w, h = term.getSize()
    term.clear()
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    for i=1, #messageTable do
        term.setCursorPos(padding, padding+i-1)
        term.write(messageTable[i])
end
    term.setCursorPos(2, h - 1)
    term.write("Press [ENTER] to continue")
end
function displayAddItem()
    local padding = 6
    local w, h = term.getSize()
    term.clear()
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
term.setCursorPos(padding, padding)
    term.write("Add Task")
term.setCursorPos(padding, padding+1)
    term.write("-----------------------")
    term.setCursorPos(2, h - 2)
    term.write("Press [ENTER] to insert new item")
term.setCursorPos(2, h - 1)
    term.write("Enter nothing (blank string) to cancel")

    --we have to draw the whole screen first!
    term.setCursorPos(padding, padding+3)
    term.write("Task Name: ")
    local newTask = read()
    if newTask ~= "" then
    tasks[#tasks+1] = newTask
end
state = "list" --return our state back to the main list
end

tasks = loadTasks(currentTask)

timer = os.startTimer(0)
while running do
local event, p1 = os.pullEvent()
if event == "key" then
if state == "list" then
    if p1 == keys.q then
        running = false
    elseif p1 == keys.up then
        selectedMenuItem=selectedMenuItem-1
        if selectedMenuItem <= 0 then
            selectedMenuItem = #tasks
        end
    elseif p1 == keys.down then
        selectedMenuItem=selectedMenuItem+1
        if selectedMenuItem > #tasks then
            selectedMenuItem = 1
        end
    elseif p1 == keys.a then
        state = "additem"
    elseif p1 == keys.d then
        table.remove(tasks, selectedMenuItem)
    elseif p1 == keys.enter then
        showMessage({
"You selected number: #"..selectedMenuItem,
"",
"Value: "..tasks[selectedMenuItem]
})
end
        elseif state == "msg" then
if p1 == keys.enter then
        state = "list"
    end
end
end
if event == "timer" and p1 == timer then
    if state == "list" then
        printTasks(tasks)
    elseif state == "additem" then
        displayAddItem()
    elseif state == "msg" then
        displayMsg(currentMessage)
end
timer = os.startTimer(0.1)
end
end

saveTasks(currentTask, tasks)

term.clear()
term.setCursorPos(1,1)
term.write("Thanks for using my task program")
term.setCursorPos(1,3)
sleep(2)