-- Function to clear the terminal and set the cursor position
local function clearScreen()
  term.clear()
  term.setCursorPos(1, 1)
end

-- Function to display centered ASCII art
local function displayCenteredArt(art, text)
  clearScreen()
  local lines = {}
  for line in art:gmatch("[^\n]+") do
    table.insert(lines, line)
  end

  local _, h = term.getSize()
  local startY = math.floor((h - #lines) / 2) + 1
  for i, line in ipairs(lines) do
    local w, _ = term.getSize()
    local startX = math.floor((w - #line) / 2) + 1
    term.setCursorPos(startX, startY + i - 1)
    print(line)
  end

  if text then
    local textX = math.floor((term.getSize() - #text) / 2) + 1
    term.setCursorPos(textX, startY + #lines + 1)
    print(text)
  end
end

-- Function to draw a menu system
local function drawMenu(title, options)
  clearScreen()
  local w, h = term.getSize()
  local boxWidth = 40
  local boxHeight = #options + 6
  local startX = math.floor((w - boxWidth) / 2) + 1
  local startY = math.floor((h - boxHeight) / 2) + 1

  -- Draw menu background and header
  paintutils.drawBox(startX, startY, startX + boxWidth - 1, startY + boxHeight - 1, colors.blue)
  paintutils.drawFilledBox(startX + 1, startY + 1, startX + boxWidth - 2, startY + boxHeight - 2, colors.lightBlue)
  term.setTextColor(colors.white)
  term.setCursorPos(startX + 2, startY + 1)
  print(title)

  -- Draw options
  for i, option in ipairs(options) do
    term.setCursorPos(startX + 2, startY + 2 + i)
    print(i .. ". " .. option)
  end
end

-- Function to handle menu selection
local function menuSelection(title, options)
  drawMenu(title, options)
  local w, h = term.getSize()
  local startX = math.floor((w - 40) / 2) + 2
  local startY = math.floor((h - (#options + 6)) / 2) + #options + 5
  term.setCursorPos(startX, startY)
  term.write("Select an option: ")
  local choice = tonumber(read())
  if choice and choice > 0 and choice <= #options then
    return choice
  else
    return nil
  end
end


local MAX_ATTEMPTS = 3   -- Maximum number of incorrect password attempts allowed
local LOCKOUT_TIME = 30  -- Lockout time in seconds after reaching maximum attempts

local USERS_FOLDER = "/disk/users/"
local ERROR_FOLDER = "/disk/error/"
local BSOD_PROGRAM = "BSOD.lua"
local CURRENT_USER_FILE = ".currentusr"
local SHOW_ALL_USERS_FILE = "/disk/config/security/login/ShowAllUsers.cfg"

-- Utility function to draw a centered popup window with a text-based border
local function drawPopupWindow(headerText, contentLines, windowWidth, windowHeight)
    term.clear()  -- Clear the screen before drawing the popup window

    local w, h = term.getSize()
    local maxLength = #headerText
    for _, line in ipairs(contentLines) do
        maxLength = math.max(maxLength, #line)
    end

    -- Calculate the window dimensions if not provided
    windowWidth = windowWidth or (maxLength + 4)
    windowHeight = windowHeight or (#contentLines + 4)

    local xStart = math.floor(w / 2 - windowWidth / 2)
    local yStart = math.floor(h / 2 - windowHeight / 2)

    -- Draw border
    term.setCursorPos(xStart, yStart)
    term.write("+" .. string.rep("-", windowWidth - 2) .. "+")
    for i = 1, windowHeight - 2 do
        term.setCursorPos(xStart, yStart + i)
        term.write("|" .. string.rep(" ", windowWidth - 2) .. "|")
    end
    term.setCursorPos(xStart, yStart + windowHeight - 1)
    term.write("+" .. string.rep("-", windowWidth - 2) .. "+")

    -- Draw header
    term.setCursorPos(xStart + 2, yStart + 1)
    term.write(headerText)

    -- Draw content
    for i, line in ipairs(contentLines) do
        term.setCursorPos(xStart + 2, yStart + 1 + i + 1)
        term.write(line)
    end
end

-- Function to list all users
local function listUsers()
    local users = fs.list(USERS_FOLDER)
    local usernames = {}
    for _, user in ipairs(users) do
        local userDir = fs.combine(USERS_FOLDER, user)
        if fs.isDir(userDir) then
            table.insert(usernames, user)
        end
    end
    return usernames
end

-- Function to handle user selection from the list
local function drawUsersScreen(usernames, selectedIndex)
    local w, h = term.getSize()
    local contentLines = {}
    for i, username in ipairs(usernames) do
        if i == selectedIndex then
            table.insert(contentLines, "> " .. username)
        else
            table.insert(contentLines, "  " .. username)
        end
    end

    -- Increase the border size for a larger window
    drawPopupWindow("Select a User", contentLines, 30, #contentLines + 4)
    term.setCursorPos(1, h)  -- Move cursor out of the way after drawing
end

-- Function to handle arrow key navigation and selection
local function selectUserFromList()
    local usernames = listUsers()
    local selectedIndex = 1

    while true do
        drawUsersScreen(usernames, selectedIndex)

        local event, key = os.pullEvent("key")
        if key == keys.up then
            selectedIndex = math.max(1, selectedIndex - 1)
        elseif key == keys.down then
            selectedIndex = math.min(#usernames, selectedIndex + 1)
        elseif key == keys.enter then
            return usernames[selectedIndex]
        end
    end
end

-- Function to get user credentials
local function getUserCredentials(username)
    local passwordFile = fs.combine(USERS_FOLDER .. username, "password.txt")

    if fs.exists(passwordFile) then
        local file = fs.open(passwordFile, "r")
        local storedPassword = file.readLine()
        file.close()
        return storedPassword
    else
        return nil  -- User does not exist
    end
end

-- Function to draw login screen
local function drawLoginScreen(username, attemptsLeft)
    local contentLines = {
        "Username: " .. username,
        "Attempts left: " .. attemptsLeft,
        "",
        "Enter password:"
    }
    drawPopupWindow("Login to Doggy OS", contentLines)
    term.setCursorPos(math.floor(term.getSize() / 2) - 2, math.floor(term.getSize() / 2) + 1)  -- Position cursor for password input
end

-- Function to lockout user after failed attempts
local function lockoutUser(username)
    local disabledFile = fs.combine(USERS_FOLDER .. username, "disabled.txt")
    local file = fs.open(disabledFile, "w")
    file.close()
end

-- Function to check if user is disabled
local function checkDisabled(username)
    local disabledFile = fs.combine(USERS_FOLDER .. username, "disabled.txt")
    return fs.exists(disabledFile)
end

-- Function to save the current user
local function saveCurrentUser(username)
    if fs.exists(CURRENT_USER_FILE) then
        fs.delete(CURRENT_USER_FILE)  -- Delete existing file
    end
    local file = fs.open(CURRENT_USER_FILE, "w")
    file.write(username)
    file.close()
end

-- Function to check credentials and login
local function checkCredentials(username)
    if checkDisabled(username) then
        drawPopupWindow("Access Denied", {"This user has been disabled due to security reasons.", "", "Contact your administrator for help."})
        os.sleep(5)  -- Display the disabled message for 5 seconds
        shell.run("/disk/os/lock.lua")  -- Run the lock.lua program
        return false
    end

    local storedPassword = getUserCredentials(username)

    if not storedPassword then
        return false  -- User does not exist
    end

    local attempts = 0

    repeat
        drawLoginScreen(username, MAX_ATTEMPTS - attempts)

        local enteredPassword = read("*")
        attempts = attempts + 1

        if enteredPassword == storedPassword then
            saveCurrentUser(username)  -- Save the logged-in user
            return true
        else
            drawPopupWindow("Access Denied", {"Incorrect password. Please try again."})
            os.sleep(2)  -- Display the error message for 2 seconds
        end
    until attempts > MAX_ATTEMPTS

    drawPopupWindow("Account Disabled", {"Too many incorrect attempts. User has been disabled."})
    lockoutUser(username)
    os.sleep(2)  -- Display the lockout message for 2 seconds

    return false
end

-- Function to handle user login process
local function main()
    -- Set the text color to white and the background color to black
    term.setTextColor(colors.white)
    term.setBackgroundColor(colors.black)
    term.clear()

    -- If the ShowAllUsers.cfg file exists, show all users
    if fs.exists(SHOW_ALL_USERS_FILE) then
        local username = selectUserFromList()
        if checkCredentials(username) then
            drawPopupWindow("Welcome", {"Access granted. Welcome, " .. username .. "!"})
            os.sleep(2)  -- Display the success message for 2 seconds
            shell.run("/disk/os/gui")
        else
            drawPopupWindow("Access Denied", {"Incorrect credentials."})
            os.sleep(2)  -- Display the access denied message for 2 seconds
            shell.run("/disk/os/lock.lua")
        end
    else
        drawPopupWindow("Protected by Doggy OS Security", {"Enter username:"})
        local enteredUsername = read()

        if checkDisabled(enteredUsername) then
            drawPopupWindow("Access Denied", {"This user has been disabled due to security reasons."})
            os.sleep(5)
            shell.run("/disk/os/lock.lua")
        elseif checkCredentials(enteredUsername) then
            drawPopupWindow("Welcome", {"Access granted. Welcome, " .. enteredUsername .. "!"})
            os.sleep(2)
            shell.run("/disk/os/gui")
        else
            drawPopupWindow("Access Denied", {"Incorrect credentials."})
            os.sleep(2)
            shell.run("/disk/os/lock.lua")
        end
    end
end

-- Start the login process
main()