-- GUI-Based Login System for Doggy OS
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 window
local function drawWindow(x, y, width, height, title)
    paintutils.drawFilledBox(x, y, x + width - 1, y + height - 1, colors.gray)  -- Window background
    paintutils.drawBox(x, y, x + width - 1, y + height - 1, colors.lightGray)   -- Window border
    term.setCursorPos(x + 2, y)
    term.setTextColor(colors.white)
    term.write(title)
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 display a selection menu
local function selectUserFromList(usernames)
    local w, h = term.getSize()
    local windowWidth, windowHeight = 30, #usernames + 4
    local x, y = math.floor(w / 2 - windowWidth / 2), math.floor(h / 2 - windowHeight / 2)

    local selectedIndex = 1
    while true do
        drawWindow(x, y, windowWidth, windowHeight, "Select User")
        for i, username in ipairs(usernames) do
            term.setCursorPos(x + 2, y + 1 + i)
            if i == selectedIndex then
                term.setTextColor(colors.yellow)
                term.write("> " .. username)
            else
                term.setTextColor(colors.white)
                term.write("  " .. username)
            end
        end

        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
    end
end

-- Function to display login screen
local function drawLoginScreen(username, attemptsLeft)
    local w, h = term.getSize()
    local windowWidth, windowHeight = 40, 8
    local x, y = math.floor(w / 2 - windowWidth / 2), math.floor(h / 2 - windowHeight / 2)

    drawWindow(x, y, windowWidth, windowHeight, "Login to Doggy OS")
    term.setCursorPos(x + 2, y + 2)
    term.write("Username: " .. username)
    term.setCursorPos(x + 2, y + 3)
    term.write("Attempts left: " .. attemptsLeft)
    term.setCursorPos(x + 2, y + 5)
    term.write("Enter password: ")
    term.setCursorPos(x + 18, y + 5)
end

-- Function to lockout user
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)
    end
    local file = fs.open(CURRENT_USER_FILE, "w")
    file.write(username)
    file.close()
end

-- Function to handle user login
local function checkCredentials(username)
    if checkDisabled(username) then
        drawWindow(10, 10, 40, 6, "Access Denied")
        term.setCursorPos(12, 12)
        term.write("Account is disabled.")
        os.sleep(2)
        return false
    end

    local storedPassword = getUserCredentials(username)
    if not storedPassword then
        return false
    end

    local attempts = 0
    while attempts < MAX_ATTEMPTS do
        drawLoginScreen(username, MAX_ATTEMPTS - attempts)
        local enteredPassword = read("*")
        if enteredPassword == storedPassword then
            saveCurrentUser(username)
            drawWindow(10, 10, 40, 6, "Access Granted")
            term.setCursorPos(12, 12)
            term.write("Welcome, " .. username .. "!")
            os.sleep(2)
            return true
        else
            attempts = attempts + 1
            drawWindow(10, 10, 40, 6, "Access Denied")
            term.setCursorPos(12, 12)
            term.write("Incorrect password.")
            os.sleep(2)
        end
    end

    drawWindow(10, 10, 40, 6, "Account Disabled")
    term.setCursorPos(12, 12)
    term.write("Too many failed attempts.")
    lockoutUser(username)
    os.sleep(2)
    return false
end

-- Main function
local function main()
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.clear()

    if fs.exists(SHOW_ALL_USERS_FILE) then
        local usernames = listUsers()
        local username = selectUserFromList(usernames)
        if username and checkCredentials(username) then
            shell.run("/disk/os/gui")
        else
            shell.run("/disk/os/lock.lua")
        end
    else
        drawWindow(10, 10, 40, 6, "Doggy OS")
        term.setCursorPos(12, 12)
        term.write("Enter username:")
        term.setCursorPos(28, 12)
        local username = read()

        if checkCredentials(username) then
            shell.run("/disk/os/gui")
        else
            shell.run("/disk/os/lock.lua")
        end
    end
end

main()