os.pullEvent = os.pullEventRaw

local w, h = term.getSize()
local nOption = 1
local isStartMenuOpen = false
local isPowerMenuOpen = false
local menuOptions = {"Command", "Programs", "Power Menu"}
local powerOptions = {"Shutdown", "Reboot", "Sign Out", "Cancel"}

-- Create windows for taskbar, start menu, and power menu
local taskbar = window.create(term.current(), 1, h, w, 1)
local startMenu = window.create(term.current(), 1, h - 10, 20, 10, false)
local powerMenu = window.create(term.current(), math.floor(w / 2) - 12, math.floor(h / 2) - 7, 24, 15, false)

-- Helper function to draw the taskbar with the current time
local function drawTaskbar()
    taskbar.setBackgroundColor(colors.green)
    taskbar.clear()
    taskbar.setCursorPos(1, 1)
    taskbar.setTextColor(colors.white)
    taskbar.write("[ Start ]")

    -- Display the current time on the right side
    local currentTime = os.date("%H:%M:%S")
    local timeX = w - string.len(currentTime) - 1
    taskbar.setCursorPos(timeX, 1)
    taskbar.write(currentTime)
end

-- Helper function to draw the start menu
local function drawStartMenu()
    if not isStartMenuOpen then
        startMenu.setVisible(false)
        return
    end

    startMenu.setVisible(true)
    startMenu.setBackgroundColor(colors.green)
    startMenu.clear()

    startMenu.setTextColor(colors.white)
    startMenu.setCursorPos(2, 1)
    startMenu.write("=== Start Menu ===")

    for i, option in ipairs(menuOptions) do
        startMenu.setCursorPos(2, 2 + i)
        if nOption == i then
            startMenu.setTextColor(colors.black)
            startMenu.setBackgroundColor(colors.white)
            startMenu.write("[ " .. option .. " ]")
            startMenu.setBackgroundColor(colors.green)
            startMenu.setTextColor(colors.white)
        else
            startMenu.write("[ " .. option .. " ]")
        end
    end
end

-- Helper function to draw the power menu
local function drawPowerMenu()
    if not isPowerMenuOpen then
        powerMenu.setVisible(false)
        return
    end

    powerMenu.setVisible(true)
    powerMenu.setBackgroundColor(colors.black)
    powerMenu.clear()

    powerMenu.setTextColor(colors.white)
    powerMenu.setCursorPos(2, 1)
    powerMenu.write("=== Power Menu ===")

    for i, option in ipairs(powerOptions) do
        powerMenu.setCursorPos(2, 3 + i)
        if nOption == i then
            powerMenu.setTextColor(colors.black)
            powerMenu.setBackgroundColor(colors.white)
            powerMenu.write("[ " .. option .. " ]")
            powerMenu.setBackgroundColor(colors.black)
            powerMenu.setTextColor(colors.white)
        else
            powerMenu.write("[ " .. option .. " ]")
        end
    end
end

-- Helper function to draw ASCII art in the center
local function drawASCIIArt()
    local art = {
        "     |\\_/|                  ",
        "     | @ @   Woof!         ",
        "     |   <>              _  ",
        "     |  _/\\------____ ((| |))",
        "     |               `--' |   ",
        " ____|_       ___|   |___.'  ",
        "/_/_____/____/_______|        "
    }
    local startX = math.floor((w - 26) / 2)  -- Centering the art horizontally
    local startY = math.floor((h - #art) / 2)  -- Centering the art vertically

    term.setTextColor(colors.white)
    for i, line in ipairs(art) do
        term.setCursorPos(startX, startY + i - 1)
        term.write(line)
    end
end

-- Function to draw an error screen
local function drawErrorScreen(message)
    -- Create an error window with a red background
    local errorWindow = window.create(term.current(), math.floor(w / 2) - 12, math.floor(h / 2) - 5, 24, 7, false)
    errorWindow.setBackgroundColor(colors.red)
    errorWindow.clear()

    -- Set up text color and positioning for the error message
    errorWindow.setTextColor(colors.white)
    errorWindow.setCursorPos(2, 2)
    errorWindow.write("ERROR: " .. message)

    -- Provide an option for the user to close the error screen
    errorWindow.setCursorPos(2, 5)
    errorWindow.setTextColor(colors.yellow)
    errorWindow.write("Press any key to return.")

    -- Wait for any key press to close the error window
    os.pullEvent("key")
    errorWindow.setVisible(false)  -- Hide the error window after key press
end

-- Check if the user is an admin (assuming .currentusr contains the current user)
local function isAdminUser()
    local userFile = "/disk/users/" .. fs.readFile(".currentusr") .. "/admin.txt"
    return fs.exists(".currentusr")
end

-- Function to run the program or action based on the selected option
local function runProgramOrAction(option)
    -- Check if the user is allowed to run commands
    if option == 1 and not isAdminUser() then
        -- Show the error screen if the user is not an admin
        drawErrorScreen("You must be an admin to run this.")
        return true  -- Prevent running the command
    end

    -- Normal handling for power menu actions
    if isPowerMenuOpen then
        if option == 1 then
            shell.run("/disk/ACPI/shutdown")  -- Shutdown
        elseif option == 2 then
            shell.run("/disk/ACPI/reboot")    -- Reboot
        elseif option == 3 then
            shell.run("/disk/ACPI/logoff")    -- Sign Out
        elseif option == 4 then
            shell.run("/disk/os/gui")          -- Run GUI when Cancel is selected
            return true
        end
        return true  -- Indicate an action was taken
    end

    -- Handle running programs for the main menu
    if option == 1 then
        shell.run("/disk/os/home.lua")
    elseif option == 2 then
        shell.run("/disk/os/programs")
    end

    return false  -- Indicate no action was taken
end

-- Function to redraw the entire UI
local function redrawUI()
    term.setBackgroundColor(colors.blue)
    term.clear()
    drawTaskbar()
    drawASCIIArt()  -- Draw ASCII art
    if isPowerMenuOpen then
        drawPowerMenu()
    else
        drawStartMenu()
    end
end

-- Initial UI drawing
redrawUI()

-- Start the timer for updating the time every second
local timerId = os.startTimer(1)

-- Function to handle mouse clicks
local function handleMouseClick(x, y)
    if y == h and x >= 1 and x <= 7 then
        isStartMenuOpen = not isStartMenuOpen
        isPowerMenuOpen = false
        redrawUI()
    elseif isStartMenuOpen and x >= 1 and x <= 20 and y >= h - 10 and y <= h - 1 then
        local clickedOption = y - (h - 10) - 1
        if clickedOption >= 1 and clickedOption <= #menuOptions then
            nOption = clickedOption
            if nOption == 3 then
                isStartMenuOpen = false
                isPowerMenuOpen = true
                redrawUI()
            else
                return true
            end
        end
    end
    return false
end

-- Main event handling loop
while true do
    local e, p1, p2, p3 = os.pullEvent()

    if e == "mouse_click" then
        local button, x, y = p1, p2, p3
        if handleMouseClick(x, y) then
            runProgramOrAction(nOption)  -- Execute action
        end
    elseif e == "key" and (isStartMenuOpen or isPowerMenuOpen) then
        local key = p1

        if key == keys.up then
            if nOption > 1 then
                nOption = nOption - 1
            else
                nOption = #menuOptions
            end
            redrawUI()
        elseif key == keys.down then
            if isPowerMenuOpen then
                if nOption < #powerOptions then
                    nOption = nOption + 1
                else
                    nOption = 1 -- Wrap around to "Shutdown"
                end
            else
                if nOption < #menuOptions then
                    nOption = nOption + 1
                else
                    nOption = 1
                end
            end
            redrawUI()
        elseif key == keys.enter then
            if runProgramOrAction(nOption) then
                -- Do nothing, action taken
            else
                break  -- Exit loop only if no action taken
            end
        end
    elseif e == "timer" and p1 == timerId then
        drawTaskbar()  -- Redraw taskbar to update time
        timerId = os.startTimer(1)  -- Reset the timer for the next second
    end
end

-- Final screen settings before running the selected action
term.setBackgroundColor(colors.black)
term.setTextColor(colors.white)
term.clear()