-- Transition Effect with CRT Scanlines
local function transitionToCRT(colorSequence, delay)
    local _, height = term.getSize()  -- Get terminal width and height

    for _, color in ipairs(colorSequence) do
        term.setBackgroundColor(color)
        term.clear()

        -- Simulating CRT scanlines (by alternating row colors)
        for y = 1, height do
            term.setCursorPos(1, y)
            if y % 2 == 0 then
                -- Dark row for scanline effect
                term.write(" ")
            else
                -- Normal row
                term.write(" ")
            end
        end

        sleep(delay)
    end
end

-- Intro Transition: Fade to Black with CRT Effect
local function introTransition()
    local colorsToFade = {
        colors.white, colors.lightGray, colors.gray, colors.black
    }
    transitionToCRT(colorsToFade, 0.1)
end

-- Outro Transition: Fade to White with CRT Effect
local function outroTransition()
    local colorsToFade = {
        colors.black, colors.gray, colors.lightGray, colors.white
    }
    transitionToCRT(colorsToFade, 0.1)
end

-- Main Program
introTransition() -- Smooth transition to blank screen with CRT effect
os.pullEvent("key") -- Wait for any key press
outroTransition() -- Smooth transition to white with CRT effect
sleep(0.1) -- Wait an additional 0.1 seconds after the outro transition
shell.run("/disk/os/lock") -- Run the lock program