local w, h = term.getSize()

-- Function to center text horizontally
local function centerText(y, text)
    local x = math.floor((w - #text) / 2)
    term.setCursorPos(x, y)
    term.write(text)
end

-- Function to draw the spinner animation
local function drawSpinner(x, y, duration)
    local spinnerFrames = {
        "[    ]",
        "[=   ]",
        "[==  ]",
        "[=== ]",
        "[====]",
        "[ ===]",
        "[  ==]",
        "[   =]",
        "[    ]",
        "[   =]",
        "[  ==]",
        "[ ===]",
        "[====]",
        "[=== ]",
        "[==  ]",
        "[=   ]"
    }
    local delay = 0.1
    local frameCount = #spinnerFrames

    local spinnerX = x
    local spinnerY = y

    local spinnerIndex = 1
    local startTime = os.clock()
    while os.clock() - startTime < duration do
        term.setCursorPos(spinnerX, spinnerY)
        term.write(spinnerFrames[spinnerIndex])

        spinnerIndex = spinnerIndex % frameCount + 1
        os.sleep(delay)
    end
end

-- ASCII art dog image
local dogImage = {
    "     |\\_/|                  ",
    "     | @ @   Doggy OS        ",
    "     |   <>              _   ",
    "     |  _/\\------____ ((| |))",
    "     |               `--' |  ",
    " _____|_       ___|   |___.' ",
    "/_/_____/____/_______|       "
}

-- Function to draw the ASCII art
local function drawASCIIArt(y)
    for i, line in ipairs(dogImage) do
        centerText(y + i - 1, line)
    end
end

-- Fade Animation
local function fade(colorsToFade, delay)
    for _, color in ipairs(colorsToFade) do
        term.setBackgroundColor(color)
        term.clear()
        sleep(delay)
    end
end

-- Function to draw the shutdown screen
local function drawShutdownScreen()
    term.setBackgroundColor(colors.black)
    term.clear()

    term.setTextColor(colors.white)
    local artHeight = #dogImage
    local artY = math.floor((h - artHeight) / 2)
    drawASCIIArt(artY)

    -- Calculate spinner position
    local spinnerX = math.floor(w / 2) - 3
    local spinnerY = artY + artHeight + 2

    -- Add "Please wait" text 1 line below the spinner
    local waitText = "Please wait..."
    local waitX = math.floor((w - #waitText) / 2)  -- Center the text
    term.setCursorPos(waitX, spinnerY + 2)  -- Position it 1 row lower than previous
    term.write(waitText)

    -- Start spinner animation
    drawSpinner(spinnerX, spinnerY, 9)  -- Spinner runs for 9 seconds
end

-- Function to display the welcome screen with fade animation
local function showWelcomeScreen()
    -- Fade to black
    fade({colors.white, colors.lightGray, colors.gray, colors.black}, 0.1)

    -- Show the welcome message
    term.setBackgroundColor(colors.black)
    term.clear()

    term.setTextColor(colors.white)
    centerText(math.floor(h / 2) - 2, "Welcome to")
    centerText(math.floor(h / 2) - 1, "Doggy OS!!")

    -- Show the ASCII art below the message
    drawASCIIArt(math.floor(h / 2) + 1)

    -- Fade back to white after the message and art
    fade({colors.black, colors.gray, colors.lightGray, colors.white}, 0.1)
end

-- Main program
drawShutdownScreen()

-- Clear screen after shutdown
term.setBackgroundColor(colors.black)
term.clear()

-- Shutdown the computer
shell.run("disk/os/lock.lua")

-- Show welcome screen after the shutdown process
showWelcomeScreen()