-- Function to check if a file exists
local function fileExists(path)
    local file = fs.open(path, "r")
    if file then
        file.close()
        return true
    else
        return false
    end
end

-- Function to clear the screen
local function clearScreen()
    term.clear()
    term.setCursorPos(1, 1)
end

-- Function to display a styled message
local function displayMessage(message)
    clearScreen()
    term.setTextColor(colors.lightGray)
    term.setBackgroundColor(colors.black)
    term.setCursorPos(1, 1)
    print("Doggy OS Developer System Bootloader")
    print("===================================")
    print()
    term.setTextColor(colors.red)
    print("WARNING: UNSTABLE DEVELOPER BUILD")
    term.setTextColor(colors.white)
    print("This bootloader is intended for modifying and testing Doggy OS.")
    print()
    print(message)
    print()
end

-- Function to display the GUI
local function displayGUI(message, options)
    displayMessage(message)

    term.setTextColor(colors.cyan)
    term.setBackgroundColor(colors.black)
    term.setCursorPos(1, 8)
    print("Select an option:")
    term.setTextColor(colors.yellow)

    local maxOptionWidth = 0
    for _, option in ipairs(options) do
        local optionText = string.format(" %d. %s", _, option)
        if #optionText > maxOptionWidth then
            maxOptionWidth = #optionText
        end
    end

    local baseLine = 9
    for i, option in ipairs(options) do
        local optionText = string.format(" %d. %s", i, option)
        term.setCursorPos(1, baseLine + i)
        print(optionText .. string.rep(" ", maxOptionWidth - #optionText + 2))
    end
end

-- Function to shutdown the system
local function shutdownSystem()
    clearScreen()
    displayMessage("Shutting down the system...")
    sleep(2)  -- Simulate shutdown process
    os.shutdown()
end

-- Function to handle user choice
local function getUserChoice(numOptions)
    local choice
    repeat
        term.setTextColor(colors.white)
        term.setBackgroundColor(colors.black)
        term.setCursorPos(1, 11 + numOptions)
        print("Enter choice (1-" .. numOptions .. "): ")
        term.setTextColor(colors.yellow)
        choice = tonumber(read())
    until choice and choice >= 1 and choice <= numOptions
    return choice
end

-- Main program logic
local function main()
    local devCfgPath = "dev.cfg"
    local biosPath = "/disk/boot/BIOS"

    -- Check if dev.cfg exists
    if not fileExists(devCfgPath) then
        displayGUI("dev.cfg not found. Please select an option below:", {"Run BIOS"})
        if fileExists(biosPath) then
            shell.run(biosPath)
        else
            displayMessage("Error: BIOS file not found.")
        end
        return
    end

    -- The disk paths to check
    local startupFilePath = "startup"
    local startupFileFound = false

    -- Check if startup file exists
    if fileExists(startupFilePath) or fileExists(startupFilePath .. ".lua") then
        startupFileFound = true
    end

    if startupFileFound then
        displayGUI("Boot Device found. Select an option below:", {"Boot", "Shutdown system"})
        local choice = getUserChoice(2)

        if choice == 1 then
            clearScreen()
            if fileExists(startupFilePath .. ".lua") then
                shell.run(startupFilePath .. ".lua")
            elseif fileExists(startupFilePath) then
                shell.run(startupFilePath)
            end
        elseif choice == 2 then
            shutdownSystem()
        end
    else
        displayGUI("No boot device found. Please select an option below:", {"Run BIOS"})
        if fileExists(biosPath) then
            shell.run(biosPath)
        else
            displayMessage("Error: BIOS file not found.")
        end
    end
end

-- Run the main function
main()