-- User authentication and decryption program with UI

local function xorEncryptDecrypt(data, key)
    local result = ""
    for i = 1, #data do
        result = result .. string.char(bit.bxor(data:byte(i), key))
    end
    return result
end

local function drawUI()
    term.clear()
    term.setCursorPos(1, 1)
    print("========================================")
    print("     Doggy OS Administrator File System")
    print("          Protection API v1.0")
    print("========================================")
end

local function authenticateUser()
    drawUI()
    print("Enter username:")
    local username = read()
    drawUI()
    print("Enter password:")
    local password = read("*") -- Masked input for password

    local userPath = "/disk/users/" .. username .. "/password.txt"
    if not fs.exists(userPath) then
        drawUI()
        print("User does not exist.")
        sleep(2)
        return false
    end

    local fileHandle = fs.open(userPath, "r")
    local storedPassword = fileHandle.readAll()
    fileHandle.close()

    local decryptedPassword = xorEncryptDecrypt(storedPassword, 123)
    if password == decryptedPassword then
        local adminFilePath = "/disk/users/" .. username .. "/admin.txt"
        if fs.exists(adminFilePath) then
            return true
        else
            drawUI()
            print("User is not an admin.")
            sleep(2)
            return false
        end
    else
        drawUI()
        print("Incorrect password.")
        sleep(2)
        return false
    end
end

local function decryptDirectory(directory)
    local files = fs.list(directory)
    for _, file in ipairs(files) do
        local path = fs.combine(directory, file)
        if fs.isDir(path) then
            decryptDirectory(path)
        else
            local fileHandle = fs.open(path, "r")
            local content = fileHandle.readAll()
            fileHandle.close()
            local decryptedContent = xorEncryptDecrypt(content, 123)
            fileHandle = fs.open(path, "w")
            fileHandle.write(decryptedContent)
            fileHandle.close()
            print("Decrypted: " .. path)
        end
    end
end

-- Main program
drawUI()
print("Welcome to Doggy OS Administrator File System Protection API.")
sleep(2)
if authenticateUser() then
    drawUI()
    print("Authentication successful. Starting decryption...")
    decryptDirectory("/disk/")
    print("Decryption completed.")
else
    drawUI()
    print("Authentication failed. Exiting.")
end