-- Function to generate a random key of specified length
local function generateKey(length)
    local key = ""
    for i = 1, length do
        key = key .. string.char(math.random(0, 255))
    end
    return key
end

-- XOR encryption/decryption function
local function xorEncryptDecrypt(data, key)
    local result = {}
    for i = 1, #data do
        local keyIndex = (i - 1) % #key + 1
        result[i] = string.char(bit.bxor(string.byte(data, i), string.byte(key, keyIndex)))
    end
    return table.concat(result)
end

-- Function to encrypt all files in a directory
local function encryptFilesInDirectory(directory, key)
    local files = fs.list(directory)
    for _, file in ipairs(files) do
        local filePath = fs.combine(directory, file)
        if not fs.isDir(filePath) then
            -- Read file contents
            local fileHandle = fs.open(filePath, "r")
            local data = fileHandle.readAll()
            fileHandle.close()

            -- Encrypt data
            local encryptedData = xorEncryptDecrypt(data, key)

            -- Write encrypted data back to the file
            fileHandle = fs.open(filePath, "w")
            fileHandle.write(encryptedData)
            fileHandle.close()
        end
    end
end

-- Function to decrypt all files in a directory
local function decryptFilesInDirectory(directory, key)
    local files = fs.list(directory)
    for _, file in ipairs(files) do
        local filePath = fs.combine(directory, file)
        if not fs.isDir(filePath) then
            -- Read encrypted file contents
            local fileHandle = fs.open(filePath, "r")
            local encryptedData = fileHandle.readAll()
            fileHandle.close()

            -- Decrypt data
            local decryptedData = xorEncryptDecrypt(encryptedData, key)

            -- Write decrypted data back to the file
            fileHandle = fs.open(filePath, "w")
            fileHandle.write(decryptedData)
            fileHandle.close()
        end
    end
end

-- Function to encrypt files and save the key
local function mainEncrypt()
    -- Path to the disk
    local diskPath = "/disk"

    -- Generate a random encryption key
    local key = generateKey(16) -- 16 bytes key

    -- Save the key to a file
    local keyFilePath = fs.combine(diskPath, "encryption_key.txt")
    local keyFileHandle = fs.open(keyFilePath, "w")
    keyFileHandle.write(key)
    keyFileHandle.close()

    -- Encrypt all files in the disk directory
    encryptFilesInDirectory(diskPath, key)

    print("Encryption complete. Key saved to " .. keyFilePath)
end

-- Function to decrypt files using a saved key
local function mainDecrypt()
    -- Path to the disk
    local diskPath = "/disk"

    -- Read the encryption key from the file
    local keyFilePath = fs.combine(diskPath, "encryption_key.txt")
    local keyFileHandle = fs.open(keyFilePath, "r")
    local key = keyFileHandle.readAll()
    keyFileHandle.close()

    -- Decrypt all files in the disk directory
    decryptFilesInDirectory(diskPath, key)

    print("Decryption complete using key from " .. keyFilePath)
end

-- Main function to prompt user for action
local function main()
    print("Do you want to (E)ncrypt or (D)ecrypt files? (E/D): ")
    local choice = io.read():upper()

    if choice == "E" then
        mainEncrypt()
    elseif choice == "D" then
        mainDecrypt()
    else
        print("Invalid choice. Please enter 'E' for encryption or 'D' for decryption.")
    end
end

-- Run the main function
main()