Encrypted user creation API

-- Function to generate a key for encryption and decryption
function generateKey()
    local chars = {}
    for i = 32, 126 do -- ASCII range for printable characters
        table.insert(chars, string.char(i))
    end

    local key = {}
    while #chars > 0 do
        local index = math.random(#chars)
        table.insert(key, table.remove(chars, index))
    end

    return table.concat(key)
end

-- Function to create a map from a key
function createMap(key)
    local map = {}
    for i = 32, 126 do
        map[string.char(i)] = key:sub(i - 31, i - 31)
    end
    return map
end

-- Function to invert a map
function invertMap(map)
    local invMap = {}
    for k, v in pairs(map) do
        invMap[v] = k
    end
    return invMap
end

-- Function to encrypt text using a key
function encrypt(text, key)
    local map = createMap(key)
    local encrypted = {}
    for i = 1, #text do
        local char = text:sub(i, i)
        table.insert(encrypted, map[char] or char)
    end
    return table.concat(encrypted)
end

-- Function to decrypt text using a key
function decrypt(text, key)
    local map = invertMap(createMap(key))
    local decrypted = {}
    for i = 1, #text do
        local char = text:sub(i, i)
        table.insert(decrypted, map[char] or char)
    end
    return table.concat(decrypted)
end

-- Function to save the key to a file
function saveKeyToFile(key, dir)
    local randomNumber = math.random(1, 1000)
    local fileName = dir .. "/key" .. randomNumber .. ".txt"
    local file = fs.open(fileName, "w")
    file.write(key)
    file.close()
    return fileName
end

-- Function to load the key from a file
function loadKeyFromFile(fileName)
    local file = fs.open(fileName, "r")
    local key = file.readAll()
    file.close()
    return key
end

-- Function to find the key file in a directory
function findKeyFile(dir)
    local files = fs.list(dir)
    for _, file in ipairs(files) do
        if file:match("^key%d+%.txt$") then
            return dir .. "/" .. file
        end
    end
    return nil
end

-- Function to load the encrypted text from the password file
function loadEncryptedText(userDir)
    local fileName = userDir .. "/password.txt"
    if not fs.exists(fileName) then
        print("Password file does not exist.")
        return nil
    end
    local file = fs.open(fileName, "r")
    local encryptedText = file.readAll()
    file.close()
    return encryptedText
end

-- API Functions
function create(username, text)
    local userDir = "/disk/users/" .. username

    if not fs.exists(userDir) then
        fs.makeDir(userDir)
    end

    local key = generateKey()
    local encryptedText = encrypt(text, key)
    local keyFileName = saveKeyToFile(key, userDir)

    local passwordFile = fs.open(userDir .. "/password.txt", "w")
    passwordFile.write(encryptedText)
    passwordFile.close()

    return { status = "success", encryptedText = encryptedText, keyFileName = keyFileName }
end

function delete(username)
    local userDir = "/disk/users/" .. username

    if fs.exists(userDir) then
        fs.delete(userDir)
        return { status = "success", message = "User directory deleted." }
    else
        return { status = "error", message = "User directory not found." }
    end
end

function authenticate(adminUsername, adminPassword)
    -- Replace with actual admin credential verification
    if adminUsername == "admin" and adminPassword == "password" then
        return { status = "success", message = "Authenticated successfully." }
    else
        return { status = "error", message = "Authentication failed." }
    end
end

-- Example Usage
local tArgs = {...}
if #tArgs < 1 then
    print("Usage: api <command> <args>")
    return
end

local command = tArgs[1]
if command == "create" then
    if #tArgs < 3 then
        print("Usage: api create <username> <text>")
        return
    end
    local username = tArgs[2]
    local text = table.concat(tArgs, " ", 3)
    local result = create(username, text)
    print(textutils.serialize(result))
elseif command == "delete" then
    if #tArgs < 2 then
        print("Usage: api delete <username>")
        return
    end
    local username = tArgs[2]
    local result = delete(username)
    print(textutils.serialize(result))
elseif command == "authenticate" then
    if #tArgs < 3 then
        print("Usage: api authenticate <adminUsername> <adminPassword>")
        return
    end
    local adminUsername = tArgs[2]
    local adminPassword = tArgs[3]
    local result = authenticate(adminUsername, adminPassword)
    print(textutils.serialize(result))
else
    print("Invalid command. Use 'create', 'delete', or 'authenticate'.")
end