student.lua

local modem = peripheral.find("modem")
if not modem then error("No modem found. Please attach a wireless modem.") end

modem.open(1) -- Use channel 1 for all communications

local function encrypt(text)
    local result = ""
    for i = 1, #text do
        result = result .. string.char((string.byte(text, i) + 5) % 256)
    end
    return result
end

local function decrypt(text)
    local result = ""
    for i = 1, #text do
        result = result .. string.char((string.byte(text, i) - 5) % 256)
    end
    return result
end

local function saveUsername(username)
    local file = fs.open(".userdata", "w")
    file.write(encrypt(username))
    file.close()
end

local function loadUsername()
    if fs.exists(".userdata") then
        local file = fs.open(".userdata", "r")
        local encryptedUsername = file.readAll()
        file.close()
        return decrypt(encryptedUsername)
    end
    return nil
end

local function sendRequest(request)
    modem.transmit(1, 1, request)
    local timer = os.startTimer(5)
    while true do
        local event, param1, _, _, message = os.pullEvent()
        if event == "modem_message" and type(message) == "table" then
            return message
        elseif event == "timer" and param1 == timer then
            return nil
        end
    end
end

local function createAccount()
    print("Enter new student ID:")
    local newId = read()
    print("Enter password:")
    local password = read("*")
    local response = sendRequest({type = "create_account", studentId = newId, password = password})
    if response and response.success then
        print(response.message)
        saveUsername(newId)
        return newId
    else
        print(response and response.message or "Failed to create account")
        return nil
    end
end

local function login(savedUsername)
    local username = savedUsername
    if not username then
        print("Enter your student ID:")
        username = read()
    else
        print("Logged in as: " .. username)
    end
    print("Enter your password:")
    local password = read("*")
    local response = sendRequest({type = "login", studentId = username, password = password})
    if response and response.success then
        print(response.message)
        saveUsername(username)
        return username, password
    else
        print(response and response.message or "Login failed")
        return nil, nil
    end
end

local function showNews()
    local response = sendRequest({type = "get_news"})
    if response and response.type == "news" then
        print("\nNews:")
        print(response.content)
    else
        print("Failed to retrieve news")
    end
end

local function showDoors(studentId, password)
    local response = sendRequest({type = "get_doors", studentId = studentId, password = password})
    if response and response.type == "doors_list" then
        print("\nDoors you have access to:")
        if response.doors ~= "" then
            local doors = {}
            for door in response.doors:gmatch("[^\r\n]+") do
                table.insert(doors, door)
            end
            for i, door in ipairs(doors) do
                print(i .. ". " .. door)
            end
        else
            print("No doors available")
        end
    else
        print("Failed to retrieve door list")
    end
end

local function openDoor(studentId, password)
    local response = sendRequest({type = "get_doors", studentId = studentId, password = password})
    if response and response.type == "doors_list" then
        if response.doors ~= "" then
            print("\nDoors you have access to:")
            local doors = {}
            for door in response.doors:gmatch("[^\r\n]+") do
                table.insert(doors, door)
            end
            for i, door in ipairs(doors) do
                print(i .. ". " .. door)
            end
            print("Enter the number of the door to open:")
            local choice = tonumber(read())
            if choice and doors[choice] then
                local doorId = doors[choice]
                local openResponse = sendRequest({type = "door_access", studentId = studentId, password = password, doorId = doorId, action = "open"})
                if openResponse and openResponse.type == "access_response" then
                    if openResponse.granted then
                        print("Door " .. doorId .. " command sent successfully.")
                    else
                        print("Failed to open door " .. doorId .. ": " .. (openResponse.message or "Unknown error"))
                    end
                else
                    print("Failed to receive a valid response for door " .. doorId)
                end
            else
                print("Invalid choice")
            end
        else
            print("No doors available")
        end
    else
        print("Failed to retrieve door list")
    end
end

local function checkBalance(studentId, password)
    local response = sendRequest({type = "get_balance", studentId = studentId, password = password})
    if response and response.type == "balance_response" then
        print("\nYour balance: " .. response.balance .. " diamonds")
    else
        print("Failed to retrieve balance")
    end
end

local function transferMoney(studentId, password)
    print("Enter recipient's student ID:")
    local recipientId = read()

    -- Verify recipient exists
    local response = sendRequest({type = "verify_student", recipientId = recipientId})
    if not response or not response.exists then
        print("Recipient does not exist.")
        return
    end

    print("Enter amount to transfer:")
    local amount = tonumber(read())
    if not amount or amount <= 0 then
        print("Invalid amount.")
        return
    end

    -- Verify sufficient funds
    local balanceResponse = sendRequest({type = "get_balance", studentId = studentId, password = password})
    if not balanceResponse or not balanceResponse.balance then
        print("Failed to retrieve balance.")
        return
    end

    local balance = tonumber(balanceResponse.balance)
    if balance < amount then
        print("Insufficient funds.")
        return
    end

    -- Send transfer request
    local transferResponse = sendRequest({
        type = "transfer_money",
        studentId = studentId,
        password = password,
        recipientId = recipientId,
        amount = amount
    })

    if transferResponse and transferResponse.success then
        print("Transfer successful. New balance: " .. transferResponse.newBalance)
    else
        print("Transfer failed: " .. (transferResponse and transferResponse.message or "Unknown error"))
    end
end

-- Main program
while true do
    local studentId = loadUsername()
    local password
    if not studentId then
        print("\n1. Create Account")
        print("2. Login")
        print("3. Exit")
        local choice = read()
        if choice == "1" then
            studentId = createAccount()
        elseif choice == "2" then
            studentId, password = login()
        elseif choice == "3" then
            break
        end
    else
        studentId, password = login(studentId)
    end

    if studentId and password then
        while true do
            print("\n1. Show News")
            print("2. Show Accessible Doors")
            print("3. Open a Door")
            print("4. Check Balance")
            print("5. Transfer Money")
            print("6. Logout")
            local choice = read()
            if choice == "1" then
                showNews()
            elseif choice == "2" then
                showDoors(studentId, password)
            elseif choice == "3" then
                openDoor(studentId, password)
            elseif choice == "4" then
                checkBalance(studentId, password)
            elseif choice == "5" then
                transferMoney(studentId, password)
            elseif choice == "6" then
                break
            end
        end
    end
end