-- Remote Desktop Program for CC Tweaked
-- Ensure rednet is enabled on both systems.

-- Constants
local REMOTE_PORT = 8080

-- Function to detect and open modem on any side
local function open_modem()
    local sides = {"left", "right", "top", "bottom", "front", "back"}
    for _, side in ipairs(sides) do
        if peripheral.isPresent(side) and peripheral.getType(side) == "modem" then
            rednet.open(side)
            return true
        end
    end
    return false
end

-- Function to send commands to the remote computer
local function remote_client()
    print("Enter the ID of the computer to connect to:")
    local targetID = tonumber(read())

    if not targetID then
        print("Invalid ID.")
        return
    end

    if not open_modem() then
        print("No modem found.")
        return
    end

    print("Connecting to computer " .. targetID .. "...")

    print("Waiting for connection acceptance...")
    rednet.send(targetID, "REQUEST_CONNECTION", REMOTE_PORT)

    local senderID, response, protocol = rednet.receive(REMOTE_PORT, 10)
    if senderID == targetID and response == "ACCEPT_CONNECTION" then
        print("Connection accepted.")
    else
        print("Connection denied or timeout.")
        rednet.close()
        return
    end

    while true do
        write("Remote> ")
        local command = read()

        if command:lower() == "exit" then
            print("Exiting remote session.")
            break
        end

        rednet.send(targetID, command, REMOTE_PORT)

        local senderID, response, protocol = rednet.receive(REMOTE_PORT, 5)
        if senderID == targetID and response then
            print(response)
        else
            print("No response or timeout.")
        end
    end

    rednet.close()
end

-- Function to listen for and execute commands from a remote computer
local function remote_server()
    print("Starting remote desktop server...")
    if not open_modem() then
        print("No modem found.")
        return
    end

    while true do
        local senderID, command, protocol = rednet.receive(REMOTE_PORT)
        if command == "REQUEST_CONNECTION" then
            print("Connection request from computer " .. senderID .. ". Accept? (yes/no)")
            local response = read()
            if response:lower() == "yes" then
                rednet.send(senderID, "ACCEPT_CONNECTION", REMOTE_PORT)
                print("Connection accepted.")
            else
                rednet.send(senderID, "DENY_CONNECTION", REMOTE_PORT)
                print("Connection denied.")
            end
        elseif command then
            print("Command received from " .. senderID .. ": " .. command)

            local success, output = pcall(function()
                return shell.run(command)
            end)

            if not success then
                output = "Error: " .. tostring(output)
            end

            rednet.send(senderID, output, REMOTE_PORT)
        end
    end

    rednet.close()
end

-- Main menu
print("Remote Desktop Program")
print("1. Connect to a remote computer")
print("2. Start remote desktop server")
write("Select an option: ")
local choice = tonumber(read())

if choice == 1 then
    remote_client()
elseif choice == 2 then
    remote_server()
else
    print("Invalid option.")
end