ChunkLoad Receiver

-- Description: This will receive all the messages sent over from the cunkloader detectors
local modem = peripheral.find("modem", rednet.open)
local monitor = peripheral.find("monitor")

local nodes = {}

function Draw()
    while (true) do

        term.clear()

        for i, node in ipairs(nodes) do
            term.setCursorPos(1, i)
            print(node.name .. "(" .. node.x .. "/" .. node.y .. "/" .. node.z .. ") " .. node.lastPing .. "s")
        end

        sleep(1)
    end
end

function checkNodes()
    while (true) do

        for i, node in ipairs(nodes) do
            if (node.lastPing > 10) then
                table.remove(nodes, i)
                break
            else
                node.lastPing = node.lastPing + 1
            end
        end

        sleep(1)
    end
end

function receivePing()
    while (true) do

        local event, sender, message, protocol = os.pullEvent("rednet_message")
        local Data = textutils.unserialiseJSON(tostring(message))

        -- Check if the node already exists and update last ping time
        local exists = false
        for i, node in ipairs(nodes) do
            if (node.name == Data.name) then
                node.lastPing = 0
                exists = true
                break
            end
        end

        -- Create node if non existent
        if (exists == false) then
            Data.lastPing = 0
            table.insert(nodes, Data)
        end

    end
end

-- It there is a monitor use it
if (monitor ~= nil) then
    term.redirect(monitor)
end

-- Main loops
parallel.waitForAny(
    function()
        Draw()
    end,
    function()
        checkNodes()
    end,
    function()
        receivePing()
    end
)