sys2_service_log

--sys2_service_log
os.loadAPI("sys/syslib")

--syslib end
local lines = {}
local monitor = peripheral.find("monitor")
local width, height = monitor.getSize()
local line = 1

function exLog(group, txt)
    txt = group .. ": " .. txt
    local pts = {}
    while string.len(txt) > width do
        table.insert(pts, string.sub(txt, 1, width))
        txt = string.sub(txt, width + 1, -1)
    end
    table.insert(pts, txt)
    for i, txt in pairs(pts) do
        monitor.setCursorPos(1, line)
        lines[line] = txt
        monitor.write(lines[line])
        if line > height then
            for i = 1, line - 1 do
                lines[i] = lines[i + 1]
            end
            lines[line] = nil
            monitor.clear()
            for i = 1, line - 1 do
                monitor.setCursorPos(1, i)
                monitor.write(lines[i])
            end
        else
            line = line + 1
        end
    end
end

monitor.clear()
exLog("root", "started system")
while true do
    local id, msg = syslib.receiveRednet()
    local tag, pts = syslib.getMsgData(msg)
    if tag == "@log" then
        print("recv: ", msg)
        if pts[1] == nil or pts[2] == nil then
            if pts[1] == "clear" then
                monitor.clear()
                line=1
            else print("unsupported log-data: " .. msg)
            end
        else
            exLog(pts[1], pts[2])
        end
    end
end