ip

--[[
CC IP API has custom events:
    IP_connect          connected with the network
    IP_connect_time_out failed to connect to the network
    IP_connection_lost  lost connection to the network
    IP_message          a message is recieved
        sender adress
        IP message channel
        IP message reply channel
        message
        is broadcast    (not implemented)
    IP_host_resolved    hostname has been resolved
        hostname
        real adress
    IP_host_error       hostname cannot be resolved
]]--

local function split(str, chr)
    r = {}
    at = 1
    for i = 1, str:len() do
        if string.sub(str, i, i) == chr then
            at = at + 1
        else
            if r[at] == nil then
                r[at] = string.sub(str, i, i)
            else
                r[at] = r[at].. string.sub(str, i, i)
            end
        end
    end
    return r
end

reqport = 8976
adress = "."
adress_giver = "."
modem = nil
modem_side = nil
connect_timer = nil
check_timer = nil
dns_timer = nil
connect_time = 5
check_time = 3
dns_time = 3
get_ip = false
log = false
lmid = -1
dns_cache = {}
message_queue = {}

function initialize(side)
    if pocket then
        side = "back"
        if log then
            print("pocket computer, forcing modem to \"back\"")
        end
    end
    if peripheral.getType(side) == "modem" then
        modem = peripheral.wrap(side)
        modem_side = side
        if log then
            print("successfully initialised IP API with modem \"".. side.. "\"")
        end
        modem.open(reqport)
        connect()
    else
        error("IP API: initialise: side ".. side.. " does not have a modem attached!")
    end
end
function open(port)
    modem.open(port + 1000)
    if log then
        print("opened port ".. port)
    end
end
function close(port)
    modem.close(port + 1000)
    if log then
        print("closed port ".. port)
    end
end
function transmit(to, port, reply, message)
    if not isIP(to) and to ~= "broadcast" then
        if dns_cache[to] ~= nil then
            to = dns_cache[to]
        else
            resolveHostname(to)
            if message_queue[to] == nil then
                message_queue[to] = {}
            end
            message_queue[to][#message_queue[to] + 1] = {}
            message_queue[to][#message_queue[to]].port = port
            message_queue[to][#message_queue[to]].reply = reply
            message_queue[to][#message_queue[to]].message = message
            return
        end
    end
    mmsgid = math.floor(math.random(0, 99999))
    lmid = mmsgid
    modem.transmit(port + 1000, reply + 1000, adress.. ":".. mmsgid.. ":".. to.. ":".. message)
end
function broadcast(port, reply, message)
    transmit("broadcast", port, reply, message)
end
function doLogs(b)
    log = b
    if log then
        print("logging set to true")
    end
end
function deInitialize()
    adress = "."
    adress_giver = "."
    modem = nil
    connect_timer = nil
    check_timer = nil
    get_ip = false
    if log then
        print("successfully de-initialised IP API")
    end
end
function getConnectionStatus()
    r1 = adress ~= "."
    r2 = adress
    return r1, r2
end
function checkConnectStatus()
    check_timer = os.startTimer(check_time)
    connect_timer = os.startTimer(connect_time)
    modem.transmit(reqport, reqport, adress.. ":".. adress.. ":".. adress_giver.. ":ping")
    if log then
        print("connection is OK")
    end
end
function clearCache()
    dns_cache = {}
end
function resolveHostname(name)
    if isIP(name) then
        os.queueEvent("IP_host_resolved", name, name)
        return true
    elseif dns_cache[name] ~= nil then
        os.queueEvent("IP_host_resolved", name, dns_cache[name])
        return true
    else
        dns_timer = os.startTimer(dns_time)
        modem.transmit(reqport, reqport, adress.. ":".. adress.. ":DNS:get:".. name)
        if log then
            print("awaiting DNS")
        end
        return false
    end
end
function isIP(name)
    s = split(name, ".")
    if #s < 4 then
        return false
    end
    n1 = tonumber(s[1])
    n2 = tonumber(s[1])
    n3 = tonumber(s[1])
    n4 = tonumber(s[1])
    return n1 >= 0 and n1 % 1 == 0 and n2 >= 0 and n2 % 1 == 0 and n3 >= 0 and n3 % 1 == 0 and n4 >= 0 and n4 % 1 == 0
end
function checkEvents(event, p1, p2, p3, p4, p5)
    if event == "IP_host_resolved" then
        if message_queue[p1] ~= nil then
            for i = 1, #message_queue[p1] do
                transmit(p1, message_queue[p1][i].port, message_queue[p1][i].reply, message_queue[p1][i].message)
            end
        end
    elseif event == "timer" then
        if p1 == dns_timer then
            os.queueEvent("IP_host_error")
        elseif p1 == check_timer then
            checkConnectStatus()
        elseif p1 == connect_timer then
            if get_ip then
                get_ip = false
                os.queueEvent("IP_connect_time_out")
                if log then
                    print("connection timed out!")
                end
            else
                adress = "."
                os.queueEvent("IP_connection_lost")
                if log then
                    print("connection lost!")
                end
            end
            if adress ~= "." then
                checkConnectStatus()
            else
                connect()
            end
            return true
        end
    elseif event == "modem_message" then
        if p1 == modem_side and p2 ~= reqport then
            sendChannel = p2
            replyChannel = p3
            trace, mraw = decodeMessage(p4)
            msg = mraw[3]
            for i = 4, #mraw do
                msg = msg..":".. mraw[i]
            end
            tarr = split(trace, ">")
            sendAdress = tarr[#tarr]
            if (mraw[2] == adress or mraw[2] == "broadcast") and tonumber(mraw[1]) ~= lmid then
                os.queueEvent("IP_message", sendAdress, sendChannel - 1000, replyChannel - 1000, msg)
                lmid = tonumber(mraw[1])
            end
        end
        if p1 == modem_side and p2 == reqport then
            trace, msg = decodeMessage(p4)
            if log then
                print("message trace: ".. trace)
                print("message:")
                for i = 1, #msg do
                    print(msg[i])
                end
            end
            if #msg == 3 then
                if get_ip and msg[1] == tostring(os.getComputerID()) and msg[2] == "adress" then
                    adress = msg[3]
                    satr = split(trace, ">")
                    adress_giver = satr[#satr]
                    get_ip = false
                    if log then
                        print("connected and got adress ".. adress)
                        print("from ".. adress_giver)
                    end
                    os.queueEvent("IP_connect", adress)
                    check_timer = os.startTimer(check_time)
                    connect_timer = nil
                    return true
                end
                if not get_ip and msg[1] == adress_giver and msg[2] == adress and msg[3] == "pong" then
                    ckeck_timer = os.startTimer(check_time)
                    return true
                end
            end
            if #msg == 4 then
                if msg[1] == "DNS" and msg[2] == adress then
                    dns_cache[msg[3]] = msg[4]
                    os.queueEvent("IP_host_resolved", msg[3], msg[4])
                end
            end
            return true
        end
        return false
    end
    return false
end
function decodeMessage(raw)
    arr = split(raw, ":")
    sendTrace = arr[1]
    message = {}
    for i = 2, #arr do
        message[i - 1] = arr[i]
    end
    return sendTrace, message
end
function connect()
    get_ip = true
    connect_timer = os.startTimer(connect_time)
    modem.transmit(reqport, reqport, os.getComputerID().. ":getadress")
    if log then
        print("connecting...")
    end
end