local ipapi = {
    currentIP = "0.0.0.0",
    spoofMode = false,
    gateway = "",
    isIpRenewRequested = false,
    gatewayMac = "",
    debug=true,
    currentMac = require("component").modem.address
}


local component = require("component")
local modem = component.modem
local ser = require("serialization")
local event = require("event")

function ipapi.newPacket(type, payload, receiver, receiverMac, port)
    local packet = {}

    packet.senderIp = ipapi.currentIP
    packet.senderMac = require("computer").address()
    packet.toIP = receiver or "255.255.255.255"
    packet.payload = payload or ""
    packet.toMac = receiverMac
    packet.port = port or 255
    packet.type = type

    function packet:send()
        packet.send = nil
        if ipapi.gatewayMac == "" then
            if packet.toMac ~= nil then
                modem.send(packet.toMac, packet.port, "ipPacket", ser.serialize(packet))
            else
                print(packet.port, "ipPacket", ser.serialize(packet))
                modem.broadcast(packet.port, "ipPacket", ser.serialize(packet))
            end
        else
            if packet.toIP == "255.255.255.255" then
                modem.broadcast(packet.port, "ipPacket", ser.serialize(packet))
            else
                modem.send(ipapi.gatewayMac, 255, "ipPacket", ser.serialize(packet))
            end
        end
    end

    return packet
end

function ipapi.renewIP()
    if ipapi.debug then
        print("Renewing IP")
    end
    ipapi.isIpRenewRequested = true
    local packet = ipapi.newPacket("DHCPDiscover")
    packet:send()
end

event.listen("modem_message", function(...)
    local _, _, _, _, _, msg, packet = ...
    if msg == "ipPacket" then
        local packet = ser.unserialize(packet)

        if packet.senderIp == ipapi.currentIP or (packet.toIP ~= ipapi.currentIP and ipapi.spoofMode == false) or packet.toIP == "255.255.255.255" then
            return
        end
        print("Received packet from " .. packet.senderIp .. " to " .. packet.toIP..", payload: "..packet.payload)

        event.push("ip_message", packet.senderIp, packet.senderMac, packet.type, packet.payload, packet)

        if packet.type == "DHCPOffer" and ipapi.isIpRenewRequested then
            if ipapi.debug then
                print("Got DHCPOffer")
            end
            local offeredIp = packet.payload.ip
            local offeredGateway = packet.payload.gateway
            local offeredDNS = packet.payload.dns

            local packet = ipapi.newPacket("DHCPRequest", {
                ip = ipapi.currentIP,
            }, "255.255.255.255", packet.senderMac)

        end
        if packet.type == "DHCPACK" then
            if ipapi.debug then
                print("DHCP acknowledged. new ip set.")
            end
            ipapi.currentIP = packet.payload.ip
            ipapi.gateway = packet.payload.gateway
            ipapi.isIpRenewRequested = false
            event.push("new_ip", ipapi.currentIP, ipapi.gatewayMac)
        end
        if packet.type == "pong" then
            if ipapi.debug then
                print("Got pong")
            end

        end
        if packet.type == "ping" then
            if ipapi.debug then
                print("Got ping")
            end
            local packet = ipapi.newPacket("pong", nil, packet.senderIp)
            packet:send()
        end
        if packet.type == "ARPRequest" then
            if ipapi.debug then
                print("Got ARPRequest")
            end
            local requestedIp = packet.payload.ip

            if requestedIp == ipapi.currentIP then
                local packet = ipapi.newPacket("ARPReply", {
                    ip = ipapi.currentIP,
                    mac = ipapi.currentMac
                }, packet.senderIp == "0.0.0.0" and "255.255.255.255" or packet.senderIp)
                packet:send()
            end
        end



    end
end)

if modem.isOpen(255) == false then
    modem.open(255)
end

return ipapi