package core

import (
    "eruhs/core/parser"
    "github.com/google/gopacket"
)

func (c *Capture) handlePacket(packet gopacket.Packet) (*DataPack, error) {
    parsedPack := DataPack{}
    data := packet.Data()
    parsedPack.TotalLength = len(data)
    eth, err := parser.DecodeEthernet(data)
    if err != nil {
        return nil, err
    }

    parsedPack.AddLayer(eth)

    switch eth.Type {
    case parser.EthernetTypeARP:
        return c.handleARP(eth.Payload, parsedPack)
    case parser.EthernetTypeIPv4:
        return c.handleIPv4(eth.Payload, parsedPack)
    //case custom.EthernetTypeIPv6:
    default:
    }

    return &parsedPack, nil
}

func (c *Capture) handleARP(data []byte, parsedPack DataPack) (*DataPack, error) {
    arp, err := parser.DecodeARP(data)
    if err != nil {
        return &parsedPack, err
    }

    parsedPack.AddLayer(arp)
    return &parsedPack, nil
}

func (c *Capture) handleIPv4(data []byte, parsedPack DataPack) (*DataPack, error) {
    ipv4, err := parser.DecodeIPV4(data)
    if err != nil {
        return &parsedPack, err
    }

    parsedPack.AddLayer(ipv4)

    switch ipv4.Protocol {
    case parser.IPv4ProtoTCP:
        return c.handleTCP(ipv4.Payload, parsedPack)
    case parser.IPv4ProtoUDP:
        return c.handleUDP(ipv4.Payload, parsedPack)
    default:
        // unsupported protocol
    }

    return &parsedPack, nil
}

func (c *Capture) handleTCP(data []byte, parsedPack DataPack) (*DataPack, error) {
    tcp, err := parser.DecodeTCP(data)
    if err != nil {
        return &parsedPack, err
    }

    parsedPack.AddLayer(tcp)
    return &parsedPack, nil
}

func (c *Capture) handleUDP(data []byte, parsedPack DataPack) (*DataPack, error) {
    udp, err := parser.DecodeUDP(data)
    if err != nil {
        return &parsedPack, err
    }

    parsedPack.AddLayer(udp)
    return &parsedPack, nil
}