#pragma once
#include <cstdint>
#include <span>
#include "eth.h"
#include "ipv4.h"
#include "span_writer.h"

namespace igmp {

static constexpr ipv4::ip4_addr ALL_HOSTS = {224, 0, 0, 1};

struct __attribute__((packed)) message {
    uint8_t type;
    uint8_t max_resp_time;
    uint16_t checksum;
    ipv4::ip4_addr group;
};
static_assert(sizeof(message) == 8);

eth::mac_addr mac_for_ip(const ipv4::ip4_addr& group);
bool is_member(const ipv4::ip4_addr& ip);
bool is_member_mac(const eth::mac_addr& mac);

void join(const ipv4::ip4_addr& group);

void send_all_reports();

void handle(std::span<const uint8_t> frame, span_writer& tx);

template <typename Buf>
void prepend_report(Buf& buf, const eth::mac_addr& src_mac, ipv4::ip4_addr src_ip,
                    const ipv4::ip4_addr& group) {
    auto* m = buf.template prepend<message>();
    m->type = 0x16;
    m->max_resp_time = 0;
    m->checksum = 0;
    m->group = group;
    m->checksum = ipv4::checksum(m, sizeof(message));
    ipv4::prepend(buf, mac_for_ip(group), src_mac, src_ip, group, 2, sizeof(message), 1);
}

template <typename Buf>
void prepend_query(Buf& buf, const eth::mac_addr& src_mac, ipv4::ip4_addr src_ip,
                   const ipv4::ip4_addr& group) {
    ipv4::ip4_addr dst_ip = (group == ipv4::ip4_addr{0, 0, 0, 0}) ? ALL_HOSTS : group;
    auto* m = buf.template prepend<message>();
    m->type = 0x11;
    m->max_resp_time = 100;
    m->checksum = 0;
    m->group = group;
    m->checksum = ipv4::checksum(m, sizeof(message));
    ipv4::prepend(buf, mac_for_ip(dst_ip), src_mac, src_ip, dst_ip, 2, sizeof(message), 1);
}

bool parse_report(std::span<const uint8_t> frame, ipv4::ip4_addr& group);

} // namespace igmp