#include "dhcp.h"
#include <span>
#include "w6300.h"

namespace dhcp_opt {
    constexpr uint8_t message_type = 53;
    constexpr uint8_t param_request = 55;
    constexpr uint8_t end = 255;
    constexpr uint8_t discover = 1;
    constexpr uint8_t subnet_mask = 1;
}

struct __attribute__((packed)) dhcp_discover {
    uint8_t op = 1;
    uint8_t htype = 1;
    uint8_t hlen = 6;
    uint8_t hops = 0;
    uint32_t xid = __builtin_bswap32(0x12345678);
    uint16_t secs = 0;
    uint16_t flags = __builtin_bswap16(0x8000);
    std::array<uint8_t, 4> ciaddr = {};
    std::array<uint8_t, 4> yiaddr = {};
    std::array<uint8_t, 4> siaddr = {};
    std::array<uint8_t, 4> giaddr = {};
    std::array<uint8_t, 16> chaddr = {};
    std::array<uint8_t, 64> sname = {};
    std::array<uint8_t, 128> file = {};
    std::array<uint8_t, 4> magic = {99, 130, 83, 99};
    uint8_t opt_msg_type[3] = {dhcp_opt::message_type, 1, dhcp_opt::discover};
    uint8_t opt_params[3] = {dhcp_opt::param_request, 1, dhcp_opt::subnet_mask};
    uint8_t opt_end = dhcp_opt::end;
};

static_assert(sizeof(dhcp_discover) == 247);

static void send_discover(timer_queue& timers, const std::array<uint8_t, 6>& mac) {
    auto sn = w6300::socket_id{0};
    w6300::open_socket(sn, w6300::protocol::udp, w6300::port_num{68}, w6300::sock_flag::none);

    dhcp_discover pkt;
    std::copy(mac.begin(), mac.end(), pkt.chaddr.begin());

    w6300::ip_address broadcast = {};
    broadcast.ip = {255, 255, 255, 255};
    broadcast.len = 4;

    w6300::sendto(sn, std::span{reinterpret_cast<uint8_t*>(&pkt), sizeof(pkt)}, broadcast, w6300::port_num{67});

    timers.schedule_ms(5000, [&timers, mac]() { send_discover(timers, mac); });
}

void dhcp_start(timer_queue& timers, const std::array<uint8_t, 6>& mac) {
    send_discover(timers, mac);
}