#include <Kernel/UDPSocket.h>
#include <Kernel/UDP.h>
#include <Kernel/NetworkAdapter.h>
#include <Kernel/Process.h>

Lockable<HashMap<word, UDPSocket*>>& UDPSocket::sockets_by_port()
{
    static Lockable<HashMap<word, UDPSocket*>>* s_map;
    if (!s_map)
        s_map = new Lockable<HashMap<word, UDPSocket*>>;
    return *s_map;
}

UDPSocketHandle UDPSocket::from_port(word port)
{
    RetainPtr<UDPSocket> socket;
    {
        LOCKER(sockets_by_port().lock());
        auto it = sockets_by_port().resource().find(port);
        if (it == sockets_by_port().resource().end())
            return { };
        socket = (*it).value;
        ASSERT(socket);
    }
    return { move(socket) };
}


UDPSocket::UDPSocket(int protocol)
    : IPv4Socket(SOCK_DGRAM, protocol)
{
}

UDPSocket::~UDPSocket()
{
    LOCKER(sockets_by_port().lock());
    sockets_by_port().resource().remove(source_port());
}

Retained<UDPSocket> UDPSocket::create(int protocol)
{
    return adopt(*new UDPSocket(protocol));
}

int UDPSocket::protocol_receive(const ByteBuffer& packet_buffer, void* buffer, size_t buffer_size, int flags, sockaddr* addr, socklen_t* addr_length)
{
    (void)flags;
    (void)addr_length;
    ASSERT(!packet_buffer.is_null());
    auto& ipv4_packet = *(const IPv4Packet*)(packet_buffer.pointer());
    auto& udp_packet = *static_cast<const UDPPacket*>(ipv4_packet.payload());
    ASSERT(udp_packet.length() >= sizeof(UDPPacket)); // FIXME: This should be rejected earlier.
    ASSERT(buffer_size >= (udp_packet.length() - sizeof(UDPPacket)));
    if (addr) {
        auto& ia = *(sockaddr_in*)addr;
        ia.sin_port = htons(udp_packet.destination_port());
    }
    memcpy(buffer, udp_packet.payload(), udp_packet.length() - sizeof(UDPPacket));
    return udp_packet.length() - sizeof(UDPPacket);
}

int UDPSocket::protocol_send(const void* data, int data_length)
{
    // FIXME: Figure out the adapter somehow differently.
    auto& adapter = *NetworkAdapter::from_ipv4_address(IPv4Address(192, 168, 5, 2));
    auto buffer = ByteBuffer::create_zeroed(sizeof(UDPPacket) + data_length);
    auto& udp_packet = *(UDPPacket*)(buffer.pointer());
    udp_packet.set_source_port(source_port());
    udp_packet.set_destination_port(destination_port());
    udp_packet.set_length(sizeof(UDPPacket) + data_length);
    memcpy(udp_packet.payload(), data, data_length);
    kprintf("sending as udp packet from %s:%u to %s:%u!\n",
        adapter.ipv4_address().to_string().characters(),
        source_port(),
        destination_address().to_string().characters(),
        destination_port());
    adapter.send_ipv4(MACAddress(), destination_address(), IPv4Protocol::UDP, move(buffer));
    return data_length;
}

KResult UDPSocket::protocol_connect()
{
    return KSuccess;
}

void UDPSocket::protocol_allocate_source_port()
{
    // This is not a very efficient allocation algorithm.
    // FIXME: Replace it with a bitmap or some other fast-paced looker-upper.
    LOCKER(sockets_by_port().lock());
    for (word port = 2000; port < 60000; ++port) {
        auto it = sockets_by_port().resource().find(port);
        if (it == sockets_by_port().resource().end()) {
            set_source_port(port);
            sockets_by_port().resource().set(port, this);
            return;
        }
    }
}