#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

in_addr_t get_ipv4_address(const char* query)
{
	if (in_addr_t ipv4 = inet_addr(query); ipv4 != (in_addr_t)(-1))
		return ipv4;

	int socket = ::socket(AF_UNIX, SOCK_SEQPACKET, 0);
	if (socket == -1)
	{
		perror("socket");
		return -1;
	}

	sockaddr_un addr;
	addr.sun_family = AF_UNIX;
	strcpy(addr.sun_path, "/tmp/resolver.sock");
	if (connect(socket, (sockaddr*)&addr, sizeof(addr)) == -1)
	{
		perror("connect");
		close(socket);
		return -1;
	}

	if (send(socket, query, strlen(query), 0) == -1)
	{
		perror("send");
		close(socket);
		return -1;
	}

	sockaddr_storage storage;
	if (recv(socket, &storage, sizeof(storage), 0) == -1)
	{
		perror("recv");
		close(socket);
		return -1;
	}

	close(socket);

	return *reinterpret_cast<in_addr_t*>(storage.ss_storage);
}

int main(int argc, char** argv)
{
	if (argc != 2)
	{
		fprintf(stderr, "usage: %s IPADDR\n", argv[0]);
		return 1;
	}

	in_addr_t ipv4 = get_ipv4_address(argv[1]);
	if (ipv4 == (in_addr_t)(-1))
	{
		fprintf(stderr, "could not parse address '%s'\n", argv[1]);
		return 1;
	}

	int socket = ::socket(AF_INET, SOCK_STREAM, 0);
	if (socket == -1)
	{
		perror("socket");
		return 1;
	}

	printf("connecting to %s\n", inet_ntoa({ .s_addr = ipv4 }));

	sockaddr_in server_addr;
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(80);
	server_addr.sin_addr.s_addr = ipv4;
	if (connect(socket, (sockaddr*)&server_addr, sizeof(server_addr)) == -1)
	{
		perror("connect");
		return 1;
	}

	char request[128];
	strcpy(request, "GET / HTTP/1.1\r\n");
	strcat(request, "Host: "); strcat(request, argv[1]); strcat(request, "\r\n");
	strcat(request, "Accept: */*\r\n");
	strcat(request, "Connection: close\r\n");
	strcat(request, "\r\n");
	if (send(socket, request, strlen(request), 0) == -1)
	{
		perror("send");
		return 1;
	}

	char buffer[1024];
	for (;;)
	{
		ssize_t nrecv = recv(socket, buffer, sizeof(buffer), 0);
		if (nrecv == -1)
		{
			perror("recv");
			break;
		}
		write(STDOUT_FILENO, buffer, nrecv);
	}

	close(socket);
	return 0;
}