#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <string_view>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <thread>
#include <unistd.h>

#include "ConflictSet.h"
#include "third_party/nadeau.h"

void workload(weaselab::ConflictSet *cs) {
  int64_t version = 0;
  constexpr int kWindowSize = 45e6;
  for (;;) {
    uint8_t buf[sizeof(version)];
    int64_t be = __builtin_bswap64(version);
    memcpy(buf, &be, sizeof(be));
    weaselab::ConflictSet::WriteRange w;
    w.begin.p = buf;
    w.begin.len = sizeof(buf);
    w.end.len = 0;
    cs->addWrites(&w, 1, version);
    ++version;
    if (version - kWindowSize >= 0) {
      cs->setOldestVersion(version - kWindowSize);
    }
  }
}

// Adapted from getaddrinfo man page
int getListenFd(const char *node, const char *service) {

  struct addrinfo hints;
  struct addrinfo *result, *rp;
  int sfd, s;

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_UNSPEC;     /* Allow IPv4 or IPv6 */
  hints.ai_socktype = SOCK_STREAM; /* stream socket */
  hints.ai_flags = AI_PASSIVE;     /* For wildcard IP address */
  hints.ai_protocol = 0;           /* Any protocol */
  hints.ai_canonname = nullptr;
  hints.ai_addr = nullptr;
  hints.ai_next = nullptr;

  s = getaddrinfo(node, service, &hints, &result);
  if (s != 0) {
    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
    abort();
  }

  /* getaddrinfo() returns a list of address structures.
     Try each address until we successfully bind(2).
     If socket(2) (or bind(2)) fails, we (close the socket
     and) try the next address. */

  for (rp = result; rp != nullptr; rp = rp->ai_next) {
    sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
    if (sfd == -1) {
      continue;
    }

    int val = 1;
    setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));

    if (bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0) {
      break; /* Success */
    }

    close(sfd);
  }

  freeaddrinfo(result); /* No longer needed */

  if (rp == nullptr) { /* No address succeeded */
    fprintf(stderr, "Could not bind\n");
    abort();
  }

  int rv = listen(sfd, SOMAXCONN);
  if (rv) {
    perror("listen()");
    abort();
  }

  return sfd;
}

// HTTP response
//
std::string_view part1 =
    "HTTP/1.1 200 OK \r\nContent-type: text/plain; version=0.0.4; "
    "charset=utf-8; escaping=values\r\nContent-Length: ";
// Decimal content length
std::string_view part2 = "\r\n\r\n";
// Body

double toSeconds(timeval t) {
  return double(t.tv_sec) + double(t.tv_usec) * 1e-6;
}

int main(int argc, char **argv) {
  if (argc != 3) {
    goto fail;
  }
  {
    int listenFd = getListenFd(argv[1], argv[2]);

    weaselab::ConflictSet cs{0};
    weaselab::ConflictSet::MetricsV1 *metrics;
    int metricsCount;
    cs.getMetricsV1(&metrics, &metricsCount);

    auto w = std::thread{workload, &cs};

    for (;;) {
      struct sockaddr_storage peer_addr = {};
      socklen_t peer_addr_len = sizeof(peer_addr);
      const int connfd =
          accept(listenFd, (struct sockaddr *)&peer_addr, &peer_addr_len);

      std::string body;

      rusage r;
      getrusage(RUSAGE_SELF, &r);
      body += "# HELP process_cpu_seconds_total Total user and system CPU time "
              "spent in seconds.\n# TYPE process_cpu_seconds_total counter\n"
              "process_cpu_seconds_total ";
      body += std::to_string(toSeconds(r.ru_utime) + toSeconds(r.ru_stime));
      body += "\n";
      body += "# HELP process_resident_memory_bytes Resident memory size in "
              "bytes.\n# TYPE process_resident_memory_bytes gauge\n"
              "process_resident_memory_bytes ";
      body += std::to_string(getCurrentRSS());
      body += "\n";

      for (int i = 0; i < metricsCount; ++i) {
        body += "# HELP ";
        body += metrics[i].name;
        body += " ";
        body += metrics[i].help;
        body += "\n";
        body += "# TYPE ";
        body += metrics[i].name;
        body += " ";
        body += metrics[i].type == metrics[i].Counter ? "counter" : "gauge";
        body += "\n";
        body += metrics[i].name;
        body += " ";
        body += std::to_string(metrics[i].getValue());
        body += "\n";
      }

      auto len = std::to_string(body.size());
      iovec iov[] = {
          {(void *)part1.data(), part1.size()},
          {(void *)len.data(), len.size()},
          {(void *)part2.data(), part2.size()},
          {(void *)body.data(), body.size()},
      };
      int written;
      do {
        written = writev(connfd, iov, sizeof(iov) / sizeof(iov[0]));
      } while (written < 0 && errno == EINTR);
      close(connfd);
    }
  }
fail:
  fprintf(stderr, "Expected ./%s <host> <port>\n", argv[0]);
  return 1;
}