#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <sys/time.h>
#include <unistd.h>


#include <ctype.h>

#include <amqp.h>
#include <amqp_framing.h>

#include "utils.h"


#define SUMMARY_EVERY_US 1000000




uint64_t now_microseconds(void)
{
  struct timeval tv;
  gettimeofday(&tv, NULL);
  return (uint64_t) tv.tv_sec * 1000000 + (uint64_t) tv.tv_usec;
}

void microsleep(int usec)
{
  usleep(usec);
}

void die_on_error(int x, char const *context) {
  if (x < 0) {
    char *errstr = amqp_error_string(-x);
    fprintf(stderr, "%s: %s\n", context, errstr);
    free(errstr);
    exit(1);
  }
}

void die_on_amqp_error(amqp_rpc_reply_t x, char const *context) {
  switch (x.reply_type) {
    case AMQP_RESPONSE_NORMAL:
      return;

    case AMQP_RESPONSE_NONE:
      fprintf(stderr, "%s: missing RPC reply type!\n", context);
      break;

    case AMQP_RESPONSE_LIBRARY_EXCEPTION:
      fprintf(stderr, "%s: %s\n", context, amqp_error_string(x.library_error));
      break;

    case AMQP_RESPONSE_SERVER_EXCEPTION:
      switch (x.reply.id) {
	case AMQP_CONNECTION_CLOSE_METHOD: {
	  amqp_connection_close_t *m = (amqp_connection_close_t *) x.reply.decoded;
	  fprintf(stderr, "%s: server connection error %d, message: %.*s\n",
		  context,
		  m->reply_code,
		  (int) m->reply_text.len, (char *) m->reply_text.bytes);
	  break;
	}
	case AMQP_CHANNEL_CLOSE_METHOD: {
	  amqp_channel_close_t *m = (amqp_channel_close_t *) x.reply.decoded;
	  fprintf(stderr, "%s: server channel error %d, message: %.*s\n",
		  context,
		  m->reply_code,
		  (int) m->reply_text.len, (char *) m->reply_text.bytes);
	  break;
	}
	default:
	  fprintf(stderr, "%s: unknown server error, method id 0x%08X\n", context, x.reply.id);
	  break;
      }
      break;
  }

  exit(1);
}

static void send_batch(amqp_connection_state_t conn, char const *queue_name, int rate_limit, int message_count)
{
  uint64_t start_time = now_microseconds();
  int i;
  int sent = 0;
  int previous_sent = 0;
  uint64_t previous_report_time = start_time;
  uint64_t next_summary_time = start_time + SUMMARY_EVERY_US;

  char message[256];
  amqp_bytes_t message_bytes;

  for (i = 0; i < (int)sizeof(message); i++) {
    message[i] = i & 0xff;
  }

  message_bytes.len = sizeof(message);
  message_bytes.bytes = message;

  for (i = 0; i < message_count; i++) {
    uint64_t now = now_microseconds();

    die_on_error(amqp_basic_publish(conn, 1, amqp_cstring_bytes("amq.direct"), amqp_cstring_bytes(queue_name), 0, 0, NULL, message_bytes), "Publishing");
    sent++;
    if (now > next_summary_time) {
      int countOverInterval = sent - previous_sent;
      double intervalRate = countOverInterval / ((now - previous_report_time) / 1000000.0);
      printf("%d ms: Sent %d - %d since last report (%d Hz)\n", (int)(now - start_time) / 1000, sent, countOverInterval, (int) intervalRate);

      previous_sent = sent;
      previous_report_time = now;
      next_summary_time += SUMMARY_EVERY_US;
    }

    while (((i * 1000000.0) / (now - start_time)) > rate_limit) {
      microsleep(2000);
      now = now_microseconds();
    }
  }

  {
    uint64_t stop_time = now_microseconds();
    int total_delta = stop_time - start_time;

    printf("PRODUCER - Message count: %d\n", message_count);
    printf("Total time, milliseconds: %d\n", total_delta / 1000);
    printf("Overall messages-per-second: %g\n", (message_count / (total_delta / 1000000.0)));
  }
}

int main(int argc, char const * const *argv) {
  char const *hostname;
  int port;
  int rate_limit;
  int message_count;
  int sockfd;
  amqp_connection_state_t conn;

  if (argc < 5) {
    fprintf(stderr, "Usage: amqp_producer host port rate_limit message_count\n");
    return 1;
  }

  hostname = argv[1];
  port = atoi(argv[2]);
  rate_limit = atoi(argv[3]);
  message_count = atoi(argv[4]);

  conn = amqp_new_connection();

  die_on_error(sockfd = amqp_open_socket(hostname, port), "Opening socket");

  amqp_set_sockfd(conn, sockfd);

  die_on_amqp_error(amqp_login(conn, "/", 0, 131072, 0, AMQP_SASL_METHOD_PLAIN, "guest", "guest"), "Logging in");

  amqp_channel_open(conn, 1);

  die_on_amqp_error(amqp_get_rpc_reply(conn), "Opening channel");

  send_batch(conn, "test queue", rate_limit, message_count);

  die_on_amqp_error(amqp_channel_close(conn, 1, AMQP_REPLY_SUCCESS), "Closing channel");
  die_on_amqp_error(amqp_connection_close(conn, AMQP_REPLY_SUCCESS), "Closing connection");
  die_on_error(amqp_destroy_connection(conn), "Ending connection");

  return 0;
}