#include "algo_skel.h"

struct naive_ctx {
  int ref_count;
  struct buffer_packet tcp_to_udp;
  struct buffer_packet udp_to_tcp;
  struct udp_target udp_t;
};

void free_nothing(void* app_ctx) {}
void free_naive(void* app_ctx) {
  struct naive_ctx* ctx = (struct naive_ctx*) app_ctx;
  ctx->ref_count--;
  if (ctx->ref_count <= 0) free(ctx);
}

void on_tcp_co(struct evt_core_ctx* ctx, struct evt_core_cat* cat, int fd) {
  int conn_sock1, conn_sock2, port;
  struct sockaddr_in addr;
  socklen_t in_len;
  char url[1024];
  struct evt_core_cat local_cat = {0};
  struct evt_core_fdinfo fdinfo = {0};
  fdinfo.cat = &local_cat;
  fdinfo.url = url;

  in_len = sizeof(addr);
  conn_sock1 = accept(fd, (struct sockaddr*)&addr, &in_len);

  if (conn_sock1 == -1) goto co_error;
  conn_sock2 = dup(conn_sock1);
  if (conn_sock2 == -1) goto co_error;
  //printf("fd=%d accepts, creating fds=%d,%d\n", fd, conn_sock1, conn_sock2);

  struct evt_core_fdinfo* listen_info = g_hash_table_lookup(ctx->socklist, &fd);
  if (listen_info == NULL) goto co_error;
  sscanf(listen_info->url, "tcp:listen:%d", &port);

  fdinfo.fd = conn_sock1;
  fdinfo.cat->name = "tcp-read";
  sprintf(fdinfo.url, "tcp:read:127.0.0.1:%d", port);
  evt_core_add_fd (ctx, &fdinfo);

  fdinfo.fd = conn_sock2;
  fdinfo.cat->name = "tcp-write";
  sprintf(fdinfo.url, "tcp:write:127.0.0.1:%d", port);
  evt_core_add_fd (ctx, &fdinfo);

  printf("Selected port: %d\n", port);

  return;

co_error:
  perror("Failed to handle new connection");
  exit(EXIT_FAILURE);
}

void tcp_to_udp(struct evt_core_ctx* ctx, struct evt_core_cat* cat, int fd) {
  // Get target file descriptor
  struct evt_core_cat* udp = g_hash_table_lookup (ctx->catlist, "udp-write");
  if (udp == NULL || udp->socklist->len < 1) goto co_error;
  int udp_fd = g_array_index(udp->socklist, int, 0);

  // Init data structures for the transfer
  struct naive_ctx* app_ctx = cat->app_ctx;
  struct buffer_packet* bp = &(app_ctx->tcp_to_udp);
  int read_res = FDS_READY;
  int write_res = FDS_READY;

  // Either we can read something, either we can write something
  while ((read_res != FDS_AGAIN && bp->mode == BP_READING)
         || (write_res != FDS_AGAIN && bp->mode == BP_WRITING)) {

    // 1. Read packet from TCP socket
    if (bp->mode == BP_READING) {
      read_res = read_packet_from_tcp (fd, bp);
      if (read_res == FDS_ERR) goto co_error;
    }

    // 2. Write packet to UDP socket
    if (bp->mode == BP_WRITING) {
      write_res = write_packet_to_udp(udp_fd, bp, &(app_ctx->udp_t));
      if (read_res == FDS_ERR) goto co_error;
    }
  }
  return;

co_error:
  perror("Failed to handle read write for tcp_to_udp");
  exit(EXIT_FAILURE);
}

void udp_to_tcp(struct evt_core_ctx* ctx, struct evt_core_cat* cat, int fd) {
  // Get target file descriptor
  struct evt_core_cat* tcp = g_hash_table_lookup (ctx->catlist, "tcp-write");
  if (tcp == NULL || tcp->socklist->len < 1) goto co_error;
  int tcp_fd = g_array_index(tcp->socklist, int, 0);

  // Init data structures for the transfer
  struct naive_ctx* app_ctx = cat->app_ctx;
  struct buffer_packet* bp = &(app_ctx->udp_to_tcp);
  int read_res = FDS_READY;
  int write_res = FDS_READY;

  // Either we can read something, either we can write something
  while ((read_res != FDS_AGAIN && bp->mode == BP_READING)
         || (write_res != FDS_AGAIN && bp->mode == BP_WRITING)) {

    // 1. Read packet from UDP socket
    if (bp->mode == BP_READING) {
      read_res = read_packet_from_udp (fd, bp, &(app_ctx->udp_t));
      if (read_res == FDS_ERR) goto co_error;
    }

    // 2. Write packet to TCP socket
    if (bp->mode == BP_WRITING) {
      write_res = write_packet_to_tcp(tcp_fd, bp);
      if (write_res == FDS_ERR) goto co_error;
    }
  }

  return;

co_error:
  perror("Failed to handle read write for udp_to_tcp");
  exit(EXIT_FAILURE);
}

void algo_naive(struct algo_skel* as) {
  struct naive_ctx* ctx = malloc(sizeof(struct naive_ctx));
  if (ctx == NULL) goto init_err;
  memset(ctx, 0, sizeof(struct naive_ctx));

  as->on_tcp_co.name = "tcp-listen";
  as->on_tcp_co.flags = EPOLLIN;
  as->on_tcp_co.app_ctx = NULL;
  as->on_tcp_co.free_app_ctx = free_nothing;
  as->on_tcp_co.cb = on_tcp_co;
  as->on_tcp_co.socklist = NULL;

  as->on_tcp_read.name = "tcp-read";
  as->on_tcp_read.flags = EPOLLIN | EPOLLET | EPOLLRDHUP;
  as->on_tcp_read.app_ctx = ctx;
  as->on_tcp_read.free_app_ctx = free_naive;
  as->on_tcp_read.cb = tcp_to_udp;
  as->on_tcp_read.socklist = NULL;
  ctx->ref_count++;

  as->on_udp_read.name = "udp-read";
  as->on_udp_read.flags = EPOLLIN | EPOLLET;
  as->on_udp_read.app_ctx = ctx;
  as->on_udp_read.free_app_ctx = free_naive;
  as->on_udp_read.cb = udp_to_tcp;
  as->on_udp_read.socklist = NULL;
  ctx->ref_count++;

  as->on_tcp_write.name = "tcp-write";
  as->on_tcp_write.flags = EPOLLOUT | EPOLLET | EPOLLRDHUP;
  as->on_tcp_write.app_ctx = ctx;
  as->on_tcp_write.free_app_ctx = free_naive;
  as->on_tcp_write.cb = udp_to_tcp;
  as->on_tcp_write.socklist = NULL;
  ctx->ref_count++;

  as->on_udp_write.name = "udp-write";
  as->on_udp_write.flags = EPOLLOUT | EPOLLET;
  as->on_udp_write.app_ctx = ctx;
  as->on_udp_write.free_app_ctx = free_naive;
  as->on_udp_write.cb = tcp_to_udp;
  as->on_udp_write.socklist = NULL;
  ctx->ref_count++;

  return;
init_err:
  fprintf(stderr, "Failed to init algo naive\n");
  exit(EXIT_FAILURE);
}