#include "evt_core.h"

void free_fd(void* v) {
  int* fd = (int*)v;
  close(*fd);
  free(v);
}

void free_char(void* c) {
  free(c);
}

void free_cat(void* vcat) {
  struct evt_core_cat* cat = (struct evt_core_cat*) vcat;
  cat->free_app_ctx(cat->app_ctx);
  g_array_free(cat->socklist, TRUE);
  free(cat->name);
  free(cat);
}

void evt_core_init(struct evt_core_ctx* ctx) {
  ctx->epollfd = epoll_create1(0);
  if (ctx->epollfd == -1) {
    perror("Failed to create epoll file descriptor epoll_create1");
    exit(EXIT_FAILURE);
  }

  ctx->catlist = g_hash_table_new_full(g_str_hash, g_str_equal,free_char,free_cat);
  ctx->socklist = g_hash_table_new_full(g_int_hash, g_int_equal,free_fd, NULL);
}

void evt_core_add_cat(struct evt_core_ctx* ctx, struct evt_core_cat* cat) {
  if (cat->socklist != NULL) {
    fprintf(stderr, "cat->socklist must be null. What have you done?\n");
    exit(EXIT_FAILURE);
  }

  struct evt_core_cat* dyn = NULL;
  dyn = malloc(sizeof(struct evt_core_cat));
  if (dyn == NULL) {
    fprintf(stderr, "Failed to alloc memory\n");
    exit(EXIT_FAILURE);
  }
  dyn->app_ctx = cat->app_ctx;
  dyn->free_app_ctx = cat->free_app_ctx;
  dyn->cb = cat->cb;
  dyn->name = strdup(cat->name);
  dyn->flags = cat->flags;
  dyn->socklist = g_array_new (FALSE, FALSE, sizeof(int));

  if (dyn->name == NULL) {
    perror("Unable to allocate memory for category name via strdup");
    exit(EXIT_FAILURE);
  }

  char* key = NULL;
  key = strdup(cat->name);
  if (key == NULL) {
    perror("Unable to allocate memory for key via strdup");
    exit(EXIT_FAILURE);
  }

  g_hash_table_insert (ctx->catlist, key, dyn);
}

void evt_core_add_fd(struct evt_core_ctx* ctx, char* name, int fd) {
  int* key = NULL;
  key = malloc(sizeof(int));

  if (key == NULL) {
    perror("Unable to allocate memory for key via malloc");
    exit(EXIT_FAILURE);
  }
  *key = fd;

  struct evt_core_cat* cat = g_hash_table_lookup(ctx->catlist, name);
  if (cat == NULL) {
    fprintf(stderr, "Category %s should be defined before inserting a file descriptor in it.\n", name);
    exit(EXIT_FAILURE);
  }

  g_array_append_val (cat->socklist, fd);
  g_hash_table_insert(ctx->socklist, key, cat);
  add_fd_to_epoll(ctx->epollfd, fd, cat->flags);
}

void evt_core_free(struct evt_core_ctx* ctx) {
  g_hash_table_destroy(ctx->socklist);
  g_hash_table_destroy(ctx->catlist);
}

void evt_core_loop(struct evt_core_ctx* ctx) {
  struct epoll_event current_event, events[EVT_CORE_MAX_EVENTS];
  struct evt_core_cat* cat;

  printf("--- Start main loop\n");
  int num_fd, n = 0;
  while(1) {
    num_fd = epoll_wait(ctx->epollfd, events, EVT_CORE_MAX_EVENTS, -1);
    if (num_fd == -1) {
      perror("Failed to epoll_wait");
      exit(EXIT_FAILURE);
    }

    for (n = 0 ; n < num_fd; n++) {
      if (events[n].events & (EPOLLERR | EPOLLHUP | EPOLLRDHUP)) {
        int err_fd = events[n].data.fd;
        int evt = events[n].events;
        if (evt & EPOLLRDHUP) fprintf(stderr, "Epoll Read Hup Event. ");
        if (evt & EPOLLHUP) fprintf(stderr, "Epoll Hup Event. ");
        if (evt & EPOLLERR) fprintf(stderr, "Epoll Err Event. ");
	      fprintf (stderr, "Epoll error or stream closed for fd=%d. Updating our data structures...\n", err_fd);
        struct evt_core_cat* cat = g_hash_table_lookup (ctx->socklist, &err_fd);
        if (cat != NULL) {
          fprintf(stderr, "The fd was belonging to category %s, clearing it.\n", cat->name);
          g_hash_table_remove(ctx->socklist, &err_fd);
          for (int i = 0; i < cat->socklist->len; i++) {
            if (g_array_index(cat->socklist, int, i) == err_fd) {
              g_array_remove_index(cat->socklist, i);
            }
          }
        } else {
          fprintf(stderr, "The file descriptor is not registered in a category, this is probably a logic error\n");
	        close (events[n].data.fd);
        }
	      continue;
	    }

      cat = g_hash_table_lookup(ctx->socklist, &(events[n].data.fd));
      if (cat == NULL) {
        fprintf(stderr, "Ignoring file descriptor %d as it is not registered. This is a bug.\n", events[n].data.fd);
        continue;
      }
      cat->cb(ctx, cat, events[n].data.fd);

    }
  }

  evt_core_free(ctx);
}