/*
 *  Feynman -- Wayland compositor for GNU Emacs
 *
 * Copyright (c) 2022 Sameer Rahmani <lxsameer@gnu.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "compositor.h"
#include "export.h"
#include "queue.h"
#include "utils.h"

#include <assert.h>
#include <emacs-module.h>

/* Declare mandatory GPL symbol.  */
FEYNMAN_EXPORT int plugin_is_GPL_compatible = 0;

// static queue_t *feynman_events_q;

// This value will hold a global reference to a `feynman_server` struct
emacs_value server_state;

static void
free_value (void *ptr)
{
  free (ptr);
};

void *
start_event_loop (void *server_ptr)
{
  assert (server_ptr);
  struct feynman_server *server = (struct feynman_server *)server_ptr;

  start_feynman (server);
  return NULL;
}

static emacs_value
feynman_start (emacs_env *env, ptrdiff_t nargs, emacs_value args[], void *data)
{
  (void)nargs;
  (void)args;
  (void)data;
  emacs_value nil = env->intern (env, "nil");

  struct feynman_server *server = malloc (sizeof (struct feynman_server));
  int err                       = init_feynman_server (env, server);
  if (err != 0)
    {
      em_error (env, "Start process failed.Received none zero error code: %d",
                err);
      return nil;
    }
  // feynman_events_q = (queue_t *)init_queue(100);

  pthread_create (&server->server_thread_id, NULL, start_event_loop,
                  (void *)server);
  server_state = env->make_global_ref (
      env, env->make_user_ptr (env, free_value, (void *)server));

  return server_state;
}

static emacs_value
/* cppcheck-suppress constParameter */
feynman_stop (emacs_env *env, ptrdiff_t nargs, emacs_value args[], void *data)
{
  (void)nargs;
  (void)data;
  emacs_value nil       = env->intern (env, "nil");
  emacs_value first_arg = args[0];

  if (env->eq (env, first_arg, nil))
    {
      em_message (env, "server parameter is nil");
      return nil;
    }

  struct feynman_server *server
      = (struct feynman_server *)env->get_user_ptr (env, first_arg);

  stop_feynman (env, server);
  // deinit_queue(feynman_events_q);

  emacs_value t = env->intern (env, "t");
  return t;
}

/* Bind NAME to FUN.  */
static void
bind_function (emacs_env *env, const char *name, emacs_value Sfun)
{
  /* Set the function cell of the symbol named NAME to SFUN using
     the 'fset' function.  */

  /* Convert the strings to symbols by interning them */
  emacs_value Qfset = env->intern (env, "fset");
  emacs_value Qsym  = env->intern (env, name);

  /* Prepare the arguments array */
  emacs_value args[] = { Qsym, Sfun };

  /* Make the call (2 == nb of arguments) */
  env->funcall (env, Qfset, 2, args);
}

/* Provide FEATURE to Emacs.  */
static void
provide (emacs_env *env, const char *feature)
{
  /* call 'provide' with FEATURE converted to a symbol */

  emacs_value Qfeat    = env->intern (env, feature);
  emacs_value Qprovide = env->intern (env, "provide");
  emacs_value args[]   = { Qfeat };

  env->funcall (env, Qprovide, 1, args);
}

FEYNMAN_EXPORT int
emacs_module_init (struct emacs_runtime *ert)
{
  emacs_env *env = ert->get_environment (ert);
  /* create a lambda (returns an emacs_value) */
  emacs_value startfn = env->make_function (
      env, 0,                      /* min. number of arguments */
      0,                           /* max. number of arguments */
      feynman_start,               /* actual function pointer */
      "Initialize the compositor", /* docstring */
      NULL /* user pointer of your choice (data param in feynman_init) */
  );
  bind_function (env, "feynman/start", startfn);

  emacs_value stopfn = env->make_function (
      env, 1,                /* min. number of arguments */
      1,                     /* max. number of arguments */
      feynman_stop,          /* actual function pointer */
      "Stop the compositor", /* docstring */
      NULL /* user pointer of your choice (data param in feynman_init) */
  );
  bind_function (env, "feynman/stop", stopfn);

  provide (env, "feynman");
  return 0;
}