#include <internal.h>
#include <uv.h>

#include "gc.h"
#include "sugar.h"
#include "reactor.h"

#include "modules/fs.h"
#include "modules/timer.h"
#include "modules/fetch.h"
#include "modules/child_process.h"
#include "modules/readline.h"
#include "modules/process.h"

static reactor_poll_hook_t g_poll_hook = NULL;
static void *g_poll_hook_data = NULL;

void js_reactor_set_poll_hook(reactor_poll_hook_t hook, void *data) {
  g_poll_hook = hook;
  g_poll_hook_data = data;
}

void js_poll_events(ant_t *js) {
  coros_this_tick = 0;
  
  fetch_poll_events();
  fs_poll_events();
  child_process_poll_events();
  
  process_immediates(js);
  process_microtasks(js);
  
  for (coroutine_t *temp = pending_coroutines.head, *next; temp; temp = next) {
    next = temp->next;
    if (!temp->is_ready || !temp->mco || mco_status(temp->mco) != MCO_SUSPENDED) continue;
    remove_coroutine(temp);
    
    coro_saved_state_t saved = coro_enter(temp->js, temp);
    mco_result res = mco_resume(temp->mco);
    coro_leave(temp->js, temp, saved);
    
    if (res == MCO_SUCCESS && mco_status(temp->mco) != MCO_DEAD) {
      temp->is_ready = false;
      enqueue_coroutine(temp);
    } else free_coroutine(temp);
  }
  
  if (js->needs_gc) {
    js->needs_gc = false;
    if (js_gc_compact(js) > 0) js->gc_alloc_since = 0;
  }
  
  if (g_poll_hook) g_poll_hook(g_poll_hook_data);
}

static inline work_flags_t get_pending_work(void) {
  work_flags_t flags = 0;
  if (has_pending_microtasks())          flags |= WORK_MICROTASKS;
  if (has_pending_timers())              flags |= WORK_TIMERS;
  if (has_pending_immediates())          flags |= WORK_IMMEDIATES;
  if (has_pending_coroutines())       flags |= WORK_COROUTINES;
  if (has_ready_coroutines())            flags |= WORK_COROUTINES_READY;
  if (has_pending_fetches())             flags |= WORK_FETCHES;
  if (has_pending_fs_ops())              flags |= WORK_FS_OPS;
  if (has_pending_child_processes())     flags |= WORK_CHILD_PROCS;
  if (has_active_readline_interfaces())  flags |= WORK_READLINE;
  if (has_active_stdin())                flags |= WORK_STDIN;
  return flags;
}

void js_run_event_loop(ant_t *js) {
  work_flags_t work;
  int uv_alive = UV_CHECK_ALIVE;
  
  while (((work = get_pending_work()) & WORK_PENDING) || uv_alive) {
    js_poll_events(js);
    
    work = get_pending_work();
    uv_alive = UV_CHECK_ALIVE;
  
    if (work & WORK_BLOCKING) uv_run(uv_default_loop(), UV_RUN_NOWAIT);
    else if ((work & WORK_ASYNC) || uv_alive) {
      js_gc_maybe(js);
      uv_run(uv_default_loop(), UV_RUN_ONCE);
    } else if (work & WORK_COROUTINES) break;
  }
  
  js_poll_events(js);
}