#include <libk/assert.h>
#include <libk/rbtree.h>
#include <libk/std.h>
#include <proc/mutex.h>
#include <proc/proc.h>
#include <sync/spin_lock.h>
#include <sys/debug.h>

void proc_mutex_lock (struct proc* proc, struct proc_mutex* mutex) {
  while (atomic_flag_test_and_set_explicit (&mutex->flag, memory_order_acquire))
    proc_suspend (proc, &mutex->suspension_q);

  /* taken */

  mutex->owner = proc;
}

bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex) {
  if (mutex->owner != proc)
    return false;

  atomic_flag_clear_explicit (&mutex->flag, memory_order_release);

  struct proc* resumed_proc;
  struct rb_node_link* node;
  rbtree_first (&mutex->suspension_q.proc_tree, node);

  while (node) {
    struct rb_node_link* next;
    rbtree_next (node, next);

    resumed_proc = rbtree_entry (node, struct proc, suspension_link);

    proc_resume (resumed_proc);

    node = next;
  }

  assert (mutex->suspension_q.proc_tree == NULL);

  return true;
}