#include <kapi/tracked_mutex.hpp>

#include <kapi/cpu.hpp>
#include <kapi/system.hpp>

#include <atomic>

namespace kapi
{

  auto tracked_mutex::lock() -> void
  {
    auto self = kapi::cpu::current_id();
    auto expected = kapi::cpu::invalid_id;

    while (!m_owner.compare_exchange_weak(expected, self, std::memory_order::acquire, std::memory_order::relaxed))
    {
      if (expected == self)
      {
        system::panic("[OS] CPU {} tried to reacquire a mutex it already holds!", self);
      }
      expected = kapi::cpu::invalid_id;
    }
  }

  auto tracked_mutex::try_lock() -> bool
  {
    auto self = kapi::cpu::current_id();
    auto expected = kapi::cpu::invalid_id;

    if (m_owner.compare_exchange_strong(expected, self, std::memory_order::acquire, std::memory_order::relaxed))
    {
      return true;
    }

    if (expected == self)
    {
      system::panic("[OS] CPU {} tried to reacquire a mutex it already holds!", self);
    }

    return false;
  }

  auto tracked_mutex::unlock() -> void
  {
    auto self = kapi::cpu::current_id();
    auto expected = self;

    if (!m_owner.compare_exchange_strong(expected, kapi::cpu::invalid_id, std::memory_order::release))
    {
      system::panic("[OS] CPU {} released a mutex it did not hold!", self);
    }
  }

}  // namespace kapi