#include "stdafx.h"

#include "Emu/IdManager.h"
#include "Emu/System.h"
#include "util/serialization.hpp"

#include "Emu/Cell/ErrorCodes.h"
#include "Emu/Cell/PPUThread.h"

#include "sys_cond.h"

#include "util/asm.hpp"

LOG_CHANNEL(sys_cond);

lv2_cond::lv2_cond(utils::serial &ar) noexcept
    : key(ar), name(ar), mtx_id(ar),
      mutex(idm::check_unlocked<lv2_obj, lv2_mutex>(mtx_id)),
      _mutex(idm::get_unlocked<lv2_obj, lv2_mutex>(mtx_id)) // May be nullptr
{}

lv2_cond::lv2_cond(u64 key, u64 name, u32 mtx_id,
                   shared_ptr<lv2_obj> mutex0) noexcept
    : key(key), name(name), mtx_id(mtx_id),
      mutex(static_cast<lv2_mutex *>(mutex0.get())), _mutex(mutex0) {}

CellError lv2_cond::on_id_create() {
  exists++;

  static auto do_it = [](lv2_cond *_this) -> CellError {
    if (lv2_obj::check(_this->mutex)) {
      _this->mutex->cond_count++;
      return {};
    }

    // Mutex has been destroyed, cannot create conditional variable
    return CELL_ESRCH;
  };

  if (mutex) {
    return do_it(this);
  }

  ensure(!!Emu.DeserialManager());

  Emu.PostponeInitCode([this]() {
    if (!mutex) {
      _mutex = static_cast<shared_ptr<lv2_obj>>(
          ensure(idm::get_unlocked<lv2_obj, lv2_mutex>(mtx_id)));
    }

    // Defer function
    ensure(CellError{} == do_it(this));
  });

  return {};
}

std::function<void(void *)> lv2_cond::load(utils::serial &ar) {
  return load_func(make_shared<lv2_cond>(exact_t<utils::serial &>(ar)));
}

void lv2_cond::save(utils::serial &ar) { ar(key, name, mtx_id); }

error_code sys_cond_create(ppu_thread &ppu, vm::ptr<u32> cond_id, u32 mutex_id,
                           vm::ptr<sys_cond_attribute_t> attr) {
  ppu.state += cpu_flag::wait;

  sys_cond.trace("sys_cond_create(cond_id=*0x%x, mutex_id=0x%x, attr=*0x%x)",
                 cond_id, mutex_id, attr);

  auto mutex = idm::get_unlocked<lv2_obj, lv2_mutex>(mutex_id);

  if (!mutex) {
    return CELL_ESRCH;
  }

  const auto _attr = *attr;

  const u64 ipc_key = lv2_obj::get_key(_attr);

  if (ipc_key) {
    sys_cond.warning("sys_cond_create(cond_id=*0x%x, attr=*0x%x): IPC=0x%016x",
                     cond_id, attr, ipc_key);
  }

  if (const auto error =
          lv2_obj::create<lv2_cond>(_attr.pshared, ipc_key, _attr.flags, [&] {
            return make_single<lv2_cond>(ipc_key, _attr.name_u64, mutex_id,
                                         std::move(mutex));
          })) {
    return error;
  }

  ppu.check_state();
  *cond_id = idm::last_id();
  return CELL_OK;
}

error_code sys_cond_destroy(ppu_thread &ppu, u32 cond_id) {
  ppu.state += cpu_flag::wait;

  sys_cond.trace("sys_cond_destroy(cond_id=0x%x)", cond_id);

  const auto cond = idm::withdraw<lv2_obj, lv2_cond>(
      cond_id, [&](lv2_cond &cond) -> CellError {
        std::lock_guard lock(cond.mutex->mutex);

        if (atomic_storage<ppu_thread *>::load(cond.sq)) {
          return CELL_EBUSY;
        }

        cond.mutex->cond_count--;
        lv2_obj::on_id_destroy(cond, cond.key);
        return {};
      });

  if (!cond) {
    return CELL_ESRCH;
  }

  if (cond->key) {
    sys_cond.warning("sys_cond_destroy(cond_id=0x%x): IPC=0x%016x", cond_id,
                     cond->key);
  }

  if (cond.ret) {
    return cond.ret;
  }

  return CELL_OK;
}

error_code sys_cond_signal(ppu_thread &ppu, u32 cond_id) {
  ppu.state += cpu_flag::wait;

  sys_cond.trace("sys_cond_signal(cond_id=0x%x)", cond_id);

  while (true) {
    if (ppu.test_stopped()) {
      ppu.state += cpu_flag::again;
      return {};
    }

    bool finished = true;

    ppu.state += cpu_flag::wait;

    const auto cond = idm::check<lv2_obj, lv2_cond>(
        cond_id, [&, notify = lv2_obj::notify_all_t()](lv2_cond &cond) {
          if (atomic_storage<ppu_thread *>::load(cond.sq)) {
            std::lock_guard lock(cond.mutex->mutex);

            if (ppu.state & cpu_flag::suspend) {
              // Test if another signal caused the current thread to be
              // suspended, in which case it needs to wait until the thread
              // wakes up (otherwise the signal may cause unexpected results)
              finished = false;
              return;
            }

            if (const auto cpu =
                    cond.schedule<ppu_thread>(cond.sq, cond.mutex->protocol)) {
              if (static_cast<ppu_thread *>(cpu)->state & cpu_flag::again) {
                ppu.state += cpu_flag::again;
                return;
              }

              // TODO: Is EBUSY returned after reqeueing, on sys_cond_destroy?

              if (cond.mutex->try_own(*cpu)) {
                cond.awake(cpu);
              }
            }
          } else {
            cond.mutex->mutex.lock_unlock();

            if (ppu.state & cpu_flag::suspend) {
              finished = false;
            }
          }
        });

    if (!finished) {
      continue;
    }

    if (!cond) {
      return CELL_ESRCH;
    }

    return CELL_OK;
  }
}

error_code sys_cond_signal_all(ppu_thread &ppu, u32 cond_id) {
  ppu.state += cpu_flag::wait;

  sys_cond.trace("sys_cond_signal_all(cond_id=0x%x)", cond_id);

  while (true) {
    if (ppu.test_stopped()) {
      ppu.state += cpu_flag::again;
      return {};
    }

    bool finished = true;

    ppu.state += cpu_flag::wait;

    const auto cond = idm::check<lv2_obj, lv2_cond>(
        cond_id, [&, notify = lv2_obj::notify_all_t()](lv2_cond &cond) {
          if (atomic_storage<ppu_thread *>::load(cond.sq)) {
            std::lock_guard lock(cond.mutex->mutex);

            if (ppu.state & cpu_flag::suspend) {
              // Test if another signal caused the current thread to be
              // suspended, in which case it needs to wait until the thread
              // wakes up (otherwise the signal may cause unexpected results)
              finished = false;
              return;
            }

            for (auto cpu = +cond.sq; cpu; cpu = cpu->next_cpu) {
              if (cpu->state & cpu_flag::again) {
                ppu.state += cpu_flag::again;
                return;
              }
            }

            cpu_thread *result = nullptr;
            auto sq = cond.sq;
            atomic_storage<ppu_thread *>::release(cond.sq, nullptr);

            while (const auto cpu =
                       cond.schedule<ppu_thread>(sq, SYS_SYNC_PRIORITY)) {
              if (cond.mutex->try_own(*cpu)) {
                ensure(!std::exchange(result, cpu));
              }
            }

            if (result) {
              cond.awake(result);
            }
          } else {
            cond.mutex->mutex.lock_unlock();

            if (ppu.state & cpu_flag::suspend) {
              finished = false;
            }
          }
        });

    if (!finished) {
      continue;
    }

    if (!cond) {
      return CELL_ESRCH;
    }

    return CELL_OK;
  }
}

error_code sys_cond_signal_to(ppu_thread &ppu, u32 cond_id, u32 thread_id) {
  ppu.state += cpu_flag::wait;

  sys_cond.trace("sys_cond_signal_to(cond_id=0x%x, thread_id=0x%x)", cond_id,
                 thread_id);

  while (true) {
    if (ppu.test_stopped()) {
      ppu.state += cpu_flag::again;
      return {};
    }

    bool finished = true;

    ppu.state += cpu_flag::wait;

    const auto cond = idm::check<lv2_obj, lv2_cond>(
        cond_id, [&, notify = lv2_obj::notify_all_t()](lv2_cond &cond) {
          if (!idm::check_unlocked<named_thread<ppu_thread>>(thread_id)) {
            return -1;
          }

          if (atomic_storage<ppu_thread *>::load(cond.sq)) {
            std::lock_guard lock(cond.mutex->mutex);

            if (ppu.state & cpu_flag::suspend) {
              // Test if another signal caused the current thread to be
              // suspended, in which case it needs to wait until the thread
              // wakes up (otherwise the signal may cause unexpected results)
              finished = false;
              return 0;
            }

            for (auto cpu = +cond.sq; cpu; cpu = cpu->next_cpu) {
              if (cpu->id == thread_id) {
                if (static_cast<ppu_thread *>(cpu)->state & cpu_flag::again) {
                  ppu.state += cpu_flag::again;
                  return 0;
                }

                ensure(cond.unqueue(cond.sq, cpu));

                if (cond.mutex->try_own(*cpu)) {
                  cond.awake(cpu);
                }

                return 1;
              }
            }
          } else {
            cond.mutex->mutex.lock_unlock();

            if (ppu.state & cpu_flag::suspend) {
              finished = false;
              return 0;
            }
          }

          return 0;
        });

    if (!finished) {
      continue;
    }

    if (!cond || cond.ret == -1) {
      return CELL_ESRCH;
    }

    if (!cond.ret) {
      return not_an_error(CELL_EPERM);
    }

    return CELL_OK;
  }
}

error_code sys_cond_wait(ppu_thread &ppu, u32 cond_id, u64 timeout) {
  ppu.state += cpu_flag::wait;

  sys_cond.trace("sys_cond_wait(cond_id=0x%x, timeout=%lld)", cond_id, timeout);

  // Further function result
  ppu.gpr[3] = CELL_OK;

  auto &sstate = *ppu.optional_savestate_state;

  const auto cond = idm::get<lv2_obj, lv2_cond>(
      cond_id, [&, notify = lv2_obj::notify_all_t()](lv2_cond &cond) -> s64 {
        if (!ppu.loaded_from_savestate &&
            atomic_storage<u32>::load(cond.mutex->control.raw().owner) !=
                ppu.id) {
          return -1;
        }

        lv2_obj::prepare_for_sleep(ppu);

        std::lock_guard lock(cond.mutex->mutex);

        const u64 syscall_state = sstate.try_read<u64>().second;
        sstate.clear();

        if (ppu.loaded_from_savestate) {
          if (syscall_state & 1) {
            // Mutex sleep
            ensure(!cond.mutex->try_own(ppu));
          } else {
            lv2_obj::emplace(cond.sq, &ppu);
          }

          cond.sleep(ppu, timeout);
          return static_cast<u32>(syscall_state >> 32);
        }

        // Register waiter
        lv2_obj::emplace(cond.sq, &ppu);

        // Unlock the mutex
        const u32 count = cond.mutex->lock_count.exchange(0);

        if (const auto cpu = cond.mutex->reown<ppu_thread>()) {
          if (cpu->state & cpu_flag::again) {
            ensure(cond.unqueue(cond.sq, &ppu));
            ppu.state += cpu_flag::again;
            return 0;
          }

          cond.mutex->append(cpu);
        }

        // Sleep current thread and schedule mutex waiter
        cond.sleep(ppu, timeout);

        // Save the recursive value
        return count;
      });

  if (!cond) {
    return CELL_ESRCH;
  }

  if (ppu.state & cpu_flag::again) {
    return {};
  }

  if (cond.ret < 0) {
    return CELL_EPERM;
  }

  while (auto state = +ppu.state) {
    if (state & cpu_flag::signal &&
        ppu.state.test_and_reset(cpu_flag::signal)) {
      break;
    }

    if (is_stopped(state)) {
      std::lock_guard lock(cond->mutex->mutex);

      bool mutex_sleep = false;
      bool cond_sleep = false;

      for (auto cpu = atomic_storage<ppu_thread *>::load(cond->sq); cpu;
           cpu = cpu->next_cpu) {
        if (cpu == &ppu) {
          cond_sleep = true;
          break;
        }
      }

      for (auto cpu = atomic_storage<ppu_thread *>::load(
               cond->mutex->control.raw().sq);
           cpu; cpu = cpu->next_cpu) {
        if (cpu == &ppu) {
          mutex_sleep = true;
          break;
        }
      }

      if (!cond_sleep && !mutex_sleep) {
        break;
      }

      const u64 optional_syscall_state =
          u32{mutex_sleep} | (u64{static_cast<u32>(cond.ret)} << 32);
      sstate(optional_syscall_state);

      ppu.state += cpu_flag::again;
      return {};
    }

    for (usz i = 0; cpu_flag::signal - ppu.state && i < 50; i++) {
      busy_wait(500);
    }

    if (ppu.state & cpu_flag::signal) {
      continue;
    }

    if (timeout) {
      if (lv2_obj::wait_timeout(timeout, &ppu)) {
        const u64 start_time = ppu.start_time;

        // Wait for rescheduling
        if (ppu.check_state()) {
          continue;
        }

        ppu.state += cpu_flag::wait;

        std::lock_guard lock(cond->mutex->mutex);

        // Try to cancel the waiting
        if (cond->unqueue(cond->sq, &ppu)) {
          // TODO: Is EBUSY returned after reqeueing, on sys_cond_destroy?
          ppu.gpr[3] = CELL_ETIMEDOUT;

          // Own or requeue
          if (cond->mutex->try_own(ppu)) {
            break;
          }
        } else if (atomic_storage<u32>::load(
                       cond->mutex->control.raw().owner) == ppu.id) {
          break;
        }

        cond->mutex->sleep(ppu);
        ppu.start_time =
            start_time; // Restore start time because awake has been called
        timeout = 0;
        continue;
      }
    } else {
      ppu.state.wait(state);
    }
  }

  // Verify ownership
  ensure(atomic_storage<u32>::load(cond->mutex->control.raw().owner) == ppu.id);

  // Restore the recursive value
  cond->mutex->lock_count.release(static_cast<u32>(cond.ret));

  return not_an_error(ppu.gpr[3]);
}