#include "stdafx.h"

#include "sys_event_flag.h"

#include "Emu/IdManager.h"

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

#include "rx/asm.hpp"

LOG_CHANNEL(sys_event_flag);

lv2_event_flag::lv2_event_flag(utils::serial &ar)
    : protocol(ar), key(ar), type(ar), name(ar) {
  ar(pattern);
}

std::function<void(void *)> lv2_event_flag::load(utils::serial &ar) {
  return load_func(make_shared<lv2_event_flag>(exact_t<utils::serial &>(ar)));
}

void lv2_event_flag::save(utils::serial &ar) {
  ar(protocol, key, type, name, pattern);
}

error_code sys_event_flag_create(ppu_thread &ppu, vm::ptr<u32> id,
                                 vm::ptr<sys_event_flag_attribute_t> attr,
                                 u64 init) {
  ppu.state += cpu_flag::wait;

  sys_event_flag.warning(
      "sys_event_flag_create(id=*0x%x, attr=*0x%x, init=0x%llx)", id, attr,
      init);

  if (!id || !attr) {
    return CELL_EFAULT;
  }

  const auto _attr = *attr;

  const u32 protocol = _attr.protocol;

  if (protocol != SYS_SYNC_FIFO && protocol != SYS_SYNC_PRIORITY) {
    sys_event_flag.error("sys_event_flag_create(): unknown protocol (0x%x)",
                         protocol);
    return CELL_EINVAL;
  }

  const u32 type = _attr.type;

  if (type != SYS_SYNC_WAITER_SINGLE && type != SYS_SYNC_WAITER_MULTIPLE) {
    sys_event_flag.error("sys_event_flag_create(): unknown type (0x%x)", type);
    return CELL_EINVAL;
  }

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

  if (const auto error = lv2_obj::create<lv2_event_flag>(
          _attr.pshared, ipc_key, _attr.flags, [&] {
            return make_shared<lv2_event_flag>(
                _attr.protocol, ipc_key, _attr.type, _attr.name_u64, init);
          })) {
    return error;
  }

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

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

  sys_event_flag.warning("sys_event_flag_destroy(id=0x%x)", id);

  const auto flag = idm::withdraw<lv2_obj, lv2_event_flag>(
      id, [&](lv2_event_flag &flag) -> CellError {
        if (flag.sq) {
          return CELL_EBUSY;
        }

        lv2_obj::on_id_destroy(flag, flag.key);
        return {};
      });

  if (!flag) {
    return CELL_ESRCH;
  }

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

  return CELL_OK;
}

error_code sys_event_flag_wait(ppu_thread &ppu, u32 id, u64 bitptn, u32 mode,
                               vm::ptr<u64> result, u64 timeout) {
  ppu.state += cpu_flag::wait;

  sys_event_flag.trace("sys_event_flag_wait(id=0x%x, bitptn=0x%llx, mode=0x%x, "
                       "result=*0x%x, timeout=0x%llx)",
                       id, bitptn, mode, result, timeout);

  // Fix function arguments for external access
  ppu.gpr[3] = -1;
  ppu.gpr[4] = bitptn;
  ppu.gpr[5] = mode;
  ppu.gpr[6] = 0;

  // Always set result
  struct store_result {
    vm::ptr<u64> ptr;
    u64 val = 0;

    ~store_result() noexcept {
      if (ptr) {
        cpu_thread::get_current()->check_state();
        *ptr = val;
      }
    }
  } store{result};

  if (!lv2_event_flag::check_mode(mode)) {
    sys_event_flag.error("sys_event_flag_wait(): unknown mode (0x%x)", mode);
    return CELL_EINVAL;
  }

  const auto flag = idm::get<lv2_obj, lv2_event_flag>(
      id,
      [&, notify = lv2_obj::notify_all_t()](lv2_event_flag &flag) -> CellError {
        if (flag.pattern
                .fetch_op([&](u64 &pat) {
                  return lv2_event_flag::check_pattern(pat, bitptn, mode,
                                                       &ppu.gpr[6]);
                })
                .second) {
          // TODO: is it possible to return EPERM in this case?
          return {};
        }

        lv2_obj::prepare_for_sleep(ppu);

        std::lock_guard lock(flag.mutex);

        if (flag.pattern
                .fetch_op([&](u64 &pat) {
                  return lv2_event_flag::check_pattern(pat, bitptn, mode,
                                                       &ppu.gpr[6]);
                })
                .second) {
          return {};
        }

        if (flag.type == SYS_SYNC_WAITER_SINGLE && flag.sq) {
          return CELL_EPERM;
        }

        flag.sleep(ppu, timeout);
        lv2_obj::emplace(flag.sq, &ppu);
        return CELL_EBUSY;
      });

  if (!flag) {
    return CELL_ESRCH;
  }

  if (flag.ret) {
    if (flag.ret != CELL_EBUSY) {
      return flag.ret;
    }
  } else {
    store.val = ppu.gpr[6];
    return CELL_OK;
  }

  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(flag->mutex);

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

      break;
    }

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

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

    if (timeout) {
      if (lv2_obj::wait_timeout(timeout, &ppu)) {
        // Wait for rescheduling
        if (ppu.check_state()) {
          continue;
        }

        ppu.state += cpu_flag::wait;

        if (!atomic_storage<ppu_thread *>::load(flag->sq)) {
          // Waiters queue is empty, so the thread must have been signaled
          flag->mutex.lock_unlock();
          break;
        }

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

        if (!flag->unqueue(flag->sq, &ppu)) {
          break;
        }

        ppu.gpr[3] = CELL_ETIMEDOUT;
        ppu.gpr[6] = flag->pattern;
        break;
      }
    } else {
      ppu.state.wait(state);
    }
  }

  store.val = ppu.gpr[6];
  return not_an_error(ppu.gpr[3]);
}

error_code sys_event_flag_trywait(ppu_thread &ppu, u32 id, u64 bitptn, u32 mode,
                                  vm::ptr<u64> result) {
  ppu.state += cpu_flag::wait;

  sys_event_flag.trace(
      "sys_event_flag_trywait(id=0x%x, bitptn=0x%llx, mode=0x%x, result=*0x%x)",
      id, bitptn, mode, result);

  // Always set result
  struct store_result {
    vm::ptr<u64> ptr;
    u64 val = 0;

    ~store_result() noexcept {
      if (ptr) {
        cpu_thread::get_current()->check_state();
        *ptr = val;
      }
    }
  } store{result};

  if (!lv2_event_flag::check_mode(mode)) {
    sys_event_flag.error("sys_event_flag_trywait(): unknown mode (0x%x)", mode);
    return CELL_EINVAL;
  }

  u64 pattern{};

  const auto flag =
      idm::check<lv2_obj, lv2_event_flag>(id, [&](lv2_event_flag &flag) {
        return flag.pattern
            .fetch_op([&](u64 &pat) {
              return lv2_event_flag::check_pattern(pat, bitptn, mode, &pattern);
            })
            .second;
      });

  if (!flag) {
    return CELL_ESRCH;
  }

  if (!flag.ret) {
    return not_an_error(CELL_EBUSY);
  }

  store.val = pattern;
  return CELL_OK;
}

error_code sys_event_flag_set(cpu_thread &cpu, u32 id, u64 bitptn) {
  cpu.state += cpu_flag::wait;

  // Warning: may be called from SPU thread.
  sys_event_flag.trace("sys_event_flag_set(id=0x%x, bitptn=0x%llx)", id,
                       bitptn);

  const auto flag = idm::get_unlocked<lv2_obj, lv2_event_flag>(id);

  if (!flag) {
    return CELL_ESRCH;
  }

  if ((flag->pattern & bitptn) == bitptn) {
    return CELL_OK;
  }

  if (lv2_obj::notify_all_t notify; true) {
    std::lock_guard lock(flag->mutex);

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

        // Fake error for abort
        return not_an_error(CELL_EAGAIN);
      }
    }

    u32 count = 0;

    // Process all waiters in single atomic op
    for (u64 pattern = flag->pattern, to_write = pattern, dependant_mask = 0;;
         to_write = pattern, dependant_mask = 0) {
      count = 0;
      to_write |= bitptn;
      dependant_mask = 0;

      for (auto ppu = +flag->sq; ppu; ppu = ppu->next_cpu) {
        ppu->gpr[7] = 0;
      }

      auto first = +flag->sq;

      auto get_next = [&]() -> ppu_thread * {
        s32 prio = smax;
        ppu_thread *it{};

        for (auto ppu = first; ppu; ppu = ppu->next_cpu) {
          if (!ppu->gpr[7] && (flag->protocol != SYS_SYNC_PRIORITY ||
                               ppu->prio.load().prio <= prio)) {
            it = ppu;
            prio = ppu->prio.load().prio;
          }
        }

        if (it) {
          // Mark it so it won't reappear
          it->gpr[7] = 1;
        }

        return it;
      };

      while (auto it = get_next()) {
        auto &ppu = *it;

        const u64 pattern = ppu.gpr[4];
        const u64 mode = ppu.gpr[5];

        // If it's OR mode, set bits must have waken up the thread therefore no
        // dependency on old value
        const u64 dependant_mask_or =
            ((mode & 0xf) == SYS_EVENT_FLAG_WAIT_OR ||
                     (bitptn & pattern & to_write) == pattern
                 ? 0
                 : pattern);

        if (lv2_event_flag::check_pattern(to_write, pattern, mode,
                                          &ppu.gpr[6])) {
          dependant_mask |= dependant_mask_or;
          ppu.gpr[3] = CELL_OK;
          count++;

          if (!to_write) {
            break;
          }
        } else {
          ppu.gpr[3] = -1;
        }
      }

      dependant_mask &= ~bitptn;

      auto [new_val, ok] = flag->pattern.fetch_op([&](u64 &x) {
        if ((x ^ pattern) & dependant_mask) {
          return false;
        }

        x |= bitptn;

        // Clear the bit-wise difference
        x &= ~((pattern | bitptn) & ~to_write);
        return true;
      });

      if (ok) {
        break;
      }

      pattern = new_val;
    }

    if (!count) {
      return CELL_OK;
    }

    // Remove waiters
    for (auto next_cpu = &flag->sq; *next_cpu;) {
      auto &ppu = **next_cpu;

      if (ppu.gpr[3] == CELL_OK) {
        atomic_storage<ppu_thread *>::release(*next_cpu, ppu.next_cpu);
        ppu.next_cpu = nullptr;
        flag->append(&ppu);
        continue;
      }

      next_cpu = &ppu.next_cpu;
    };

    lv2_obj::awake_all();
  }

  return CELL_OK;
}

error_code sys_event_flag_clear(ppu_thread &ppu, u32 id, u64 bitptn) {
  ppu.state += cpu_flag::wait;

  sys_event_flag.trace("sys_event_flag_clear(id=0x%x, bitptn=0x%llx)", id,
                       bitptn);

  const auto flag = idm::check<lv2_obj, lv2_event_flag>(
      id, [&](lv2_event_flag &flag) { flag.pattern &= bitptn; });

  if (!flag) {
    return CELL_ESRCH;
  }

  return CELL_OK;
}

error_code sys_event_flag_cancel(ppu_thread &ppu, u32 id, vm::ptr<u32> num) {
  ppu.state += cpu_flag::wait;

  sys_event_flag.trace("sys_event_flag_cancel(id=0x%x, num=*0x%x)", id, num);

  if (num)
    *num = 0;

  const auto flag = idm::get_unlocked<lv2_obj, lv2_event_flag>(id);

  if (!flag) {
    return CELL_ESRCH;
  }

  u32 value = 0;
  {
    lv2_obj::notify_all_t notify;

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

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

    // Get current pattern
    const u64 pattern = flag->pattern;

    // Signal all threads to return CELL_ECANCELED (protocol does not matter)
    while (auto ppu = flag->schedule<ppu_thread>(flag->sq, SYS_SYNC_FIFO)) {
      ppu->gpr[3] = CELL_ECANCELED;
      ppu->gpr[6] = pattern;

      value++;
      flag->append(ppu);
    }

    if (value) {
      lv2_obj::awake_all();
    }
  }

  static_cast<void>(ppu.test_stopped());

  if (num)
    *num = value;
  return CELL_OK;
}

error_code sys_event_flag_get(ppu_thread &ppu, u32 id, vm::ptr<u64> flags) {
  ppu.state += cpu_flag::wait;

  sys_event_flag.trace("sys_event_flag_get(id=0x%x, flags=*0x%x)", id, flags);

  const auto flag = idm::check<lv2_obj, lv2_event_flag>(
      id, [](lv2_event_flag &flag) { return +flag.pattern; });

  ppu.check_state();

  if (!flag) {
    if (flags)
      *flags = 0;
    return CELL_ESRCH;
  }

  if (!flags) {
    return CELL_EFAULT;
  }

  *flags = flag.ret;
  return CELL_OK;
}