#include "PapyrusVM.h"
#include "GameAPI.h"

// 3740B7AD44E615CF1BB4401806BB6F9DB42DA46D+12
RelocPtr <SkyrimVM*> g_skyrimVM(0x01F5F4F8);

void VMClassInfo::AddRef(void)
{
	InterlockedIncrement(&refCount);
}

void VMClassInfo::Release(void)
{
	if(!InterlockedDecrement(&refCount))
	{
		CALL_MEMBER_FN(this, Destroy)();
		Heap_Free(this);
	}
}

UInt64 VMIdentifier::GetHandle(void)
{
	UInt64	result = (*g_objectHandlePolicy)->GetInvalidHandle();

	SInt32	oldLock = Lock();
	result = m_handle;
	Unlock(oldLock);

	return result;
}

SInt32 VMIdentifier::Lock(void)
{
	UInt32	spinCount = 0;
	SInt32	lockValue;

	while(true)
	{
		lockValue = m_lock;

		if(lockValue & kLockBit)
		{
			// someone else is holding the lock, sleep
			if(spinCount <= kFastSpinThreshold)
			{
				Sleep(0);
				spinCount++;
			}
			else
			{
				Sleep(1);
			}
		}
		else
		{
			// try to take the lock
			if(InterlockedCompareExchange(&m_lock, lockValue | kLockBit, lockValue) == lockValue)
				break;
		}
	}

	return lockValue;
}

void VMIdentifier::Unlock(SInt32 oldLock)
{
	m_lock = oldLock;
}

// try to increment the lock
// on 1 -> 2, call IObjectHandlePolicy::Unk_09(m_handle) with the lock held
void VMIdentifier::IncrementLock(void)
{
	UInt32	spinCount = 0;
	
	while(true)
	{
		SInt32	lockValue = m_lock;

		if(lockValue & kLockBit)
		{
			if(spinCount <= kFastSpinThreshold)
			{
				Sleep(0);
				spinCount++;
			}
			else
			{
				Sleep(1);
			}
		}
		else
		{
			if(lockValue == 1)
			{
				if(InterlockedCompareExchange(&m_lock, lockValue | kLockBit, lockValue) == lockValue)
				{
					(*g_objectHandlePolicy)->AddRef(m_handle);
					m_lock = 2;
					break;
				}
			}
			else
			{
				if(InterlockedCompareExchange(&m_lock, lockValue + 1, lockValue) == lockValue)
					break;
			}
		}
	}
}

// try to decrement the lock
// on 2 -> 1, call IObjectHandlePolicy::Unk_0A(m_handle) with the lock held
SInt32 VMIdentifier::DecrementLock(void)
{
	UInt32	spinCount = 0;

	while(true)
	{
		SInt32	lockValue = m_lock;

		if(lockValue & kLockBit)
		{
			if(spinCount <= kFastSpinThreshold)
			{
				Sleep(0);
				spinCount++;
			}
			else
			{
				Sleep(1);
			}
		}
		else
		{
			if(lockValue == 2)
			{
				if(InterlockedCompareExchange(&m_lock, lockValue | kLockBit, lockValue) == lockValue)
				{
					(*g_objectHandlePolicy)->Release(m_handle);
					m_lock = 1;
					return 1;
				}
			}
			else
			{
				if(InterlockedCompareExchange(&m_lock, lockValue - 1, lockValue) == lockValue)
					return lockValue - 1;
			}
		}
	}
}

void VMIdentifier::Destroy(void)
{
	CALL_MEMBER_FN(this, Destroy_Internal)();
	Heap_Free(this);
}

UInt32 VMValue::GetUnmangledType(void)
{
	if(type <= 0x0F)
		return type;

	return (type & 1) ? kType_Unk0B : kType_Identifier;
}

VMStackInfo* VMClassRegistry::GetStackInfo(UInt32 stackId)
{
	VMStackInfo* result = NULL;

	stackLock.Lock();

	VMStackTableItem* item = allStacks.Find(&stackId);

	if (item != NULL &&
		item->data != NULL &&
		item->data->unkData != NULL)
	{
		result = item->data->unkData->stackInfo;
	}	

	stackLock.Release();

	return result;
}

UInt32 SkyrimVM::ClearInvalidRegistrations(void)
{
	IObjectHandlePolicy * policy = m_classRegistry->GetHandlePolicy();
	UInt64 invalidHandle = policy->GetInvalidHandle();

	m_updateLock.Lock();

	UInt32 count = 0;
	while(m_updateRegHolder.Remove(invalidHandle) == true)
		count++;

	while(m_updateGameTimeRegHolder.Remove(invalidHandle) == true)
		count++;

	m_updateLock.Release();

	return count;
}