#include "precompiled.h"

NavDirType Opposite[NUM_DIRECTIONS] = { SOUTH, WEST, NORTH, EAST };

CNavNode *CNavNode::m_list = nullptr;
unsigned int CNavNode::m_listLength = 0;

CNavNode::CNavNode(const Vector *pos, const Vector *normal, CNavNode *parent)
{
	m_pos = *pos;
	m_normal = *normal;

	static unsigned int nextID = 1;
	m_id = nextID++;

	for (int i = 0; i < NUM_DIRECTIONS; i++)
		m_to[i] = nullptr;

	m_visited = 0;
	m_parent = parent;

	m_next = m_list;
	m_list = this;
	m_listLength++;

	m_isCovered = FALSE;
	m_area = nullptr;

	m_attributeFlags = 0;
}

// Create a connection FROM this node TO the given node, in the given direction
void CNavNode::ConnectTo(CNavNode *node, NavDirType dir)
{
	m_to[dir] = node;
}

// Return node at given position
// TODO: Need a hash table to make this lookup fast
const CNavNode *CNavNode::GetNode(const Vector *pos)
{
	const float tolerance = 0.45f * GenerationStepSize;
	for (const CNavNode *node = m_list; node; node = node->m_next)
	{
		float dx = abs(node->m_pos.x - pos->x);
		float dy = abs(node->m_pos.y - pos->y);
		float dz = abs(node->m_pos.z - pos->z);

		if (dx < tolerance && dy < tolerance && dz < tolerance)
			return node;
	}

	return nullptr;
}

// Return true if this node is bidirectionally linked to
// another node in the given direction
BOOL CNavNode::IsBiLinked(NavDirType dir) const
{
	if (m_to[dir] &&  m_to[dir]->m_to[Opposite[dir]] == this)
		return true;

	return false;
}

// Return true if this node is the NW corner of a quad of nodes
// that are all bidirectionally linked
BOOL CNavNode::IsClosedCell() const
{
	if (IsBiLinked(SOUTH) && IsBiLinked(EAST) && m_to[EAST]->IsBiLinked(SOUTH) && m_to[SOUTH]->IsBiLinked(EAST)
		&& m_to[EAST]->m_to[SOUTH] == m_to[SOUTH]->m_to[EAST])
		return true;

	return false;
}