#include "AdjacentInfo.h"

// 索引相同的顶点是同一个点
bool operator==(const FAdjacentVertex& left, const FAdjacentVertex& right)
{
    return left.Index() == right.Index();
}

// 只要边连接的两个顶点相同（顺序可以相反）就是同一个边
bool operator==(const FAdjacentEdge& left, const FAdjacentEdge& right)
{
    return (left.V1() == right.V1() && left.V2() == right.V2()) || (left.V1() == right.V2() && left.V2() == right.V1());
}

void FAdjacentVertex::CalculateType()
{
    // 是边界点
    if (inBorder)
    {
        if (angle > 1.5f * PI)
        {
            type = 2.0f;
        }
        else if (angle < 0.5f * PI)
        {
            type = 3.0f;
        }
        else
        {
            type = 1.0f;
        }
    }
    else
    {
        type = 0.0f;
    }
}

void FAdjacentVertex::CalculateSoftNormalByAdjVertice()
{
    if (!inBorder)
        return;
    uint32 innerAdjVerticeCount = 0;
    for (FAdjacentVertex* v: adjVertice)
        if (!v->inBorder)
            ++innerAdjVerticeCount;

    softNormal = FVector::ZeroVector;
    // 如果相邻顶点有内部顶点，使用内部顶点方向
    if (innerAdjVerticeCount)
    {
        for (FAdjacentVertex* v: adjVertice)
        {
            if (!v->inBorder)
            {
                FVector dir = pos - v->pos;
                dir.Normalize();
                softNormal += dir;
            }
        }
    }
    else
    {
        for (FAdjacentVertex* v: adjVertice)
        {
            FVector dir = pos - v->pos;
            dir.Normalize();
            softNormal += dir;
        }
    }
    softNormal.Normalize();
}

void FAdjacentVertex::ProjectSoftNormalOnNormalPlane()
{
    normal.Normalize();
    if (inBorder)
    {
        softNormal.Normalize();
        softNormal -= FVector::DotProduct(normal, softNormal) * normal;
        softNormal.Normalize();
    }
}

FAdjacentEdge::FAdjacentEdge(FAdjacentVertex& v1, FAdjacentVertex& v2): v1(v1), v2(v2), count(1)
{
    length = (v1.Pos() - v2.Pos()).Size();
}

void FAdjacentEdge::SetInBorder()
{
    v1.InBorder() = true;
    v2.InBorder() = true;
}

void FAdjacentEdge::AddVertexToEdge()
{
    v1.AdjVertice().Add(&v2);
    v2.AdjVertice().Add(&v1);
}

FAdjacentPolygon::FAdjacentPolygon(const TArray<FAdjacentVertex*>& Vertices, const TArray<FAdjacentEdge*>& Edges, int32 N)
    : v(Vertices), e(Edges), n(N)
{
    // 计算面法线
    FVector dirAB = V(1).Pos() - V(0).Pos();
    FVector dirBC = V(2).Pos() - V(1).Pos();
    normal        = FVector::CrossProduct(dirAB, dirBC);
    normal.Normalize();
}

void FAdjacentPolygon::CalculateVertexNormal()
{
    // 对于三角形的每个顶点，计算该顶点角度和方向
    for (int i = 0; i < n; ++i)
    {
        // 顶点
        FAdjacentVertex& A = V(i);
        FAdjacentVertex& B = V((i - 1 + n) % n);
        FAdjacentVertex& C = V((i + 1) % n);

        FVector dirBA      = A.Pos() - B.Pos();
        FVector dirCA      = A.Pos() - C.Pos();

        dirBA.Normalize();
        dirCA.Normalize();

        float cosA = FVector::DotProduct(dirBA, dirCA);
        // 顶点A的角度
        float angle     = FMath::Acos(cosA);

        FVector vNormal = normal * angle;

        A.Normal() += vNormal;

        if (A.InBorder())  // 边界顶点 计算边界延伸方向
        {
            // angle为权重
            A.SoftNormal() += (dirBA + dirCA).GetUnsafeNormal() * angle;
        }
        A.Angle() += angle;
    }
}