#include "solvespace.h"

char *Entity::DescriptionString(void) {
    Request *r = SS.GetRequest(h.request());
    return r->DescriptionString();
}

void Entity::Csys2dGetBasisVectors(Vector *u, Vector *v) {
    double q[4];
    for(int i = 0; i < 4; i++) {
        q[i] = SS.GetParam(param.h[i])->val;
    }
    Quaternion quat = Quaternion::MakeFrom(q[0], q[1], q[2], q[3]);

    *u = quat.RotationU();
    *v = quat.RotationV();
}

void Entity::Csys2dGetBasisExprs(Expr **u, Expr **v) {
    Expr *a = Expr::FromParam(param.h[0]);
    Expr *b = Expr::FromParam(param.h[1]);
    Expr *c = Expr::FromParam(param.h[2]);
    Expr *d = Expr::FromParam(param.h[3]);

    Expr *two = Expr::FromConstant(2);

    u[0] = a->Square();
    u[0] = (u[0])->Plus(b->Square());
    u[0] = (u[0])->Minus(c->Square());
    u[0] = (u[0])->Minus(d->Square());
    u[1] = two->Times(a->Times(d));
    u[1] = (u[1])->Plus(two->Times(b->Times(c)));
    u[2] = two->Times(b->Times(d));
    u[2] = (u[2])->Minus(two->Times(a->Times(c)));

    v[0] = two->Times(b->Times(c));
    v[0] = (v[0])->Minus(two->Times(a->Times(d)));
    v[1] = a->Square();
    v[1] = (v[1])->Minus(b->Square());
    v[1] = (v[1])->Plus(c->Square());
    v[1] = (v[1])->Minus(d->Square());
    v[2] = two->Times(a->Times(b));
    v[2] = (v[2])->Plus(two->Times(c->Times(d)));
}

bool Entity::IsPoint(void) {
    switch(type) {
        case POINT_IN_3D:
        case POINT_IN_2D:
            return true;
        default:
            return false;
    }
}

bool Entity::PointIsFromReferences(void) {
    hRequest hr = h.request();
    if(hr.v == Request::HREQUEST_REFERENCE_XY.v) return true;
    if(hr.v == Request::HREQUEST_REFERENCE_YZ.v) return true;
    if(hr.v == Request::HREQUEST_REFERENCE_ZX.v) return true;
    return false;
}

void Entity::PointForceTo(Vector p) {
    switch(type) {
        case POINT_IN_3D:
            SS.GetParam(param.h[0])->ForceTo(p.x);
            SS.GetParam(param.h[1])->ForceTo(p.y);
            SS.GetParam(param.h[2])->ForceTo(p.z);
            break;

        case POINT_IN_2D: {
            Entity *c = SS.GetEntity(csys);
            Vector u, v;
            c->Csys2dGetBasisVectors(&u, &v);
            SS.GetParam(param.h[0])->ForceTo(p.Dot(u));
            SS.GetParam(param.h[1])->ForceTo(p.Dot(v));
            break;
        }
        default: oops();
    }
}

Vector Entity::PointGetCoords(void) {
    Vector p;
    switch(type) {
        case POINT_IN_3D:
            p.x = SS.GetParam(param.h[0])->val;
            p.y = SS.GetParam(param.h[1])->val;
            p.z = SS.GetParam(param.h[2])->val;
            break;

        case POINT_IN_2D: {
            Entity *c = SS.GetEntity(csys);
            Vector u, v;
            c->Csys2dGetBasisVectors(&u, &v);
            p =        u.ScaledBy(SS.GetParam(param.h[0])->val);
            p = p.Plus(v.ScaledBy(SS.GetParam(param.h[1])->val));
            break;
        }
        default: oops();
    }
    return p;
}

void Entity::PointGetExprs(Expr **x, Expr **y, Expr **z) {
    switch(type) {
        case POINT_IN_3D:
            *x = Expr::FromParam(param.h[0]);
            *y = Expr::FromParam(param.h[1]);
            *z = Expr::FromParam(param.h[2]);
            break;

        case POINT_IN_2D: {
            Entity *c = SS.GetEntity(csys);
            Expr *u[3], *v[3];
            c->Csys2dGetBasisExprs(u, v);

            *x =            Expr::FromParam(param.h[0])->Times(u[0]);
            *x = (*x)->Plus(Expr::FromParam(param.h[1])->Times(v[0]));

            *y =            Expr::FromParam(param.h[0])->Times(u[1]);
            *y = (*y)->Plus(Expr::FromParam(param.h[1])->Times(v[1]));

            *z =            Expr::FromParam(param.h[0])->Times(u[2]);
            *z = (*z)->Plus(Expr::FromParam(param.h[1])->Times(v[2]));
            break;
        }
        default: oops();
    }
}

void Entity::LineDrawOrGetDistance(Vector a, Vector b) {
    if(dogd.drawing) {
        glBegin(GL_LINE_STRIP);
            glxVertex3v(a);
            glxVertex3v(b);
        glEnd();
    } else {
        Point2d ap = SS.GW.ProjectPoint(a);
        Point2d bp = SS.GW.ProjectPoint(b);

        double d = dogd.mp.DistanceToLine(ap, bp.Minus(ap), true);
        dogd.dmin = min(dogd.dmin, d);
    }
}

void Entity::Draw(void) {
    dogd.drawing = true;
    DrawOrGetDistance();
}

double Entity::GetDistance(Point2d mp) {
    dogd.drawing = false;
    dogd.mp = mp;
    dogd.dmin = 1e12;

    DrawOrGetDistance();
    
    return dogd.dmin;
}

void Entity::DrawOrGetDistance(void) {  
    glxColor(1, 1, 1);

    switch(type) {
        case POINT_IN_3D:
        case POINT_IN_2D: {
            Entity *isfor = SS.GetEntity(h.request().entity(0));
            if(!SS.GW.show2dCsyss && isfor->type == Entity::CSYS_2D) break;

            Vector v = PointGetCoords();

            if(dogd.drawing) {
                double s = 4;
                Vector r = SS.GW.projRight.ScaledBy(s/SS.GW.scale);
                Vector d = SS.GW.projUp.ScaledBy(s/SS.GW.scale);

                glxColor(0, 0.8, 0);
                glBegin(GL_QUADS);
                    glxVertex3v(v.Plus (r).Plus (d));
                    glxVertex3v(v.Plus (r).Minus(d));
                    glxVertex3v(v.Minus(r).Minus(d));
                    glxVertex3v(v.Minus(r).Plus (d));
                glEnd();
            } else {
                Point2d pp = SS.GW.ProjectPoint(v);
                dogd.dmin = pp.DistanceTo(dogd.mp) - 8;
            }
            break;
        }

        case CSYS_2D: {
            if(!SS.GW.show2dCsyss) break;

            Vector p;
            p = SS.GetEntity(assoc[0])->PointGetCoords();

            Vector u, v;
            Csys2dGetBasisVectors(&u, &v);

            double s = (min(SS.GW.width, SS.GW.height))*0.4/SS.GW.scale;

            Vector us = u.ScaledBy(s);
            Vector vs = v.ScaledBy(s);

            Vector pp = p.Plus (us).Plus (vs);
            Vector pm = p.Plus (us).Minus(vs);
            Vector mm = p.Minus(us).Minus(vs);
            Vector mp = p.Minus(us).Plus (vs);

            glxColor(0, 0.4, 0.4);
            LineDrawOrGetDistance(pp, pm);
            LineDrawOrGetDistance(pm, mm);
            LineDrawOrGetDistance(mm, mp);
            LineDrawOrGetDistance(mp, pp);

            if(dogd.drawing) {
                glPushMatrix();
                    glxTranslatev(mm);
                    glxOntoCsys(u, v);
                    glxWriteText(DescriptionString());
                glPopMatrix();
            }
            break;
        }

        case LINE_SEGMENT: {
            Vector a = SS.GetEntity(assoc[0])->PointGetCoords();
            Vector b = SS.GetEntity(assoc[1])->PointGetCoords();
            LineDrawOrGetDistance(a, b);
            break;
        }

        default:
            oops();
    }
}