/*
 * =====================================================================================
 *
 *       Filename:  state.cpp
 *
 *    Description:  A Class for managing body and features.
 *
 *        Version:  1.0
 *        Created:  03/17/2017 07:55:56 PM
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Martin Miller (MHM), miller7@illinois.edu
 *   Organization:  Aerospace Robotics and Controls Lab (ARC)
 *
 * =====================================================================================
 */
#include "state.h"

State::State ( )
{
    body = new Body;
    P = Matrix<double,Dynamic,Dynamic>::Zero(9,9);
    P.block<3,3>(6,6) = 1e-6*Matrix3d::Identity();
    return ;
}		/* -----  end of method State::State  ----- */

void
State::vel ( const Matrix<double,3,1> &v )
{
    body->vel(v);
    return ;
}		/* -----  end of method State::vel  ----- */

void
State::pos ( const UTM &utm )
{
    utm_c = utm.zone_c;
    utm_i = utm.zone_i;
    body->pos(utm);
    return ;
}		/* -----  end of method State::pos  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: H
 * Description:  Returns the matrix H for the measurements z
 *--------------------------------------------------------------------------------------
 */
MatrixXd
State::H ( const Quaterniond &q, const std::vector<measurement_t> &z )
{
    Vector3d pos;
    pos = body->ned();
    MatrixXd h;
    // Determine the size of H
    int cols = 9 + 3*features.size();
    int rows = Hrows(z);
    h = MatrixXd::Zero(rows,cols);
    for (int i=0,row=0; i<z.size(); ++i) {
        switch ( z[i].z_type ) {
            int col;
            Feature *fi;
            case REFLECTION:	
                col = rowById(z[i].id);
                if (col==-1) {
                    fprintf(stderr, "Feature %d not found, quitting.\n", z[i].id);
                    exit(1);
                }

                fi = featureById(z[i].id);

                h.block<6,9>(row,0) = fi->Hx(pos,q);
                h.block<6,3>(row,col) = fi->Hy(pos,q);
                row += 6;
                break;

            case MONO:	
                col = rowById(z[i].id);
                if (col==-1) {
                    fprintf(stderr, "Feature %d not found, quitting.\n", z[i].id);
                    exit(1);
                }
                fi = featureById( z[i].id );
                h.block<4,9>(row,0) = fi->Hx(pos,q);
                break;

            case HEIGHT:	
                h.block<1,9>(row,0) = body->H();
                row += 1;
                break;

            default:	
                break;
        }				/* -----  end switch  ----- */
    }
    return h;
}		/* -----  end of method State::H  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: Hrows
 * Description:  Returns the number of rows in the measurement vector based on
 * the number and types of measurements.
 *--------------------------------------------------------------------------------------
 */
int
State::Hrows ( const std::vector<measurement_t> &z) 
{
    int rows = 0;
    for (auto i=z.begin(); i!=z.end(); ++i) {
        switch ( i->z_type ) {
            case REFLECTION:	
                rows += 6;
                break;

            case MONO:	
                rows += 4;
                break;

            case HEIGHT:	
                rows += 1;
                break;

            default:	
                break;
        }				/* -----  end switch  ----- */
    }
    return rows ;
}		/* -----  end of method State::Hrows  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: R
 * Description:  Returns the measurement noise matrix.
 *--------------------------------------------------------------------------------------
 */
MatrixXd
State::R ( const std::vector<measurement_t> &z )
{
    int rows = Hrows(z);
    MatrixXd r;
    r = MatrixXd::Zero(rows,rows);

    for (int i=0,row=0; i<z.size(); ++i) {
        switch ( z[i].z_type ) {
            case REFLECTION:	
                Feature *fi;
                fi = featureById(z[i].id);
                r.block<6,6>(row,row) = fi->R();
                row += 6;
                break;

            case MONO:	
                fprintf(stderr, "mono points not supported.\n");
                exit(1);
                break;

            case HEIGHT:	
                r.block<1,1>(row,row) = body->R();
                row += 1;
                break;

            default:	
                break;
        }				/* -----  end switch  ----- */
    }

    return r ;
}		/* -----  end of method State::R  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: kalmanUpdate
 * Description:  Performs the kalman update. 
 *--------------------------------------------------------------------------------------
 */
void
State::kalmanUpdate( const MatrixXd &h, const MatrixXd &S, 
        const std::vector<measurement_t> &z, const Quaterniond &q)
{
    MatrixXd K;
    // P^T is implied here since P is symmetric
    K = S.fullPivLu().solve(h*P).transpose();

    // Compute P_k|k
    P = (MatrixXd::Identity(P.rows(),P.rows())-K*h)*P;
    P = 0.5*(P+P.transpose());

    // Compute the innovation or error
    Matrix<double,Dynamic,1> y;
    y = innovation(z,q);

    // Get the update
    Matrix<double,Dynamic,1> dx;
    dx = K*y;
    body->dx(dx.segment<9>(0));
    {
        int row=9;
        for (auto i=features.begin(); i!=features.end(); ++i, row+=3) {
            (*i)->dx(dx.segment<3>(row));
        }
    }
    
    return ;
}		/* -----  end of method State::kalmanUpdate  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: innovation
 * Description:  Returns the innovation vector z-hhat
 *--------------------------------------------------------------------------------------
 */
Matrix<double,Dynamic,1>
State::innovation( const std::vector<measurement_t> &z, const Quaterniond &q)
{
    Matrix<double,Dynamic,1> y;
    int rows = Hrows(z);
    y = Matrix<double,Dynamic,1>::Zero(rows,1);

    for (int i=0,row=0; i<z.size(); ++i) {
        measurement_type mt=z[i].z_type;
        if (mt==REFLECTION) {
            Feature *fi;
            fi = featureById(z[i].id);
            Matrix<double,6,1> hi, zi;
            hi = fi->h(body->ned(), q);
            zi = fi->measurement_vector(z[i].source, z[i].reflection);
            y.segment<6>(row) = zi-hi;
            row += 6;
        } else if (mt==MONO) {
            fprintf(stderr, "mono points not supported.\n");
            exit(1);
        } else if (mt==HEIGHT) {
            Matrix<double,1,1> zi, hi;
            zi[0] = z[i].height;
            Vector3d xbw;
            xbw = body->ned();
            hi[0] = xbw[2];

            y.segment<1>(row) = zi-hi;
            row += 1;
        } else {
            fprintf(stderr, "Unknown measurement type\n");
        }
    }

    return y;
}

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: handle_measurements
 * Description:  Update EKF, and adds new features to state.
 *--------------------------------------------------------------------------------------
 */
void
State::handle_measurements ( const std::vector<measurement_t> &z, const Quaterniond &q)
{
    std::vector<measurement_t> featuresToAdd;
    std::vector<measurement_t> featuresToUpdate;
    double zmeas = body->ned()[2];
    for (auto i=z.begin(); i!=z.end(); ++i) {
        if (i->z_type==HEIGHT) {
            featuresToUpdate.push_back(*i);
            zmeas = i->height;
        } else if (exists(i->id)) {
            featuresToUpdate.push_back(*i);
        } else {
            featuresToAdd.push_back(*i);
        }
    }
    if (featuresToUpdate.size()>1) {
#ifdef  FULLS
        MatrixXd h;
        h = H(q,featuresToUpdate);
        MatrixXd S;
        S = h*P*h.transpose() + R(featuresToUpdate);
        kalmanUpdate(h,S,featuresToUpdate,q);
#else      /* -----  not FULLS  ----- */
    
#endif     /* -----  not FULLS  ----- */
    }
    addFeatures( featuresToAdd, q, zmeas);

    return ;
}		/* -----  end of method State::feature_update  ----- */

void
State::addFeatures ( std::vector<measurement_t> &F, const Quaterniond &q, double z)
{
    // Add new features
    Vector3d pos = body->ned();
    for (auto i=F.begin(); i!=F.end(); ++i) {
        if (features.size()>MAXFEATURES) break;
        // Create feature
        Feature *f = new Feature(i->id, i->source, i->reflection, pos, q, z);
        if (!f->sane()) {
            delete f;
            continue;
        }
        features.push_back(f);

        // Expand P
        expandP(f->P0());
    }
    return ;
}		/* -----  end of method State::addFeatures  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: initializePi
 * Description:  Zeros out the off-diagonal blocks and sets the Pii block to Pi.
 *--------------------------------------------------------------------------------------
 */
    void
State::initializePi ( int i, const Matrix<double,3,3> &Pi )
{
    int pt=9+3*(i-1);
    P.block(pt,0,3,P.cols()) = MatrixXd::Zero(3,P.cols());
    P.block(0,pt,P.rows(),3) = MatrixXd::Zero(P.rows(),3);
    P.block<3,3>(pt,pt) = Pi;

    return ;
}		/* -----  end of method State::initializePi  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: Q
 * Description:  Compose full Q from body and features.
 *--------------------------------------------------------------------------------------
 */
MatrixXd
State::Q ( double dt )
{
    MatrixXd q;
    int rows = 9 + 3*features.size();
    q = MatrixXd::Zero(rows,rows);
    q.topLeftCorner<9,9>() = body->Q(dt);
    { // limit i's scope
        auto i = features.begin();
        for (int row=9; row<rows; row+=3, ++i) {
            q.block<3,3>(row,row) = (*i)->Q(dt);
        }
    }
    return q;
}		/* -----  end of method State::q  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: F
 * Description:  Compose full F from body and features
 *--------------------------------------------------------------------------------------
 */
MatrixXd
State::F ( const Quaterniond &q, const Vector3d &w, double dt )
{
    Vector3d v;
    v = body->vel();
    // Allocate matrix F
    MatrixXd f;
    int rows = 9 + 3*features.size();
    f = MatrixXd::Zero(rows,rows);

    // Set body F
    f.topLeftCorner<9,9>() = body->F(w,q,dt);
    // Set Fxi Fyi
    { // limit i's scope
        auto i = features.begin();
        for (int row=9; row<rows; row+=3,++i) {
            f.block<3,9>(row,0) = (*i)->Fx(dt);
            f.block<3,3>(row,row) = (*i)->Fy(v,w,dt);
        }
    }

    return f ;
}		/* -----  end of method State::F  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: Pkk1
 * Description:  Updates P_k|k-1
 *--------------------------------------------------------------------------------------
 */
void
State::Pkk1 ( const Vector3d &ang, const Quaterniond &q, const double dt)
{
    MatrixXd f,fullQ;
    fullQ = Q(dt);
    f = F ( q, ang, dt );
    P = f*P*f.transpose()+fullQ;
    // Enforce symmetry
    P = 0.5*(P+P.transpose());
    return ;
}		/* -----  end of method State::Pkk1  ----- */

void
State::motionModel ( const Vector3d &acc, const Vector3d &ang,
    const Quaterniond &q, const double dt)
{
    Pkk1(ang,q,dt);
    body->motionModel(acc,ang,q,dt);

    Vector3d vel;
    vel = body->vel();
    
#ifdef  FASTMOTIONMODEL
    Matrix<double,Dynamic,6> fullL;
    fullL = L();

    Matrix<double,6,1> V;
    V << vel[1], vel[2], vel[0], ang[1], ang[2], ang[0];

    Matrix<double,Dynamic,1> f;
    f = fullL*V*dt;

    // Update features' states
    {
        int rows = 3*features.size();
        auto i = features.begin();
        for (int row=0; row<rows; row+=3, ++i) {
            Vector3d dx;
            dx = f.segment<3>(row);
            (*i)->dx(dx);
        }
    }
    
#else      /* -----  not FASTMOTIONMODEL  ----- */
    for (auto i=features.begin(); i!=features.end(); ++i) {
        (*i)->motionModel(ang,vel,dt);
    }
#endif     /* -----  not FASTMOTIONMODEL  ----- */

    // Remove features that leave FOV
    {
        auto i = features.begin();
        int j=0;
        while (i!=features.end()) {
            if ((*i)->inFOV()) {
                ++i;
                ++j;
            } else {
                i=removeFeature(i,j);
            }
        }
    }


    return ;
}		/* -----  end of method State::motionModel  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: removeFeature
 * Description:  Remove the Feature i and Pj in a clean fashion.
 *--------------------------------------------------------------------------------------
 */
std::list<Feature *>::iterator
State::removeFeature ( std::list<Feature *>::iterator &i, int j )
{
    // It is important to shrink P first, because it depends on knowing the
    // current size of the feature vector.
    shrinkP(j);
    delete *i;
    i = features.erase(i);
    return i;
}		/* -----  end of method State::removeFeature  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: L
 * Description:  Return the composition of all Li's of the features
 *--------------------------------------------------------------------------------------
 */
Matrix<double,Dynamic,6>
State::L (  )
{
    Matrix<double,Dynamic,6> l;
    int rows = 3*features.size();
    l = Matrix<double,Dynamic,6>::Zero(rows,6);
    {
        auto i=features.begin();
        for (int row=0; row<rows; row+=3, ++i) {
            l.block<3,6>(row,0) = (*i)->L();
        }
    }
    return l;
}		/* -----  end of method State::L  ----- */

void
State::position_covariance ( const Matrix<double,3,3> &p )
{
    P.block(0,0,3,3) = p;
    return ;
}		/* -----  end of method State::position_covariance  ----- */

void
State::velocity_covariance ( const Matrix<double,3,3> &p )
{
    P.block(3,3,3,3) = p;
    return ;
}		/* -----  end of method State::velocity_covariance  ----- */

void
State::unicsv ( )
{
    body->unicsv();
    return ;
}		/* -----  end of method State::unicsv  ----- */

void
State::accelerometer_bias ( const Vector3d &b)
{
    body->accelerometer_bias(b);
    return ;
}		/* -----  end of method State::accelerometer_bias  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: exists
 * Description:  Tests if the id is a current feature.
 *--------------------------------------------------------------------------------------
 */
bool
State::exists ( int id )
{
    for (auto i=features.begin(); i!=features.end(); ++i) {
        if ((*i)->id()==id) return true;
    }
    return false;
}		/* -----  end of method State::exists  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: rowById
 * Description:  Returns the first row of the feature with the given ID. Returns
 * -1 if not found.
 *--------------------------------------------------------------------------------------
 */
int
State::rowById ( int id )
{
    int j=9;
    for (auto i=features.begin(); i!=features.end(); ++i, j+=3) {
        if ((*i)->id()==id) return j;
    }
    return -1;
}		/* -----  end of method State::rowById  ----- */

Feature *
State::featureById ( int id )
{
    for (auto i=features.begin(); i!=features.end(); ++i) {
        if ((*i)->id()==id) return *i;
    }
    return NULL;
}		/* -----  end of method State::featureById  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: expandP
 * Description:  Expand the P matrix to fit one more feature.
 *--------------------------------------------------------------------------------------
 */
void
State::expandP ( const Matrix3d &Pi)
{
    P.conservativeResizeLike(MatrixXd::Zero(3+P.cols(),3+P.cols()));
    P.bottomRightCorner<3,3>() = Pi;
    return ;
}		/* -----  end of method State::expandP  ----- */

Matrix<double,9,9>
State::Pxx ( )
{
    return P.topLeftCorner<9,9>() ;
}		/* -----  end of method State::Pxx  ----- */

/*
 *--------------------------------------------------------------------------------------
 *       Class:  State
 *      Method:  State :: shrinkP
 * Description:  Delete the ith feature from P
 *--------------------------------------------------------------------------------------
 */
void
State::shrinkP ( int i )
{
    int N = 9 + 3*features.size();
    int I = 9 + 3*i;

    P.block(I,0,N-I-3,I) = P.bottomLeftCorner(N-I-3,I);
    P.block(0,I,I,N-I-3) = P.topRightCorner(I,N-I-3);
    P.block(I,I,N-I-3,N-I-3) = P.bottomRightCorner(N-I-3,N-I-3);
    P.conservativeResize(N-3,N-3);

    return ;
}		/* -----  end of method State::shrinkP  ----- */