// Copyright (2019-2022) Paul Scherrer Institute
// SPDX-License-Identifier: GPL-3.0-or-later

#include <cmath>
#include "CrystalLattice.h"

#define DEG_TO_RAD static_cast<float>(M_PI/180.0)

CrystalLattice::CrystalLattice() {}

CrystalLattice::CrystalLattice(const UnitCell &cell) {
    vec[0] = {cell.a, 0, 0};
    vec[1] = {cell.b * cosf(cell.gamma * DEG_TO_RAD), cell.b * sinf(cell.gamma * DEG_TO_RAD), 0};
    float cx = cell.c * cosf(cell.beta * DEG_TO_RAD);
    float cy = cell.c
                * (cosf(cell.alpha * DEG_TO_RAD) - cosf(cell.beta * DEG_TO_RAD) * cosf(cell.gamma * DEG_TO_RAD))
                / sinf(cell.gamma * DEG_TO_RAD);
    vec[2] = {cx, cy, sqrtf(cell.c*cell.c-cx*cx-cy*cy)};
}

CrystalLattice CrystalLattice::ReciprocalLattice() const {
    Eigen::Matrix3f m = GetEigenMatrix().transpose().inverse();
    return {m};
}

UnitCell CrystalLattice::GetUnitCell() {
    UnitCell cell;
    cell.a = vec[0].Length();
    cell.b = vec[1].Length();
    cell.c = vec[2].Length();
    cell.alpha = angle_deg(vec[1], vec[2]);
    cell.beta = angle_deg(vec[0], vec[2]);
    cell.gamma = angle_deg(vec[0], vec[1]);
    return cell;
}

Coord &CrystalLattice::Vec0() {
    return vec[0];
}

Coord &CrystalLattice::Vec1() {
    return vec[1];
}

Coord &CrystalLattice::Vec2() {
    return vec[2];
}

Eigen::Matrix3f CrystalLattice::GetEigenMatrix() const {
    Eigen::Matrix3f m;
    m << vec[0].x, vec[0].y, vec[0].z,
            vec[1].x, vec[1].y, vec[1].z,
            vec[2].x, vec[2].y, vec[2].z;
    return m;
}

CrystalLattice::CrystalLattice(const Eigen::Matrix3f &m) {
    for (int i = 0; i < 3; i++) {
        vec[i].x = m(i, 0);
        vec[i].y = m(i, 1);
        vec[i].z = m(i, 2);
    }
}