/*
MIT License

Copyright (C) 2024 Ryan L. Guy

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#ifndef FLUIDENGINE_GRID3D_H
#define FLUIDENGINE_GRID3D_H

#include "aabb.h"
#include "gridindexvector.h"

namespace Grid3d {
    
    inline void positionToGridIndex(double x, double y, double z, double dx,
                                                   int *i, int *j, int *k) {
        double invdx = 1.0 / dx;
        *i = (int)floor(x*invdx);
        *j = (int)floor(y*invdx);
        *k = (int)floor(z*invdx);
    }

    inline void positionToGridIndex(vmath::vec3 p, double dx,
                                    int *i, int *j, int *k) {
        double invdx = 1.0 / dx;
        *i = (int)floor(p.x*invdx);
        *j = (int)floor(p.y*invdx);
        *k = (int)floor(p.z*invdx);
    }

    inline GridIndex positionToGridIndex(double x, double y, double z, double dx) {
        double invdx = 1.0 / dx;
        return GridIndex((int)floor(x*invdx),
                         (int)floor(y*invdx),
                         (int)floor(z*invdx));
    }

    inline GridIndex positionToGridIndex(vmath::vec3 p, double dx) {
        double invdx = 1.0 / dx;
        return GridIndex((int)floor(p.x*invdx),
                         (int)floor(p.y*invdx),
                         (int)floor(p.z*invdx));
    }

    inline void GridIndexToPosition(int i, int j, int k, double dx, 
                                    double *x, double *y, double *z) {
        *x = (double)i*dx;
        *y = (double)j*dx;
        *z = (double)k*dx;
    }

    inline void GridIndexToPosition(GridIndex g, double dx, 
                                    double *x, double *y, double *z) {
        *x = (double)g.i*dx;
        *y = (double)g.j*dx;
        *z = (double)g.k*dx;
    }

    inline vmath::vec3 GridIndexToPosition(int i, int j, int k, double dx) {
        return vmath::vec3((float)i*dx, (float)j*dx, (float)k*dx);
    }

    inline vmath::vec3 GridIndexToPosition(GridIndex g, double dx) {
        return vmath::vec3((float)g.i*dx, (float)g.j*dx, (float)g.k*dx);
    }

    inline void GridIndexToCellCenter(int i, int j, int k, double dx, 
                                      double *x, double *y, double *z) {
        double hw = 0.5*dx;
        *x = (double)i*dx + hw;
        *y = (double)j*dx + hw;
        *z = (double)k*dx + hw;
    }

    inline void GridIndexToCellCenter(GridIndex g, double dx, 
                                      double *x, double *y, double *z) {
        double hw = 0.5*dx;
        *x = (double)g.i*dx + hw;
        *y = (double)g.j*dx + hw;
        *z = (double)g.k*dx + hw;
    }

    inline vmath::vec3 GridIndexToCellCenter(int i, int j, int k, double dx) {
        double hw = 0.5*dx;
        return vmath::vec3((float)i*dx + hw, (float)j*dx + hw, (float)k*dx + hw);
    }

    inline vmath::vec3 GridIndexToCellCenter(GridIndex g, double dx) {
                                             double hw = 0.5*dx;
        return vmath::vec3((float)g.i*dx + hw, (float)g.j*dx + hw, (float)g.k*dx + hw);
    }

    inline vmath::vec3 FaceIndexToPositionU(int i, int j, int k, double dx) {
        return vmath::vec3((float)i*dx, ((float)j + 0.5)*dx, ((float)k + 0.5)*dx);
    }

    inline vmath::vec3 FaceIndexToPositionU(GridIndex g, double dx) {
        return vmath::vec3((float)g.i*dx, ((float)g.j + 0.5)*dx, ((float)g.k + 0.5)*dx);
    }

    inline vmath::vec3 FaceIndexToPositionV(int i, int j, int k, double dx) {
        return vmath::vec3(((float)i + 0.5)*dx, (float)j*dx, ((float)k + 0.5)*dx);
    }

    inline vmath::vec3 FaceIndexToPositionV(GridIndex g, double dx) {
        return vmath::vec3(((float)g.i + 0.5)*dx, (float)g.j*dx, ((float)g.k + 0.5)*dx);
    }

    inline vmath::vec3 FaceIndexToPositionW(int i, int j, int k, double dx) {
        return vmath::vec3(((float)i + 0.5)*dx, ((float)j + 0.5)*dx, (float)k*dx);
    }

    inline vmath::vec3 FaceIndexToPositionW(GridIndex g, double dx) {
        return vmath::vec3(((float)g.i + 0.5)*dx, ((float)g.j + 0.5)*dx, (float)g.k*dx);
    }

    inline bool isPositionInGrid(double x, double y, double z, double dx, int i, int j, int k) {
        return x >= 0 && y >= 0 && z >= 0 && x < dx*i && y < dx*j && z < dx*k;
    }

    inline bool isPositionInGrid(vmath::vec3 p, double dx, int i, int j, int k) {
        return p.x >= 0 && p.y >= 0 && p.z >= 0 && p.x < dx*i && p.y < dx*j && p.z < dx*k;
    }

    inline bool isPositionInGrid(double x, double y, double z, double dx, GridIndex g) {
        return x >= 0 && y >= 0 && z >= 0 && x < dx*g.i && y < dx*g.j && z < dx*g.k;
    }

    inline bool isPositionInGrid(vmath::vec3 p, double dx, GridIndex g) {
        return p.x >= 0 && p.y >= 0 && p.z >= 0 && p.x < dx*g.i && p.y < dx*g.j && p.z < dx*g.k;
    }

    inline bool isGridIndexInRange(int i, int j, int k, int imax, int jmax, int kmax) {
        return i >= 0 && j >= 0 && k >= 0 && i < imax && j < jmax && k < kmax;
    }

    inline bool isGridIndexInRange(GridIndex g, int imax, int jmax, int kmax) {
        return g.i >= 0 && g.j >= 0 && g.k >= 0 && g.i < imax && g.j < jmax && g.k < kmax;
    }

    inline bool isGridIndexInRange(int i, int j, int k, GridIndex gmax) {
        return i >= 0 && j >= 0 && k >= 0 && i < gmax.i && j < gmax.j && k < gmax.k;
    }

    inline bool isGridIndexInRange(GridIndex g, GridIndex gmax) {
        return g.i >= 0 && g.j >= 0 && g.k >= 0 && g.i < gmax.i && g.j < gmax.j && g.k < gmax.k;
    }

    inline bool isGridIndicesNeighbours(int i1, int j1, int k1, int i2, int j2, int k2) {
        return std::abs(i1 - i2) <= 1 && std::abs(j1 - j2) <= 1 && std::abs(k1 - k2) <= 1;
    }

    inline bool isGridIndicesNeighbours(GridIndex g1, int i2, int j2, int k2) {
        return std::abs(g1.i - i2) <= 1 && std::abs(g1.j - j2) <= 1 && std::abs(g1.k - k2) <= 1;
    }

    inline bool isGridIndicesNeighbours(int i1, int j1, int k1, GridIndex g2) {
        return std::abs(i1 - g2.i) <= 1 && std::abs(j1 - g2.j) <= 1 && std::abs(k1 - g2.k) <= 1;
    }

    inline bool isGridIndicesNeighbours(GridIndex g1, GridIndex g2) {
        return std::abs(g1.i - g2.i) <= 1 && std::abs(g1.j - g2.j) <= 1 && std::abs(g1.k - g2.k) <= 1;
    }

    inline bool isGridIndexOnBorder(int i, int j, int k, int imax, int jmax, int kmax) {
        return i == 0 || j == 0 || k == 0 ||
               i == imax - 1 || j == jmax - 1 || k == kmax - 1;
    }

    inline bool isGridIndexOnBorder(GridIndex g, int imax, int jmax, int kmax) {
        return g.i == 0 || g.j == 0 || g.k == 0 ||
               g.i == imax - 1 || g.j == jmax - 1 || g.k == kmax - 1;
    }

    inline bool isGridIndexOnBorder(int i, int j, int k, GridIndex gmax) {
        return i == 0 || j == 0 || k == 0 ||
               i == gmax.i - 1 || j == gmax.j - 1 || k == gmax.k - 1;
    }

    inline bool isGridIndexOnBorder(GridIndex g, GridIndex gmax) {
        return g.i == 0 || g.j == 0 || g.k == 0 ||
               g.i == gmax.i - 1 || g.j == gmax.j - 1 || g.k == gmax.k - 1;
    }

    inline void getNeighbourGridIndices6(int i, int j, int k, GridIndex n[6]) {
        n[0] = GridIndex(i-1, j,   k);
        n[1] = GridIndex(i+1, j,   k);
        n[2] = GridIndex(i,   j-1, k);
        n[3] = GridIndex(i,   j+1, k);
        n[4] = GridIndex(i,   j,   k-1);
        n[5] = GridIndex(i,   j,   k+1);
    }

    inline void getNeighbourGridIndices6(GridIndex g, GridIndex n[6]) {
        n[0] = GridIndex(g.i-1, g.j,   g.k);
        n[1] = GridIndex(g.i+1, g.j,   g.k);
        n[2] = GridIndex(g.i,   g.j-1, g.k);
        n[3] = GridIndex(g.i,   g.j+1, g.k);
        n[4] = GridIndex(g.i,   g.j,   g.k-1);
        n[5] = GridIndex(g.i,   g.j,   g.k+1);

    }

    inline void getNeighbourGridIndices26(int i, int j, int k, GridIndex n[26]) {
        int idx = 0;
        for (int nk = k-1; nk <= k+1; nk++) {
            for (int nj = j-1; nj <= j+1; nj++) {
                for (int ni = i-1; ni <= i+1; ni++) {
                    if (!(ni == i && nj == j && nk == k)) {
                        n[idx] = GridIndex(ni, nj, nk);
                        idx++;
                    }
                }
            }
        }
    }

    inline void getNeighbourGridIndices26(GridIndex g, GridIndex n[26]) {
        int idx = 0;
        for (int nk = g.k-1; nk <= g.k+1; nk++) {
            for (int nj = g.j-1; nj <= g.j+1; nj++) {
                for (int ni = g.i-1; ni <= g.i+1; ni++) {
                    if (!(ni == g.i && nj == g.j && nk == g.k)) {
                        n[idx] = GridIndex(ni, nj, nk);
                        idx++;
                    }
                }
            }
        }
    }

    inline void getNeighbourGridIndices124(int i, int j, int k, GridIndex n[124]) {
        int idx = 0;
        for (int nk = k-2; nk <= k+2; nk++) {
            for (int nj = j-2; nj <= j+2; nj++) {
                for (int ni = i-2; ni <= i+2; ni++) {
                    if (!(ni == i && nj == j && nk == k)) {
                        n[idx] = GridIndex(ni, nj, nk);
                        idx++;
                    }
                }
            }
        }
    }

    inline void getNeighbourGridIndices124(GridIndex g, GridIndex n[124]) {
        int idx = 0;
        for (int nk = g.k-2; nk <= g.k+2; nk++) {
            for (int nj = g.j-2; nj <= g.j+2; nj++) {
                for (int ni = g.i-2; ni <= g.i+2; ni++) {
                    if (!(ni == g.i && nj == g.j && nk == g.k)) {
                        n[idx] = GridIndex(ni, nj, nk);
                        idx++;
                    }
                }
            }
        }
    }

    inline void getSubdividedGridIndices(int i, int j, int k, int subdivisions, GridIndex *n) {
        GridIndex start = GridIndex(i*subdivisions, j*subdivisions, k*subdivisions);
        int idx = 0;
        for (int kidx = 0; kidx < subdivisions; kidx++) {
            for (int jidx = 0; jidx < subdivisions; jidx++) {
                for (int iidx = 0; iidx < subdivisions; iidx++) {
                    n[idx] = GridIndex(start.i + iidx, start.j + jidx, start.k + kidx);
                    idx++;
                }
            }
        }
    }

    inline void getSubdividedGridIndices(GridIndex g, int subdivisions, GridIndex *n) {
        GridIndex start = GridIndex(g.i*subdivisions, g.j*subdivisions, g.k*subdivisions);
        int idx = 0;
        for (int kidx = 0; kidx < subdivisions; kidx++) {
            for (int jidx = 0; jidx < subdivisions; jidx++) {
                for (int iidx = 0; iidx < subdivisions; iidx++) {
                    n[idx] = GridIndex(start.i + iidx, start.j + jidx, start.k + kidx);
                    idx++;
                }
            }
        }
    }

    inline void getGridIndexVertices(int i, int j, int k, GridIndex v[8]) {
        v[0] = GridIndex(i,     j,     k);
        v[1] = GridIndex(i + 1, j,     k);
        v[2] = GridIndex(i + 1, j,     k + 1);
        v[3] = GridIndex(i,     j,     k + 1);
        v[4] = GridIndex(i,     j + 1, k);
        v[5] = GridIndex(i + 1, j + 1, k);
        v[6] = GridIndex(i + 1, j + 1, k + 1);
        v[7] = GridIndex(i,     j + 1, k + 1);
    }

    inline void getGridIndexVertices(GridIndex g, GridIndex v[8]) {
        v[0] = GridIndex(g.i, g.j,         g.k);
        v[1] = GridIndex(g.i + 1, g.j,     g.k);
        v[2] = GridIndex(g.i + 1, g.j,     g.k + 1);
        v[3] = GridIndex(g.i,     g.j,     g.k + 1);
        v[4] = GridIndex(g.i,     g.j + 1, g.k);
        v[5] = GridIndex(g.i + 1, g.j + 1, g.k);
        v[6] = GridIndex(g.i + 1, g.j + 1, g.k + 1);
        v[7] = GridIndex(g.i,     g.j + 1, g.k + 1);
    }

    inline void getVertexGridIndexNeighbours(int i, int j, int k, GridIndex n[8]) {
        n[0] = GridIndex(i,     j,     k);
        n[1] = GridIndex(i - 1, j,     k);
        n[2] = GridIndex(i,     j,     k - 1);
        n[3] = GridIndex(i - 1, j,     k - 1);
        n[4] = GridIndex(i,     j - 1, k);
        n[5] = GridIndex(i - 1, j - 1, k);
        n[6] = GridIndex(i,     j - 1, k - 1);
        n[7] = GridIndex(i - 1, j - 1, k - 1);
    }

    inline void getVertexGridIndexNeighbours(GridIndex v, GridIndex n[8]) {
        n[0] = GridIndex(v.i,     v.j,     v.k);
        n[1] = GridIndex(v.i - 1, v.j,     v.k);
        n[2] = GridIndex(v.i,     v.j,     v.k - 1);
        n[3] = GridIndex(v.i - 1, v.j,     v.k - 1);
        n[4] = GridIndex(v.i,     v.j - 1, v.k);
        n[5] = GridIndex(v.i - 1, v.j - 1, v.k);
        n[6] = GridIndex(v.i,     v.j - 1, v.k - 1);
        n[7] = GridIndex(v.i - 1, v.j - 1, v.k - 1);
    }

    inline void getGridIndexBounds(vmath::vec3 p, double r, double dx,
                                   int imax, int jmax, int kmax, 
                                   GridIndex *g1, GridIndex *g2) {
        GridIndex c = positionToGridIndex(p, dx);
        vmath::vec3 cpos = GridIndexToPosition(c, dx);
        vmath::vec3 trans = p - cpos;
        double inv = 1.0 / dx;

        int gimin = c.i - (int)fmax(0, ceil((r-trans.x)*inv));
        int gjmin = c.j - (int)fmax(0, ceil((r-trans.y)*inv));
        int gkmin = c.k - (int)fmax(0, ceil((r-trans.z)*inv));
        int gimax = c.i + (int)fmax(0, ceil((r-dx+trans.x)*inv));
        int gjmax = c.j + (int)fmax(0, ceil((r-dx+trans.y)*inv));
        int gkmax = c.k + (int)fmax(0, ceil((r-dx+trans.z)*inv));

        *g1 = GridIndex((int)fmax(gimin, 0), 
                          (int)fmax(gjmin, 0), 
                          (int)fmax(gkmin, 0));
        *g2 = GridIndex((int)fmin(gimax, imax-1), 
                          (int)fmin(gjmax, jmax-1), 
                          (int)fmin(gkmax, kmax-1));
    }

    inline void getGridIndexBounds(vmath::vec3 p, double r, double dx, GridIndex gmax, 
                                   GridIndex *g1, GridIndex *g2) {
        GridIndex c = positionToGridIndex(p, dx);
        vmath::vec3 cpos = GridIndexToPosition(c, dx);
        vmath::vec3 trans = p - cpos;
        double inv = 1.0 / dx;

        int imin = c.i - (int)fmax(0, ceil((r-trans.x)*inv));
        int jmin = c.j - (int)fmax(0, ceil((r-trans.y)*inv));
        int kmin = c.k - (int)fmax(0, ceil((r-trans.z)*inv));
        int imax = c.i + (int)fmax(0, ceil((r-dx+trans.x)*inv));
        int jmax = c.j + (int)fmax(0, ceil((r-dx+trans.y)*inv));
        int kmax = c.k + (int)fmax(0, ceil((r-dx+trans.z)*inv));

        *g1 = GridIndex((int)fmax(imin, 0), 
                          (int)fmax(jmin, 0), 
                          (int)fmax(kmin, 0));
        *g2 = GridIndex((int)fmin(imax, gmax.i-1), 
                          (int)fmin(jmax, gmax.j-1), 
                          (int)fmin(kmax, gmax.k-1));
    }

    inline void getGridIndexBounds(vmath::vec3 p, double r, vmath::mat3 G, double dx, 
                                   int imax, int jmax, int kmax, 
                                   GridIndex *g1, GridIndex *g2) {

        double lenx = r*vmath::length(G[0]);
        double leny = r*vmath::length(G[1]);
        double lenz = r*vmath::length(G[2]);

        double minx = p.x - lenx;
        double maxx = p.x + lenx;
        double miny = p.y - leny;
        double maxy = p.y + leny;
        double minz = p.z - lenz;
        double maxz = p.z + lenz;

        *g1 = positionToGridIndex(vmath::vec3(minx, miny, minz), dx);
        *g2 = positionToGridIndex(vmath::vec3(maxx, maxy, maxz), dx);

        *g1 = GridIndex((int)fmax((*g1).i, 0), 
                        (int)fmax((*g1).j, 0), 
                        (int)fmax((*g1).k, 0));
        *g2 = GridIndex((int)fmin((*g2).i, imax-1), 
                         (int)fmin((*g2).j, jmax-1), 
                         (int)fmin((*g2).k, kmax-1));
    }

    inline void getGridIndexBounds(vmath::vec3 p, double r, vmath::mat3 G, double dx, GridIndex gmax, 
                                   GridIndex *g1, GridIndex *g2) {
        getGridIndexBounds(p, r, G, dx, gmax.i, gmax.j, gmax.k, g1, g2);
    }

    inline void getGridIndexBounds(AABB bbox, double dx, 
                                   int imax, int jmax, int kmax,
                                    GridIndex *g1, GridIndex *g2) {
        vmath::vec3 trans = vmath::vec3(bbox.width, bbox.height, bbox.depth);
        *g1 = positionToGridIndex(bbox.position, dx);
        *g2 = positionToGridIndex(bbox.position + trans, dx);

        *g1 = GridIndex((int)fmax((*g1).i, 0), 
                        (int)fmax((*g1).j, 0), 
                        (int)fmax((*g1).k, 0));
        *g2 = GridIndex((int)fmin((*g2).i, imax-1), 
                         (int)fmin((*g2).j, jmax-1), 
                         (int)fmin((*g2).k, kmax-1));
    }

    inline void getGridIndexBounds(AABB bbox, double dx, GridIndex gmax,
                                   GridIndex *g1, GridIndex *g2) {
        vmath::vec3 trans = vmath::vec3(bbox.width, bbox.height, bbox.depth);
        *g1 = positionToGridIndex(bbox.position, dx);
        *g2 = positionToGridIndex(bbox.position + trans, dx);

        *g1 = GridIndex((int)fmax((*g1).i, 0), 
                        (int)fmax((*g1).j, 0), 
                        (int)fmax((*g1).k, 0));
        *g2 = GridIndex((int)fmin((*g2).i, gmax.i-1), 
                         (int)fmin((*g2).j, gmax.j-1), 
                         (int)fmin((*g2).k, gmax.k-1));
    }

    inline void getGridCellOverlap(AABB bbox, double dx, int imax, int jmax, int kmax, 
                                   GridIndexVector &cells) {
        GridIndex gmin, gmax;
        getGridIndexBounds(bbox, dx, imax, jmax, kmax, &gmin, &gmax);

        cells.reserve(cells.size() + (gmax.i - gmin.i)*(gmax.j - gmin.j)*(gmax.k - gmin.k));
        for (int k = gmin.k; k <= gmax.k; k++) {
            for (int j = gmin.j; j <= gmax.j; j++) {
                for (int i = gmin.i; i <= gmax.i; i++) {
                    cells.push_back(i, j, k);
                }
            }
        }
    }

    inline void getGridCellOverlap(AABB bbox, double dx, GridIndexVector &cells) {
        vmath::vec3 trans = vmath::vec3(bbox.width, bbox.height, bbox.depth);
        GridIndex gmin = positionToGridIndex(bbox.position, dx);
        GridIndex gmax = positionToGridIndex(bbox.position + trans, dx);

        cells.reserve(cells.size() + (gmax.i - gmin.i)*(gmax.j - gmin.j)*(gmax.k - gmin.k));
        for (int k = gmin.k; k <= gmax.k; k++) {
            for (int j = gmin.j; j <= gmax.j; j++) {
                for (int i = gmin.i; i <= gmax.i; i++) {
                    cells.push_back(i, j, k);
                }
            }
        }
    }

    inline AABB fitAABBtoGrid(AABB bbox, double dx, int imax, int jmax, int kmax) {
        vmath::vec3 pmin = bbox.getMinPoint();
        vmath::vec3 pmax = bbox.getMaxPoint();
        GridIndex gmin = positionToGridIndex(pmin, dx);
        GridIndex gmax = positionToGridIndex(pmax, dx);

        if (!isGridIndexInRange(gmin, imax, jmax, kmax)) {
            pmin = vmath::vec3();
        }

        vmath::vec3 eps = vmath::vec3(10e-9f, 10e-9f, 10e-9f);
        if (!isGridIndexInRange(gmax, imax, jmax, kmax)) {
            pmax = GridIndexToPosition(gmax, dx) + vmath::vec3(dx, dx, dx) - eps;
        }

        return AABB(pmin, pmax);
    }

    inline AABB fitAABBtoGrid(AABB bbox, double dx, GridIndex gmax) {
        return fitAABBtoGrid(bbox, dx, gmax.i, gmax.j, gmax.k);
    }

    inline unsigned int getFlatIndex(GridIndex g, int isize, int jsize) {
        return (unsigned int)g.i + (unsigned int)isize *
                   ((unsigned int)g.j + (unsigned int)jsize * (unsigned int)g.k);
    }

    inline unsigned int getFlatIndex(int i, int j, int k, int isize, int jsize) {
        return (unsigned int)i + (unsigned int)isize *
                   ((unsigned int)j + (unsigned int)jsize * (unsigned int)k);
    }

    inline GridIndex getUnflattenedIndex(unsigned int flatidx, int isize, int jsize) {
        int i = flatidx % isize;
        int j = (flatidx / isize) % jsize;
        int k = flatidx / (jsize * isize); 
        return GridIndex(i, j, k);
    }
}

#endif
