/*
Crafter®.Math
Copyright (C) 2026 Catcrafts®
catcrafts.net

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License version 3.0 as published by the Free Software Foundation;

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

export module Crafter.Math:Intersection;
import :VectorF32;
import :MatrixRowMajor;
import std;

namespace Crafter {
    // All intersection tests are batched over four primitives at a time so they
    // feed the VectorF32<3,1>::Dot / Cross / Length / Normalize four-pair
    // overloads directly. The single-primitive case is just "pass the same
    // primitive four times and read lane 0" - there is no single-vector
    // fast-path because the SIMD pipelines want full lanes.

    // Möller-Trumbore against four triangles sharing one ray. Returns ray
    // parameter t per triangle, or float max where the ray misses.
    export inline VectorF32<1, 4> IntersectionTestRayTriangle(
        VectorF32<3, 1> rayOrigin, VectorF32<3, 1> rayDir,
        VectorF32<3, 1> aV0, VectorF32<3, 1> aV1, VectorF32<3, 1> aV2,
        VectorF32<3, 1> bV0, VectorF32<3, 1> bV1, VectorF32<3, 1> bV2,
        VectorF32<3, 1> cV0, VectorF32<3, 1> cV1, VectorF32<3, 1> cV2,
        VectorF32<3, 1> dV0, VectorF32<3, 1> dV1, VectorF32<3, 1> dV2
    ) {
        VectorF32<3, 1> aE1 = aV1 - aV0;
        VectorF32<3, 1> aE2 = aV2 - aV0;
        VectorF32<3, 1> bE1 = bV1 - bV0;
        VectorF32<3, 1> bE2 = bV2 - bV0;
        VectorF32<3, 1> cE1 = cV1 - cV0;
        VectorF32<3, 1> cE2 = cV2 - cV0;
        VectorF32<3, 1> dE1 = dV1 - dV0;
        VectorF32<3, 1> dE2 = dV2 - dV0;

        VectorF32<3, 1> aH = VectorF32<3, 1>::Cross(rayDir, aE2);
        VectorF32<3, 1> bH = VectorF32<3, 1>::Cross(rayDir, bE2);
        VectorF32<3, 1> cH = VectorF32<3, 1>::Cross(rayDir, cE2);
        VectorF32<3, 1> dH = VectorF32<3, 1>::Cross(rayDir, dE2);

        VectorF32<3, 1> aS = rayOrigin - aV0;
        VectorF32<3, 1> bS = rayOrigin - bV0;
        VectorF32<3, 1> cS = rayOrigin - cV0;
        VectorF32<3, 1> dS = rayOrigin - dV0;

        VectorF32<3, 1> aQ = VectorF32<3, 1>::Cross(aS, aE1);
        VectorF32<3, 1> bQ = VectorF32<3, 1>::Cross(bS, bE1);
        VectorF32<3, 1> cQ = VectorF32<3, 1>::Cross(cS, cE1);
        VectorF32<3, 1> dQ = VectorF32<3, 1>::Cross(dS, dE1);

        // Four 3-component dots packed into one __m128 per call.
        VectorF32<1, 4> det = VectorF32<3, 1>::Dot(
            aE1, aH, bE1, bH, cE1, cH, dE1, dH);
        VectorF32<1, 4> uNum = VectorF32<3, 1>::Dot(
            aS, aH, bS, bH, cS, cH, dS, dH);
        VectorF32<1, 4> vNum = VectorF32<3, 1>::Dot(
            rayDir, aQ, rayDir, bQ, rayDir, cQ, rayDir, dQ);
        VectorF32<1, 4> tNum = VectorF32<3, 1>::Dot(
            aE2, aQ, bE2, bQ, cE2, cQ, dE2, dQ);

        std::array<float, 4> detArr = det.template Store<float>();
        std::array<float, 4> uArr = uNum.template Store<float>();
        std::array<float, 4> vArr = vNum.template Store<float>();
        std::array<float, 4> tArr = tNum.template Store<float>();

        constexpr float eps = std::numeric_limits<float>::epsilon();
        constexpr float maxF = std::numeric_limits<float>::max();
        alignas(16) std::array<float, 4> out{};
        for (std::uint8_t i = 0; i < 4; ++i) {
            float d = detArr[i];
            if (d <= eps) { out[i] = maxF; continue; }
            float invD = 1.0f / d;
            float u = uArr[i] * invD;
            if (u < 0.0f || u > 1.0f) { out[i] = maxF; continue; }
            float v = vArr[i] * invD;
            if (v < 0.0f || u + v > 1.0f) { out[i] = maxF; continue; }
            out[i] = tArr[i] * invD;
        }
        return VectorF32<1, 4>(out.data());
    }

    // One ray against four spheres. radii must hold {rA, rB, rC, rD} in lanes
    // 0..3.
    export inline VectorF32<1, 4> IntersectionTestRaySphere(
        VectorF32<3, 1> rayOrigin, VectorF32<3, 1> rayDir,
        VectorF32<3, 1> posA, VectorF32<3, 1> posB,
        VectorF32<3, 1> posC, VectorF32<3, 1> posD,
        VectorF32<1, 4> radii
    ) {
        VectorF32<3, 1> sA = rayOrigin - posA;
        VectorF32<3, 1> sB = rayOrigin - posB;
        VectorF32<3, 1> sC = rayOrigin - posC;
        VectorF32<3, 1> sD = rayOrigin - posD;

        // dirDotS_i = rayDir · (rayOrigin - pos_i)
        VectorF32<1, 4> dirDotS = VectorF32<3, 1>::Dot(
            rayDir, sA, rayDir, sB, rayDir, sC, rayDir, sD);
        // sqDist_i = |rayOrigin - pos_i|² (a.k.a. LengthSq of the s vectors)
        VectorF32<1, 4> sqDist = VectorF32<3, 1>::LengthSq(sA, sB, sC, sD);
        // aScalar = rayDir · rayDir, broadcast across four lanes.
        VectorF32<1, 4> aScalar = VectorF32<3, 1>::LengthSq(
            rayDir, rayDir, rayDir, rayDir);

        VectorF32<1, 4> two(2.0f);
        VectorF32<1, 4> four(4.0f);
        VectorF32<1, 4> b = two * dirDotS;
        VectorF32<1, 4> c = sqDist - radii * radii;
        // discriminant = b² - 4·a·c
        VectorF32<1, 4> disc = b * b - four * aScalar * c;

        std::array<float, 4> discArr = disc.template Store<float>();
        std::array<float, 4> bArr = b.template Store<float>();
        std::array<float, 4> aArr = aScalar.template Store<float>();

        constexpr float maxF = std::numeric_limits<float>::max();
        alignas(16) std::array<float, 4> out{};
        for (std::uint8_t i = 0; i < 4; ++i) {
            float d = discArr[i];
            if (d < 0.0f) { out[i] = maxF; continue; }
            float sqrtD = std::sqrt(d);
            float t = -0.5f * (bArr[i] + sqrtD) / aArr[i];
            out[i] = (t > 0.0f) ? t : maxF;
        }
        return VectorF32<1, 4>(out.data());
    }

    // One ray against four OBBs. Each box is described by world-space position,
    // half-extent vector (per-axis sizes), and a unit quaternion rotation.
    export inline VectorF32<1, 4> IntersectionTestRayOrientedBox(
        VectorF32<3, 1> rayOrigin, VectorF32<3, 1> rayDir,
        VectorF32<3, 1> posA, VectorF32<3, 1> sizeA, VectorF32<4, 1> rotA,
        VectorF32<3, 1> posB, VectorF32<3, 1> sizeB, VectorF32<4, 1> rotB,
        VectorF32<3, 1> posC, VectorF32<3, 1> sizeC, VectorF32<4, 1> rotC,
        VectorF32<3, 1> posD, VectorF32<3, 1> sizeD, VectorF32<4, 1> rotD
    ) {
        // Conjugate quaternion: negate xyz, keep w. Negate<{true,true,true,false}>
        // is constant-folded into a single XOR with a mask vector.
        VectorF32<4, 1> invRotA = rotA.template Negate<{{true, true, true, false}}>();
        VectorF32<4, 1> invRotB = rotB.template Negate<{{true, true, true, false}}>();
        VectorF32<4, 1> invRotC = rotC.template Negate<{{true, true, true, false}}>();
        VectorF32<4, 1> invRotD = rotD.template Negate<{{true, true, true, false}}>();

        VectorF32<3, 1> localOriginA = VectorF32<3, 1>::Rotate(rayOrigin - posA, invRotA);
        VectorF32<3, 1> localOriginB = VectorF32<3, 1>::Rotate(rayOrigin - posB, invRotB);
        VectorF32<3, 1> localOriginC = VectorF32<3, 1>::Rotate(rayOrigin - posC, invRotC);
        VectorF32<3, 1> localOriginD = VectorF32<3, 1>::Rotate(rayOrigin - posD, invRotD);

        VectorF32<3, 1> localDirA = VectorF32<3, 1>::Rotate(rayDir, invRotA);
        VectorF32<3, 1> localDirB = VectorF32<3, 1>::Rotate(rayDir, invRotB);
        VectorF32<3, 1> localDirC = VectorF32<3, 1>::Rotate(rayDir, invRotC);
        VectorF32<3, 1> localDirD = VectorF32<3, 1>::Rotate(rayDir, invRotD);

        VectorF32<3, 1> halfA = sizeA * 0.5f;
        VectorF32<3, 1> halfB = sizeB * 0.5f;
        VectorF32<3, 1> halfC = sizeC * 0.5f;
        VectorF32<3, 1> halfD = sizeD * 0.5f;

        std::array<std::array<float, 4>, 4> origLanes{
            localOriginA.template Store<float>(),
            localOriginB.template Store<float>(),
            localOriginC.template Store<float>(),
            localOriginD.template Store<float>(),
        };
        std::array<std::array<float, 4>, 4> dirLanes{
            localDirA.template Store<float>(),
            localDirB.template Store<float>(),
            localDirC.template Store<float>(),
            localDirD.template Store<float>(),
        };
        std::array<std::array<float, 4>, 4> halfLanes{
            halfA.template Store<float>(),
            halfB.template Store<float>(),
            halfC.template Store<float>(),
            halfD.template Store<float>(),
        };

        constexpr float eps = std::numeric_limits<float>::epsilon();
        constexpr float maxF = std::numeric_limits<float>::max();
        alignas(16) std::array<float, 4> out{};
        for (std::uint8_t b = 0; b < 4; ++b) {
            float tMin = 0.0f;
            float tMax = maxF;
            bool miss = false;
            for (std::uint8_t i = 0; i < 3; ++i) {
                float d = dirLanes[b][i];
                float o = origLanes[b][i];
                float h = halfLanes[b][i];
                if (std::abs(d) < eps) {
                    if (o < -h || o > h) { miss = true; break; }
                } else {
                    float invD = 1.0f / d;
                    float t1 = (-h - o) * invD;
                    float t2 = ( h - o) * invD;
                    if (t1 > t2) std::swap(t1, t2);
                    tMin = std::max(tMin, t1);
                    tMax = std::min(tMax, t2);
                    if (tMin > tMax) { miss = true; break; }
                }
            }
            out[b] = miss ? maxF : (tMin >= 0.0f ? tMin : tMax);
        }
        return VectorF32<1, 4>(out.data());
    }

    // One sphere against four OBBs. boxMatrix encodes rotation in m[r][0..2]
    // and translation in m[r][3].
    export inline VectorF32<1, 4> IntersectionTestSphereOrientedBox(
        VectorF32<3, 1> sphereCenter, VectorF32<1, 4> radii,
        VectorF32<3, 1> sizeA, MatrixRowMajor<float, 4, 3, 1> boxA,
        VectorF32<3, 1> sizeB, MatrixRowMajor<float, 4, 3, 1> boxB,
        VectorF32<3, 1> sizeC, MatrixRowMajor<float, 4, 3, 1> boxC,
        VectorF32<3, 1> sizeD, MatrixRowMajor<float, 4, 3, 1> boxD
    ) {
        auto perBox = [&](MatrixRowMajor<float, 4, 3, 1> const& m,
                          VectorF32<3, 1> const& size,
                          VectorF32<3, 1>& xAxis,
                          VectorF32<3, 1>& yAxis,
                          VectorF32<3, 1>& zAxis,
                          VectorF32<3, 1>& delta) {
            // Existing semantics: the OBB axes are read from the rows of the
            // upper 3x3 block, and the translation column is gathered from the
            // w lane of each row.
            std::array<float, 4> r0 = m.rows[0].template Store<float>();
            std::array<float, 4> r1 = m.rows[1].template Store<float>();
            std::array<float, 4> r2 = m.rows[2].template Store<float>();
            alignas(16) float xBuf[4] = { r0[0], r0[1], r0[2], 0.0f };
            alignas(16) float yBuf[4] = { r1[0], r1[1], r1[2], 0.0f };
            alignas(16) float zBuf[4] = { r2[0], r2[1], r2[2], 0.0f };
            alignas(16) float oBuf[4] = { r0[3], r1[3], r2[3], 0.0f };
            xAxis = VectorF32<3, 1>(xBuf);
            yAxis = VectorF32<3, 1>(yBuf);
            zAxis = VectorF32<3, 1>(zBuf);
            VectorF32<3, 1> origin(oBuf);
            delta = sphereCenter - origin;
            (void)size;
        };

        VectorF32<3, 1> xA, yA, zA, dA;
        VectorF32<3, 1> xB, yB, zB, dB;
        VectorF32<3, 1> xC, yC, zC, dC;
        VectorF32<3, 1> xD, yD, zD, dD;
        perBox(boxA, sizeA, xA, yA, zA, dA);
        perBox(boxB, sizeB, xB, yB, zB, dB);
        perBox(boxC, sizeC, xC, yC, zC, dC);
        perBox(boxD, sizeD, xD, yD, zD, dD);

        // Local sphere center per box: project delta onto each box axis. We
        // produce {lx, ly, lz, lx, ly, lz, lx, ly, lz, lx, ly, lz} as three
        // packed 4-wide Dot results (one Dot per axis).
        VectorF32<1, 4> locX = VectorF32<3, 1>::Dot(
            dA, xA, dB, xB, dC, xC, dD, xD);
        VectorF32<1, 4> locY = VectorF32<3, 1>::Dot(
            dA, yA, dB, yB, dC, yC, dD, yD);
        VectorF32<1, 4> locZ = VectorF32<3, 1>::Dot(
            dA, zA, dB, zB, dC, zC, dD, zD);

        std::array<float, 4> lxArr = locX.template Store<float>();
        std::array<float, 4> lyArr = locY.template Store<float>();
        std::array<float, 4> lzArr = locZ.template Store<float>();
        std::array<float, 4> rArr  = radii.template Store<float>();
        std::array<std::array<float, 4>, 4> sizeLanes{
            sizeA.template Store<float>(),
            sizeB.template Store<float>(),
            sizeC.template Store<float>(),
            sizeD.template Store<float>(),
        };

        alignas(16) std::array<float, 4> out{};
        for (std::uint8_t i = 0; i < 4; ++i) {
            float lx = lxArr[i], ly = lyArr[i], lz = lzArr[i];
            float sx = sizeLanes[i][0], sy = sizeLanes[i][1], sz = sizeLanes[i][2];
            float cx = std::clamp(lx, -sx, sx);
            float cy = std::clamp(ly, -sy, sy);
            float cz = std::clamp(lz, -sz, sz);
            float dx = lx - cx, dy = ly - cy, dz = lz - cz;
            float distSq = dx * dx + dy * dy + dz * dz;
            float r = rArr[i];
            // Returns 0.0 on hit, max on miss - keeps a consistent
            // "t-like" output signature with the other intersection tests.
            out[i] = (distSq <= r * r) ? 0.0f : std::numeric_limits<float>::max();
        }
        return VectorF32<1, 4>(out.data());
    }

    // Eight local corners of a unit OBB transformed by `matrix`. Uses one
    // batched 4-pair Dot per result row (x, y, z), reproducing the corners in
    // two groups of four.
    export inline std::array<VectorF32<3, 1>, 8> GetOBBCorners(
        VectorF32<3, 1> size, MatrixRowMajor<float, 4, 3, 1> matrix
    ) {
        std::array<float, 4> sz = size.template Store<float>();
        const float sx = sz[0], sy = sz[1], sz_ = sz[2];

        VectorF32<4, 1> mx = matrix.rows[0];
        VectorF32<4, 1> my = matrix.rows[1];
        VectorF32<4, 1> mz = matrix.rows[2];

        // Eight homogeneous corner vectors with w=1 so the translation column
        // of `matrix` participates in the dot product.
        alignas(16) float c0[4] = { -sx, -sy, -sz_, 1.0f };
        alignas(16) float c1[4] = {  sx, -sy, -sz_, 1.0f };
        alignas(16) float c2[4] = { -sx,  sy, -sz_, 1.0f };
        alignas(16) float c3[4] = {  sx,  sy, -sz_, 1.0f };
        alignas(16) float c4[4] = { -sx, -sy,  sz_, 1.0f };
        alignas(16) float c5[4] = {  sx, -sy,  sz_, 1.0f };
        alignas(16) float c6[4] = { -sx,  sy,  sz_, 1.0f };
        alignas(16) float c7[4] = {  sx,  sy,  sz_, 1.0f };
        VectorF32<4, 1> v0(c0), v1(c1), v2(c2), v3(c3);
        VectorF32<4, 1> v4(c4), v5(c5), v6(c6), v7(c7);

        // First four corners (0..3): batch x, y, z dots.
        VectorF32<1, 4> xLo = VectorF32<4, 1>::Dot(mx, v0, mx, v1, mx, v2, mx, v3);
        VectorF32<1, 4> yLo = VectorF32<4, 1>::Dot(my, v0, my, v1, my, v2, my, v3);
        VectorF32<1, 4> zLo = VectorF32<4, 1>::Dot(mz, v0, mz, v1, mz, v2, mz, v3);
        // Second four corners (4..7).
        VectorF32<1, 4> xHi = VectorF32<4, 1>::Dot(mx, v4, mx, v5, mx, v6, mx, v7);
        VectorF32<1, 4> yHi = VectorF32<4, 1>::Dot(my, v4, my, v5, my, v6, my, v7);
        VectorF32<1, 4> zHi = VectorF32<4, 1>::Dot(mz, v4, mz, v5, mz, v6, mz, v7);

        std::array<float, 4> xLoA = xLo.template Store<float>();
        std::array<float, 4> yLoA = yLo.template Store<float>();
        std::array<float, 4> zLoA = zLo.template Store<float>();
        std::array<float, 4> xHiA = xHi.template Store<float>();
        std::array<float, 4> yHiA = yHi.template Store<float>();
        std::array<float, 4> zHiA = zHi.template Store<float>();

        std::array<VectorF32<3, 1>, 8> result;
        for (std::uint8_t i = 0; i < 4; ++i) {
            alignas(16) float buf[4] = { xLoA[i], yLoA[i], zLoA[i], 0.0f };
            result[i] = VectorF32<3, 1>(buf);
        }
        for (std::uint8_t i = 0; i < 4; ++i) {
            alignas(16) float buf[4] = { xHiA[i], yHiA[i], zHiA[i], 0.0f };
            result[4 + i] = VectorF32<3, 1>(buf);
        }
        return result;
    }

    // SAT against fifteen separating axes (3 box-A, 3 box-B, 9 cross products).
    // We compute every corner projection with batched 4-pair Dots: each axis
    // projects four corners per call, two calls per axis covers the 8 corners.
    export inline bool IntersectionTestOrientedBoxOrientedBox(
        VectorF32<3, 1> sizeA, MatrixRowMajor<float, 4, 3, 1> boxA,
        VectorF32<3, 1> sizeB, MatrixRowMajor<float, 4, 3, 1> boxB
    ) {
        std::array<VectorF32<3, 1>, 8> cornersA = GetOBBCorners(sizeA, boxA);
        std::array<VectorF32<3, 1>, 8> cornersB = GetOBBCorners(sizeB, boxB);

        // Axes are the upper-3 lanes of each matrix row (same convention as
        // SphereOrientedBox). ExtractLo<3> just retypes the SIMD register; the
        // 4th lane is ignored by the Len=3 ops below.
        std::array<VectorF32<3, 1>, 3> axesA = {
            boxA.rows[0].template ExtractLo<3>(),
            boxA.rows[1].template ExtractLo<3>(),
            boxA.rows[2].template ExtractLo<3>(),
        };
        std::array<VectorF32<3, 1>, 3> axesB = {
            boxB.rows[0].template ExtractLo<3>(),
            boxB.rows[1].template ExtractLo<3>(),
            boxB.rows[2].template ExtractLo<3>(),
        };

        std::array<VectorF32<3, 1>, 15> axes{};
        axes[0] = axesA[0]; axes[1] = axesA[1]; axes[2] = axesA[2];
        axes[3] = axesB[0]; axes[4] = axesB[1]; axes[5] = axesB[2];
        // Normalize all nine cross axes together with a single batched
        // Normalize call (Packing=3 not in the API, so two calls of four +
        // one of one would be needed; for now just normalize in two batches
        // of four and the trailing one inline).
        std::array<VectorF32<3, 1>, 9> crossAxes{};
        std::uint8_t k = 0;
        for (std::uint8_t i = 0; i < 3; ++i) {
            for (std::uint8_t j = 0; j < 3; ++j) {
                crossAxes[k++] = VectorF32<3, 1>::Cross(axesA[i], axesB[j]);
            }
        }
        auto norm0 = VectorF32<3, 1>::Normalize(crossAxes[0], crossAxes[1], crossAxes[2], crossAxes[3]);
        auto norm1 = VectorF32<3, 1>::Normalize(crossAxes[4], crossAxes[5], crossAxes[6], crossAxes[7]);
        auto norm2 = VectorF32<3, 1>::Normalize(crossAxes[8], crossAxes[8], crossAxes[8], crossAxes[8]);
        axes[6]  = std::get<0>(norm0);
        axes[7]  = std::get<1>(norm0);
        axes[8]  = std::get<2>(norm0);
        axes[9]  = std::get<3>(norm0);
        axes[10] = std::get<0>(norm1);
        axes[11] = std::get<1>(norm1);
        axes[12] = std::get<2>(norm1);
        axes[13] = std::get<3>(norm1);
        axes[14] = std::get<0>(norm2);

        for (std::uint8_t axisIdx = 0; axisIdx < 15; ++axisIdx) {
            VectorF32<3, 1> axis = axes[axisIdx];
            // Project all 8 corners of each box onto `axis` using two batched
            // 4-pair Dot calls (lo and hi corners).
            VectorF32<1, 4> projA_lo = VectorF32<3, 1>::Dot(
                cornersA[0], axis, cornersA[1], axis,
                cornersA[2], axis, cornersA[3], axis);
            VectorF32<1, 4> projA_hi = VectorF32<3, 1>::Dot(
                cornersA[4], axis, cornersA[5], axis,
                cornersA[6], axis, cornersA[7], axis);
            VectorF32<1, 4> projB_lo = VectorF32<3, 1>::Dot(
                cornersB[0], axis, cornersB[1], axis,
                cornersB[2], axis, cornersB[3], axis);
            VectorF32<1, 4> projB_hi = VectorF32<3, 1>::Dot(
                cornersB[4], axis, cornersB[5], axis,
                cornersB[6], axis, cornersB[7], axis);

            std::array<float, 4> aLo = projA_lo.template Store<float>();
            std::array<float, 4> aHi = projA_hi.template Store<float>();
            std::array<float, 4> bLo = projB_lo.template Store<float>();
            std::array<float, 4> bHi = projB_hi.template Store<float>();

            float minA = aLo[0], maxA = aLo[0];
            for (std::uint8_t i = 1; i < 4; ++i) {
                minA = std::min(minA, aLo[i]);
                maxA = std::max(maxA, aLo[i]);
            }
            for (std::uint8_t i = 0; i < 4; ++i) {
                minA = std::min(minA, aHi[i]);
                maxA = std::max(maxA, aHi[i]);
            }
            float minB = bLo[0], maxB = bLo[0];
            for (std::uint8_t i = 1; i < 4; ++i) {
                minB = std::min(minB, bLo[i]);
                maxB = std::max(maxB, bLo[i]);
            }
            for (std::uint8_t i = 0; i < 4; ++i) {
                minB = std::min(minB, bHi[i]);
                maxB = std::max(maxB, bHi[i]);
            }

            if (maxA < minB || maxB < minA) return false;
        }
        return true;
    }
}