// This is an incomplete port of http://glmatrix.net/
//
// Copyright (c) 2013 Brandon Jones, Colin MacKenzie IV
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the
// use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not claim
//    that you wrote the original software. If you use this software in a
//    product, an acknowledgment in the product documentation would be
//    appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not be
//    misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.

#include <mbgl/util/mat4.hpp>

#include <cmath>

namespace mbgl {

namespace matrix {

void identity(mat4& out) {
    out[0] = 1.0f;
    out[1] = 0.0f;
    out[2] = 0.0f;
    out[3] = 0.0f;
    out[4] = 0.0f;
    out[5] = 1.0f;
    out[6] = 0.0f;
    out[7] = 0.0f;
    out[8] = 0.0f;
    out[9] = 0.0f;
    out[10] = 1.0f;
    out[11] = 0.0f;
    out[12] = 0.0f;
    out[13] = 0.0f;
    out[14] = 0.0f;
    out[15] = 1.0f;
}

bool invert(mat4& out, const mat4& a) {
    double a00 = a[0];
    double a01 = a[1];
    double a02 = a[2];
    double a03 = a[3];
    double a10 = a[4];
    double a11 = a[5];
    double a12 = a[6];
    double a13 = a[7];
    double a20 = a[8];
    double a21 = a[9];
    double a22 = a[10];
    double a23 = a[11];
    double a30 = a[12];
    double a31 = a[13];
    double a32 = a[14];
    double a33 = a[15];
    double b00 = a00 * a11 - a01 * a10;
    double b01 = a00 * a12 - a02 * a10;
    double b02 = a00 * a13 - a03 * a10;
    double b03 = a01 * a12 - a02 * a11;
    double b04 = a01 * a13 - a03 * a11;
    double b05 = a02 * a13 - a03 * a12;
    double b06 = a20 * a31 - a21 * a30;
    double b07 = a20 * a32 - a22 * a30;
    double b08 = a20 * a33 - a23 * a30;
    double b09 = a21 * a32 - a22 * a31;
    double b10 = a21 * a33 - a23 * a31;
    double b11 = a22 * a33 - a23 * a32;
    double // Calculate the determinant
        det = b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06;

    if (!det) {
        return true;
    }
    det = 1.0 / det;

    out[0] = (a11 * b11 - a12 * b10 + a13 * b09) * det;
    out[1] = (a02 * b10 - a01 * b11 - a03 * b09) * det;
    out[2] = (a31 * b05 - a32 * b04 + a33 * b03) * det;
    out[3] = (a22 * b04 - a21 * b05 - a23 * b03) * det;
    out[4] = (a12 * b08 - a10 * b11 - a13 * b07) * det;
    out[5] = (a00 * b11 - a02 * b08 + a03 * b07) * det;
    out[6] = (a32 * b02 - a30 * b05 - a33 * b01) * det;
    out[7] = (a20 * b05 - a22 * b02 + a23 * b01) * det;
    out[8] = (a10 * b10 - a11 * b08 + a13 * b06) * det;
    out[9] = (a01 * b08 - a00 * b10 - a03 * b06) * det;
    out[10] = (a30 * b04 - a31 * b02 + a33 * b00) * det;
    out[11] = (a21 * b02 - a20 * b04 - a23 * b00) * det;
    out[12] = (a11 * b07 - a10 * b09 - a12 * b06) * det;
    out[13] = (a00 * b09 - a01 * b07 + a02 * b06) * det;
    out[14] = (a31 * b01 - a30 * b03 - a32 * b00) * det;
    out[15] = (a20 * b03 - a21 * b01 + a22 * b00) * det;

    return false;
}

void ortho(mat4& out, double left, double right, double bottom, double top, double near, double far) {
    double lr = 1.0f / (left - right);
    double bt = 1.0f / (bottom - top);
    double nf = 1.0f / (near - far);
    out[0] = -2.0f * lr;
    out[1] = 0.0f;
    out[2] = 0.0f;
    out[3] = 0.0f;
    out[4] = 0.0f;
    out[5] = -2.0f * bt;
    out[6] = 0.0f;
    out[7] = 0.0f;
    out[8] = 0.0f;
    out[9] = 0.0f;
    out[10] = 2.0f * nf;
    out[11] = 0.0f;
    out[12] = (left + right) * lr;
    out[13] = (top + bottom) * bt;
    out[14] = (far + near) * nf;
    out[15] = 1.0f;
}

void perspective(mat4& out, double fovy, double aspect, double near, double far) {
    double f = 1.0f / std::tan(fovy / 2.0f);
    double nf = 1.0f / (near - far);
    out[0] = f / aspect;
    out[1] = 0.0f;
    out[2] = 0.0f;
    out[3] = 0.0f;
    out[4] = 0.0f;
    out[5] = f;
    out[6] = 0.0f;
    out[7] = 0.0f;
    out[8] = 0.0f;
    out[9] = 0.0f;
    out[10] = (far + near) * nf;
    out[11] = -1.0f;
    out[12] = 0.0f;
    out[13] = 0.0f;
    out[14] = (2.0f * far * near) * nf;
    out[15] = 0.0f;
}

void copy(mat4& out, const mat4& a) {
    out[0] = a[0];
    out[1] = a[1];
    out[2] = a[2];
    out[3] = a[3];
    out[4] = a[4];
    out[5] = a[5];
    out[6] = a[6];
    out[7] = a[7];
    out[8] = a[8];
    out[9] = a[9];
    out[10] = a[10];
    out[11] = a[11];
    out[12] = a[12];
    out[13] = a[13];
    out[14] = a[14];
    out[15] = a[15];
}

void translate(mat4& out, const mat4& a, double x, double y, double z) {
    if (&a == &out) {
        out[12] = a[0] * x + a[4] * y + a[8] * z + a[12];
        out[13] = a[1] * x + a[5] * y + a[9] * z + a[13];
        out[14] = a[2] * x + a[6] * y + a[10] * z + a[14];
        out[15] = a[3] * x + a[7] * y + a[11] * z + a[15];
    } else {
        double a00;
        double a01;
        double a02;
        double a03;
        double a10;
        double a11;
        double a12;
        double a13;
        double a20;
        double a21;
        double a22;
        double a23;

        a00 = a[0]; a01 = a[1]; a02 = a[2]; a03 = a[3];
        a10 = a[4]; a11 = a[5]; a12 = a[6]; a13 = a[7];
        a20 = a[8]; a21 = a[9]; a22 = a[10]; a23 = a[11];

        out[0] = a00; out[1] = a01; out[2] = a02; out[3] = a03;
        out[4] = a10; out[5] = a11; out[6] = a12; out[7] = a13;
        out[8] = a20; out[9] = a21; out[10] = a22; out[11] = a23;

        out[12] = a00 * x + a10 * y + a20 * z + a[12];
        out[13] = a01 * x + a11 * y + a21 * z + a[13];
        out[14] = a02 * x + a12 * y + a22 * z + a[14];
        out[15] = a03 * x + a13 * y + a23 * z + a[15];
    }
}

void rotate_x(mat4& out, const mat4& a, double rad) {
    double s = std::sin(rad);
    double c = std::cos(rad);
    double a10 = a[4];
    double a11 = a[5];
    double a12 = a[6];
    double a13 = a[7];
    double a20 = a[8];
    double a21 = a[9];
    double a22 = a[10];
    double a23 = a[11];

    if (&a != &out) { // If the source and destination differ, copy the unchanged rows
        out[0]  = a[0];
        out[1]  = a[1];
        out[2]  = a[2];
        out[3]  = a[3];
        out[12] = a[12];
        out[13] = a[13];
        out[14] = a[14];
        out[15] = a[15];
    }

    // Perform axis-specific matrix multiplication
    out[4] = a10 * c + a20 * s;
    out[5] = a11 * c + a21 * s;
    out[6] = a12 * c + a22 * s;
    out[7] = a13 * c + a23 * s;
    out[8] = a20 * c - a10 * s;
    out[9] = a21 * c - a11 * s;
    out[10] = a22 * c - a12 * s;
    out[11] = a23 * c - a13 * s;
}

void rotate_y(mat4& out, const mat4& a, double rad) {
    double s = std::sin(rad);
    double c = std::cos(rad);
    double a00 = a[0];
    double a01 = a[1];
    double a02 = a[2];
    double a03 = a[3];
    double a20 = a[8];
    double a21 = a[9];
    double a22 = a[10];
    double a23 = a[11];

    if (&a != &out) { // If the source and destination differ, copy the unchanged rows
        out[4]  = a[4];
        out[5]  = a[5];
        out[6]  = a[6];
        out[7]  = a[7];
        out[12] = a[12];
        out[13] = a[13];
        out[14] = a[14];
        out[15] = a[15];
    }

    // Perform axis-specific matrix multiplication
    out[0] = a00 * c - a20 * s;
    out[1] = a01 * c - a21 * s;
    out[2] = a02 * c - a22 * s;
    out[3] = a03 * c - a23 * s;
    out[8] = a00 * s + a20 * c;
    out[9] = a01 * s + a21 * c;
    out[10] = a02 * s + a22 * c;
    out[11] = a03 * s + a23 * c;
}

void rotate_z(mat4& out, const mat4& a, double rad) {
    double s = std::sin(rad);
    double c = std::cos(rad);
    double a00 = a[0];
    double a01 = a[1];
    double a02 = a[2];
    double a03 = a[3];
    double a10 = a[4];
    double a11 = a[5];
    double a12 = a[6];
    double a13 = a[7];

    if (&a != &out) { // If the source and destination differ, copy the unchanged last row
        out[8]  = a[8];
        out[9]  = a[9];
        out[10] = a[10];
        out[11] = a[11];
        out[12] = a[12];
        out[13] = a[13];
        out[14] = a[14];
        out[15] = a[15];
    }

    // Perform axis-specific matrix multiplication
    out[0] = a00 * c + a10 * s;
    out[1] = a01 * c + a11 * s;
    out[2] = a02 * c + a12 * s;
    out[3] = a03 * c + a13 * s;
    out[4] = a10 * c - a00 * s;
    out[5] = a11 * c - a01 * s;
    out[6] = a12 * c - a02 * s;
    out[7] = a13 * c - a03 * s;
}

void scale(mat4& out, const mat4& a, double x, double y, double z) {
    out[0] = a[0] * x;
    out[1] = a[1] * x;
    out[2] = a[2] * x;
    out[3] = a[3] * x;
    out[4] = a[4] * y;
    out[5] = a[5] * y;
    out[6] = a[6] * y;
    out[7] = a[7] * y;
    out[8] = a[8] * z;
    out[9] = a[9] * z;
    out[10] = a[10] * z;
    out[11] = a[11] * z;
    out[12] = a[12];
    out[13] = a[13];
    out[14] = a[14];
    out[15] = a[15];
}

void multiply(mat4& out, const mat4& a, const mat4& b) {
    double a00 = a[0];
    double a01 = a[1];
    double a02 = a[2];
    double a03 = a[3];
    double a10 = a[4];
    double a11 = a[5];
    double a12 = a[6];
    double a13 = a[7];
    double a20 = a[8];
    double a21 = a[9];
    double a22 = a[10];
    double a23 = a[11];
    double a30 = a[12];
    double a31 = a[13];
    double a32 = a[14];
    double a33 = a[15];

    // Cache only the current line of the second matrix
    double b0 = b[0];
    double b1 = b[1];
    double b2 = b[2];
    double b3 = b[3];
    out[0] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
    out[1] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
    out[2] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
    out[3] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;

    b0 = b[4]; b1 = b[5]; b2 = b[6]; b3 = b[7];
    out[4] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
    out[5] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
    out[6] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
    out[7] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;

    b0 = b[8]; b1 = b[9]; b2 = b[10]; b3 = b[11];
    out[8] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
    out[9] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
    out[10] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
    out[11] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;

    b0 = b[12]; b1 = b[13]; b2 = b[14]; b3 = b[15];
    out[12] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
    out[13] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
    out[14] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
    out[15] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;
}

void transformMat4(vec4& out, const vec4& a, const mat4& m) {
    double x = a[0];
    double y = a[1];
    double z = a[2];
    double w = a[3];
    out[0] = m[0] * x + m[4] * y + m[8] * z + m[12] * w;
    out[1] = m[1] * x + m[5] * y + m[9] * z + m[13] * w;
    out[2] = m[2] * x + m[6] * y + m[10] * z + m[14] * w;
    out[3] = m[3] * x + m[7] * y + m[11] * z + m[15] * w;
}

} // namespace matrix

} // namespace mbgl