#include <cmath>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtx/string_cast.hpp>
#include "MVP.hpp"
#include "Math.hpp"

namespace Math::MVP {

Matrix<4, 4> transformation_matrix(Vector<3> position) {
    return {
            1.0f, 0.0f, 0.0f, position.x(),
            0.0f, 1.0f, 0.0f, position.y(),
            0.0f, 0.0f, 1.0f, position.z(),
            0.0f, 0.0f, 0.0f, 1.0f
    };
}

Matrix<4, 4> rotation_matrix(Rotation angles) {
    auto c = angles.vector.apply(cos);
    auto s = angles.vector.apply(sin);

    Matrix<4, 4> rotation_x{
            1.0f, 0.0f,  0.0f,   0.0f,
            0.0f, c.x(), -s.x(), 0.0f,
            0.0f, s.x(), c.x(),  0.0f,
            0.0f, 0.0f,  0.0f,   1.0f,
    };

    Matrix<4, 4> rotation_y{
            c.y(),  0.0f, s.y(),  0.0f,
            0.0f,   1.0f, 0.0f,   0.0f,
            -s.y(), 0.0f, c.y(),  0.0f,
            0.0f,   0.0f, 0.0f,   1.0f,
    };

    Matrix<4, 4> rotation_z{
            c.z(), -s.z(), 0.0f,  0.0f,
            s.z(), c.z(),  0.0f,  0.0f,
            0.0f,  0.0f,   1.0f,  0.0f,
            0.0f,  0.0f,   0.0f,  1.0f,
    };

    return rotation_x * rotation_y * rotation_z;
}

Matrix<4, 4> model(Vector<3> position, Rotation angles) {
    auto transformation = transformation_matrix(position);
    auto rotation = rotation_matrix(angles);

    return transformation * rotation;
}

Matrix<4, 4> view(Vector<3> position, Rotation angles) {
    auto transformation = transformation_matrix(position);
    auto rotation = rotation_matrix(angles);

    return transformation * rotation;
}

Matrix<4, 4> projection(float aspect, float fov, float near, float far) {
    auto fov_radians = (fov * M_PI) / 180.0f;

    float x_scale = 1.0f / (tan(fov_radians / 2.0f) * aspect);
    float y_scale = 1.0f / tan(fov_radians / 2.0f);

    float frustum_length = far - near;
    float z_near = -(far + near) / frustum_length;
    float z_far = -(2 * far * near) / frustum_length;

    Matrix<4, 4> projection{
        x_scale, 0.0f,    0.0f,   0.0f,
        0.0f,    y_scale, 0.0f,   0.0f,
        0.0f,    0.0f,    z_near, z_far,
        0.0f,    0.0f,    -1.0f,   0.0f,
    };

    return projection;
}

}