#include "GlutRender.hpp"

#include <GL/gl.h>
#include <GL/glut.h>
#include <cstring>

GlutRender& GlutRender::get_instance() {
    static GlutRender instance;
    return instance;
}

GlutRender::GlutRender() { }

void GlutRender::init(int* argc, char** argv,
        int wid, int hei, const char* win_name)
{
   glutInit(argc, argv);
   glutInitDisplayMode(GLUT_DOUBLE);
   glutInitWindowSize(wid, hei);
   glutCreateWindow(win_name);

   glutDisplayFunc(display_handle);
   glutReshapeFunc(reshape_handle);

   glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Background color
   glClearDepth(1.0f);                   // Set background depth to farthest
   glEnable(GL_DEPTH_TEST);
   glDepthFunc(GL_LEQUAL);
   glShadeModel(GL_SMOOTH); // Enable smooth shading
   glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

}

void GlutRender::cleanup() {
}

void GlutRender::add_mesh(Mesh* mesh) {
    meshes.insert(mesh);
}

void GlutRender::remove_mesh(Mesh* mesh) {
    meshes.erase(mesh);
}

void GlutRender::run() {
    glutMainLoop();
}

void GlutRender::reshape(int wid, int hei) {
	if (hei == 0)
        hei = 1;
	GLfloat aspect = (GLfloat)wid / (GLfloat)hei;

	glViewport(0, 0, wid, hei);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	// Enable perspective projection with fovy, aspect, zNear and zFar
	gluPerspective(45.0f, aspect, 0.1f, 100.0f);
}

void GlutRender::display() {
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glMatrixMode(GL_MODELVIEW);

    // Camera position and orientation
    glLoadIdentity();
    glTranslatef(0., 0., -6.);

    for(Mesh* mesh: meshes) {
        const Point& mesh_center = mesh->get_center();

        const std::vector<Point>& points = mesh->get_vertices();

        glBegin(GL_TRIANGLES);
        for(const Face& face: mesh->get_faces()) {
            Point p0 = face.pt(0, points) + mesh_center,
                  p1 = face.pt(1, points) + mesh_center,
                  p2 = face.pt(2, points) + mesh_center;
            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(p0[0], p0[1], p0[2]);
            glVertex3f(p1[0], p1[1], p1[2]);
            glVertex3f(p2[0], p2[1], p2[2]);
        }
        glEnd();
    }

	glutSwapBuffers();
}

void GlutRender::reshape_handle(int wid, int hei) {
    get_instance().reshape(wid, hei);
}
void GlutRender::display_handle() {
    get_instance().display();
}