// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

// This program 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 General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

// Copyright 2007, Daniel Fontijne, University of Amsterdam -- fontijne@science.uva.nl

#ifdef WIN32
#include <windows.h>
#endif

#include <GL/gl.h>
#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#include <vector>

#include <libgasandbox/h3ga.h>
#include <libgasandbox/h3ga_draw.h>
#include <libgasandbox/h3ga_util.h>
#include <libgasandbox/gl_util.h>
#include <libgasandbox/glut_util.h>
#include <libgasandbox/timing.h>

using namespace h3ga;
using namespace mv_draw;

const char *WINDOW_TITLE = "Geometric Algebra, Chapter 11, Example 1: Working with Points";

// GLUT state information
int g_viewportWidth = 800;
int g_viewportHeight = 600;

// mouse position on last call to MouseButton() / MouseMotion()
h3ga::vector g_prevMousePos;

// when true, MouseMotion() will rotate the model
bool g_rotateModel = false;
bool g_rotateModelOutOfPlane = false;

// what point to drag (or -1 for none)
int g_dragPoint = -1;
float g_dragDistance = -1.0f;

// rotation of the model
h3ga::rotor g_modelRotor(_rotor(1.0f));

const int NB_POINTS = 3;
const int NB_NORMALIZED_POINTS = 3;

// the regular points:
point g_points[NB_POINTS] = {
// note that we deliberately give weights to the points (1.0, 2.0, 3.0)
    _point(1.0f * (e1 + e2 + e0)),
    _point(2.0f * (2.0f * e1 + 0.5f * e2 + e0)),
    _point(3.0f * (e1 + 0.5f * e3 + e0)),
};
// the normalized points:
normalizedPoint g_normalizedPoints[NB_NORMALIZED_POINTS] = {
// note the hack here: because normalizedPoints have a
// constant 'e0' coordinate, no need to do '+ e0' for each point.
// You can initialize a normalizedPoint straight for a '3D vector'
    _normalizedPoint(-e1 + e2),
    _normalizedPoint(-1.5f * e1 + 0.5f * e2),
    _normalizedPoint(-e1 + 0.5f * e3),
};



void display() {
    doIntelWarning(); // warn for possible problems with pciking on Intel graphics chipsets

    // setup projection & transform for the vectors:
    glViewport(0, 0, g_viewportWidth, g_viewportHeight);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glMatrixMode(GL_PROJECTION);
    const float screenWidth = 1600.0f;
    glLoadIdentity();
    pickLoadMatrix();
    GLpick::g_frustumWidth = 2.0 *  (double)g_viewportWidth / screenWidth;
    GLpick::g_frustumHeight = 2.0 *  (double)g_viewportHeight / screenWidth;
    glFrustum(
        -GLpick::g_frustumWidth / 2.0, GLpick::g_frustumWidth / 2.0,
        -GLpick::g_frustumHeight / 2.0, GLpick::g_frustumHeight / 2.0,
        GLpick::g_frustumNear, GLpick::g_frustumFar);
    glMatrixMode(GL_MODELVIEW);
    glTranslatef(0.0f, 0.0f, -8.0f);


    glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glEnable(GL_DEPTH_TEST);
    glPolygonMode(GL_FRONT, GL_FILL);
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glLineWidth(2.0f);


    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();

    rotorGLMult(g_modelRotor);

    // draw points
    glColor3fm(1.0f, 0.0f, 0.0f);
    for (int i = 0; i < NB_POINTS; i++) {
        if (GLpick::g_pickActive) glLoadName(i);
        draw(g_points[i]);
    }

    // draw normalized points
    glColor3fm(0.0f, 1.0f, 0.0f);
    for (int i = 0; i < NB_NORMALIZED_POINTS; i++) {
        if (GLpick::g_pickActive) glLoadName(NB_POINTS + i);
        draw(g_normalizedPoints[i]);
    }

    if (!GLpick::g_pickActive) {



        // draw loops through the points:
        glDisable(GL_LIGHTING);
        glColor3f(1.0f, 1.0f, 1.0f);
        glBegin(GL_LINE_LOOP);
        for (int i = 0; i < NB_POINTS; i++) {
            const point &P = g_points[i];
            glVertex4fv(P.getC(point_e1_e2_e3_e0));
            // or:
            // glVertex4f(P.e1(), P.e2(), P.e3(), P.e0());
        }
        glEnd();

        // draw loops through the normalized points:
        glBegin(GL_LINE_LOOP);
        for (int i = 0; i < NB_NORMALIZED_POINTS; i++) {
            const normalizedPoint &P = g_normalizedPoints[i];
            glVertex3fv(P.getC(normalizedPoint_e1_e2_e3_e0f1_0)); //note e0 'fixed' at 1.0
            // or:
            // glVertex3f(P.e1(), P.e2(), P.e3());
        }
        glEnd();
    }

    glPopMatrix();

    if (!GLpick::g_pickActive) {
        glViewport(0, 0, g_viewportWidth, g_viewportHeight);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0, g_viewportWidth, 0, g_viewportHeight, -100.0, 100.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        glDisable(GL_LIGHTING);
        glColor3f(1.0f, 1.0f, 1.0f);
        void *font = GLUT_BITMAP_HELVETICA_12;
        renderBitmapString(20, 40, font, "This simple example demonstrates using (normalized) points with OpenGL.");
        renderBitmapString(20, 20, font, "Use the mouse buttons to drag the red/green points.");
    }

    if (!GLpick::g_pickActive) {
        glutSwapBuffers();
    }
}

void reshape(GLint width, GLint height) {
    g_viewportWidth = width;
    g_viewportHeight = height;

    // redraw viewport
    glutPostRedisplay();
}

h3ga::vector vectorAtDepth(double depth, const h3ga::vector &v2d) {
    if ((GLpick::g_frustumWidth <= 0) || (GLpick::g_frustumHeight <= 0) ||
        (GLpick::g_frustumNear <= 0) || (GLpick::g_frustumFar <= 0)) {
        return h3ga::vector();
    }

    return _vector((depth * (double)v2d.e1() * GLpick::g_frustumWidth) / (g_viewportWidth * GLpick::g_frustumNear) * e1 +
        (depth * (double)v2d.e2() * GLpick::g_frustumHeight) / (g_viewportHeight * GLpick::g_frustumNear) * e2);
}

h3ga::vector mousePosToVector(int x, int y) {
    x -= g_viewportWidth / 2;
    y -= g_viewportHeight / 2;
    return h3ga::_vector((float)x * h3ga::e1 - (float)y * h3ga::e2);
}

void MouseButton(int button, int state, int x, int y) {
    g_rotateModel = false;

    g_prevMousePos = mousePosToVector(x, y);

    g_dragPoint = pick(x, g_viewportHeight - y, display, &g_dragDistance);

    if (g_dragPoint < 0) {
        h3ga::vector mousePos = mousePosToVector(x, y);
        g_rotateModel = true;
        if ((_Float(norm_e(mousePos)) / _Float(norm_e(g_viewportWidth * e1 + g_viewportHeight * e2))) < 0.2)
            g_rotateModelOutOfPlane = true;
        else g_rotateModelOutOfPlane = false;
    }
}

void MouseMotion(int x, int y) {
    // get mouse position, motion
    h3ga::vector mousePos = mousePosToVector(x, y);
    h3ga::vector motion = _vector(mousePos - g_prevMousePos);
    if (g_rotateModel) {
        // update rotor
        if (g_rotateModelOutOfPlane)
            g_modelRotor = _rotor(h3ga::exp(0.005f * (motion ^ h3ga::e3)) * g_modelRotor);
        else g_modelRotor = _rotor(h3ga::exp(0.00001f * (motion ^ mousePos)) * g_modelRotor);
    }
    else if (g_dragPoint >= 0) {
        h3ga::vector T = vectorAtDepth(g_dragDistance, motion);
        T = _vector(inverse(g_modelRotor) * T * g_modelRotor);
//      printf("T = %s\n", T.c_str());

        if (g_dragPoint < NB_POINTS) {
            int idx = g_dragPoint;
            g_points[idx] = _point(g_points[idx] + (T ^ (e0 << g_points[idx])));
        }
        else {
            int idx = g_dragPoint - NB_POINTS;
            g_normalizedPoints[idx] =
                _normalizedPoint(g_normalizedPoints[idx] + (T ^ (e0 << g_normalizedPoints[idx])));
        }
    }

    // remember mouse pos for next motion:
    g_prevMousePos = mousePos;

    // redraw viewport
    glutPostRedisplay();
}

int main(int argc, char*argv[]) {
    // profiling for Gaigen 2:
    h3ga::g2Profiling::init();

    // GLUT Window Initialization:
    glutInit (&argc, argv);
    glutInitWindowSize(g_viewportWidth, g_viewportHeight);
    glutInitDisplayMode( GLUT_RGB | GLUT_ALPHA | GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow(WINDOW_TITLE);

    // Register callbacks:
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutMouseFunc(MouseButton);
    glutMotionFunc(MouseMotion);


    glutMainLoop();

    return 0;
}