// 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/c3ga.h>
#include <libgasandbox/c3ga_draw.h>
#include <libgasandbox/c3ga_util.h>
#include <libgasandbox/gl_util.h>
#include <libgasandbox/glut_util.h>
#include <libgasandbox/timing.h>
#include <libgasandbox/mv_analyze.h>

using namespace c3ga;
using namespace mv_draw;

const char *WINDOW_TITLE = "Geometric Algebra, Chapter 15, Example 3: Euclidean Projections";

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

// mouse position on last call to MouseButton() / MouseMotion()
vectorE2GA g_prevMousePos;

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

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

// what point to drag (or -1 for none)
int g_dragPoint = -1;
float g_dragDistance = 0.0f;

// the points:
const int NB_POINTS = 6;
normalizedPoint g_points[NB_POINTS] = {
    c3gaPoint(1, 2, 2),
    c3gaPoint(-1, 2, 2),
    c3gaPoint(1, -2, 2),
    c3gaPoint(-1, -2, -2),
    c3gaPoint(1, 2, -2),
    c3gaPoint(-1, 2, -2)
};

const int MODE_LINE = 1;
const int MODE_CIRCLE = 2;
const int MODE_DRAW_PLUNGE = 4;
const int MODE_CIRCLE_WITH_SPHERE = MODE_CIRCLE | MODE_DRAW_PLUNGE;
const int MODE_LINE_WITH_PLANE = MODE_LINE | MODE_DRAW_PLUNGE;

int g_mode = MODE_CIRCLE;

vectorE3GA vectorAtDepth(double depth, const vectorE2GA &v2d);

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, -16.0f);


    glClearColor(1.0f, 1.0f, 1.0f, 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 the points
    glColor3fm(1.0f, 0.0f, 0.0f);
    g_drawState.m_pointSize = 0.1f;
    for (unsigned int i = 0; i < NB_POINTS; i++) {
        if (GLpick::g_pickActive) glLoadName(i);
        draw(g_points[i]);
    }

    if (GLpick::g_pickActive) glLoadName((GLuint)-1);

    g_drawState.pushDrawModeOff(OD_MAGNITUDE);
    if (!GLpick::g_pickActive) {
        // compute circle or line, depending on mode
        circle CL;
        if (g_mode & MODE_CIRCLE)
            CL =_circle(g_points[0] ^ g_points[1] ^ g_points[2]); // compute circle
        else CL =_circle(g_points[0] ^ g_points[1] ^ ni); // compute line

        // draw the circle or the line:
        glColor3fm(0.0f, 1.0f, 0.0f);
        draw(CL);



        // compute the plane:
        plane PL = _plane(g_points[3] ^ g_points[4] ^ g_points[5] ^ ni);

        // draw the projected circle / line:
        glColor3fm(0.0f, 1.0f, 1.0f);
        draw((CL << inverse(PL)) << PL);

        g_drawState.pushDrawModeOff(OD_ORIENTATION);
        glDepthMask(GL_FALSE);
        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

        // compute/draw the plane:
        glColor4fm(0.0f, 0.0f, 1.0f, 0.5f);
        draw(PL);

        if (g_mode & 4) {
            // Draw the sphere (CL ^ PL*)
            // That is: the sphere that contains both the circle and its projection.
            glColor4fm(0.0f, 1.0f, 1.0f, 0.5f);
            draw(CL ^ dual(PL));
        }

        glDisable(GL_BLEND);
        glDepthMask(GL_TRUE);
        g_drawState.popDrawMode();


    }

    g_drawState.popDrawMode();


    glPopMatrix();

    {
        glViewport(0, 0, g_viewportWidth, g_viewportHeight);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        pickLoadMatrix();
        glOrtho(0, g_viewportWidth, 0, g_viewportHeight, -100.0, 100.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        glDisable(GL_LIGHTING);
        glColor3f(0.0f, 0.0f, 0.0f);
        void *font = GLUT_BITMAP_HELVETICA_12;

        if (!GLpick::g_pickActive) {
            renderBitmapString(20, 40, font, "Use the left mouse button to manipulate the points, and to orbit the scene.");
            renderBitmapString(20, 20, font, "Use the other mouse buttons to access the popup menu.");
        }

    }

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

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

    // redraw viewport
    glutPostRedisplay();
}

vectorE3GA vectorAtDepth(double depth, const vectorE2GA &v2d) {
    if ((GLpick::g_frustumWidth <= 0) || (GLpick::g_frustumHeight <= 0) ||
        (GLpick::g_frustumNear <= 0) || (GLpick::g_frustumFar <= 0)) {
        return c3ga::vectorE3GA();
    }

    return _vectorE3GA((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);
}

vectorE2GA mousePosToVector(int x, int y) {
    x -= g_viewportWidth / 2;
    y -= g_viewportHeight / 2;
    return _vectorE2GA((float)x * e1 - (float)y * e2);
}

void MouseButton(int button, int state, int x, int y) {
    if (state != GLUT_DOWN) return; // don't respond when button goes up . . .

    g_rotateModel = false;

    g_prevMousePos = mousePosToVector(x, y);

    g_dragPoint = pick(x, g_viewportHeight - y, display, &g_dragDistance);
    g_rotateModel = (g_dragPoint < 0);
    if (g_rotateModel) {
        vectorE2GA mousePos = mousePosToVector(x, y);
        g_rotateModel = true;
        if ((_Float(norm_e(mousePos)) / _Float(norm_e(g_viewportWidth * e1 + g_viewportHeight * e2))) < 0.2f)
            g_rotateModelOutOfPlane = true;
        else g_rotateModelOutOfPlane = false;
    }

    // redraw viewport
    glutPostRedisplay();
}

void MouseMotion(int x, int y) {
    // get mouse position, motion
    vectorE2GA mousePos = mousePosToVector(x, y);
    vectorE2GA motion = _vectorE2GA(mousePos - g_prevMousePos);
    if (g_rotateModel) {
        // update rotor
        if (g_rotateModelOutOfPlane)
            g_modelRotor = _rotor(c3ga::exp(0.005f * (motion ^ e3)) * g_modelRotor);
        else g_modelRotor = _rotor(c3ga::exp(0.00001f * (motion ^ mousePos)) * g_modelRotor);
    }
    else if (g_dragPoint >= 0) {
        vectorE3GA t = vectorAtDepth(g_dragDistance, motion);
        t = _vectorE3GA(inverse(g_modelRotor) * t * g_modelRotor);
        normalizedTranslator T = exp(_freeVector(-0.5f * (t ^ ni)));

        // note the hack required here (repeated application of translators turns points into spheres, at least, with 32-bit floats  :(     )
        g_points[g_dragPoint] =
                c3gaPoint(_vectorE3GA(T * g_points[g_dragPoint] * inverse(T)));
    }

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

    // redraw viewport
    glutPostRedisplay();
}

void menuCallback(int value) {
    g_mode = value;

    // redraw viewport
    glutPostRedisplay();
}

int main(int argc, char*argv[]) {
    // profiling for Gaigen 2:
    c3ga::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);

    g_GLUTmenu = glutCreateMenu(menuCallback);
    glutAddMenuEntry("line mode", MODE_LINE);
    glutAddMenuEntry("circle mode", MODE_CIRCLE);
    glutAddMenuEntry("line mode + plunge", MODE_LINE_WITH_PLANE);
    glutAddMenuEntry("circle mode + plunge", MODE_CIRCLE_WITH_SPHERE);

    glutAttachMenu(GLUT_MIDDLE_BUTTON);
    glutAttachMenu(GLUT_RIGHT_BUTTON);

    glutMainLoop();

    return 0;
}