/*
 *  OpenSCAD (www.openscad.org)
 *  Copyright (C) 2009-2011 Clifford Wolf <clifford@clifford.at> and
 *                          Marius Kintel <marius@kintel.net>
 *
 *  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.
 *
 *  As a special exception, you have permission to link this program
 *  with the CGAL library and distribute executables, as long as you
 *  follow the requirements of the GNU GPL in regard to all of the
 *  software in the executable aside from CGAL.
 *
 *  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
 *
 */

#include "GLView.h"
#include "Preferences.h"
#include "renderer.h"

#include <QApplication>
#include <QWheelEvent>
#include <QCheckBox>
#include <QDialogButtonBox>
#include <QMouseEvent>
#include <QMessageBox>
#include <QPushButton>
#include <QSettings>
#include <QTimer>
#include <QTextEdit>
#include <QVBoxLayout>
#include "mathc99.h"
#include <stdio.h>

#ifdef ENABLE_OPENCSG
#  include <opencsg.h>
#endif

#ifdef _WIN32
#include <GL/wglew.h>
#elif !defined(__APPLE__)
#include <GL/glxew.h>
#endif

#define FAR_FAR_AWAY 100000.0

GLView::GLView(QWidget *parent) : QGLWidget(parent), renderer(NULL)
{
	init();
}

GLView::GLView(const QGLFormat & format, QWidget *parent) : QGLWidget(format, parent)
{
	init();
}

void GLView::init()
{
	this->viewer_distance = 500;
	this->object_rot_x = 35;
	this->object_rot_y = 0;
	this->object_rot_z = -25;
	this->object_trans_x = 0;
	this->object_trans_y = 0;
	this->object_trans_z = 0;

	this->mouse_drag_active = false;

	this->showedges = false;
	this->showfaces = true;
	this->orthomode = false;
	this->showaxes = false;
	this->showcrosshairs = false;

	for (int i = 0; i < 10; i++)
		this->shaderinfo[i] = 0;

	this->statusLabel = NULL;

	setMouseTracking(true);
#ifdef ENABLE_OPENCSG
	this->is_opencsg_capable = false;
	this->has_shaders = false;
	this->opencsg_support = true;
	static int sId = 0;
	this->opencsg_id = sId++;
#endif
}

void GLView::setRenderer(Renderer *r)
{
	this->renderer = r;
	updateGL();
}

void GLView::initializeGL()
{
	glEnable(GL_DEPTH_TEST);
	glDepthRange(-FAR_FAR_AWAY, +FAR_FAR_AWAY);

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	GLfloat light_diffuse[] = {1.0, 1.0, 1.0, 1.0};
	GLfloat light_position0[] = {-1.0, -1.0, +1.0, 0.0};
	GLfloat light_position1[] = {+1.0, +1.0, -1.0, 0.0};

	glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
	glLightfv(GL_LIGHT0, GL_POSITION, light_position0);
	glEnable(GL_LIGHT0);
	glLightfv(GL_LIGHT1, GL_DIFFUSE, light_diffuse);
	glLightfv(GL_LIGHT1, GL_POSITION, light_position1);
	glEnable(GL_LIGHT1);
	glEnable(GL_LIGHTING);
	glEnable(GL_NORMALIZE);

	glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
	glEnable(GL_COLOR_MATERIAL);

#ifdef ENABLE_OPENCSG
	GLenum err = glewInit();
	if (GLEW_OK != err) {
		fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
	}

	const char *openscad_disable_gl20_env = getenv("OPENSCAD_DISABLE_GL20");
	if (openscad_disable_gl20_env && !strcmp(openscad_disable_gl20_env, "0")) {
		openscad_disable_gl20_env = NULL;
	}

	// All OpenGL 2 contexts are OpenCSG capable
	if (GLEW_VERSION_2_0 && !openscad_disable_gl20_env) this->is_opencsg_capable = true;
	// If OpenGL < 2, check for extensions
	else if (GLEW_ARB_framebuffer_object) this->is_opencsg_capable = true;
	else if (GLEW_EXT_framebuffer_object && GLEW_EXT_packed_depth_stencil) {
		this->is_opencsg_capable = true;
	}
#ifdef WIN32
	else if (WGLEW_ARB_pbuffer && WGLEW_ARB_pixel_format) this->is_opencsg_capable = true;
#elif !defined(__APPLE__)
	else if (GLXEW_SGIX_pbuffer && GLXEW_SGIX_fbconfig) this->is_opencsg_capable = true;
#endif

	if (GLEW_VERSION_2_0 && !openscad_disable_gl20_env) this->has_shaders = true;

	if (!this->is_opencsg_capable) {
		opencsg_support = false;
		QSettings settings;
		// FIXME: This should be an OpenCSG capability warning, not an OpenGL 2 warning
		if (settings.value("editor/opengl20_warning_show",true).toBool()) {
			QTimer::singleShot(0, this, SLOT(display_opencsg_warning()));
		}
	}
	if (opencsg_support && this->has_shaders) {
		const char *vs_source =
			"uniform float xscale, yscale;\n"
			"attribute vec3 pos_b, pos_c;\n"
			"attribute vec3 trig, mask;\n"
			"varying vec3 tp, tr;\n"
			"varying float shading;\n"
			"void main() {\n"
			"  vec4 p0 = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
			"  vec4 p1 = gl_ModelViewProjectionMatrix * vec4(pos_b, 1.0);\n"
			"  vec4 p2 = gl_ModelViewProjectionMatrix * vec4(pos_c, 1.0);\n"
			"  float a = distance(vec2(xscale*p1.x/p1.w, yscale*p1.y/p1.w), vec2(xscale*p2.x/p2.w, yscale*p2.y/p2.w));\n"
			"  float b = distance(vec2(xscale*p0.x/p0.w, yscale*p0.y/p0.w), vec2(xscale*p1.x/p1.w, yscale*p1.y/p1.w));\n"
			"  float c = distance(vec2(xscale*p0.x/p0.w, yscale*p0.y/p0.w), vec2(xscale*p2.x/p2.w, yscale*p2.y/p2.w));\n"
			"  float s = (a + b + c) / 2.0;\n"
			"  float A = sqrt(s*(s-a)*(s-b)*(s-c));\n"
			"  float ha = 2.0*A/a;\n"
			"  gl_Position = p0;\n"
			"  tp = mask * ha;\n"
			"  tr = trig;\n"
			"  vec3 normal, lightDir;\n"
			"  normal = normalize(gl_NormalMatrix * gl_Normal);\n"
			"  lightDir = normalize(vec3(gl_LightSource[0].position));\n"
			"  shading = abs(dot(normal, lightDir));\n"
			"}\n";

		const char *fs_source =
			"uniform vec4 color1, color2;\n"
			"varying vec3 tp, tr, tmp;\n"
			"varying float shading;\n"
			"void main() {\n"
			"  gl_FragColor = vec4(color1.r * shading, color1.g * shading, color1.b * shading, color1.a);\n"
			"  if (tp.x < tr.x || tp.y < tr.y || tp.z < tr.z)\n"
			"    gl_FragColor = color2;\n"
			"}\n";

		GLuint vs = glCreateShader(GL_VERTEX_SHADER);
		glShaderSource(vs, 1, (const GLchar**)&vs_source, NULL);
		glCompileShader(vs);

		GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
		glShaderSource(fs, 1, (const GLchar**)&fs_source, NULL);
		glCompileShader(fs);

		GLuint edgeshader_prog = glCreateProgram();
		glAttachShader(edgeshader_prog, vs);
		glAttachShader(edgeshader_prog, fs);
		glLinkProgram(edgeshader_prog);

		shaderinfo[0] = edgeshader_prog;
		shaderinfo[1] = glGetUniformLocation(edgeshader_prog, "color1");
		shaderinfo[2] = glGetUniformLocation(edgeshader_prog, "color2");
		shaderinfo[3] = glGetAttribLocation(edgeshader_prog, "trig");
		shaderinfo[4] = glGetAttribLocation(edgeshader_prog, "pos_b");
		shaderinfo[5] = glGetAttribLocation(edgeshader_prog, "pos_c");
		shaderinfo[6] = glGetAttribLocation(edgeshader_prog, "mask");
		shaderinfo[7] = glGetUniformLocation(edgeshader_prog, "xscale");
		shaderinfo[8] = glGetUniformLocation(edgeshader_prog, "yscale");

		GLenum err = glGetError();
		if (err != GL_NO_ERROR) {
			fprintf(stderr, "OpenGL Error: %s\n", gluErrorString(err));
		}

		GLint status;
		glGetProgramiv(edgeshader_prog, GL_LINK_STATUS, &status);
		if (status == GL_FALSE) {
			int loglen;
			char logbuffer[1000];
			glGetProgramInfoLog(edgeshader_prog, sizeof(logbuffer), &loglen, logbuffer);
			fprintf(stderr, "OpenGL Program Linker Error:\n%.*s", loglen, logbuffer);
		} else {
			int loglen;
			char logbuffer[1000];
			glGetProgramInfoLog(edgeshader_prog, sizeof(logbuffer), &loglen, logbuffer);
			if (loglen > 0) {
				fprintf(stderr, "OpenGL Program Link OK:\n%.*s", loglen, logbuffer);
			}
			glValidateProgram(edgeshader_prog);
			glGetProgramInfoLog(edgeshader_prog, sizeof(logbuffer), &loglen, logbuffer);
			if (loglen > 0) {
				fprintf(stderr, "OpenGL Program Validation results:\n%.*s", loglen, logbuffer);
			}
		}
	}
#endif /* ENABLE_OPENCSG */
}

#ifdef ENABLE_OPENCSG
void GLView::display_opencsg_warning()
{
	// data
	QString title = QString("OpenGL context is not OpenCSG capable");

	QString rendererinfo;
	rendererinfo.sprintf("GLEW version %s\n"
											 "%s (%s)\n"
											 "OpenGL version %s\n",
											 glewGetString(GLEW_VERSION),
											 glGetString(GL_RENDERER), glGetString(GL_VENDOR),
											 glGetString(GL_VERSION));

	QString message = QString("Warning: Missing OpenGL capabilities for OpenCSG - OpenCSG has been disabled.\n\n"
			"It is highly recommended to use OpenSCAD on a system with OpenGL 2.0, "
			"or support for the framebuffer_object or pbuffer extensions. "
			"Your renderer information is as follows:\n\n%1").arg(rendererinfo);

	QString note = QString("Uncheck to hide this message in the future");

	// presentation
	QDialog *dialog = new QDialog(this);
	dialog->setSizeGripEnabled(true);
	dialog->setWindowTitle(title);
	dialog->resize(500,300);

	QVBoxLayout *layout = new QVBoxLayout(dialog);
	dialog->setLayout(layout);

	QTextEdit *textEdit = new QTextEdit(dialog);
	textEdit->setPlainText(message);
	layout->addWidget(textEdit);

	QCheckBox *checkbox = new QCheckBox(note,dialog);
	checkbox->setCheckState(Qt::Checked);
	layout->addWidget(checkbox);

	QDialogButtonBox *buttonbox =
		new QDialogButtonBox(	QDialogButtonBox::Ok, Qt::Horizontal,dialog);
	layout->addWidget(buttonbox);
	buttonbox->button(QDialogButtonBox::Ok)->setFocus();
	buttonbox->button(QDialogButtonBox::Ok)->setDefault(true);

	// action
	connect(buttonbox, SIGNAL(accepted()), dialog, SLOT(accept()));
	connect(checkbox, SIGNAL(clicked(bool)),
		Preferences::inst()->openCSGWarningBox, SLOT(setChecked(bool)));
	connect(checkbox, SIGNAL(clicked(bool)),
		Preferences::inst(), SLOT(openCSGWarningChanged(bool)));
	dialog->exec();
}
#endif

void GLView::resizeGL(int w, int h)
{
#ifdef ENABLE_OPENCSG
	shaderinfo[9] = w;
	shaderinfo[10] = h;
#endif
	glViewport(0, 0, w, h);
	w_h_ratio = sqrt((double)w / (double)h);

	setupPerspective();
}

void GLView::setupPerspective()
{
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glFrustum(-w_h_ratio, +w_h_ratio, -(1/w_h_ratio), +(1/w_h_ratio), +10.0, +FAR_FAR_AWAY);
}

void GLView::setupOrtho(double distance, bool offset)
{
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	if(offset)
		glTranslated(-0.8, -0.8, 0);
	double l = distance/10;
	glOrtho(-w_h_ratio*l, +w_h_ratio*l,
			-(1/w_h_ratio)*l, +(1/w_h_ratio)*l,
			-FAR_FAR_AWAY, +FAR_FAR_AWAY);
}

void GLView::paintGL()
{
	glEnable(GL_LIGHTING);

	if (orthomode)
		setupOrtho(viewer_distance);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	const QColor &bgcol = Preferences::inst()->color(Preferences::BACKGROUND_COLOR);
	glClearColor(bgcol.redF(), bgcol.greenF(), bgcol.blueF(), 0.0);

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

	gluLookAt(0.0, -viewer_distance, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0);

	glTranslated(object_trans_x, object_trans_y, object_trans_z);

	glRotated(object_rot_x, 1.0, 0.0, 0.0);
	glRotated(object_rot_y, 0.0, 1.0, 0.0);
	glRotated(object_rot_z, 0.0, 0.0, 1.0);

  // FIXME: Crosshairs and axes are lighted, this doesn't make sense and causes them
  // to change color based on view orientation.
	if (showcrosshairs)
	{
		glLineWidth(3);
		const QColor &col = Preferences::inst()->color(Preferences::CROSSHAIR_COLOR);
		glColor3f(col.redF(), col.greenF(), col.blueF());
		glBegin(GL_LINES);
		for (double xf = -1; xf <= +1; xf += 2)
		for (double yf = -1; yf <= +1; yf += 2) {
			double vd = viewer_distance/20;
			glVertex3d(-xf*vd, -yf*vd, -vd);
			glVertex3d(+xf*vd, +yf*vd, +vd);
		}
		glEnd();
	}

	// Large gray axis cross inline with the model
  // FIXME: This is always gray - adjust color to keep contrast with background
	if (showaxes)
	{
		glLineWidth(1);
		glColor3d(0.5, 0.5, 0.5);
		glBegin(GL_LINES);
		double l = viewer_distance/10;
		glVertex3d(-l, 0, 0);
		glVertex3d(+l, 0, 0);
		glVertex3d(0, -l, 0);
		glVertex3d(0, +l, 0);
		glVertex3d(0, 0, -l);
		glVertex3d(0, 0, +l);
		glEnd();
	}

	glDepthFunc(GL_LESS);
	glCullFace(GL_BACK);
	glDisable(GL_CULL_FACE);

	glLineWidth(2);
	glColor3d(1.0, 0.0, 0.0);

	if (this->renderer) {
#if defined(ENABLE_MDI) && defined(ENABLE_OPENCSG)
		// FIXME: This belongs in the OpenCSG renderer, but it doesn't know about this ID yet
		OpenCSG::setContext(this->opencsg_id);
#endif
		this->renderer->draw(showfaces, showedges);
	}

	// Small axis cross in the lower left corner
	if (showaxes)
	{
		glDepthFunc(GL_ALWAYS);

		setupOrtho(1000,true);

		gluLookAt(0.0, -1000, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0);

		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
		glRotated(object_rot_x, 1.0, 0.0, 0.0);
		glRotated(object_rot_y, 0.0, 1.0, 0.0);
		glRotated(object_rot_z, 0.0, 0.0, 1.0);

		glLineWidth(1);
		glBegin(GL_LINES);
		glColor3d(1.0, 0.0, 0.0);
		glVertex3d(0, 0, 0); glVertex3d(10, 0, 0);
		glColor3d(0.0, 1.0, 0.0);
		glVertex3d(0, 0, 0); glVertex3d(0, 10, 0);
		glColor3d(0.0, 0.0, 1.0);
		glVertex3d(0, 0, 0); glVertex3d(0, 0, 10);
		glEnd();

		GLdouble mat_model[16];
		glGetDoublev(GL_MODELVIEW_MATRIX, mat_model);

		GLdouble mat_proj[16];
		glGetDoublev(GL_PROJECTION_MATRIX, mat_proj);

		GLint viewport[4];
		glGetIntegerv(GL_VIEWPORT, viewport);

		GLdouble xlabel_x, xlabel_y, xlabel_z;
		gluProject(12, 0, 0, mat_model, mat_proj, viewport, &xlabel_x, &xlabel_y, &xlabel_z);
		xlabel_x = round(xlabel_x); xlabel_y = round(xlabel_y);

		GLdouble ylabel_x, ylabel_y, ylabel_z;
		gluProject(0, 12, 0, mat_model, mat_proj, viewport, &ylabel_x, &ylabel_y, &ylabel_z);
		ylabel_x = round(ylabel_x); ylabel_y = round(ylabel_y);

		GLdouble zlabel_x, zlabel_y, zlabel_z;
		gluProject(0, 0, 12, mat_model, mat_proj, viewport, &zlabel_x, &zlabel_y, &zlabel_z);
		zlabel_x = round(zlabel_x); zlabel_y = round(zlabel_y);

		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glTranslated(-1, -1, 0);
		glScaled(2.0/viewport[2], 2.0/viewport[3], 1);

		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();

		// FIXME: This was an attempt to keep contrast with background, but is suboptimal
		// (e.g. nearly invisible against a gray background).
		int r,g,b;
		bgcol.getRgb(&r, &g, &b);
		glColor3d((255.0-r)/255.0, (255.0-g)/255.0, (255.0-b)/255.0);
		glBegin(GL_LINES);
		// X Label
		glVertex3d(xlabel_x-3, xlabel_y-3, 0); glVertex3d(xlabel_x+3, xlabel_y+3, 0);
		glVertex3d(xlabel_x-3, xlabel_y+3, 0); glVertex3d(xlabel_x+3, xlabel_y-3, 0);
		// Y Label
		glVertex3d(ylabel_x-3, ylabel_y-3, 0); glVertex3d(ylabel_x+3, ylabel_y+3, 0);
		glVertex3d(ylabel_x-3, ylabel_y+3, 0); glVertex3d(ylabel_x, ylabel_y, 0);
		// Z Label
		glVertex3d(zlabel_x-3, zlabel_y-3, 0); glVertex3d(zlabel_x+3, zlabel_y-3, 0);
		glVertex3d(zlabel_x-3, zlabel_y+3, 0); glVertex3d(zlabel_x+3, zlabel_y+3, 0);
		glVertex3d(zlabel_x-3, zlabel_y-3, 0); glVertex3d(zlabel_x+3, zlabel_y+3, 0);
		glEnd();

		//Restore perspective for next paint
		if(!orthomode)
			setupPerspective();
	}

	if (statusLabel) {
		QString msg;
		msg.sprintf("Viewport: translate = [ %.2f %.2f %.2f ], rotate = [ %.2f %.2f %.2f ], distance = %.2f",
			-object_trans_x, -object_trans_y, -object_trans_z,
			fmodf(360 - object_rot_x + 90, 360), fmodf(360 - object_rot_y, 360), fmodf(360 - object_rot_z, 360), viewer_distance);
		statusLabel->setText(msg);
	}
}

void GLView::keyPressEvent(QKeyEvent *event)
{
	if (event->key() == Qt::Key_Plus) {
		viewer_distance *= 0.9;
		updateGL();
		return;
	}
	if (event->key() == Qt::Key_Minus) {
		viewer_distance /= 0.9;
		updateGL();
		return;
	}
}

void GLView::wheelEvent(QWheelEvent *event)
{
	viewer_distance *= pow(0.9, event->delta() / 120.0);
	updateGL();
}

void GLView::mousePressEvent(QMouseEvent *event)
{
	mouse_drag_active = true;
	last_mouse = event->globalPos();
	grabMouse();
	setFocus();
}


void GLView::normalizeAngle(GLdouble& angle)
{
	while(angle < 0)
		angle += 360;
	while(angle > 360)
		angle -= 360;
}

void GLView::mouseMoveEvent(QMouseEvent *event)
{
	QPoint this_mouse = event->globalPos();
	double dx = (this_mouse.x()-last_mouse.x()) * 0.7;
	double dy = (this_mouse.y()-last_mouse.y()) * 0.7;
	if (mouse_drag_active) {
		if ((event->buttons() & Qt::LeftButton) != 0) {
			object_rot_x += dy;
			if ((QApplication::keyboardModifiers() & Qt::ShiftModifier) != 0)
				object_rot_y += dx;
			else
				object_rot_z += dx;

			normalizeAngle(object_rot_x);
			normalizeAngle(object_rot_y);
			normalizeAngle(object_rot_z);
		} else {
			if ((QApplication::keyboardModifiers() & Qt::ShiftModifier) != 0) {
				viewer_distance += (GLdouble)dy;
			} else {
				object_trans_x += dx;
				object_trans_z -= dy;
			}
		}
		updateGL();
		emit doAnimateUpdate();
	}
	last_mouse = this_mouse;
}

void GLView::mouseReleaseEvent(QMouseEvent*)
{
	mouse_drag_active = false;
	releaseMouse();
}