/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>

#include "util/util_opengl.h"
#include "util/util_string.h"
#include "util/util_time.h"
#include "util/util_version.h"
#include "util/util_view.h"

#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

CCL_NAMESPACE_BEGIN

/* structs */

struct View {
	ViewInitFunc initf;
	ViewExitFunc exitf;
	ViewResizeFunc resize;
	ViewDisplayFunc display;
	ViewKeyboardFunc keyboard;
	ViewMotionFunc motion;

	bool first_display;
	bool redraw;

	int mouseX, mouseY;
	int mouseBut0, mouseBut2;

	int width, height;
} V;

/* public */

static void view_display_text(int x, int y, const char *text)
{
	const char *c;

	glRasterPos3f(x, y, 0);

	for(c = text; *c != '\0'; c++)
		glutBitmapCharacter(GLUT_BITMAP_HELVETICA_10, *c);
}

void view_display_info(const char *info)
{
	const int height = 20;

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glColor4f(0.1f, 0.1f, 0.1f, 0.8f);
	glRectf(0.0f, V.height - height, V.width, V.height);
	glDisable(GL_BLEND);

	glColor3f(0.5f, 0.5f, 0.5f);

	view_display_text(10, 7 + V.height - height, info);

	glColor3f(1.0f, 1.0f, 1.0f);
}

void view_display_help()
{
	const int w = (int)((float)V.width  / 1.15f);
	const int h = (int)((float)V.height / 1.15f);

	const int x1 = (V.width - w) / 2;
	const int x2 = x1 + w;

	const int y1 = (V.height - h) / 2;
	const int y2 = y1 + h;

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glColor4f(0.5f, 0.5f, 0.5f, 0.8f);
	glRectf(x1, y1, x2, y2);
	glDisable(GL_BLEND);

	glColor3f(0.8f, 0.8f, 0.8f);

	string info = string("Cycles Renderer ") + CYCLES_VERSION_STRING;

	view_display_text(x1+20, y2-20, info.c_str());
	view_display_text(x1+20, y2-40, "(C) 2011-2016 Blender Foundation");
	view_display_text(x1+20, y2-80, "Controls:");
	view_display_text(x1+20, y2-100, "h:  Info/Help");
	view_display_text(x1+20, y2-120, "r:  Reset");
	view_display_text(x1+20, y2-140, "p:  Pause");
	view_display_text(x1+20, y2-160, "esc:  Cancel");
	view_display_text(x1+20, y2-180, "q:  Quit program");

	view_display_text(x1+20, y2-210, "i:  Interactive mode");
	view_display_text(x1+20, y2-230, "Left mouse:  Move camera");
	view_display_text(x1+20, y2-250, "Right mouse:  Rotate camera");
	view_display_text(x1+20, y2-270, "W/A/S/D:  Move camera");
	view_display_text(x1+20, y2-290, "0/1/2/3:  Set max bounces");

	glColor3f(1.0f, 1.0f, 1.0f);
}

static void view_display()
{
	if(V.first_display) {
		if(V.initf) V.initf();
		if(V.exitf) atexit(V.exitf);

		V.first_display = false;
	}

	glClearColor(0.05f, 0.05f, 0.05f, 0.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, V.width, 0, V.height);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	glRasterPos3f(0, 0, 0);

	if(V.display)
		V.display();

	glutSwapBuffers();
}

static void view_reshape(int width, int height)
{
	if(width <= 0 || height <= 0)
		return;

	V.width = width;
	V.height = height;

	glViewport(0, 0, width, height);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	if(V.resize)
		V.resize(width, height);
}

static void view_keyboard(unsigned char key, int x, int y)
{
	if(V.keyboard)
		V.keyboard(key);

	if(key == 'm')
		printf("mouse %d %d\n", x, y);
	if(key == 'q') {
		if(V.exitf) V.exitf();
		exit(0);
	}
}

static void view_mouse(int button, int state, int x, int y)
{
	if(button == 0) {
		if(state == GLUT_DOWN) {
			V.mouseX = x;
			V.mouseY = y;
			V.mouseBut0 = 1;
		}
		else if(state == GLUT_UP) {
			V.mouseBut0 = 0;
		}
	}
	else if(button == 2) {
		if(state == GLUT_DOWN) {
			V.mouseX = x;
			V.mouseY = y;
			V.mouseBut2 = 1;
		}
		else if(state == GLUT_UP) {
			V.mouseBut2 = 0;
		}
	}
}

static void view_motion(int x, int y)
{
	const int but = V.mouseBut0? 0:2;
	const int distX = x - V.mouseX;
	const int distY = y - V.mouseY;

	if(V.motion)
		V.motion(distX, distY, but);

	V.mouseX = x;
	V.mouseY = y;
}

static void view_idle(void)
{
	if(V.redraw) {
		V.redraw = false;
		glutPostRedisplay();
	}

	time_sleep(0.1);
}

void view_main_loop(const char *title, int width, int height,
	ViewInitFunc initf, ViewExitFunc exitf,
	ViewResizeFunc resize, ViewDisplayFunc display,
	ViewKeyboardFunc keyboard, ViewMotionFunc motion)
{
	const char *name = "app";
	char *argv = (char*)name;
	int argc = 1;

	memset(&V, 0, sizeof(V));
	V.width = width;
	V.height = height;
	V.first_display = true;
	V.redraw = false;
	V.initf = initf;
	V.exitf = exitf;
	V.resize = resize;
	V.display = display;
	V.keyboard = keyboard;
	V.motion = motion;

	glutInit(&argc, &argv);
	glutInitWindowSize(width, height);
	glutInitWindowPosition(0, 0);
	glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE|GLUT_DEPTH);
	glutCreateWindow(title);

	mxMakeCurrentContext(mxCreateContext());

	view_reshape(width, height);

	glutDisplayFunc(view_display);
	glutIdleFunc(view_idle);
	glutReshapeFunc(view_reshape);
	glutKeyboardFunc(view_keyboard);
	glutMouseFunc(view_mouse);
	glutMotionFunc(view_motion);

	glutMainLoop();
}

void view_redraw()
{
	V.redraw = true;
}

CCL_NAMESPACE_END