/*
	This file is part of Warzone 2100.
	Copyright (C) 2007-2008  Warzone Resurrection Project

	Warzone 2100 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.

	Warzone 2100 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 Warzone 2100; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/

#include "wzmviewer.h"

#include <SDL.h>
#include <SDL_opengl.h>
#include <png.h>

#if (defined(WIN64) || defined(_WIN64) || defined(__WIN64__) || defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__))
#  define strcasecmp _stricmp
#  define strncasecmp _strnicmp
#  define inline __inline
#  define alloca _alloca
#  define fileno _fileno
#  define isfinite _finite
#endif

// The WZM format is a proposed successor to the PIE format used by Warzone.
// For an explanation of the WZM format, see http://wiki.wz2100.net/WZM_format

// To compile: gcc -o wzmviewer wzmviewer.c wzmutils.c -Wall -g -O0 -Wshadow -lpng `sdl-config --libs --cflags` -lGL -lGLU

static char *input = "";
static char *texPath = "";
static SDL_Surface *screen;
static uint32_t now = 0;

static void parse_args(int argc, char **argv)
{
	unsigned int i = 1;

	if (argc < 2 + i)
	{
		fprintf(stderr, "Syntax: wzmviewer filename.wzm path_to_textures\n");
		exit(1);
	}
	input = argv[i++];
	texPath = argv[i++];
}

static void resizeWindow(int width, int height)
{
	glViewport(0, 0, width, height);
}

// Adjust the vector in vec1 with the vector to be in vec2 by fractional value in
// fraction which indicates how far we've come toward vec2. The result is put into
// the result vector.
static void interpolateVectors(Vector3f vec1, Vector3f vec2, Vector3f *result, double fraction)
{
	result->x = vec1.x * (1.0 - fraction) + vec2.x * fraction;
	result->y = vec1.y * (1.0 - fraction) + vec2.y * fraction;
	result->z = vec1.z * (1.0 - fraction) + vec2.z * fraction;
}

static void drawModel(MODEL *psModel, int x, int y)
{
	int i;

	glColor3f(1.0f, 1.0f, 1.0f);
	for (i = 0; i < psModel->meshes; i++)
	{
		MESH *psMesh = &psModel->mesh[i];

		if (psMesh->frameArray)
		{
			FRAME *psFrame = &psMesh->frameArray[psMesh->currentFrame];
			FRAME *nextFrame = psFrame;
			double fraction = 1.0f / (psFrame->timeSlice * 1000) * (now - psMesh->lastChange); // until next frame
			Vector3f vec;

			assert(psMesh->currentFrame < psMesh->frames);

			if (psMesh->currentFrame == psMesh->frames - 1)
			{
				nextFrame = &psMesh->frameArray[0];	// wrap around
			}
			else
			{
				nextFrame = &psMesh->frameArray[psMesh->currentFrame + 1];
			}

			// Try to avoid a crash from crap drivers
			assert(isfinite(psFrame->translation.x) && isfinite(psFrame->translation.y) && isfinite(psFrame->translation.z));
			assert(psFrame->translation.x >= 0.0f && psFrame->translation.y >= 0.0f && psFrame->translation.z >= 0.0f);
			assert(psFrame->rotation.x >= 0.0f && psFrame->rotation.y >= 0.0f && psFrame->rotation.z >= 0.0f);
			assert(psFrame->rotation.x <= 360.0f && psFrame->rotation.y <= 360.0f && psFrame->rotation.z <= 360.0f);

			// Translate
			interpolateVectors(psFrame->translation, nextFrame->translation, &vec, fraction);
			glTranslatef(vec.x, vec.y, vec.z);

			// Rotate
			interpolateVectors(psFrame->rotation, nextFrame->rotation, &vec, fraction);
			glRotatef(vec.x, 1, 0, 0);
			glRotatef(vec.y, 0, 1, 0);
			glRotatef(vec.z, 0, 0, 1);
		}

		glTexCoordPointer(2, GL_FLOAT, 0, psMesh->textureArray[psMesh->currentFrame]);
		glVertexPointer(3, GL_FLOAT, 0, psMesh->vertexArray);

		glDrawElements(GL_TRIANGLES, psMesh->faces * 3, GL_UNSIGNED_INT, psMesh->indexArray);
	}
}

static void prepareModel(MODEL *psModel)
{
	glGenTextures(1, &psModel->texture);
	glBindTexture(GL_TEXTURE_2D, psModel->texture);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, psModel->pixmap->w, psModel->pixmap->h, 0, GL_RGBA,
	             GL_UNSIGNED_BYTE, psModel->pixmap->pixels);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}

int main(int argc, char **argv)
{
	MODEL *psModel;
	const int width = 640, height = 480;
	SDL_Event event;
	GLfloat angle = 0.0f;
	const float aspect = (float)width / (float)height;
	bool quit = false;
	float dimension = 0.0f;
	int i;

	parse_args(argc, argv);

	/* Initialize SDL */
	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) < 0)
	{
		fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
		exit(EXIT_FAILURE);
	}
	atexit(SDL_Quit);

	psModel = readModel(input, texPath);
	psModel->pixmap = readPixmap(psModel->texPath);

	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

	/* Initialize the display */
	screen = SDL_SetVideoMode(width, height, 0, SDL_OPENGL|SDL_ANYFORMAT);
	if (screen == NULL)
	{
		fprintf(stderr, "Couldn't initialize display: %s\n", SDL_GetError());
		exit(EXIT_FAILURE);
	}

	printf("OpenGL version: %s\n", glGetString(GL_VERSION));
	printf("OpenGL renderer: %s\n", glGetString(GL_RENDERER));
	printf("OpenGL vendor: %s\n", glGetString(GL_VENDOR));

	resizeWindow(width, height);
	glEnable(GL_TEXTURE_2D);
	glDisable(GL_FOG);
	glDisable(GL_LIGHTING);
	glEnable(GL_BLEND);
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);
	glClearDepth(1.0f);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glEnableClientState(GL_VERTEX_ARRAY);
	glEnableClientState(GL_TEXTURE_COORD_ARRAY);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0f, aspect, 0.1f, 500.0f);
	glMatrixMode(GL_MODELVIEW);

	prepareModel(psModel);
	for (i = 0; i < psModel->meshes; i++)
	{
		int j;
		MESH *psMesh = &psModel->mesh[i];

		for (j = 0; j < psMesh->vertices * 3; j++)
		{
			dimension = MAX(fabs(psMesh->vertexArray[j]), dimension);
		}
	}

	/* Find model size */

	while (!quit)
	{
		now = SDL_GetTicks();
		while (SDL_PollEvent(&event))
		{
			SDL_keysym *keysym = &event.key.keysym;

			switch (event.type)
			{
				case SDL_VIDEORESIZE:
					resizeWindow(event.resize.w, event.resize.h);
					break;
				case SDL_QUIT:
					quit = true;
					break;
				case SDL_KEYDOWN:
					switch (keysym->sym)
					{
						case SDLK_F1:
							glEnable(GL_CULL_FACE);
							printf("Culling enabled.\n");
							break;
						case SDLK_F2:
							glDisable(GL_CULL_FACE);
							printf("Culling disabled.\n");
							break;
						case SDLK_F3:
							glDisable(GL_TEXTURE_2D);
							glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
							printf("Wireframe mode.\n");
							break;
						case SDLK_F4:
							glEnable(GL_TEXTURE_2D);
							glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
							printf("Texturing mode.\n");
							break;
						case SDLK_ESCAPE:
							quit = true;
							break;
						case SDLK_KP_PLUS:
						case SDLK_PLUS:
							for (i = 0; i < psModel->meshes; i++)
							{
								MESH *psMesh = &psModel->mesh[i];

								if (psMesh->currentFrame < psMesh->frames - 1)
								{
									psMesh->currentFrame++;
								}
								else
								{
									psMesh->currentFrame = 0;
								}
							}
							break;
						default:
							break;
					}
					break;
			}
		}
		// Animation support! :-)
		for (i = 0; i < psModel->meshes; i++)
		{
			MESH *psMesh = &psModel->mesh[i];
			FRAME *psFrame;

			if (!psMesh->frameArray)
			{
				continue;
			}
			psFrame = &psMesh->frameArray[psMesh->currentFrame];

			assert(psMesh->currentFrame < psMesh->frames && psMesh->currentFrame >= 0);
			if (psFrame->timeSlice != 0 && psFrame->timeSlice * 1000 + psMesh->lastChange < now)
			{
				psMesh->lastChange = now;
				psMesh->currentFrame++;
				if (psMesh->currentFrame >= psMesh->frames)
				{
					psMesh->currentFrame = 0;	// loop
				}
			}
		}
		glLoadIdentity();
		glTranslatef(0.0f, -30.0f, -50.0f + -(dimension * 2.0f));;
		glRotatef(angle, 0, 1, 0);
		glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
		drawModel(psModel, 0, 0);
		SDL_GL_SwapBuffers();
		SDL_Delay(10);
		angle += 0.1;
		if (angle > 360.0f)
		{
			angle = 0.0f;
		}
	}

	glDisableClientState(GL_VERTEX_ARRAY);
	glDisableClientState(GL_TEXTURE_COORD_ARRAY);
	freeModel(psModel);
	
	return 0;
}