/*
   startuptest.c : Previews Hexen STARTUP screens for GZDoom mods.
   Requires SDL2 and SDL2_mixer.
   (C)2021 Marisa the Magician, UnSX Team.
   Released under the MIT License.
*/

#define _POSIX_C_SOURCE 199309L
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_mixer.h>
#include <time.h>
#include <math.h>

SDL_Window *w = 0;
SDL_Surface *ws = 0, *st = 0;

Mix_Music *startmus = 0;
Mix_Chunk *ticksnd = 0, *dripsnd = 0;

#define ST_MAX_NOTCHES	32
#define ST_NOTCH_WIDTH	16
#define ST_NOTCH_HEIGHT	23
#define ST_PROGRESS_X	64
#define ST_PROGRESS_Y	441

#define ST_NETPROGRESS_X	288
#define ST_NETPROGRESS_Y	32
#define ST_NETNOTCH_WIDTH	4	// 8 in vanilla hexen
#define ST_NETNOTCH_HEIGHT	16
#define ST_MAX_NETNOTCHES	8

SDL_Color pal[16], pals[16] = {{0,0,0,0xFF}};
Uint8 startup[640*480], notch[ST_NOTCH_WIDTH*ST_NOTCH_HEIGHT], netnotch[ST_NETNOTCH_WIDTH*ST_NETNOTCH_HEIGHT];
int donet = 0;

int ReadFiles( const char *s, const char *n, const char *nn )
{
	FILE *f = fopen(s,"rb");
	if ( !f )
	{
		fprintf(stderr,"Could not open startup file: %s\n",strerror(errno));
		return 1;
	}
	// read palette
	for ( int i=0; i<16; i++ )
	{
		fread(&pal[i],1,3,f);
		pal[i].r <<= 2;
		pal[i].g <<= 2;
		pal[i].b <<= 2;
		pal[i].a = 0xFF;
	}
	// read image
	memset(&startup[0],0,640*480);
	for ( int i=0; i<4; i++ ) for ( int j=0; j<(640*480); j+=8 )
	{
		Uint8 bits;
		fread(&bits,1,1,f);
		startup[j] |= ((bits>>7)&1)<<i;
		startup[j+1] |= ((bits>>6)&1)<<i;
		startup[j+2] |= ((bits>>5)&1)<<i;
		startup[j+3] |= ((bits>>4)&1)<<i;
		startup[j+4] |= ((bits>>3)&1)<<i;
		startup[j+5] |= ((bits>>2)&1)<<i;
		startup[j+6] |= ((bits>>1)&1)<<i;
		startup[j+7] |= (bits&1)<<i;
	}
	fclose(f);
	// read notch
	memset(&notch[0],0,ST_NOTCH_WIDTH*ST_NOTCH_HEIGHT);
	f = fopen(n,"rb");
	if ( !f )
	{
		fprintf(stderr,"Could not open notch file: %s\n",strerror(errno));
		return 1;
	}
	for ( int i=0; i<(ST_NOTCH_WIDTH*ST_NOTCH_HEIGHT); i+=2 )
	{
		Uint8 bits;
		fread(&bits,1,1,f);
		notch[i] = (bits>>4)&0xF;
		notch[i+1] = bits&0xF;
	}
	fclose(f);
	// read netnotch
	memset(&netnotch[0],0,ST_NETNOTCH_WIDTH*ST_NETNOTCH_HEIGHT);
	if ( !donet ) return 0;
	f = fopen(nn,"rb");
	if ( !f )
	{
		fprintf(stderr,"Could not open netnotch file: %s\n",strerror(errno));
		return 1;
	}
	for ( int i=0; i<(ST_NETNOTCH_WIDTH*ST_NETNOTCH_HEIGHT); i+=2 )
	{
		Uint8 bits;
		fread(&bits,1,1,f);
		netnotch[i] = (bits>>4)&0xF;
		netnotch[i+1] = bits&0xF;
	}
	fclose(f);
	return 0;
}

enum EStartupState
{
	STATE_FADEIN,
	STATE_NOTCH,
	STATE_NETNOTCH,
	STATE_WAIT
};

double gametime;

#define NANOS_SEC 1000000000L

long ticker( void )
{
	struct timespec ts;
	clock_gettime(CLOCK_MONOTONIC_RAW,&ts);
	return ts.tv_nsec+ts.tv_sec*NANOS_SEC;
}

int main( int argc, char **argv )
{
	if ( (argc > 1) && !strcmp(argv[1],"-n") ) donet = 1;
	if ( argc < 3+donet*2 )
	{
		fprintf(stderr,	"usage: startuptest <startup path> <notch path> [music path] [tick path]\n"
				"       startuptest -n <startup path> <notch path> <netnotch path> [music path] [tick path] [drip path]\n");
		return 1;
	}
	if ( ReadFiles(argv[1+donet],argv[2+donet],donet?argv[4]:"") )
		return 1;
	SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO|SDL_INIT_TIMER|SDL_INIT_EVENTS);
	w = SDL_CreateWindow("STARTUP TEST",SDL_WINDOWPOS_UNDEFINED,SDL_WINDOWPOS_UNDEFINED,640,480,SDL_WINDOW_SHOWN);
	ws = SDL_GetWindowSurface(w);
	st = SDL_CreateRGBSurface(0,640,480,8,0,0,0,0);
	SDL_SetSurfaceBlendMode(st,SDL_BLENDMODE_NONE);
	SDL_SetPaletteColors(st->format->palette,&pals[0],0,16);
	Mix_Init(MIX_INIT_FLAC|MIX_INIT_MOD|MIX_INIT_MP3|MIX_INIT_OGG);
	Mix_OpenAudio(48000,MIX_DEFAULT_FORMAT,2,4096);
	if ( argc > 3+donet*2 ) startmus = Mix_LoadMUS(argv[3+donet*2]);
	if ( argc > 4+donet*2 ) ticksnd = Mix_LoadWAV(argv[4+donet*2]);
	if ( donet && (argc > 7) ) dripsnd = Mix_LoadWAV(argv[7]);
	SDL_Event e;
	int active = 1;
	long tick, tock;
	if ( startmus ) Mix_PlayMusic(startmus,-1);
	// first blit
	SDL_LockSurface(st);
	memcpy(st->pixels,&startup[0],640*480);
	SDL_UnlockSurface(st);
	int state = STATE_FADEIN;
	int fadestep = 0;
	int ncnt = 0;
	while ( active )
	{
		tick = ticker();
		while ( SDL_PollEvent(&e) ) if ( (e.type == SDL_QUIT)
			|| ((e.type == SDL_KEYDOWN)
			&& (e.key.keysym.sym == SDLK_ESCAPE)) ) active = 0;
		switch ( state )
		{
		case STATE_FADEIN:
			switch ( fadestep )
			{
			case 0:
				if ( gametime > .125 )
				{
					fadestep = 1;
					gametime = 0.;
				}
				break;
			case 1:
				ncnt++;
				for ( int i=0; i<16; i++ )
				{
					pals[i].r = (pal[i].r*ncnt)/8;
					pals[i].g = (pal[i].g*ncnt)/8;
					pals[i].b = (pal[i].b*ncnt)/8;
				}
				SDL_SetPaletteColors(st->format->palette,&pals[0],0,16);
				fadestep = 0;
				gametime = 0.;
				if ( ncnt >= 8 )
				{
					ncnt = 0;
					state = STATE_NOTCH;
					gametime = -1.;
				}
				break;
			}
			break;
		case STATE_NOTCH:
			switch ( fadestep )
			{
			case 0:
				if ( gametime > 1. )
				{
					fadestep++;
					gametime = (float)ncnt/(ST_MAX_NOTCHES);
					gametime = powf(gametime,.25)*.9;
				}
				break;
			case 1:
				if ( ticksnd ) Mix_PlayChannel(0,ticksnd,0);
				SDL_LockSurface(st);
				// draw notch
				for ( int i=0; i<ST_NOTCH_HEIGHT; i++ )
					memcpy((Uint8*)st->pixels+(ST_PROGRESS_Y+i)*640+ST_PROGRESS_X+ST_NOTCH_WIDTH*ncnt,&notch[0]+ST_NOTCH_WIDTH*i,ST_NOTCH_WIDTH);
				SDL_UnlockSurface(st);
				ncnt++;
				if ( ncnt >= ST_MAX_NOTCHES ) fadestep = 2;
				else fadestep = 0;
				break;
			case 2:
				if ( donet ) state = STATE_NETNOTCH;
				else state = STATE_WAIT;
				fadestep = 0;
				gametime = 0.;
				ncnt = 0;
				break;
			}
			break;
		case STATE_NETNOTCH:
			switch ( fadestep )
			{
			case 0:
				if ( gametime > 1. )
				{
					fadestep++;
					gametime = 0.;
				}
				break;
			case 1:
				if ( dripsnd ) Mix_PlayChannel(0,dripsnd,0);
				SDL_LockSurface(st);
				// draw netnotch
				for ( int i=0; i<ST_NETNOTCH_HEIGHT; i++ )
					memcpy((Uint8*)st->pixels+(ST_NETPROGRESS_Y+i)*640+ST_NETPROGRESS_X+ST_NETNOTCH_WIDTH*ncnt,&netnotch[0]+ST_NETNOTCH_WIDTH*i,ST_NETNOTCH_WIDTH);
				SDL_UnlockSurface(st);
				ncnt++;
				if ( ncnt >= ST_MAX_NETNOTCHES ) fadestep = 2;
				else fadestep = 0;
				break;
			case 2:
				state = STATE_WAIT;
				fadestep = 0;
				gametime = 0.;
				break;
			}
			break;
		case STATE_WAIT:
			// wow it's literally nothing
			break;
		}
		SDL_BlitSurface(st,0,ws,0);
		SDL_UpdateWindowSurface(w);
		tock = ticker();
		gametime += (float)(tock-tick)/NANOS_SEC;
	}
	if ( startmus ) Mix_HaltMusic();
	if ( dripsnd ) Mix_FreeChunk(dripsnd);
	if ( ticksnd ) Mix_FreeChunk(ticksnd);
	if ( startmus ) Mix_FreeMusic(startmus);
	Mix_Quit();
	SDL_FreeSurface(st);
	SDL_DestroyWindow(w);
	SDL_Quit();
	return 0;
}