#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifndef _MSC_VER
#include <unistd.h>
#endif
#include "SDL.h"
#include "SDL_net.h"

#define TIMEOUT (5000) /*five seconds */
#define ERROR (0xff)

int udpsend(UDPsocket sock, int channel, UDPpacket *out, UDPpacket *in, Uint32 delay, Uint8 expect, int timeout)
{
	Uint32 t,t2;
	int err;
	
	in->data[0]=0;
	t=SDL_GetTicks();
	do
	{
		t2=SDL_GetTicks();
		if(t2-t>(Uint32) timeout)
		{
			printf("timed out\n");
			return(0);
		}
		if(!SDLNet_UDP_Send(sock, channel, out))
		{
			printf("SDLNet_UDP_Send: %s\n",SDLNet_GetError());
			exit(1);
		}
		err=SDLNet_UDP_Recv(sock, in);
		if(!err)
			SDL_Delay(delay);
	} while(!err || (in->data[0]!=expect && in->data[0]!=ERROR));
	if(in->data[0]==ERROR)
		printf("received error code\n");
	return(in->data[0]==ERROR?-1:1);
}

int udprecv(UDPsocket sock, UDPpacket *in, Uint32 delay, Uint8 expect, int timeout)
{
	Uint32 t,t2;
	int err;
	
	in->data[0]=0;
	t=SDL_GetTicks();
	do
	{
		t2=SDL_GetTicks();
		if(t2-t>(Uint32) timeout)
		{
			/*printf("timed out\n"); // this is commented to look nicer... */
			return(0);
		}
		err=SDLNet_UDP_Recv(sock, in);
		if(!err)
			SDL_Delay(delay);
	} while(!err || (in->data[0]!=expect && in->data[0]!=ERROR));
	if(in->data[0]==ERROR)
		printf("received error code\n");
	return(in->data[0]==ERROR?-1:1);
}

int main(int argc, char **argv)
{
	Uint16 port;
	char *host,*fname,*fbasename;
	Sint32 flen,pos,p2;
	int len,blocks,i,err=0;
	Uint32 ack;
	IPaddress ip;
	UDPsocket sock;
	UDPpacket *in, *out;
	FILE *f;
	
	/* check our commandline */
	if(argc<4)
	{
		printf("%s host port file\n",argv[0]);
		exit(0);
	}
	
	/* initialize SDL */
	if(SDL_Init(0)==-1)
	{
		printf("SDL_Init: %s\n",SDL_GetError());
		exit(1);
	}

	/* initialize SDL_net */
	if(SDLNet_Init()==-1)
	{
		printf("SDLNet_Init: %s\n",SDLNet_GetError());
		exit(2);
	}

	/* get the host from the commandline */
	host=argv[1];
	/* get the port from the commandline */
	port=(Uint16) strtol(argv[2],NULL,0);
	if(!port)
	{
		printf("a server port cannot be 0.\n");
		exit(3);
	}
	/* get filename to get from server from commandline */
	fname=argv[3];

	if(SDLNet_ResolveHost(&ip,host,port)==-1)
	{
		printf("SDLNet_ResolveHost: %s\n",SDLNet_GetError());
		exit(4);
	}
	
	/* open udp client socket */
	if(!(sock=SDLNet_UDP_Open(0)))
	{
		printf("SDLNet_UDP_Open: %s\n",SDLNet_GetError());
		exit(5);
	}

	/* allocate max packet */
	if(!(out=SDLNet_AllocPacket(65535)))
	{
		printf("SDLNet_AllocPacket: %s\n",SDLNet_GetError());
		exit(6);
	}
	if(!(in=SDLNet_AllocPacket(65535)))
	{
		printf("SDLNet_AllocPacket: %s\n",SDLNet_GetError());
		exit(6);
	}
	
	/* bind server address to channel 0 */
	if(SDLNet_UDP_Bind(sock, 0, &ip)==-1)
	{
		printf("SDLNet_UDP_Bind: %s\n",SDLNet_GetError());
		exit(7);
	}

	/* open output file */
	fbasename=strrchr(fname,'/');
	if(!fbasename)
		fbasename=fname;
	else
		fbasename++;
	printf("writting file: %s\n",fbasename);
	if(!(f=fopen(fbasename,"wb")))
	{
		perror("fopen");
		exit(8);
	}

	/* request file / expect filesize */
	printf("requesting file=%s\n",fname);
	out->data[0]=1<<4;
	strcpy((char*)out->data+1,fname);
	out->len=strlen(fname)+2;
	if(udpsend(sock,0,out,in,200,1,TIMEOUT)<1)
		exit(9);
	
	flen=SDLNet_Read32(in->data+1);
	len=SDLNet_Read32(in->data+5);
	blocks=(flen+len-1)/len;
	printf("flen=%d blocksize=%d blocks=%d\n",flen,len,blocks);

	/* send ready / expect file */
	printf("starting transfer\n");
	out->data[0]=2<<4;
	out->len=1;
	if(udpsend(sock,0,out,in,10,2,TIMEOUT)<1)
		exit(10);
	
	if(flen<0)
	{
		printf("file not available...\n");
		exit(11);
	}

	pos=0; /* count per 32 blocks */
	while(pos*32<blocks && !err)
	{
		/*printf("pos=%d\n",pos); */
		ack=0;
		if((pos+1)*32>=blocks)
		{
			for(i=blocks%32;i<32;i++)
				ack|=1<<i;
		}
		printf("\r                                                                  "
				"\r%3d%% %08x: ",(pos*3200)/blocks,pos*32*len);
		while(ack!=0xffffffff && !err)
		{
			i=in->data[1];
			p2=SDLNet_Read32(in->data+2);
			/*printf("received %d,%d\n",i,p2); */
			if(!(ack&1<<i) && p2>=pos*32*len)
			{
				fseek(f,p2,SEEK_SET);
				fwrite(in->data+6,in->len-6,1,f);
				ack|=1<<i;

				printf(".");
				fflush(stdout);
			}
			if(ack!=0xffffffff)
				err=udprecv(sock,in,10,2,500);
			if(err<0)
				continue; /* error... */
			if(!err)
			{
				/*printf("sending ack 0x%0X\n",ack); */
				out->data[0]=3<<4;
				SDLNet_Write32(pos*32*len,out->data+1);
				SDLNet_Write32(ack,out->data+5);
				out->len=9;
				SDLNet_UDP_Send(sock,0,out);
			}
			err=0;
		}
		pos++;
	}
	
	printf("\ndone.\n");

	fclose(f);
	
	/* close the socket */
	SDLNet_UDP_Close(sock);
	
	/* free packets */
	SDLNet_FreePacket(out);
	SDLNet_FreePacket(in);
	
	/* shutdown SDL_net */
	SDLNet_Quit();

	/* shutdown SDL */
	SDL_Quit();

	return(0);
}