#include <u.h>
#include <libc.h>
#include <bio.h>

int ctlfd=-1;
int loop = 1;
long n=0;
int fs=1024*1024;
Biobuf *b;
char *buf;
char c;

void
rfile(char *file, Biobuf *b, char *buf)
{
	if((b=Bopen(file, OREAD)) == nil) sysfatal("Bopen: %r");
	n=Bread(b, buf, fs-1);
	buf[n]=0;
	Bterm(b);
}

void
wfile(char *file, Biobuf *b, char *buf)
{
	if((b=Bopen(file, OWRITE | OTRUNC)) == nil) sysfatal("Bopen: %r");
	if((n=Bwrite(b, buf, fs)) < 0)  sysfatal("Write file: %r");
	Bterm(b);
}

void
main(int argc, char *argv[])
{
	/* validate args */
	if(argc != 2) sysfatal("usage: %s file", argv[0]);

	/* go into raw mode */
	if((ctlfd=open("/dev/consctl", OWRITE)) < 0) sysfatal("Open consctl: %r");
	if(write(ctlfd, "rawon", 5) != 5) sysfatal("Rawmode: %r");

	/* allocate file buffer */
	buf=malloc(fs);

	/* open the file and read it into the buffer then close again */
	rfile(argv[1], b, buf);

	/* open /dev/text and write file content to it then close*/	
	wfile("/dev/text", b, buf);

	/* main loop */
	while(loop)
	{
		read(0, &c, 1);
		switch(c)
		{
			case 0x11:			/* code for ctrl+q */
				loop = 0;
				break;
			case 'w':
				/* open /dev/text for reading and read content to buffer */
				rfile("/dev/text", b, buf);
				/* open file and write buffer to it */
				wfile(argv[1], b, buf);
				break;
			case 'q':
				loop = 0;
				break;
		}
	}
	
	free(buf);
	close(ctlfd);
	exits(nil);
}