#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <time.h>
#include <signal.h>
#include <dialog.h>
#include "../tlmplib/tlmplib.h"
#include "tlmpdia.h"
#include "tlmpdia.m"


void *forktmp_mapshare (int len)
{
	void *ret = mmap (NULL,len,PROT_READ|PROT_WRITE,MAP_SHARED|MAP_ANONYMOUS,-1,0);
	if (ret == NULL){
		tlmp_error (MSG_U(E_CANTMMAP,"Can't allocate shared memory\n"));
	}
	return ret;
}

void forktmp_unmap (void *pt, int len)
{
	munmap (pt,len);
}


struct _F_forktmp_private{
	int fdout;
	int fdin;
	pid_t pid;
	bool end;
	_F_forktmp_private(){
		pid = (pid_t)-1;
		fdout = -1;
		end = false;
	}
};

struct forkrec{
	enum {RES_NONE,RES_END,RES_JOIN} res;
	int state;
	forkrec();
};

forkrec::forkrec()
{
	res = RES_NONE;
	state = 0;
}

void _F_forktmp::kill()
{
 	::kill (priv->pid,SIGTERM);
}

void _F_forktmp::join(int state)
{
 	forkrec rec;
	rec.res = forkrec::RES_JOIN;
	rec.state = state;
	write (priv->fdout,&rec,sizeof(rec));
	read (priv->fdin,&rec,sizeof(rec));
}

void _F_forktmp::message (bool &end)
{
	end = true;
}

void _F_forktmp::joining (bool &, int)
{
	tlmp_error (MSG_U(E_NOJOINING,"Programming error\n"
		"Child request a join, no joining functag\n"));
}

void _F_forktmp::timeout (bool &end, int)
{
	end = true;
}

void _F_forktmp::failed ()
{
	tlmp_error (MSG_U(E_FORKFAILED
		,"Programming error: Child process %d failed\n")
		,priv->pid);
}

int forktmp (_F_forktmp &c, int timeout, PRIVATE_MESSAGE &endmsg)
{
	_F_forktmp_private priv;
	c.priv = &priv;
	int ret = -1;
	int fds1[2],fds2[2];
	if (pipe(fds1)==-1){
		tlmp_error (MSG_U(E_CANTPIPE,"Can't setup the internal pipe to control subprocess\n"));
	}else if (pipe(fds2)==-1){
		tlmp_error (MSG_R(E_CANTPIPE));
		close (fds1[0]);
		close (fds1[1]);
	}else{
		priv.fdout = fds1[1];
		priv.fdin = fds2[0];
		priv.pid = fork();
		if (priv.pid == 0){
			close (fds1[0]);
			close (fds2[1]);
			c.task();
			forkrec rec;
			rec.res = forkrec::RES_END;
			write (fds1[1],&rec,sizeof(rec));
			_exit (0);
		}else if (priv.pid == (pid_t)-1){
			tlmp_error (MSG_U(E_CANTFORK,"Can't fork a new process (%s)\n")
				,strerror(errno));
			close (fds1[1]);
			close (fds2[0]);
		}else{
			close (fds1[1]);
			close (fds2[0]);
			time_t start = time(NULL);
			while (!priv.end){
				fd_set fdin;
				FD_ZERO (&fdin);
				FD_SET (fds1[0],&fdin);
				int ok = diagui_select (fds1[0]+1,&fdin,timeout,endmsg);
				if (ok == 0){
					int duration = time(NULL)-start;
					c.timeout(priv.end,duration);
				}else if (ok > 0){
					forkrec rec;
					int len = read (fds1[0],&rec,sizeof(rec));
					if (len != sizeof(rec)){
						c.failed();
						priv.end = true;
						ret = -1;
					}else if(rec.res == forkrec::RES_END){
						ret = 0;
						priv.end = true;
					}else if(rec.res == forkrec::RES_JOIN){
						c.joining (priv.end,rec.state);
						if (!priv.end){
							write (fds2[1],&rec,sizeof(rec));
						}		
					}
				}else if (dialog_testmessage(endmsg)){
					c.message(priv.end);
				}
			}
			c.kill();
		}
		close (fds1[0]);
		close (fds2[1]);
	}
	return ret;
}

int forktmp (_F_forktmp &c, int timeout)
{
	PRIVATE_MESSAGE endmsg;
	return forktmp (c,timeout,endmsg);
}

int forktmp (_F_forktmp &c)
{
	PRIVATE_MESSAGE endmsg;
	return forktmp (c,-1,endmsg);
}