/***************************************************************************

  gbx_c_process.c

  (c) 2000-2009 Benoît Minisini <gambas@users.sourceforge.net>

  This program 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, or (at your option)
  any later version.

  This program 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 this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

***************************************************************************/

#define __GBX_C_PROCESS_C

#include "gbx_info.h"

#ifndef GBX_INFO

#include "gb_common.h"
#include "gb_common_buffer.h"

#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <termios.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
/* granpt(), unlockpt() and ptsname() unavailable under OpenBSD
	and are replaced with openpty() implementation because of security
	issues */
#ifdef OS_OPENBSD
#include <util.h>
#endif

#include "gb_replace.h"
#include "gbx_api.h"
#include "gambas.h"
#include "gbx_stream.h"
#include "gb_array.h"
#include "gbx_exec.h"
#include "gbx_class.h"
#include "gbx_watch.h"
#include "gbx_project.h"
#include "gbx_c_array.h"
#include "gbx_local.h"

#include "gbx_c_process.h"

//#define DEBUG_ME

extern char **environ;

DECLARE_EVENT(EVENT_Read);
DECLARE_EVENT(EVENT_Error);
DECLARE_EVENT(EVENT_Kill);

static CPROCESS *RunningProcessList = NULL;
static int _pipe_child[2];
static bool _init = FALSE;

static int _last_status = 0;

static void init_child(void);
static void exit_child(void);

static void callback_write(int fd, int type, CPROCESS *process)
{
	#ifdef DEBUG_ME
	fprintf(stderr, "callback_write: %d %p\n", fd, process);
	#endif
	
	if (process->to_string)
	{
		int n = read(fd, COMMON_buffer, 256);
		if (n > 0)
		{
			STRING_add(&process->result, COMMON_buffer, n);
			CSTREAM_stream(process)->process.read_something = TRUE;
			//#ifdef DEBUG_ME
			//fprintf(stderr, "callback_write: result = '%s'\n", process->result);
			//#endif
		}
	}
	else if (!STREAM_eof(CSTREAM_stream(process))) //process->running &&
		GB_Raise(process, EVENT_Read, 0);
}


static int callback_error(int fd, int type, CPROCESS *process)
{
	/*fprintf(stderr, ">> Write\n"); fflush(stderr);*/
	char buffer[1024];
	int n;

	#ifdef DEBUG_ME
	fprintf(stderr, "callback_error: %d %p\n", fd, process);
	#endif

	n = read(fd, buffer, sizeof(buffer));

	if (n <= 0) /* || !process->running)*/
	{
		/*close(process->err);*/
		return TRUE;
	}

	/*printf("callback_error: (%d) %.*s\n", n, n, buffer);*/

	GB_Raise(process, EVENT_Error, 1,
		GB_T_STRING, buffer, n);

	return FALSE;

	/*fprintf(stderr, "<< Write\n"); fflush(stderr);*/
}


static void update_stream(CPROCESS *process)
{
	STREAM *stream = &process->ob.stream;

	stream->type = &STREAM_process;
	(*stream->type->open)(stream, NULL, 0, process);
}


static void init_process(CPROCESS *process)
{
	process->watch = GB_WATCH_NONE;
	process->in = process->out = process->err = -1;
	update_stream(process);
	process->tag.type = GB_T_NULL;
}

static void exit_process(CPROCESS *_object)
{
	/* Normalement impossible */
	/*
	if (THIS->running)
	{
		fprintf(stderr, "WARNING: CPROCESS_free: running ?\n");
		stop_process(THIS);
	}
	*/

	#ifdef DEBUG_ME
	fprintf(stderr, "exit_process: %p\n", _object);
	#endif

	if (THIS->in >= 0)
	{
		if (THIS->in != THIS->out)
			close(THIS->in);
		THIS->in = -1;
	}

	if (THIS->out >= 0)
	{
		GB_Watch(THIS->out, GB_WATCH_NONE, NULL, 0);
		close(THIS->out);
		THIS->out = -1;
	}

	if (THIS->err >= 0)
	{
		GB_Watch(THIS->err, GB_WATCH_NONE, NULL, 0);
		close(THIS->err);
		THIS->err = -1;
	}

	// Why that ? This should be done only at process creation
	// update_stream(THIS);
	STREAM_close(&THIS->ob.stream);
	GB_StoreVariant(NULL, &THIS->tag);
}

static void stop_process_after(CPROCESS *_object)
{
	STREAM *stream;
	//long long len;

	#ifdef DEBUG_ME
	fprintf(stderr, "stop_process_after: %p\n", _object);
	#endif

	/* Vidage du tampon d'erreur */
	if (THIS->err >= 0)
		while (callback_error(THIS->err, 0, THIS) == 0);

	/* Vidage du tampon de sortie */
	if (THIS->out >= 0)
	{
		stream = CSTREAM_stream(THIS);
		while (!STREAM_eof(stream))
		{
			stream->process.read_something = FALSE;
			callback_write(THIS->out, 0, THIS);
			//GB_Raise(THIS, EVENT_Read, 0);
			if (!stream->process.read_something)
				break;
		}
	}

	GB_Raise(THIS, EVENT_Kill, 0);

	exit_process(THIS);

	OBJECT_detach((OBJECT *)THIS);

	/*printf("** stop_process_after\n");*/
	//GB_Unref((void **)&_object); /* Ref du post */
}


static void stop_process(CPROCESS *process)
{
	if (!process->running)
		return;

	#ifdef DEBUG_ME
	fprintf(stderr, "stop_process: %p\n", process);
	#endif

	/*process->pid = -1;*/

	/* Remove from running process list */

	if (process->prev)
		process->prev->next = process->next;

	if (process->next)
		process->next->prev = process->prev;

	if (process == RunningProcessList)
		RunningProcessList = process->next;

	process->running = FALSE;

	/*printf("** stop_process\n");*/

	stop_process_after(process);

	OBJECT_UNREF(process, "stop_process"); /* Le processus ne tourne plus */

	if (!RunningProcessList)
		exit_child();
}

static void init_child_tty(int fd)
{
	struct termios terminal = { 0 };
	tcgetattr(fd, &terminal);
	
	terminal.c_iflag |= ICRNL | IXON | IXOFF;
	#ifdef IUTF8
	if (LOCAL_is_UTF8) 
		terminal.c_iflag |= IUTF8;
	#endif
	
	terminal.c_oflag |= OPOST;
	
	terminal.c_lflag |= ISIG | ICANON | IEXTEN | ECHO;

	if (tcsetattr(fd, TCSADRAIN, &terminal))
		exit(127);
}

static void run_process(CPROCESS *process, int mode, void *cmd, CARRAY *env)
{
	static const char *shell[] = { "sh", "-c", NULL, NULL };

	int fdin[2], fdout[2], fderr[2];
	pid_t pid;
	char **argv;
	CARRAY *array;
	int i, n;
	sigset_t sig, old;

	/* for terminal */
	int fd_master = -1;
	int fd_slave;
	char *slave = NULL;
	//struct termios termios_stdin;
	//struct termios termios_check;
	struct termios termios_master;

	init_child();

	if (mode & PM_SHELL)
	{
		#ifdef DEBUG_ME
		fprintf(stderr, "run_process %p: %s\n", process, (char *)cmd);
		#endif

		argv = (char **)shell;

		argv[2] = (char *)cmd;

		if (argv[2] == NULL || *argv[2] == 0)
		{
			/*stop_process(process, FALSE);*/
			return;
		}
	}
	else
	{
		array = (CARRAY *)cmd;
		n = ARRAY_count(array->data);

		if (n == 0)
		{
			/*stop_process(process, FALSE);*/
			return;
		}

		ALLOC(&argv, sizeof(*argv) * (n + 1), "run_process");
		memcpy(argv, array->data, sizeof(*argv) * n);
		argv[n] = NULL;

		for (i = 0; i < n; i++)
		{
			if (!argv[i])
				argv[i] = "";
		}

		#ifdef DEBUG_ME
		{
			int i;

			fprintf(stderr, "run_process %p: ", process);
			for (i = 0; i < n; i++)
				fprintf(stderr, "%s ", argv[i]);
			fprintf(stderr, "\n");
		}
		#endif
	}

	/*printf("** run_process\n");*/
	OBJECT_REF(process, "run_process"); /* Process is running */

	/* Adding to the running process list */

	if (RunningProcessList)
		RunningProcessList->prev = process;

	process->next = RunningProcessList;
	process->prev = NULL;

	RunningProcessList = process;

	process->running = TRUE;

	if (mode & PM_STRING)
	{
		process->to_string = TRUE;
		process->result = NULL;
		mode |= PM_READ;
	}

	if (mode & PM_TERM)
	{
		#ifdef OS_OPENBSD
		if (openpty(&fd_master, &fd_slave, NULL, NULL, NULL)<0)
			THROW_SYSTEM(errno, NULL);
		#else
		fd_master = getpt();
		if (fd_master < 0)
			THROW_SYSTEM(errno, NULL);

		grantpt(fd_master);
		unlockpt(fd_master);
		#endif
		slave = ptsname(fd_master);
	}
	else
	{
		/* Create pipes */

		if ((mode & PM_WRITE) && pipe(fdin) != 0)
			THROW_SYSTEM(errno, NULL);

		if ((mode & PM_READ) && (pipe(fdout) != 0 || pipe(fderr) != 0))
			THROW_SYSTEM(errno, NULL);
	}

	/* Block SIGCHLD */

	sigemptyset(&sig);

	sigaddset(&sig, SIGCHLD);
	sigprocmask(SIG_BLOCK, &sig, &old);

	pid = fork();
	if (pid == (-1))
	{
		stop_process(process);
		sigprocmask(SIG_SETMASK, &old, &sig);
		THROW_SYSTEM(errno, NULL);
	}

	if (pid)
	{
		process->pid = pid;

		#ifdef DEBUG_ME
		fprintf(stderr, "fork: pid = %d\n", pid);
		#endif

		/*printf("Running process %d\n", pid);
		fflush(NULL);*/

		if (mode & PM_TERM)
		{
			if (tcgetattr(fd_master, &termios_master))
				THROW_SYSTEM(errno, NULL);
				
			cfmakeraw(&termios_master);
			//termios_master.c_lflag &= ~ECHO;

			if (tcsetattr(fd_master, TCSANOW, &termios_master))
				THROW_SYSTEM(errno, NULL);
		}

		if (mode & PM_WRITE)
		{
			if (mode & PM_TERM)
			{
				process->in = fd_master;
			}
			else
			{
				close(fdin[0]);
				process->in = fdin[1];
			}
		}

		if (mode & PM_READ)
		{
			if (mode & PM_TERM)
			{
				process->out = fd_master;
				process->err = -1;
			}
			else
			{
				close(fdout[1]);
				close(fderr[1]);

				process->out = fdout[0];
				process->err = fderr[0];
			}

			GB_Watch(process->out, GB_WATCH_READ, (void *)callback_write, (intptr_t)process);
			if (process->err >= 0)
			{
				fcntl(process->err, F_SETFL, fcntl(process->err, F_GETFL) | O_NONBLOCK);
				GB_Watch(process->err, GB_WATCH_READ, (void *)callback_error, (intptr_t)process);
			}
		}

		if ((mode & PM_SHELL) == 0)
		{
			FREE(&argv, "run_process");
		}

		sigprocmask(SIG_SETMASK, &old, &sig);
	}
	else /* child */
	{
		//bool stdin_isatty = isatty(STDIN_FILENO);
		
		sigprocmask(SIG_SETMASK, &old, &sig);

		if (mode & PM_TERM)
		{
			close(fd_master);
			setsid();
			fd_slave = open(slave, O_RDWR);
			if (fd_slave < 0)
				exit(127);
			
			if (mode & PM_WRITE)
			{
				if (dup2(fd_slave, STDIN_FILENO) == -1)
					exit(127);
			}

			if (mode & PM_READ)
			{
				if ((dup2(fd_slave, STDOUT_FILENO) == -1)
						|| (dup2(fd_slave, STDERR_FILENO) == -1))
					exit(127);
			}

			// Strange Linux behaviour ?
			// Terminal initialization must be done on STDIN_FILENO after using dup2().
			// If it is done on fd_slave, before using dup2(), it sometimes fails with no error.
			init_child_tty(STDIN_FILENO);
			
			/*puts("---------------------------------");
			if (stdin_isatty) puts("STDIN is a tty");*/
			/*tcgetattr(STDIN_FILENO, &termios_check);
			puts(termios_check.c_lflag & ISIG ? "+ISIG" : "-ISIG");
			//tcsetattr(STDIN_FILENO, TCSADRAIN, &termios_check);
			system("stty icanon");
			system("stty -a");
			puts("---------------------------------");*/
		}
		else
		{
			if (mode & PM_WRITE)
			{
				close(fdin[1]);

				if (dup2(fdin[0], STDIN_FILENO) == -1)
					exit(127);
			}

			if (mode & PM_READ)
			{
				close(fdout[0]);
				close(fderr[0]);

				if ((dup2(fdout[1], STDOUT_FILENO) == -1)
						|| (dup2(fderr[1], STDERR_FILENO) == -1))
					exit(127);
			}
		}

		// Return to the parent working directory
		chdir(PROJECT_oldcwd);
		
		if (env)
		{
			char *str;
			n = ARRAY_count(env->data);
			for (i = 0; i < n; i++)
			{
				str = ((char **)env->data)[i];
				if (putenv(str))
					fprintf(stderr, "warning: cannot set environment string: %s\n", str);
			}
		}
		
		execvp(argv[0], (char **)argv);
		//execve(argv[0], (char **)argv, environ);
		exit(127);
	}

	update_stream(process);
}


static void callback_child(int fd, int type, void *data)
{
	int status;
	CPROCESS *process, *next;
	int buffer;

	/*old = signal(SIGCHLD, signal_child);*/

	read(fd, (char *)&buffer, 1);

	#ifdef DEBUG_ME
	fprintf(stderr, "<< callback_child\n");
	#endif

	for (process = RunningProcessList; process; )
	{
		next = process->next;

		if (wait4(process->pid, &status, WNOHANG, NULL) == process->pid)
		{
			process->status = status;
			_last_status = status;

			#ifdef DEBUG_ME
			fprintf(stderr, "Process %d has returned %d\n", process->pid, status);
			#endif

			/*printf("** signal_child\n");*/

			stop_process(process);
			//stop_process_after(process);
			//break; // one exit at a time // why ?
		}

		process = next;
	}

	#ifdef DEBUG_ME
	fprintf(stderr, ">> callback_child\n");
	#endif
}


static void signal_child(int sig)
{
	#ifdef DEBUG_ME
	fprintf(stderr, "SIGCHLD: _pipe_child[0] = %d\n", _pipe_child[0]);
	#endif
	char buffer;

	if (!_init)
		return;

	buffer = 42;
	write(_pipe_child[1], &buffer, 1);
}


static void init_child(void)
{
	if (_init)
		return;

	#ifdef DEBUG_ME
	fprintf(stderr, "init_child()\n");
	#endif

	if (pipe(_pipe_child) != 0)
		ERROR_panic("Cannot create SIGCHLD pipes");

	fcntl(_pipe_child[0], F_SETFD, FD_CLOEXEC);
	fcntl(_pipe_child[1], F_SETFD, FD_CLOEXEC);

	#ifdef DEBUG_ME
	fprintf(stderr, "_pipe_child[0] = %d\n", _pipe_child[0]);
	#endif

	/* This may work only on Linux. Should use sigaction() instead! */
	signal(SIGCHLD, signal_child);
	GB_Watch(_pipe_child[0], GB_WATCH_READ, (void *)callback_child, 0);
	_init = TRUE;
}

static void exit_child(void)
{
	if (!_init)
		return;

	#ifdef DEBUG_ME
	fprintf(stderr, "exit_child()\n");
	#endif

	GB_Watch(_pipe_child[0], GB_WATCH_NONE, NULL, 0);
	close(_pipe_child[0]);
	close(_pipe_child[1]);
	_init = FALSE;
}


CPROCESS *CPROCESS_create(int mode, void *cmd, char *name, CARRAY *env)
{
	CPROCESS *process;

	/*printf("** CPROCESS_create <<<< \n");*/

	//if (!name || !*name)
	//	name = "Process";

	OBJECT_new((void **)(void *)&process, CLASS_Process, name, OP  ? (OBJECT *)OP : (OBJECT *)CP);

	init_process(process);
	run_process(process, mode, cmd, env);

	OBJECT_UNREF_KEEP(process, "CPROCESS_create");

	if (!name || !*name)
		STREAM_blocking(CSTREAM_stream(process), TRUE);
	
	/*printf("** CPROCESS_create >>>> \n");*/

	return process;
}


void CPROCESS_wait_for(CPROCESS *process)
{
	//sigset_t sig, old;
	//bool have_sigchld;
	int ret;

	#ifdef DEBUG_ME
	printf("Waiting for %d\n", process->pid);
	#endif

	/*sigemptyset(&sig);
	sigaddset(&sig, SIGCHLD);
	sigprocmask(SIG_BLOCK, &sig, &old);

	have_sigchld = sigismember(&old, SIGCHLD);
	if (have_sigchld)
		sigdelset(&old, SIGCHLD);*/

	/*if (process->to_string)
	{
		while (process->running)
			WATCH_loop();
	}
	else
	{
		while (process->running)
			WATCH_loop();
			//sigsuspend(&old);
	}*/
	OBJECT_REF(process, "CPROCESS_wait_for");
	while (process->running)
	{
		//HOOK_DEFAULT(wait, WATCH_wait)(0);
		#ifdef DEBUG_ME
		fprintf(stderr, "watching _pipe_child[0] = %d\n", _pipe_child[0]);
		#endif
		ret = WATCH_process(_pipe_child[0], process->out);
		if (ret == _pipe_child[0])
			callback_child(_pipe_child[0], GB_WATCH_READ, 0);
		else if (ret == process->out)
			callback_write(process->out, GB_WATCH_READ, process);
	}
	OBJECT_UNREF(process, "CPROCESS_wait_for");

	#if 0
	{
		sigsuspend(&old);
		if (!process->running)
			break;

		#ifdef DEBUG_ME
		fprintf(stderr, "Waiting: %d\n", process->running);
		#endif

		sleep(10);
	}
	#endif

	/*if (have_sigchld)
		sigaddset(&old, SIGCHLD);
	sigprocmask(SIG_SETMASK, &old, NULL);*/

	#ifdef DEBUG_ME
	printf("Got it !\n");
	#endif
}



BEGIN_METHOD_VOID(CPROCESS_exit)

	//fprintf(stderr, "CPROCESS_exit\n");

	while (RunningProcessList)
		stop_process(RunningProcessList);

	exit_child();

END_METHOD


BEGIN_METHOD_VOID(CPROCESS_new)

	init_process(THIS);

END_METHOD


BEGIN_METHOD_VOID(CPROCESS_free)

	#ifdef DEBUG_ME
	printf("CPROCESS_free %p\n", THIS);
	#endif

	exit_process(THIS);

END_METHOD


BEGIN_PROPERTY(CPROCESS_id)

	GB_ReturnInt(THIS->pid);

END_PROPERTY


BEGIN_METHOD_VOID(CPROCESS_kill)

	if (!THIS->running)
		return;

	kill(THIS->pid, SIGKILL);
	CPROCESS_wait_for(THIS);

END_METHOD

BEGIN_METHOD_VOID(CPROCESS_signal)

	if (!THIS->running)
		return;

	/*
	printf("Send SIGUSR1 to process %d\n", THIS->pid);
	fflush(NULL);*/
	kill(THIS->pid, SIGUSR1);

END_METHOD


#if 0
BEGIN_METHOD(CPROCESS_send, GB_STRING text)

	if (!THIS->running || THIS->in < 0)
		return;

	STREAM_write(&THIS->ob.stream, STRING(text), LENGTH(text));

END_METHOD
#endif

BEGIN_PROPERTY(CPROCESS_state)

	if (THIS->running)
		GB_ReturnInteger(1);
	else
	{
		if (WIFEXITED(THIS->status))
			GB_ReturnInteger(0);
		else
			GB_ReturnInteger(2);
	}

END_PROPERTY


BEGIN_PROPERTY(CPROCESS_value)

	int status;

	if (THIS->running)
	{
		GB_ReturnInteger(0);
		return;
	}

	status = THIS->status;

	if (WIFEXITED(status))
		GB_ReturnInteger(WEXITSTATUS(status));
	else if (WIFSIGNALED(status))
		GB_ReturnInteger(WTERMSIG(status));
	else
		GB_ReturnInteger(-1);

END_PROPERTY

BEGIN_PROPERTY(CPROCESS_last_state)

	if (WIFEXITED(_last_status))
		GB_ReturnInteger(0);
	else
		GB_ReturnInteger(2);

END_PROPERTY


BEGIN_PROPERTY(CPROCESS_last_value)

	int status;

	status = _last_status;

	if (WIFEXITED(status))
		GB_ReturnInteger(WEXITSTATUS(status));
	else if (WIFSIGNALED(status))
		GB_ReturnInteger(WTERMSIG(status));
	else
		GB_ReturnInteger(-1);

END_PROPERTY

BEGIN_PROPERTY(CPROCESS_tag)

	if (READ_PROPERTY)
		GB_ReturnVariant(&THIS->tag);
	else
		GB_StoreVariant(PROP(GB_VARIANT), (void *)&THIS->tag);

END_METHOD

BEGIN_METHOD_VOID(CPROCESS_wait)

	CPROCESS_wait_for(THIS);

END_METHOD

#endif

GB_DESC NATIVE_Process[] =
{
	GB_DECLARE("Process", sizeof(CPROCESS)), GB_NOT_CREATABLE(),
	GB_INHERITS("Stream"),

	GB_CONSTANT("Stopped", "i", 0),
	GB_CONSTANT("Running", "i", 1),
	GB_CONSTANT("Crashed", "i", 2),
	GB_CONSTANT("Signaled", "i", 2),

	GB_STATIC_PROPERTY_READ("LastState", "i", CPROCESS_last_state),
	GB_STATIC_PROPERTY_READ("LastValue", "i", CPROCESS_last_value),
	
	GB_PROPERTY_READ("Id", "i", CPROCESS_id),
	GB_PROPERTY_READ("Handle", "i", CPROCESS_id),
	GB_PROPERTY_READ("State", "i", CPROCESS_state),
	GB_PROPERTY_READ("Value", "i", CPROCESS_value),
	GB_PROPERTY("Tag", "v", CPROCESS_tag),

	//GB_STATIC_METHOD("_init", NULL, CPROCESS_init, NULL),
	GB_STATIC_METHOD("_exit", NULL, CPROCESS_exit, NULL),
	GB_METHOD("_new", NULL, CPROCESS_new, NULL),
	GB_METHOD("_free", NULL, CPROCESS_free, NULL),

	GB_METHOD("Kill", NULL, CPROCESS_kill, NULL),
	GB_METHOD("Signal", NULL, CPROCESS_signal, NULL),
	GB_METHOD("Wait", NULL, CPROCESS_wait, NULL),

	//GB_METHOD("Send", NULL, CPROCESS_send, "(Input)s"),
	//GB_METHOD("_print", NULL, CPROCESS_send, "(Input)s"),

	GB_EVENT("Read", NULL, NULL, &EVENT_Read),
	GB_EVENT("Error", NULL, "(Error)s", &EVENT_Error),
	GB_EVENT("Kill", NULL, NULL, &EVENT_Kill),

	GB_END_DECLARE
};