/* Copyright (c) 1992-2023 John E. Davis
 * This file is part of JED editor library source.
 *
 * You may distribute this file under the terms the GNU General Public
 * License.  See the file COPYING for more information.
 */
/* ///////////////////////////////////////////////////////////////////
//  File:	dos_os2.c
//
//  Descript:	routines that are common to dos & os/2 and `fairly'
//		compiler independent
//		included by i386.c, ibmpc.c, os2.c
//
//  Public:
//		sys_delete_file();
//		sys_suspend();
//		sys_System();
//
//  Private:	discover_shell();
//		parse_command_line();
//
//  Public:	NumLock_Is_Gold, PC_Alt_Char
//
//  Private:	---
//
//  Revisions:
//   - --- --	---	---
/////////////////////////////////////////////////////////////////// */
#ifndef __DOS_OS2_CODE_INCLUDED
#define __DOS_OS2_CODE_INCLUDED

#include "config.h"
#include "jed-feat.h"

#ifdef __GO32__
# include <fcntl.h>
# include <sys/types.h>
# include <sys/stat.h>
# include <sys/file.h>
#endif

#ifdef __os2__
#include <fcntl.h>
#include <io.h>
#include <sys/types.h>
#include <sys/stat.h>
#endif

#ifdef __MSDOS__
#include <fcntl.h>
#include <io.h>
#include <sys/stat.h>
#endif

#ifdef UNIXSLASH
const char SlashChar[2] = "/";
#else
const char SlashChar[2] = "\\";
#endif

int NumLock_Is_Gold = 0;	       /* map numlock key to F1 */
int PC_Alt_Char = 27;

/* Delete the file NAME.  returns 0 on failure, 1 on sucess
 * Under OS/2 and DOS, unlink()[UNIX] and remove()[ANSI] are equivalent.
 */

int sys_delete_file(char *name)
{
    return(1 + remove(name));
}

/* find shell (once only) */
static char *shell = NULL, *shell_switch = NULL;
static void discover_shell(void)
{
   if ( shell != NULL )  return;
#ifdef SH_SHELL			       /* maybe some day ... */
   shell_switch = "-c";
   if ( (shell = getenv("SHELL")) != NULL )  return;
#endif
   shell_switch = "/c";
   if ( (shell = getenv("COMSPEC")) != NULL ) return;
#ifdef __os2__
   shell = "cmd.exe";		       /* absolute last resort! */
#else
   shell = "command.com";	       /* absolute last resort! */
#endif
}

/* ///////////////////////////////////////////////////////////////////
//  Function:   static int parse_command_line( int *argc, char ***argv,
//					       char **fname,
//					       char *command_line );
//  Descript:	parse command_line
//
//  Returns:	the handles to redirect
//
//  Caveat:	requires spaces to separate each argument
//		ie., args>filename	will NOT work
///////////////////////////////////////////////////////////////////// */
#define DIRECT_SPAWN 0x1000	       /* some arbitrary number */
static int
parse_command_line( int *argc, char ***argv, char **fname, char *command_line )
{
   int count, handles = 0;
   char *pt;

   discover_shell();		       /* find which shell to use */
   while ( (*command_line != '\0') && (*command_line == ' '))
     command_line++;		       /* start on 1st non-space */

   if ( *command_line == '!' ) {
      handles = DIRECT_SPAWN;
      command_line++;		       /* advance past '!' */
      while ((*command_line != '\0') && (*command_line == ' '))
      	command_line++;		       /* start on next non-space */
   }

   pt = command_line;
   count = 0;
   while ( *pt != '\0' ) {
      count++;			       /* this is an argument */
      while ((*pt != '\0') && (*pt != ' '))
	{
	   if ( *pt == '|' )	       /* cannot spawn directly */
	     handles = 0;		       /* need shell for pipes */
	   pt++;			       /* advance until a space */
      }
      while ( *pt == ' '  )
      	pt++;			       /* advance until a non-space */
   }

   *argv = (char **) SLmalloc ( (count+3) * sizeof(char *) );
   if ( *argv == NULL )
     return 0;			       /* malloc error */

   *argc = 0;
   if ( !(handles & DIRECT_SPAWN) ) {
      (*argv)[ *argc ] = shell;
      (*argc)++;
      if ( count > 0 )  {
	 (*argv)[ *argc ] = shell_switch;
	 (*argc)++;
      }
      count += (*argc);
   }

   pt = command_line;
   while ((*argc < count) && (*pt != '\0')) {
      (*argv)[ *argc ] = pt;
      (*argc)++;
      while ( *pt != '\0' && *pt != ' ' )
      	pt++;			/* advance until a space */
      if ( *pt != '\0' )
      	*(pt++) = '\0';		/* parse argument here */
      while ( *pt == ' ')
      	pt++;		        /* advance until a non-space */
   }
   (*argv) [ *argc ] = (char *) NULL;	/* NULL terminated list */

/*  now examine the arguments for '>' redirect */

   for ( count = 0; count < *argc; count++ ) {
      for ( pt = (*argv)[count]; *pt && *pt != '>'; pt++ )
	 /* find '>' char */;
      if ( *pt == '>' ) {
	 if ( pt == (*argv)[count] ) {
	    handles |= 0x01;
	 } else {
	    switch ( *(--pt) ) {
	     case '1':
	       handles |= 0x01;
	       break;
	     case '2':
	       handles |= 0x02;
	       break;
	     case '&':
	       handles |= 0x03;
	       break;
	    }
	 }
	 (*argv)[count] = NULL;		/* remove from the list */
	 count++;			/* file name follows '>' */
	 if ( (*argv)[count] != NULL )
	   *fname = (*argv)[count];
      }
   }
   if ((*fname == NULL) || (**fname == '\0' ))
     handles = 0x00;		/* don't redirect if there is no name */

   return handles;
}

/* ///////////////////////////////////////////////////////////////////
//  Function:   int sys_System(char *command_line);
//
//  Descript:	shell wrapper that understands some common redirection syntax
//		command args  > filename		; stdout
//		command args 1> filename		; stdout
//		command args 2> filename		; stderr
//		command args &> filename		; stdout+stderr
//		command args  > filename 2>&1		; stdout+stderr
//
// additionally, if command is prefixed by a '!', then the command is
// spawned directly without invoking the shell
//
//  Returns:	returns error codes as per spawn*()
//
//  Caveat:	requires spaces to separate each argument
//		ie., command args>filename	will NOT work
///////////////////////////////////////////////////////////////////// */

static int execute_the_command (char **, int, char *);

int
sys_System(char *command_line1)
{
   int ret = -1, handles, argc = 0;
   char *fname = NULL, **argv = NULL, *command_line;

   if (NULL == (command_line = SLmake_string (command_line1)))
     return -1;

   handles = parse_command_line( &argc, &argv, &fname, command_line );
   /* Note: The argc that is passed bacl has nothing to do with the
    * actual number of arguments in argv if there are redirections involved.
    * However, if it is non-zero then argv was malloced.
    */
   if (argc)
     {
	ret = execute_the_command (argv, handles, fname);
	SLfree((char *)argv);
     }

   SLfree (command_line);
   return ret;
}

void sys_suspend(void)
{
   sys_System( "" );
}

static int execute_the_command (char **argv, int handles, char *file)
{
   int ret = 0;
   int fd1 = -1, fd2 = -1;
   int fd_err = -1, fd_out = -1;

   if (handles & 1)
     {
	/* save stdout file handle */
	fd1 = dup (fileno (stdout));

	if (fd1 == -1)
	  {
	     msg_error ("Unable to dup stdout");
	     return -1;
	  }

	fd_out = open (file,
		       O_CREAT | O_TRUNC | O_TEXT | O_WRONLY | O_APPEND,
		       S_IREAD | S_IWRITE);

	if ((fd_out == -1) || (-1 == dup2 (fd_out, fileno (stdout))))
	  {
	     msg_error ("Unable to redirect stdout!");
	     ret = -1;
	  }
     }

   if (handles & 0x2)		       /* stderr */
     {
	/* save stderr file handle */
	fd2 = dup (fileno (stderr));

	if (fd2 == -1)
	  {
	     msg_error ("Unable to dup stderr");
	     return -1;
	  }

	if (fd_out == -1)
	  {
	     fd_err = open (file,
			    O_CREAT | O_TRUNC | O_TEXT | O_RDWR | O_APPEND,
			    S_IREAD | S_IWRITE);
	  }
	else fd_err = fd_out;

	if ((fd_err == -1) || (-1 == dup2 (fd_err, fileno (stderr))))
	  {
	     msg_error ("Unable to redirect stderr!");
	     ret = -1;
	  }
     }

   if (fd_out != -1) close (fd_out);
   if ((fd_err != -1) && (fd_err != fd_out)) close (fd_err);

   if (ret == 0)
     {
	ret = spawnvp(P_WAIT, argv[0], (void *) argv);

	if (-1 == ret )
	  {
	     switch(errno)
	       {
		case ENOENT:
		  if (handles & DIRECT_SPAWN ) msg_error("Command not found.");
		  else msg_error("Shell not found.");
		  break;
		case ENOMEM:
		  msg_error("Insufficient Memory.");
		  break;
		default:
		  msg_error("Unknown Error.");
	       }
	  }
     }

   if (fd1 != -1)
     {
	if (-1 == dup2 (fd1, fileno (stdout)))
	  {
	     msg_error ("Unable to reattach stdout");
	  }
	close (fd1);
     }

   if (fd2 != -1)
     {
	if (-1 == dup2 (fd2, fileno (stderr)))
	  {
	     msg_error ("Unable to reattach stderr");
	  }
	close (fd2);
     }

   return ret;
}

#endif	/* whole file */
