#include <stdlib.h>
#include "defs.h"

#define ERRMSG(p)	fprintf(stderr,"%s: "p"\n",Argv[0])

enum { SUCCESS, FAILURE };		/* DO NOT CHANGE THIS LINE */

static void
Assign( int Argc, char *Argv[ ] )
{
    char *ArgPtr;

    if( Argc != 1 )
	ERRMSG( "Too many args" );
    else
    if( ( ArgPtr = strdup( Argv[ 0 ] ) ) == NULL || putenv( ArgPtr ) )
	ERRMSG( "Can't assign" );
}

static void
Set( int Argc, char *Argv[ ] )
{
    extern char **environ;		/* pointer to the environment */

    int i, ArgLen;
    char *ArgPtr;

    for( i = 0; environ[ i ] != NULL; i++ )
	printf( "%s\n", environ[ i ] );
}

int
Builtin( FullCommand *Buf )
{
    char *Path;
    int Argc = 0;
    char **Argv = Buf->Commands[ 0 ];

    while( Argv[ Argc ] != NULL )
	Argc++;

    if( Argc == 0 )
	return FAILURE;

    if( strchr( Argv[ 0 ], '=' ) != NULL )
	Assign( Argc, Argv );
    else
    if( strcmp( Argv[ 0 ], "set") == 0 )
	Set( Argc, Argv );
    else
    if( strcmp( Argv[ 0 ], "cd") == 0 )
    {
	if( Argc > 1 )
	    Path = Argv[ 1 ];
	else
	if( ( Path = getenv( "HOME" ) ) == NULL )
	    Path = ".";
	if( chdir( Path ) == -1 )
	    ERRMSG( "Can't change directories" );
    }
    else
	return FAILURE;
    if( Buf->NumPipes || Buf->InFile[0] != '\0' || Buf->OutFile[0] != '\0' )
	ERRMSG( "Illegal redirect or pipeline" );
    return SUCCESS;
}