/* Simple shell to run on SOS */
/* 
 * Orignally written by Gernot Heiser 
 * - updated by Ben Leslie 2003  
 * - updated by Charles Gray 2006
 */

#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>

/* Your OS header file */
#include <sos.h>

#define BUF_SIZ   128
#define MAX_ARGS   32

static fildes_t in;
static stat_t   sbuf;

static void 
prstat(const char *name)
{
    /* print out stat buf */

    printf("%c%c%c%c 0x%06x 0x%lx 0x%06lx %s\n",
	   sbuf.st_type ==ST_SPECIAL ? 's' : '-',
	   sbuf.st_fmode&FM_READ     ? 'r' : '-',
	   sbuf.st_fmode&FM_WRITE    ? 'w' : '-',
	   sbuf.st_fmode&FM_EXEC     ? 'x' : '-',
	   sbuf.st_size, sbuf.st_ctime, sbuf.st_atime, name);
}

static int
cat(int argc, char **argv)
{
    fildes_t fd;
    char buf[BUF_SIZ];
    int num_read, num_written = 0;

    if (argc != 2) {
	printf("Usage: cat filename\n");
	return 1;
    }

    printf("<%s>\n", argv[1]);
    
    fd = open(argv[1], FM_READ);
    
    assert(fd >= 0);

    while( (num_read = read(fd, buf, BUF_SIZ) > 0 ) )
	num_written = write(stdout_fd, buf, num_read);

    if( num_read == -1 || num_written == -1 )
    {
        printf( "error on write\n" );
	return 1;
    }

    return 0;
}


static int
cp(int argc, char **argv)
{
    fildes_t fd, fd_out;
    char *file1, *file2;
    char buf[BUF_SIZ];
    int num_read, num_written = 0;

    if (argc != 3) {
	printf("Usage: cp from to %d\n", argc);
	return 1;
    }

    file1 = argv[1];
    file2 = argv[2];

    fd = open(file1, FM_READ);
    fd_out = open(file2, FM_WRITE);
    
    assert(fd >= 0);

    while( (num_read = read( fd, buf, BUF_SIZ) ) > 0 )
	num_written = write(fd_out, buf, num_read);
    
    if( num_read == -1 || num_written == -1 )
    {
	    printf( "error on cp\n" );
	    return 1;
    }

    return 0;
}

#define MAX_PROCESSES 10

static int 
ps(int argc, char **argv)
{

    process_t *process;
    int i, processes;
    
    process = malloc( MAX_PROCESSES * sizeof(*process) );
    
    if( process == NULL )
    {
        printf( "%s: out of memory\n", argv[0] );
	return 1;
    }

    processes = process_status(process, MAX_PROCESSES);

    printf ("TID SIZE   STIME   CTIME COMMAND\n");

    for (i=0; i<processes; i++) {
	printf ("%3x %4x %7d %7d %s\n", process[i].tid, process[i].size,
	    process[i].stime, process[i].ctime, process[i].command);
    }

    free( process );

    return 0;
}

static int
exec(int argc, char **argv)
{
    pid_t pid;
    int r;
    int bg = 0;

    if (argc < 2 || (argc > 2 && argv[2][0] != '&')) {
	printf("Usage: exec filename [&]\n");
	return 1;
    }

    if ( (argc > 2) && (argv[2][0] == '&') ) {
	bg = 1;
    }

    if (bg == 0) {
	r = close(in);
	assert(r == 0);
    }

    pid = process_create(argv[1]);
    if (pid>=0) {
	printf("Child pid=%d\n", pid);
	if (bg == 0) {
	    process_wait(pid);
	}
    } else {
	printf("Failed!\n");
    }
    if (bg == 0) {
	in = open("console", FM_READ);
	assert(in>=0);
    }
    return 0;
}

static int
dir(int argc, char **argv)
{
    int  i=0, r;
    char buf[BUF_SIZ];
    
    if( argc > 2 )
    {
	    printf( "usage: %s [file]\n", argv[0] );
	    return 1;
    }

    if (argc == 2)
    {
	r = stat(argv[1], &sbuf);
	if( r < 0 )
	{
	    printf("stat(%s) failed: %d\n", buf, r);
	    return 0;
	}
	prstat(argv[1]);
	return 0;
    }
    
    while (1) {
	r = getdirent(i, buf, BUF_SIZ);
	if (r<0) {
	    printf("dirent(%d) failed: %d\n", i, r);
	    break;
	} else if (!r) {
	    break;
	}
#if 0
	printf("dirent(%d): \"%s\"\n", i, buf);
#endif
	r = stat(buf, &sbuf);
	if (r<0) {
	    printf("stat(%s) failed: %d\n", buf, r);
	    break;
	}
	prstat(buf);
	i++;
    }
    return 0;
}

struct command {
    char *name;
    int (*command)(int argc, char **argv);
};

struct command commands[] = {
    {"dir", dir},
    {"ls", dir},
    {"cat", cat},
    {"cp", cp},
    {"ps", ps},
    {"exec", exec}
};
    


int
main(void)
{
    char             buf[BUF_SIZ];
    char             *argv[MAX_ARGS];
    int              i, r, done, found, new, argc;
    char             *bp, *p;
    
    in = open("console", FM_READ);
    assert (in >= 0);
    
    bp   = buf;
    done = 0;
    new  = 1;

    printf("\n[SOS Starting]\n");

    while (!done) {
	if (new) {
	    printf("$ ");
	}
	new   = 0;
	found = 0;

	while (!found && !done) {
	    r = read(in, bp, BUF_SIZ-1+buf-bp);
	    if (r<0) {
		printf("Console read failed!\n");
		done=1;
		break;
	    }
	    bp[r] = 0;		/* terminate */
	    for (p=bp; p<bp+r; p++) {
		if (*p == '\03') {	/* ^C */
		    printf("^C\n");
		    p   = buf;
		    new = 1;
		    break;
		} else if (*p == '\04') {   /* ^D */
		    p++;
		    found = 1;
		} else if (*p == '\010' || *p == 127) {	    
		    /* ^H and BS and DEL */
		    if (p>buf) {
			printf("\010 \010");
			p--;
			r--;
		    }
		    p--;
		    r--;
		} else if (*p == '\n') {    /* ^J */
		    printf("%c",*p);
		    *p    = 0;
		    found = p>buf;
		    p     = buf;
		    new   = 1;
		    break;
		} else {
		    printf("%c",*p);
		}
	    }
	    bp = p;
	    if (bp == buf) {
		break;
	    }
	}

	if (!found) {
	    continue;
	}

	argc = 0;
	p = buf;

	while (*p != '\0')
	{
	    /* Remove any leading spaces */
	    while (*p == ' ')
		p++;
	    if (*p == '\0')
		break;
	    argv[argc++] = p; /* Start of the arg */
	    while (*p != ' ' && *p != '\0') {
		p++;
	    }
	    
	    if (*p == '\0')
		break;

	    /* Null out first space */
	    *p = '\0';
	    p++;
	}
	
	if (argc == 0) {
	    continue;
	}

	found = 0;

	for (i = 0; i < sizeof(commands) / sizeof(struct command); i++) {
	    if (strcmp(argv[0], commands[i].name) == 0) {
		commands[i].command(argc, argv);
		found = 1;
		break;
	    }
	}

	/* Didn't find a command */
	if (found == 0) {
	    /* They might try to exec a program */
	    if (stat(p, &sbuf) != 0) {
		printf("Command \"%s\" not found\n", p);
	    } else if (!(sbuf.st_fmode & FM_EXEC)) {
		printf("File \"%s\" not executable\n", p);
	    } else {
		/* Execute the program */
		argc = 2;
		argv[1] = argv[0];
		argv[0] = "exec";
		exec(argc, argv);
	    }
	}
    }
    printf("[SOS Exiting]\n");
}