#include <u.h>
#include <libn.h>

static struct Flags
{
    uchar f : 1;
    uchar i : 1;
    uchar v : 1;
} flag;

static
char *
strcpyn(char *dst, char *src, int n)
{
    while(*src && n-->0)
        *dst++ = *src++;

    *dst = 0;
    return dst;
}

static
int
mv(char *from, char *to)
{
    io·Stat src, dst;

    if(lstat(from, &src)) {
        errorf("%s", from);
        return 1;
    }

    if(!flag.f && !access(to, F_OK)) {
        int ask = 1;
        int ch, first;

        if(flag.i && !access(from, F_OK))
            fprintf(stderr, "overwrite %s? ", to);
        else
            ask = 0;

        if (ask) {
            first = ch = getchar();
            while (ch != '\n' && ch != EOF)
                ch = getchar();

            if (first != 'y' || first != 'Y')
                return 0;
        }
    }

    if(!rename(from, to)) {
        if (flag.v)
            fprintf(stdout, "%s -> %s\n", from, to);
        return 0;
    }

    /* TODO: errno = EXDEV */
    errorf("rename: %s to %s: %s", from, to, strerror(errno));
    return 1;
}

static
void
usage(void)
{
    fputs("usage: mv [-fiv] source ... dest\n", stderr);
    exit(1);
}

int
main(int argc, char *argv[])
{
    int err, len;
    io·Stat info;
    char *arg, *nm, *e, path[4096];

    ARGBEGIN{
    case 'f':
        flag.f++;
        break;
    case 'i':
        flag.i++;
        break;
    case 'v':
        flag.v++;
        break;
    default:
        usage();
    }ARGEND;

    if(argc < 2)
        usage();

    if(stat(argv[argc-1],&info) || !S_ISDIR(info.st_mode)) {
        if (argc > 2)
            usage();
        exit(mv(argv[0], argv[1]));
    }

    /* we know the last argument is a directory */
    e = strcpyn(path, argv[argc-1], sizeof path-1);
    *e++ = '/';

    for(err=0; --argc; ++argv) {
        arg = argv[0];

        if ((nm = strrchr(arg, '/')) == nil)
            nm = arg;
        else {
            /* case: name/ */
            if (!nm[1]) {
                while(nm >= arg && nm[0] == '/')
                    nm--;
                while(nm >= arg && nm[0] != '/')
                    nm--;
            }
            nm++;
        }

        if ((len = strlen(nm)) >= arrend(path)-e) {
            errorf("%s: path name overflow\n", arg);
            err++;
            continue;
        }
        memmove(e, nm, len+1);
        err += mv(arg, path);
    }
    exit(err);
}