/* Copyright (C) 2018  Causal Agent June <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <err.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sysexits.h>
#include <unistd.h>

int main(int argc, char *argv[]) {
    if (argc < 2) errx(EX_USAGE, "missing private id");

    const char *path = argv[1];
    int local = open(path, O_WRONLY);
    if (local < 0) err(EX_NOINPUT, "%s", path);

    int remote = STDIN_FILENO;

    struct winsize window;
    ssize_t size = read(remote, &window, sizeof(window));
    if (size < 0) err(EX_IOERR, "read(%d)", remote);
    if ((size_t)size < sizeof(window)) errx(EX_DATAERR, "short read(%d)", remote);

    for (;;) {
        ftruncate(local, 0);
        lseek(local, 0, SEEK_SET);

        ssize_t size = write(local, &window, sizeof(window));
        if (size < 0) err(EX_IOERR, "write(%d)", local);

        char buf[4096];
        for (size_t totalSize = 0; totalSize < 1024 * 1024; totalSize += size) {
            size = read(remote, buf, sizeof(buf));
            if (size < 0) err(EX_IOERR, "read(%d)", remote);
            if (!size) return EX_OK;

            size = write(local, buf, size);
            if (size < 0) err(EX_IOERR, "write(%d)", local);
        }
    }
}