/*
 * KISS PTY bridge for max25-bcpr (HyBBX attach via kiss_link symlink).
 */
#define _GNU_SOURCE
#include "bcpr/bcpr_kiss.h"

#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

#if defined(__linux__)
#include <pty.h>
#elif defined(__FreeBSD__)
#include <libutil.h>
#else
#include <util.h>
#endif

static int ensure_dir(const char *path)
{
    char tmp[256];
    char *p;
    size_t len;

    if (!path || !path[0]) {
        return -1;
    }
    snprintf(tmp, sizeof(tmp), "%s", path);
    len = strlen(tmp);
    if (len == 0) {
        return -1;
    }
    if (tmp[len - 1] == '/') {
        tmp[len - 1] = '\0';
    }
    for (p = tmp + 1; *p; p++) {
        if (*p == '/') {
            *p = '\0';
            (void)mkdir(tmp, 0755);
            *p = '/';
        }
    }
    return mkdir(tmp, 0755) == 0 || errno == EEXIST ? 0 : -1;
}

int bcpr_kiss_pty_open(bcpr_kiss_pty_t *kp, int idx, const char *link_path,
                       const char *state_dir)
{
    int master = -1, slave = -1;
    char slave_name[128];
    char dir[128];
    const char *slash;

    memset(kp, 0, sizeof(*kp));
    kp->idx = idx;
    kp->master_fd = -1;
    kp->slave_fd = -1;
    snprintf(kp->link_path, sizeof(kp->link_path), "%s", link_path);

    slash = strrchr(link_path, '/');
    if (slash && slash > link_path) {
        size_t n = (size_t)(slash - link_path);
        if (n >= sizeof(dir)) {
            n = sizeof(dir) - 1;
        }
        memcpy(dir, link_path, n);
        dir[n] = '\0';
        (void)ensure_dir(dir);
    } else {
        (void)ensure_dir(state_dir);
    }

    if (openpty(&master, &slave, slave_name, NULL, NULL) != 0) {
        perror("max25-bcpr openpty");
        return -1;
    }
    if (fchmod(slave, 0660) != 0) {
        perror("max25-bcpr fchmod kiss slave");
    } else {
        struct group *gr = getgrnam("dialout");
        if (gr == NULL) {
            gr = getgrnam("uucp");
        }
        if (gr == NULL) {
            gr = getgrnam("tty");
        }
        if (gr != NULL && fchown(slave, (uid_t)-1, gr->gr_gid) != 0) {
            perror("max25-bcpr fchown kiss slave");
        }
    }
    unlink(link_path);
    if (symlink(slave_name, link_path) != 0) {
        perror("max25-bcpr symlink kiss_link");
        close(slave);
        close(master);
        return -1;
    }
    fcntl(master, F_SETFL, O_NONBLOCK);
    kp->master_fd = master;
    close(slave);
    kp->slave_fd = -1;
    fprintf(stderr, "max25-bcpr: max25e0:bc%d KISS → %s -> %s\n", idx, link_path,
            slave_name);
    return 0;
}

void bcpr_kiss_pty_close(bcpr_kiss_pty_t *kp)
{
    if (!kp) {
        return;
    }
    if (kp->slave_fd >= 0) {
        close(kp->slave_fd);
        kp->slave_fd = -1;
    }
    if (kp->master_fd >= 0) {
        close(kp->master_fd);
        kp->master_fd = -1;
    }
    if (kp->link_path[0]) {
        unlink(kp->link_path);
    }
}