#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>
#include <errno.h>

#include <patty/ax25.h>

static int init_tnc(patty_ax25_if *iface, patty_ax25_if_kiss_tnc_info *info) {
    static char *prefix = "kiss";
    static int number = 0;

    iface->tnc = (info->type == PATTY_AX25_IF_KISS_TNC_INFO_FD)?
        patty_kiss_tnc_new_fd(info->fd):
        patty_kiss_tnc_new(info->path);

    if (iface->tnc == NULL) {
        goto error_kiss_tnc_new;
    }

    iface->type = PATTY_AX25_IF_KISS_TNC;

    snprintf(iface->name, sizeof(iface->name), "%s%d", prefix, number++);

    return 0;

error_kiss_tnc_new:
    return -1;
}

static void destroy_tnc(patty_ax25_if *iface) {
    patty_kiss_tnc_destroy(iface->tnc);
}

patty_ax25_if *patty_ax25_if_new(int opts, patty_ax25_if_info *info) {
    patty_ax25_if *iface;

    if ((iface = malloc(sizeof(*iface))) == NULL) {
        goto error_malloc_iface;
    }

    memset(iface, '\0', sizeof(*iface));

    if (info->addr.callsign[0] == '\0') {
        errno = EINVAL;

        goto error_invalid_address;
    }

    /*
     * TODO: Eventually inherit the half/full-duplex flag from the TNC this
     * interface is bound to
     */
    iface->flags = PATTY_AX25_PARAM_DEFAULT_CLASSES
                 | PATTY_AX25_PARAM_CLASSES_HALF_DUPLEX;

    if ((iface->rx_buf = malloc(PATTY_AX25_IF_DEFAULT_MRU)) == NULL) {
        goto error_malloc_rx_buf;
    } else {
        iface->mru = PATTY_AX25_IF_DEFAULT_MRU;
    }

    if ((iface->tx_buf = malloc(PATTY_AX25_IF_DEFAULT_MTU)) == NULL) {
        goto error_malloc_tx_buf;
    } else {
        iface->mtu = PATTY_AX25_IF_DEFAULT_MTU;
    }

    if ((iface->aliases = patty_list_new()) == NULL) {
        goto error_list_new_aliases;
    }

    if ((iface->promisc_fds = patty_dict_new()) == NULL) {
        goto error_dict_new_promisc_fds;
    }

    switch (PATTY_AX25_IF_OPT_TYPE(opts)) {
        case PATTY_AX25_IF_KISS_TNC:
            if (init_tnc(iface, (patty_ax25_if_kiss_tnc_info *)info) < 0) {
                goto error_init;
            }
            
            break;

        default:
            errno = EINVAL;

            goto error_invalid_if_type;
    }

    memcpy(&iface->addr, &info->addr, sizeof(iface->addr));

    return iface;

error_invalid_if_type:
error_init:
    patty_dict_destroy(iface->promisc_fds);

error_dict_new_promisc_fds:
    patty_list_destroy(iface->aliases);

error_list_new_aliases:
    free(iface->tx_buf);

error_malloc_tx_buf:
    free(iface->rx_buf);

error_malloc_rx_buf:
    free(iface);

error_malloc_iface:
error_invalid_address:
    return NULL;
}

void patty_ax25_if_destroy(patty_ax25_if *iface) {
    switch (iface->type) {
        case PATTY_AX25_IF_KISS_TNC:
            destroy_tnc(iface);
            break;

        default:
            break;
    }

    patty_dict_destroy(iface->promisc_fds);
    patty_list_destroy(iface->aliases);

    free(iface->tx_buf);
    free(iface->rx_buf);
    free(iface);
}

int patty_ax25_if_addr_each(patty_ax25_if *iface,
                            int (*callback)(char *, void *), void *ctx) {
    patty_list_item *item = iface->aliases->first;

    char buf[7];
    uint8_t ssid;

    if (patty_ax25_ntop(&iface->addr, buf, &ssid, sizeof(buf)) < 0) {
        goto error_ntop_addr;
    }

    if (callback(buf, ctx) < 0) {
        goto error_callback_addr;
    }

    while (item) {
        patty_ax25_addr *addr = item->value;

        if (patty_ax25_ntop(addr, buf, &ssid, sizeof(buf)) < 0) {
            goto error_ntop;
        }

        if (callback(buf, ctx) < 0) {
            goto error_callback;
        }

        item = item->next;
    }

    return 0;

error_callback:
error_ntop:
error_callback_addr:
error_ntop_addr:
    return -1;
}

static patty_ax25_addr *find_addr(patty_ax25_if *iface,
                                  const char *callsign) {
    patty_list_item *item = iface->aliases->first;

    char buf[7];
    uint8_t ssid;

    if (patty_ax25_ntop(&iface->addr, buf, &ssid, sizeof(buf)) < 0) {
        goto error_ntop_addr;
    }

    if (strncmp(buf, callsign, sizeof(buf)) == 0) {
        return &iface->addr;
    }

    while (item) {
        patty_ax25_addr *addr = item->value;

        if (patty_ax25_ntop(addr, buf, &ssid, sizeof(buf)) < 0) {
            goto error_ntop;
        }

        if (strncmp(buf, callsign, sizeof(buf)) != 0) {
            goto next;
        }
        
        return addr;
next:
        item = item->next;
    }

error_ntop:
error_ntop_addr:
    return NULL;
}

int patty_ax25_if_addr_add(patty_ax25_if *iface,
                           const char *callsign) {
    patty_ax25_addr *addr;

    if (find_addr(iface, callsign) != NULL) {
        errno = EEXIST;

        goto error_exists;
    }

    if ((addr = malloc(sizeof(*addr))) == NULL) {
        goto error_malloc_addr;
    }

    if (patty_ax25_pton(callsign, 0, addr) < 0) {
        goto error_pton;
    }

    if ((patty_list_append(iface->aliases, addr)) == NULL) {
        goto error_list_append;
    }

    return 0;

error_list_append:
error_pton:
    free(addr);

error_malloc_addr:
error_exists:
    return -1;
}

int patty_ax25_if_addr_delete(patty_ax25_if *iface,
                              const char *callsign) {
    patty_list_item *item = iface->aliases->first;
    int i = 0;

    while (item) {
        char buf[7];
        uint8_t ssid;

        patty_ax25_addr *addr = item->value;

        if (patty_ax25_ntop(addr, buf, &ssid, sizeof(buf)) < 0) {
            goto error_ntop;
        }

        if (strncmp(buf, callsign, sizeof(buf)) == 0) {
            if (patty_list_splice(iface->aliases, i) == NULL) {
                goto error_list_splice;
            }
        }

        item = item->next;
        i++;
    }

    return 0;

error_list_splice:
error_ntop:
    return -1;
}

int patty_ax25_if_promisc_add(patty_ax25_if *iface,
                              int fd) {
    patty_kiss_tnc *tnc;

    if (patty_dict_get(iface->promisc_fds, (uint32_t)fd)) {
        errno = EEXIST;

        goto error_exists;
    }

    if ((tnc = patty_kiss_tnc_new_fd(fd)) == NULL) {
        goto error_kiss_tnc_new_fd;
    }

    if (patty_dict_set(iface->promisc_fds,
                       (uint32_t)fd,
                       tnc) == NULL) {
        errno = ENOMEM;

        goto error_dict_set;
    }

    return 0;

error_dict_set:
    patty_kiss_tnc_destroy(tnc);

error_kiss_tnc_new_fd:
error_exists:
    return -1;
}

int patty_ax25_if_promisc_delete(patty_ax25_if *iface,
                                 int fd) {
    patty_kiss_tnc *tnc;

    if ((tnc = patty_dict_get(iface->promisc_fds, (uint32_t)fd)) == NULL) {
        errno = ENOENT;

        goto error_notfound;
    }

    patty_kiss_tnc_destroy(tnc);

    return patty_dict_delete(iface->promisc_fds, (uint32_t)fd);

error_notfound:
    return -1;
}

struct promisc_frame {
    const void *buf;
    size_t len;
    patty_ax25_if *iface;
};

static int handle_promisc_frame(uint32_t key,
                                void *value,
                                void *ctx) {
    patty_kiss_tnc *tnc = value;
    struct promisc_frame *frame = ctx;

    return patty_kiss_tnc_send(tnc, frame->buf, frame->len, 0);
}

ssize_t patty_ax25_if_pending(patty_ax25_if *iface) {
    return patty_kiss_tnc_pending(iface->tnc);
}

ssize_t patty_ax25_if_recv(patty_ax25_if *iface,
                           void **buf) {
    ssize_t readlen;
    int port;
    struct promisc_frame frame;

    if ((readlen = patty_kiss_tnc_recv(iface->tnc,
                                       iface->rx_buf,
                                       iface->mru,
                                       &port)) < 0) {
        goto error_kiss_tnc_recv;
    } else if (readlen == 0) {
        goto done;
    }

    *buf = iface->rx_buf;

    iface->stats.rx_frames++;
    iface->stats.rx_bytes += readlen;

    frame.buf   = iface->rx_buf;
    frame.len   = readlen;
    frame.iface = iface;

    if (patty_dict_each(iface->promisc_fds,
                        handle_promisc_frame,
                        &frame) < 0) {
        goto error_handle_promisc_frame;
    }

done:
    return readlen;

error_handle_promisc_frame:
error_kiss_tnc_recv:
    return -1;
}

ssize_t patty_ax25_if_send(patty_ax25_if *iface,
                           const void *buf,
                           size_t len) {
    ssize_t wrlen;
    struct promisc_frame frame;

    if ((wrlen = patty_kiss_tnc_send(iface->tnc, buf, len, 0)) < 0) {
        goto error_kiss_tnc_send;
    }

    iface->stats.tx_frames++;
    iface->stats.tx_bytes += wrlen;

    frame.buf   = buf;
    frame.len   = wrlen;
    frame.iface = iface;

    if (patty_dict_each(iface->promisc_fds,
                        handle_promisc_frame,
                        &frame) < 0) {
        goto error_handle_promisc_frame;
    }

    return wrlen;

error_handle_promisc_frame:
error_kiss_tnc_send:
    return -1;
}