/**

 * @file user_yang_types.c

 * @author Michal Vasko <mvasko@cesnet.cz>

 * @brief ietf-yang-types typedef validation and conversion to canonical format

 *

 * Copyright (c) 2018 CESNET, z.s.p.o.

 *

 * This source code is licensed under BSD 3-Clause License (the "License").

 * You may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     https://opensource.org/licenses/BSD-3-Clause

 */

#define _GNU_SOURCE

#include <stdlib.h>

#include <string.h>

#include <stdint.h>

#include <errno.h>

#include <time.h>

#include <ctype.h>

#include "compat.h"

#include "../user_types.h"

/**

 * @brief Storage for ID used to check plugin API version compatibility.

 */

LYTYPE_VERSION_CHECK

#ifdef __GNUC__

#  define UNUSED(x) UNUSED_ ## x __attribute__((__unused__))

#else

#  define UNUSED(x) UNUSED_ ## x

#endif

static int

date_and_time_store_clb(struct ly_ctx *UNUSED(ctx), const char *UNUSED(type_name), const char **value_str,

                        lyd_val *UNUSED(value), char **err_msg)

{

    struct tm tm, tm2;

    uint32_t i, j;

    const char *val_str = *value_str;

    int ret;

    /* \d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d+)?(Z|[\+\-]\d{2}:\d{2})

     * 2018-03-21T09:11:05(.55785...)(Z|+02:00) */

    memset(&tm, 0, sizeof tm);

    i = 0;

    /* year */

    tm.tm_year = atoi(val_str + i);

    /* if there was some invalid number, it will either be discovered in the loop below or by mktime() */

    tm.tm_year -= 1900;

    for (j = i + 4; i < j; ++i) {

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

    }

    if (val_str[i] != '-') {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", '-' expected.", val_str[i], i, val_str);

        goto error;

    }

    ++i;

    /* month */

    tm.tm_mon = atoi(val_str + i);

    tm.tm_mon -= 1;

    for (j = i + 2; i < j; ++i) {

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

    }

    if (val_str[i] != '-') {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", '-' expected.", val_str[i], i, val_str);

        goto error;

    }

    ++i;

    /* day */

    tm.tm_mday = atoi(val_str + i);

    for (j = i + 2; i < j; ++i) {

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

    }

    if (val_str[i] != 'T') {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", 'T' expected.", val_str[i], i, val_str);

        goto error;

    }

    ++i;

    /* hours */

    tm.tm_hour = atoi(val_str + i);

    for (j = i + 2; i < j; ++i) {

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

    }

    if (val_str[i] != ':') {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", ':' expected.", val_str[i], i, val_str);

        goto error;

    }

    ++i;

    /* minutes */

    tm.tm_min = atoi(val_str + i);

    for (j = i + 2; i < j; ++i) {

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

    }

    if (val_str[i] != ':') {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", ':' expected.", val_str[i], i, val_str);

        goto error;

    }

    ++i;

    /* seconds */

    tm.tm_sec = atoi(val_str + i);

    for (j = i + 2; i < j; ++i) {

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

    }

    if ((val_str[i] != '.') && (val_str[i] != 'Z') && (val_str[i] != '+') && (val_str[i] != '-')) {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", '.', 'Z', '+', or '-' expected.",

                       val_str[i], i, val_str);

        goto error;

    }

    /* validate using mktime() */

    tm2 = tm;

    errno = 0;

    mktime(&tm;;

    /* ENOENT is set when "/etc/localtime" is missing but the function suceeeds */

    if (errno && (errno != ENOENT)) {

        ret = asprintf(err_msg, "Checking date-and-time value \"%s\" failed (%s).", val_str, strerror(errno));

        goto error;

    }

    /* we now have correctly filled the remaining values, use them */

    memcpy(((char *)&tm2) + (6 * sizeof(int)), ((char *)&tm) + (6 * sizeof(int)), sizeof(struct tm) - (6 * sizeof(int)));

    /* back it up again */

    tm = tm2;

    /* let mktime() correct date & time with having the other values correct now */

    errno = 0;

    mktime(&tm;;

    if (errno && (errno != ENOENT)) {

        ret = asprintf(err_msg, "Checking date-and-time value \"%s\" failed (%s).", val_str, strerror(errno));

        goto error;

    }

    /* detect changes in the filled values */

    if (memcmp(&tm, &tm2, 6 * sizeof(int))) {

        ret = asprintf(err_msg, "Checking date-and-time value \"%s\" failed, canonical date and time is \"%04d-%02d-%02dT%02d:%02d:%02d\".",

                       val_str, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);

        goto error;

    }

    /* tenth of a second */

    if (val_str[i] == '.') {

        ++i;

        if (!isdigit(val_str[i])) {

            ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", a digit expected.", val_str[i], i, val_str);

            goto error;

        }

        do {

            ++i;

        } while (isdigit(val_str[i]));

    }

    switch (val_str[i]) {

    case 'Z':

        /* done */

        break;

    case '+':

    case '-':

        /* timezone shift */

        if ((val_str[i + 1] < '0') || (val_str[i + 1] > '2')) {

            ret = asprintf(err_msg, "Invalid timezone \"%.6s\" in date-and-time value \"%s\".", val_str + i, val_str);

            goto error;

        }

        if ((val_str[i + 2] < '0') || ((val_str[i + 1] == '2') && (val_str[i + 2] > '3')) || (val_str[i + 2] > '9')) {

            ret = asprintf(err_msg, "Invalid timezone \"%.6s\" in date-and-time value \"%s\".", val_str + i, val_str);

            goto error;

        }

        if (val_str[i + 3] != ':') {

            ret = asprintf(err_msg, "Invalid timezone \"%.6s\" in date-and-time value \"%s\".", val_str + i, val_str);

            goto error;

        }

        if ((val_str[i + 4] < '0') || (val_str[i + 4] > '5')) {

            ret = asprintf(err_msg, "Invalid timezone \"%.6s\" in date-and-time value \"%s\".", val_str + i, val_str);

            goto error;

        }

        if ((val_str[i + 5] < '0') || (val_str[i + 5] > '9')) {

            ret = asprintf(err_msg, "Invalid timezone \"%.6s\" in date-and-time value \"%s\".", val_str + i, val_str);

            goto error;

        }

        i += 5;

        break;

    default:

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", 'Z', '+', or '-' expected.", val_str[i], i, val_str);

        goto error;

    }

    /* no other characters expected */

    ++i;

    if (val_str[i]) {

        ret = asprintf(err_msg, "Invalid character '%c'[%d] in date-and-time value \"%s\", no characters expected.", val_str[i], i, val_str);

        goto error;

    }

    /* validation succeeded and we do not want to change how it is stored */

    return 0;

error:

    if (ret == -1) {

        *err_msg = NULL;

    }

    return 1;

}

static int

hex_string_store_clb(struct ly_ctx *ctx, const char *UNUSED(type_name), const char **value_str, lyd_val *value, char **err_msg)

{

    char *str;

    uint32_t i, len;

    str = strdup(*value_str);

    if (!str) {

        /* we can hardly allocate an error message */

        *err_msg = NULL;

        return 1;

    }

    len = strlen(str);

    for (i = 0; i < len; ++i) {

        if ((str[i] >= 'A') && (str[i] <= 'Z')) {

            /* make it lowercase (canonical format) */

            str[i] += 32;

        }

    }

    /* update the value correctly */

    lydict_remove(ctx, *value_str);

    *value_str = lydict_insert_zc(ctx, str);

    value->string = *value_str;

    return 0;

}

/* Name of this array must match the file name! */

struct lytype_plugin_list user_yang_types[] = {

    {"ietf-yang-types", "2013-07-15", "date-and-time", date_and_time_store_clb, NULL},

    {"ietf-yang-types", "2013-07-15", "phys-address", hex_string_store_clb, NULL},

    {"ietf-yang-types", "2013-07-15", "mac-address", hex_string_store_clb, NULL},

    {"ietf-yang-types", "2013-07-15", "hex-string", hex_string_store_clb, NULL},

    {"ietf-yang-types", "2013-07-15", "uuid", hex_string_store_clb, NULL},

    {NULL, NULL, NULL, NULL, NULL} /* terminating item */

};