/*
 * Copyright (c) 2023 Markus Hennecke <markus-hennecke@markus-hennecke.de>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */


#include <sys/types.h>
#include <ctype.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <kcgi.h>

#include "util.h"

#include <stdio.h>
#define TS_PARSE_FMT "%FT%T%z"

/*
 * Check a timestamp formed like
 * YYYY-MM-DDTHH:MM(:SS)?(.msec)?(+[0-9]{2}:[0-9]{2}|Z)?
 */
int
validate_timestamp(struct kpair *_kp)
{

	/* At least 10 characters requiered for a timestamp */
	if (_kp->valsz < 10)
		return 0;

	/* Check for date only if the strlen is 10 */
	if (_kp->valsz == 10)
		return kvalid_date(_kp);

	/* Between 10 and 16 characters can't be avalid timestamp */
	/* Next minimal timestamp has 16 characters */
	if (_kp->valsz < 16)
		return 0;

	/* Could be a timestamp with timezone, don't parse it by hand but
	 * use strptime instead */
	if (_kp->valsz >= 20) {
		if (_kp->valsz != strlen(_kp->val))
			return 0;

		struct tm tm;
		char *parse_end = strptime(_kp->val, TS_PARSE_FMT, &tm);
		if (parse_end == NULL || *parse_end != '\0')
			return 0;

		fprintf(stderr, "tm_gmtoff = %ld\n", tm.tm_gmtoff);

		_kp->parsed.i = (int64_t )timegm(&tm) - tm.tm_gmtoff;
		_kp->type = KPAIR_INTEGER;
		return 1;
	}

	if (!isdigit(_kp->val[0]) ||
	    !isdigit(_kp->val[1]) ||
	    !isdigit(_kp->val[2]) ||
	    !isdigit(_kp->val[3]) ||
	    ('-' != _kp->val[4]) ||
	    !isdigit(_kp->val[5]) ||
	    !isdigit(_kp->val[6]) ||
	    ('-' != _kp->val[7]) ||
	    !isdigit(_kp->val[8]) ||
	    !isdigit(_kp->val[9]) ||
	    ('T' != _kp->val[10]) ||
	    !isdigit(_kp->val[11]) ||
	    !isdigit(_kp->val[12]) ||
	    (':' != _kp->val[13]) ||
	    !isdigit(_kp->val[14]) ||
	    !isdigit(_kp->val[15]))
		return 0;
	if ((_kp->valsz == 16) && ('\0' != _kp->val[16]))
		return 0;

	const int year = atoi(&_kp->val[0]);
	const int month = atoi(&_kp->val[5]);
	const int day = atoi(&_kp->val[8]);
	const int hour = atoi(&_kp->val[11]);
	const int minute = atoi(&_kp->val[14]);
	int seconds = 0;

	if (_kp->valsz >= 19) {
		if ((':' != _kp->val[16]) ||
		    !isdigit(_kp->val[17]) ||
		    !isdigit(_kp->val[18]))
			return 0;
		if ((_kp->valsz == 19) && ('\0' != _kp->val[19]))
			return 0;
		seconds = atoi(&_kp->val[17]);
	}
	if (! khttp_datetime2epoch(&_kp->parsed.i, day, month, year, hour,
	    minute, seconds))
		return 0;

	_kp->type = KPAIR_INTEGER;
	return 1;
}


/*
 * Check the device ID to fit into 36 characters, e.g. it is a UUID or an
 * ID string.
 */
int
validate_device(struct kpair *_kp)
{
	if (_kp->valsz > 36)
		return 0;
	// XXX change this to kvalid_stringne if it becomes mandatory
	return kvalid_string(_kp);
}


const char *
parameter(struct kreq *r, const int param_idx)
{
	return (r->fieldmap[param_idx]) ? r->fieldmap[param_idx]->val : NULL;
}


void
response(struct kreq *r, const int status, const int content_type,
    const char *body) {
	khttp_head(r, kresps[KRESP_STATUS], "%s", khttps[status]);
	khttp_head(r, kresps[KRESP_CONTENT_TYPE],
	    "%s", kmimetypes[content_type]);
	khttp_body(r);
	if (body)
		khttp_puts(r, body);
}