/*
 * SPDX-FileCopyrightText: 2023 jordi fita mas <jfita@peritasoft.com>
 *
 * SPDX-License-Identifier: PostgreSQL
 */

#include <postgres.h>
#include <fmgr.h>
#include <utils/builtins.h>

#include "es.h"

PG_MODULE_MAGIC;

static bool
string2vatin(const char *str, text **result) {
	const char *r = str;
	char *vatin = NULL;
	size_t len;
	char country[2];
	int i;

	for (; *r == ' '; r++);
	if (*r == 0) {
		goto invalidvatin;
	}
	len = strlen(r);
	for (; *(r + len - 1) == ' '; len--);
	if (len < 3) {
		goto invalidvatin;
	}

	for(i = 0; i < 2; i++, r++, len--) {
		country[i] = toupper(*r);
	}
	if (country[0] == 'E' && country[1] == 'S') {
		vatin = check_es_vat(r, len);
		if (vatin == NULL) {
			goto invalidvatin;
		}
	} else {
		// For countries without validation yet assume it is correct
		vatin = pstrdup(r);
	}
	*result = (text *)palloc(2 + len + VARHDRSZ);
	SET_VARSIZE(*result, 2 + len + VARHDRSZ);
	memcpy(VARDATA(*result), country, 2);
	memcpy(VARDATA(*result) + 2, vatin, len);
	pfree(vatin);

	return true;

invalidvatin:
	ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for VAT number: \"%s\"", str)));
	return false;
}

PG_FUNCTION_INFO_V1(vatin_in);
	Datum
vatin_in(PG_FUNCTION_ARGS)
{
	const char *str = PG_GETARG_CSTRING(0);
	text *result = NULL;
	if (!string2vatin(str, &result)) {
		PG_RETURN_NULL();
	}
	PG_RETURN_TEXT_P(result);
}