/*
  Copyright 2019-2021 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or 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.

  THIS 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 "date_utils.h"
#include "read_utils.h"
#include "timezone.h"
#include "write_utils.h"

#include "exess/exess.h"

#include <stdlib.h>
#include <string.h>

ExessResult
read_date_numbers(ExessDate* const out, const char* const str)
{
  // Read year at the beginning
  size_t      i = skip_whitespace(str);
  ExessResult r = read_year_number(&out->year, str + i);
  if (r.status) {
    return result(r.status, i + r.count);
  }

  // Read year-month delimiter
  i += r.count;
  if (str[i] != '-') {
    return result(EXESS_EXPECTED_DASH, i);
  }

  // Read month
  ++i;
  if ((r = read_two_digit_number(&out->month, 1, 12, str + i)).status) {
    return result(r.status, i + r.count);
  }

  // Read month-day delimiter
  i += r.count;
  if (str[i] != '-') {
    return result(EXESS_EXPECTED_DASH, i);
  }

  // Read day
  ++i;
  if ((r = read_two_digit_number(&out->day, 1, 31, str + i)).status) {
    return result(r.status, i + r.count);
  }

  // Check that day is in range
  i += r.count;
  if (out->day > days_in_month(out->year, out->month)) {
    return result(EXESS_OUT_OF_RANGE, i);
  }

  return result(EXESS_SUCCESS, i);
}

ExessResult
exess_read_date(ExessDate* const out, const char* const str)
{
  memset(out, 0, sizeof(*out));

  // Read YYYY-MM-DD numbers
  size_t      i = skip_whitespace(str);
  ExessResult r = read_date_numbers(out, str + i);

  i += r.count;
  if (r.status || is_end(str[i])) {
    out->zone.quarter_hours = EXESS_LOCAL;
    return result(r.status, i);
  }

  // Read timezone
  r = exess_read_timezone(&out->zone, str + i);

  return result(r.status, i + r.count);
}

ExessResult
exess_write_date(const ExessDate value, const size_t buf_size, char* const buf)
{
  if (value.month < 1 || value.month > 12 || value.day < 1 || value.day > 31) {
    return end_write(EXESS_BAD_VALUE, buf_size, buf, 0);
  }

  ExessResult r = write_year_number(value.year, buf_size, buf);
  size_t      o = r.count;
  if (r.status) {
    return end_write(r.status, buf_size, buf, o);
  }

  o += write_char('-', buf_size, buf, o);
  o += write_two_digit_number(value.month, buf_size, buf, o);
  o += write_char('-', buf_size, buf, o);
  o += write_two_digit_number(value.day, buf_size, buf, o);

  r = write_timezone(value.zone, buf_size, buf, o);

  return end_write(r.status, buf_size, buf, o + r.count);
}