/* mal2go - MyAnimeList V2 API wrapper for Go
 * Copyright (C) 2022  Vidhu Kant Sharma <vidhukant@protonmail.ch>

 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>. */

package anime

import (
  "errors"
  "fmt"
)

/* NOTE: MAL still seems to send some fields 
 * even if they aren't requested.
 * those include Title, Picture, Id, etc */
// default fields to use when none are specified
var defaultFields []string = []string{
  "id", "title", "main_picture",
  "alternative_titles", "start_date",
  "end_date", "synopsis", "mean", "rank",
  "popularity", "num_list_users",
  "num_scoring_users", "nsfw", "created_at",
  "updated_at", "media_type", "status",
  "genres", "my_list_status", "num_episodes",
  "start_season", "broadcast", "source",
  "average_episode_duration", "rating",
  "pictures", "background", "related_anime",
  "related_manga", "recommendations",
  "studios", "statistics",
}

// if fields aren't specified
func fieldsErrHandler(fields []string) ([]string, error) {
  if cap(fields) == 0 {
    // uses all the default fields if none specified
    return defaultFields, nil
  }

  // checks if each given field is valid
  for _, j := range(fields) {
    if !isValidField(j) {
      return []string{}, errors.New(fmt.Sprintf("InvalidFieldError: Invalid field specified: \"%s\"", j))
    }
  }

  // everything's fine!
  return fields, nil
}

// if limit or error specified are above the limit
func limitsErrHandler(limit, offset int) error {
  maxOffset := 500 - limit
  if limit > 500 {
    return errors.New(fmt.Sprintf("InvalidLimitError: Limit specified too high (%d > 500).", limit))
  } else if offset > maxOffset {
    return errors.New(fmt.Sprintf("InvalidOffsetError: Offset specified too high (%d > %d).", offset, maxOffset))
  }
  // return nil if no error
  return nil
}