package funkin.play.song;

import funkin.data.song.SongRegistry;
import funkin.data.song.SongData.SongChartData;
import funkin.data.song.SongData.SongMetadata;
import funkin.data.song.SongData.SongPlayData;
import funkin.data.song.SongData.SongTimeChange;
import funkin.data.song.SongData.SongTimeFormat;

/**
 * For SongMetadata and SongChartData objects,
 * ensures mandatory fields are present and populates optional fields with default values.
 */
class SongValidator
{
  public static final DEFAULT_SONGNAME:String = "Unknown";
  public static final DEFAULT_ARTIST:String = "Unknown";
  public static final DEFAULT_TIMEFORMAT:SongTimeFormat = SongTimeFormat.MILLISECONDS;
  public static final DEFAULT_DIVISIONS:Null<Int> = null;
  public static final DEFAULT_LOOPED:Bool = false;
  public static final DEFAULT_STAGE:String = "mainStage";
  public static final DEFAULT_SCROLLSPEED:Float = 1.0;

  public static var DEFAULT_GENERATEDBY(get, never):String;

  static function get_DEFAULT_GENERATEDBY():String
  {
    return '${Constants.TITLE} - ${Constants.VERSION}';
  }

  /**
   * Validates the fields of a SongMetadata object (excluding the version field).
   *
   * @param input The SongMetadata object to validate.
   * @param songId The ID of the song being validated. Only used for error messages.
   * @return The validated SongMetadata object.
   */
  public static function validateSongMetadata(input:SongMetadata, songId:String = 'unknown'):SongMetadata
  {
    if (input == null)
    {
      trace('[SONGDATA] Could not parse metadata for song ${songId}');
      return null;
    }

    if (input.songName == null)
    {
      trace('[SONGDATA] Song ${songId} is missing a songName field. ');
      input.songName = DEFAULT_SONGNAME;
    }
    if (input.artist == null)
    {
      trace('[SONGDATA] Song ${songId} is missing an artist field. ');
      input.artist = DEFAULT_ARTIST;
    }
    if (input.timeFormat == null)
    {
      trace('[SONGDATA] Song ${songId} is missing a timeFormat field. ');
      input.timeFormat = DEFAULT_TIMEFORMAT;
    }
    if (input.generatedBy == null)
    {
      input.generatedBy = SongRegistry.DEFAULT_GENERATEDBY;
    }

    input.timeChanges = validateTimeChanges(input.timeChanges, songId);
    if (input.timeChanges == null)
    {
      trace('[SONGDATA] Song ${songId} is missing a timeChanges field. ');
      return null;
    }

    input.playData = validatePlayData(input.playData, songId);

    if (input.variation == null) input.variation = '';

    return input;
  }

  /**
   * Validates the fields of a SongPlayData object.
   *
   * @param input The SongPlayData object to validate.
   * @param songId The ID of the song being validated. Only used for error messages.
   * @return The validated SongPlayData object.
   */
  public static function validatePlayData(input:SongPlayData, songId:String = 'unknown'):SongPlayData
  {
    if (input == null)
    {
      trace('[SONGDATA] Could not parse metadata.playData for song ${songId}');
      return null;
    }

    return input;
  }

  /**
   * Validates the fields of a TimeChange object.
   *
   * @param input The TimeChange object to validate.
   * @param songId The ID of the song being validated. Only used for error messages.
   * @return The validated TimeChange object.
   */
  public static function validateTimeChange(input:SongTimeChange, songId:String = 'unknown'):SongTimeChange
  {
    if (input == null)
    {
      trace('[SONGDATA] Could not parse metadata.timeChange for song ${songId}');
      return null;
    }

    return input;
  }

  /**
   * Validates multiple TimeChange objects in an array.
   */
  public static function validateTimeChanges(input:Array<SongTimeChange>, songId:String = 'unknown'):Array<SongTimeChange>
  {
    if (input == null)
    {
      trace('[SONGDATA] Could not parse metadata.timeChange for song ${songId}');
      return null;
    }

    input = input.map((timeChange) -> validateTimeChange(timeChange, songId));

    return input;
  }

  /**
   * Validates the fields of a SongChartData object (excluding the version field).
   *
   * @param input The SongChartData object to validate.
   * @param songId The ID of the song being validated. Only used for error messages.
   * @return The validated SongChartData object.
   */
  public static function validateSongChartData(input:SongChartData, songId:String = 'unknown'):SongChartData
  {
    if (input == null)
    {
      trace('[SONGDATA] Could not parse chart data for song ${songId}');
      return null;
    }

    return input;
  }
}