namespace Highscore;

/// <summary>
///     Processing of gamer scores to determine an overall highscore
/// </summary>
public static class HighscoreProcessing
{
    private const char Separator = ';';

    /// <summary>
    ///     Executes the <see cref="HighscoreProcessing"/> program.
    /// </summary>
    public static void Run()
    {
        var scores = LoadScoresFromFile("Data/scores.csv");
        var bestScores = FindBestScorePerUser(scores);
        SortGameScores(bestScores);
        WriteOutputFileAndPrint(bestScores, "Data/highscore.csv");
    }

    /// <summary>
    ///     Writes the provided <see cref="GameScore"/> instances to a file at the supplied path.
    ///     The CSV format is Score;Date;Player.
    /// </summary>
    /// <param name="highscore">Game scores to persist</param>
    /// <param name="filePath">Path to write to</param>
    public static void WriteOutputFileAndPrint(GameScore[] highscore, string filePath)
    {
        // TODO
    }

    /// <summary>
    ///     Loads the CSV file at the supplied path and attempts to parse its content to
    ///     create an array of <see cref="GameScore"/> instances utilizing <see cref="TryParseGameScore"/>.
    /// </summary>
    /// <param name="filePath">Path to read from</param>
    /// <returns>Array of parsed items; empty array if file does not exist or is empty</returns>
    public static GameScore[] LoadScoresFromFile(string filePath)
    {
        // TODO
        return [];
    }

    /// <summary>
    ///     Attempts to parse a CSV formatted string to a <see cref="GameScore"/> object.
    /// </summary>
    /// <param name="line">String to parse</param>
    /// <param name="gameScore">Successfully parsed object; null if parsing fails</param>
    /// <returns>True if parsed successfully; false otherwise</returns>
    public static bool TryParseGameScore(string line, out GameScore? gameScore)
    {
        // TODO
        gameScore = null;
        return false;
    }

    /// <summary>
    ///     Based on the provided full set of game scores for each user the best score is determined.
    ///     If a user has two or more entries with the same score the oldest (earliest) entry is considered to
    ///     be the highest.
    /// </summary>
    /// <param name="allScores">Collection of all scores; may contain multiple entries for one user</param>
    /// <returns>An array containing the highest score of each user, based on passed scores</returns>
    public static GameScore[] FindBestScorePerUser(GameScore[] allScores)
    {
        // TODO
        return [];
    }

    /// <summary>
    ///     Sorts the provided <see cref="GameScore"/> instances so that those with the
    ///     highest score (older date is preferred if score is equal) are ranked first.
    ///     Sorting happens in-place.
    /// </summary>
    /// <param name="scores">Scores to sort</param>
    public static void SortGameScores(GameScore[] scores)
    {
        // TODO
    }

    /// <summary>
    ///     Trims empty (null) entries from the provided array.
    /// </summary>
    /// <param name="arrayToTrim">The array to process</param>
    /// <returns>A new array containing only the non-null entries from the passed array</returns>
    public static GameScore[] TrimArray(GameScore?[] arrayToTrim)
    {
        // TODO
        return [];
    }
}