ex-oop-02-horse-race/HorseRace/HorseImporter.cs

using System.Security.AccessControl;

namespace HorseRace;

public static class HorseImporter
{
    public static bool TryReadHorses(string filePath, out Horse[]? horses)
    {
        horses = null;
        if (!File.Exists(filePath))
        {
            return false;
        }
        string[] lines = File.ReadAllLines(filePath);
        if (lines.Length <= 1)
        {
            return false;
        }
        
        return FormatLines(lines, out horses);
    }

    private static bool FormatLines(string[] lines, out Horse[]? horses)
    {
        lines = RemoveFirstLine(lines);
        horses = new Horse[lines.Length];
        for (int i = 0; i < lines.Length; i++)
        {
            Horse.TryParse(lines[i], i + 1, out horses[i]!);
        }

        horses = TrimNullHorses(horses);
        
        if (horses.Length == 0)
        {
            horses = Array.Empty<Horse>();
            return false;
        }

        return true;
        
        string[] RemoveFirstLine(string[] array)
        {
            string[] changedArray = new string[array.Length - 1];
            for (int i = 0; i < changedArray.Length; i++)
            {
                changedArray[i] = array[i + 1];
            }

            return changedArray;
        }

        Horse[] TrimNullHorses(Horse?[] horses)
        {
            int count = 0;
            foreach (var horse in horses)
            {
                if (horse != null)
                {
                    count++;
                }
            }

            Horse[] result = new Horse[count];
            int index = 0;
            for (var i = 0; i < horses.Length; i++)
            {
                var horse = horses[i];
                if (horse != null)
                {
                    result[index++] = horse;
                }
            }

            return result;
        }
    }
}