namespace DocFx.Plugin.LastModified.Helpers;

using System.Linq;

/// <summary>
/// Extensions for <see cref="string"/>.
/// </summary>
public static class StringHelper
{
    /// <summary>
    ///     Truncates the string to match the specified <paramref name="length"/>.
    /// </summary>
    /// <remarks>
    ///     <para>This method is retrieved and modified from Humanizr/Humanizer.</para>
    ///     <para>MIT License (c)</para>
    ///     <para>Copyright (c) .NET Foundation and Contributors</para>
    /// </remarks>
    /// <param name="value">The string to truncate.</param>
    /// <param name="length">The target maximum length of the string.</param>
    /// <returns>
    ///     A truncated string based on the <paramref name="length" /> specified.
    /// </returns>
    public static string Truncate(this string value, int length)
    {
        const string truncationString = "...";

        if (value.Length == 0)
        {
            return value;
        }

        var alphaNumericalCharactersProcessed = 0;

        if (value.ToCharArray().Count(char.IsLetterOrDigit) <= length)
        {
            return value;
        }

        for (var i = 0; i < value.Length - truncationString.Length; i++)
        {
            if (char.IsLetterOrDigit(value[i]))
            {
                alphaNumericalCharactersProcessed++;
            }

            if (alphaNumericalCharactersProcessed + truncationString.Length == length)
            {
                return value[.. (i + 1)] + truncationString;
            }
        }

        return value;
    }
}