// ReSharper disable ClassNeverInstantiated.Global
namespace TeamCity.CSharpInteractive;

using System.Text;

internal class TextToColorStrings : ITextToColorStrings
{
    private static readonly Dictionary<int, ConsoleColor?> Colors = new()
    {
        {39, default},
        {30, ConsoleColor.Black},
        {31, ConsoleColor.DarkRed},
        {32, ConsoleColor.DarkGreen},
        {33, ConsoleColor.DarkYellow},
        {34, ConsoleColor.DarkBlue},
        {35, ConsoleColor.DarkMagenta},
        {36, ConsoleColor.DarkCyan},
        {37, ConsoleColor.Gray},
        {90, ConsoleColor.DarkGray},
        {91, ConsoleColor.Red},
        {92, ConsoleColor.Green},
        {93, ConsoleColor.Yellow},
        {94, ConsoleColor.Blue},
        {95, ConsoleColor.Magenta},
        {96, ConsoleColor.Cyan},
        {97, ConsoleColor.White}
    };

    public IEnumerable<(ConsoleColor? color, string text)> Convert(string text, ConsoleColor? defaultColor)
    {
        var curColor = defaultColor;
        foreach (var (color, str) in Split(text))
        {
            if (!string.IsNullOrWhiteSpace(color))
            {
                foreach (var colorStr in color.Split(';', StringSplitOptions.RemoveEmptyEntries))
                {
                    if (!int.TryParse(colorStr, out var colorId) || !Colors.TryGetValue(colorId, out var colorVal) || !colorVal.HasValue)
                    {
                        continue;
                    }

                    curColor = colorVal.Value;
                    break;
                }
            }

            yield return (curColor, str);
        }
    }

    // ReSharper disable once MemberCanBePrivate.Global
    internal static IEnumerable<(string color, string text)> Split(string text)
    {
        var sb = new StringBuilder(text.Length);
        var isColor = false;
        var color = string.Empty;
        foreach (var ch in text)
        {
            switch (ch)
            {
                case '\x001B':
                    if (!isColor)
                    {
                        isColor = true;
                    }
                    else
                    {
                        sb.Append(ch);
                    }

                    break;

                case '[':
                    if (sb.Length > 0 && sb[^1] == ch)
                    {
                        sb.Append(ch);
                        isColor = false;
                        break;
                    }

                    if (isColor && sb.Length > 0)
                    {
                        yield return (color, sb.ToString());
                        color = string.Empty;
                        sb.Clear();
                    }

                    sb.Append(ch);
                    break;

                case '0':
                case '1':
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7':
                case '8':
                case '9':
                case ';':
                    sb.Append(ch);
                    break;

                case 'm':
                    if (isColor && sb.Length > 1)
                    {
                        color = sb.ToString()[1..];
                        sb.Clear();
                        isColor = false;
                    }
                    else
                    {
                        sb.Append(ch);
                        isColor = false;
                    }

                    break;

                default:
                    isColor = false;
                    sb.Append(ch);
                    break;
            }
        }

        yield return (color, sb.ToString());
    }
}