using System.Text;

namespace NubLang.Diagnostics;

public class Diagnostic
{
    public class DiagnosticBuilder
    {
        private readonly DiagnosticSeverity _severity;
        private readonly string _message;
        private string? _help;

        public DiagnosticBuilder(DiagnosticSeverity severity, string message)
        {
            _severity = severity;
            _message = message;
        }

        public DiagnosticBuilder WithHelp(string help)
        {
            _help = help;
            return this;
        }

        public Diagnostic Build() => new(_severity, _message, _help);
    }

    public static DiagnosticBuilder Error(string message) => new(DiagnosticSeverity.Error, message);
    public static DiagnosticBuilder Warning(string message) => new(DiagnosticSeverity.Warning, message);
    public static DiagnosticBuilder Info(string message) => new(DiagnosticSeverity.Info, message);

    public DiagnosticSeverity Severity { get; }
    public string Message { get; }
    public string? Help { get; }

    private Diagnostic(DiagnosticSeverity severity, string message, string? help)
    {
        Severity = severity;
        Message = message;
        Help = help;
    }

    public string FormatANSI()
    {
        var sb = new StringBuilder();

        var severityText = GetSeverityText(Severity);
        sb.Append(severityText);

        sb.Append(": ");
        sb.Append(ConsoleColors.Colorize(Message, ConsoleColors.BrightWhite));

        if (!string.IsNullOrEmpty(Help))
        {
            sb.AppendLine();
            sb.Append(ConsoleColors.Colorize($"help: {Help}", ConsoleColors.Cyan));
        }

        return sb.ToString();
    }

    private static string GetSeverityText(DiagnosticSeverity severity)
    {
        return severity switch
        {
            DiagnosticSeverity.Error => ConsoleColors.Colorize("error", ConsoleColors.Bold + ConsoleColors.Red),
            DiagnosticSeverity.Warning => ConsoleColors.Colorize("warning", ConsoleColors.Bold + ConsoleColors.Yellow),
            DiagnosticSeverity.Info => ConsoleColors.Colorize("info", ConsoleColors.Bold + ConsoleColors.Blue),
            _ => throw new ArgumentOutOfRangeException(nameof(severity), severity, "Unknown diagnostic severity")
        };
    }
}

public enum DiagnosticSeverity
{
    Info,
    Warning,
    Error
}