namespace Compiler;

public sealed class Diagnostic(DiagnosticSeverity severity, string message, string? help, FileInfo? file)
{
    public static DiagnosticBuilder Info(string message) => new DiagnosticBuilder(DiagnosticSeverity.Info, message);
    public static DiagnosticBuilder Warning(string message) => new DiagnosticBuilder(DiagnosticSeverity.Warning, message);
    public static DiagnosticBuilder Error(string message) => new DiagnosticBuilder(DiagnosticSeverity.Error, message);

    public readonly DiagnosticSeverity Severity = severity;
    public readonly string Message = message;
    public readonly string? Help = help;
    public readonly FileInfo? File = file;
}

public sealed class DiagnosticBuilder(DiagnosticSeverity severity, string message)
{
    private FileInfo? file;
    private string? help;

    public DiagnosticBuilder At(string fileName, int line, int column, int length)
    {
        file = new FileInfo(fileName, line, column, length);
        return this;
    }

    public DiagnosticBuilder At(string fileName, Token? token)
    {
        if (token != null)
        {
            At(fileName, token.Line, token.Column, token.Length);
        }

        return this;
    }

    public DiagnosticBuilder At(string fileName, Node? node)
    {
        if (node != null && node.Tokens.Count != 0)
        {
            // todo(nub31): Calculate length based on last token
            At(fileName, node.Tokens[0]);
        }

        return this;
    }

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

    public Diagnostic Build()
    {
        return new Diagnostic(severity, message, help, file);
    }
}

public sealed class FileInfo(string file, int line, int column, int length)
{
    public readonly string File = file;
    public readonly int Line = line;
    public readonly int Column = column;
    public readonly int Length = length;
}

public enum DiagnosticSeverity
{
    Info,
    Warning,
    Error,
}

public sealed class CompileException(Diagnostic diagnostic) : Exception
{
    public readonly Diagnostic Diagnostic = diagnostic;
}