// Port of Go conf/lex.go token types.

using System.Text.Json;

namespace NATS.Server.Configuration;

public enum TokenType
{
    Error,
    Eof,
    Key,
    Text,
    String,
    Bool,
    Integer,
    Float,
    DateTime,
    ArrayStart,
    ArrayEnd,
    MapStart,
    MapEnd,
    Variable,
    Include,
    Comment,
}

public readonly record struct Token(TokenType Type, string Value, int Line, int Position);

/// <summary>
/// Pedantic token wrapper matching Go conf/parse.go token accessors.
/// </summary>
public sealed class PedanticToken
{
    private readonly Token _item;
    private readonly object? _value;
    private readonly bool _usedVariable;
    private readonly string _sourceFile;

    /// <summary>
    /// Creates a parser token wrapper that preserves resolved value and source metadata.
    /// </summary>
    /// <param name="item">Raw lexer token captured from the configuration source.</param>
    /// <param name="value">Optional parsed value override when token text has been normalized.</param>
    /// <param name="usedVariable">Indicates whether this token originated from variable substitution.</param>
    /// <param name="sourceFile">Source file path associated with this token, when available.</param>
    public PedanticToken(Token item, object? value = null, bool usedVariable = false, string sourceFile = "")
    {
        _item = item;
        _value = value;
        _usedVariable = usedVariable;
        _sourceFile = sourceFile ?? string.Empty;
    }

    /// <summary>
    /// Serializes the token value into JSON, matching Go parser diagnostics formatting.
    /// </summary>
    public string MarshalJson() => JsonSerializer.Serialize(Value());

    /// <summary>
    /// Returns the resolved token value, or raw token text when no typed value is stored.
    /// </summary>
    public object? Value() => _value ?? _item.Value;

    /// <summary>
    /// Returns the 1-based source line where the token was parsed.
    /// </summary>
    public int Line() => _item.Line;

    /// <summary>
    /// Returns whether variable interpolation contributed to this token.
    /// </summary>
    public bool IsUsedVariable() => _usedVariable;

    /// <summary>
    /// Returns the source file path associated with this token.
    /// </summary>
    public string SourceFile() => _sourceFile;

    /// <summary>
    /// Returns the 1-based character position of the token on its source line.
    /// </summary>
    public int Position() => _item.Position;
}