using CanonSharp.Combinator.Abstractions;

namespace CanonSharp.Combinator.Results;

/// <summary>
/// 异常类型的失败解析结果
/// </summary>
/// <param name="exception">解析中发生的异常</param>
/// <param name="state">当前输入流的状态</param>
/// <typeparam name="TToken">输入流类型</typeparam>
/// <typeparam name="TState">当前输入流状态的类型</typeparam>
/// <typeparam name="T">解析结果的类型</typeparam>
internal sealed class FailedResultWithException<TToken, TState, T>(Exception exception, TState state)
    : IFailedResult<TToken, T>
    where TState : IReadState<TToken, TState>
{
    public IReadState<TToken> State => state;

    public ParseException Exception => new(Message, exception);

    public string Message => $"Exception occured: {exception}.";

    public IFailedResult<TToken, TNext> Convert<TNext>()
        => new FailedResultWithException<TToken, TState, TNext>(exception, state);

    public override string ToString() => $"Parse failed: {Message}.";
}