using System.Diagnostics.CodeAnalysis;
using Microsoft.Extensions.Localization;

namespace Sozsoft.Mcp;

/// <summary>
/// Aracin modelle konusarak cozulecek reddi: eksik ya da hatali girdi, durum kurali, eksik yetki.
/// Istisna olarak atilmaz — bu durum aracin beklenen cevabidir; atilan istisna debugger'i durdurur
/// ve SDK'da hata logu uretir. Istemciye hata sonucu (<c>IsError</c>) olarak gider, model mesaji
/// okuyup girdiyi duzeltir ve tekrar dener.
/// </summary>
public sealed record McpProblem(string Message)
{
    public static McpProblem From(IStringLocalizer localizer, string name, params object[] arguments)
        => new(localizer[name, arguments]);
}

/// <summary>Aracin degeri ya da <see cref="McpProblem"/>'i; ikisi birden olmaz.</summary>
public readonly struct McpOutcome<T>
{
    private McpOutcome(T? value, McpProblem? problem)
    {
        Value = value;
        Problem = problem;
    }

    public T? Value { get; }

    public McpProblem? Problem { get; }

    public bool TryGetValue([MaybeNullWhen(false)] out T value, [NotNullWhen(false)] out McpProblem? problem)
    {
        value = Value!;
        problem = Problem;
        return problem is null;
    }

    public static implicit operator McpOutcome<T>(T value) => new(value, null);

    public static implicit operator McpOutcome<T>(McpProblem problem) => new(default, problem);
}

/// <summary>Yetki reddi mesajinda yetkinin gorunen adi ve kodu; rol ekraninda aranabilsin diye kod her zaman yazilir.</summary>
public static class McpPermissionText
{
    public static string Describe(IStringLocalizer localizer, string permissionName)
    {
        var displayName = localizer[permissionName];

        return displayName.ResourceNotFound || displayName.Value == permissionName
            ? permissionName
            : $"{displayName.Value} ({permissionName})";
    }
}