using System.Text;
using PnvPanel.Api.Common;
using PnvPanel.Application.Common.Messaging;
using PnvPanel.Application.Subscriptions;

namespace PnvPanel.Api.Endpoints;

public static class SubscriptionEndpoints
{
    public static IEndpointRouteBuilder MapSubscriptionEndpoints(this IEndpointRouteBuilder app)
    {
        // Вне /api по дизайну (api-design.md) — публичный эндпоинт для VPN-клиентов.
        app.MapGet("/sub/{token}", GetSubscription)
            .WithTags("Subscription")
            .RequireRateLimiting(RateLimiting.AuthPolicy)
            .Produces<string>(StatusCodes.Status200OK, "text/plain")
            .Produces(StatusCodes.Status404NotFound);

        return app;
    }

    private static async Task<IResult> GetSubscription(string token, HttpResponse response, ISender sender, CancellationToken cancellationToken)
    {
        // Токен — либо AppUser.SubscriptionToken (агрегированная подписка), либо VpnConfig.SubscriptionToken
        // (один конфиг). Пробуем пользовательский токен первым.
        var userResult = await sender.Send(new GetUserSubscriptionQuery(token), cancellationToken);
        var result = userResult.IsSuccess ? userResult : await sender.Send(new GetConfigSubscriptionQuery(token), cancellationToken);

        if (!result.IsSuccess)
            return Results.NotFound();

        var body = string.Join('\n', result.Value.ConnectionStrings);
        var base64Body = Convert.ToBase64String(Encoding.UTF8.GetBytes(body));

        var total = result.Value.UsedUpBytes + result.Value.UsedDownBytes;
        var expire = result.Value.ExpiresAt is { } exp ? exp.ToUnixTimeSeconds().ToString() : "0";
        response.Headers.Append(
            "Subscription-Userinfo",
            $"upload={result.Value.UsedUpBytes}; download={result.Value.UsedDownBytes}; total={total}; expire={expire}");
        response.Headers.Append("Profile-Update-Interval", "12");

        return Results.Text(base64Body, "text/plain; charset=utf-8");
    }
}