using FastEndpoints;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.DTO.Framework.ResponseStandard;
using GB5Shared.FastEndPoint;
using IceImportBLL.IceImportRun;
using IceImportSL.Parameters.Run;
using static GB5Shared.GB5Constant.Constant;

namespace IceImportSL.Endpoints.Run;

// Best-effort cancellation — see IIceImportRunCancellationRegistry's doc comment for the
// single-instance limitation (no distributed cancel signal across replicas in this phase).
public class CancelImportRun : BaseEndpoint<CancelImportRunParameters, ResponseStandardDTO<object>>
{
    private readonly IIceImportRunBLL _runBll;
    private readonly IIceImportRunCancellationRegistry _cancellationRegistry;

    public CancelImportRun(IIceImportRunBLL runBll, IIceImportRunCancellationRegistry cancellationRegistry)
    {
        _runBll = runBll;
        _cancellationRegistry = cancellationRegistry;
    }

    public override void Configure()
    {
        Post("/IceImport/CancelImportRun");
        AllowAnonymous();
    }

    // Mutation endpoint — never cached.
    protected override string? GetCacheKey(CancelImportRunParameters req, LoginDTO login) => null;

    protected override async Task<ResponseStandardDTO<object>> ExecuteAsync(
        CancelImportRunParameters req, LoginDTO login, CancellationToken ct)
    {
        try
        {
            // Always flip the DB row first — this is the source of truth and "sticks" even if the
            // background task is running on a different instance (see UPDATE_STAGE's own
            // WHERE STATUS IN ('Queued','Running') guard for how that stops further progress there).
            var message = await _runBll.CancelRunAsync(req.RunId, login, ct).ConfigureAwait(false);

            // Best-effort: if the background task happens to be in-process on THIS instance,
            // interrupt it immediately rather than waiting for it to notice the DB state on its
            // next write.
            _cancellationRegistry.TryCancel(req.RunId);

            return await GB5Shared.ResponseStandard.Response.CreateSuccessResponse(
                message, CacheKeyLevel.NOT_REQUIRED, login);
        }
        catch (Exception ex)
        {
            return await GB5Shared.ResponseStandard.Response.CreateExceptionError<string>(
                ex, CacheKeyLevel.NOT_REQUIRED, login, ex.Message, 500);
        }
    }
}