using FastEndpoints;
using KArtSell.BuildingBlocks.Time;
using Microsoft.Extensions.Logging;

namespace KArtSell.Host.Features.ShadowRun;

/// <summary>
/// POST /api/shadow-runs
/// Initiate a 252+ trading-day model validation run.
/// Returns 202 Accepted with job tracking info.
/// </summary>
public class InitiateShadowRunEndpoint : Endpoint<InitiateShadowRunRequest, InitiateShadowRunResponse>
{
    private InitiateShadowRunHandler? _handler;
    private ILogger<InitiateShadowRunEndpoint>? _logger;

    private static readonly Action<ILogger, Guid, Exception?> LogRequestReceived =
        LoggerMessage.Define<Guid>(
            LogLevel.Information,
            new EventId(1, nameof(LogRequestReceived)),
            "Shadow run request received: {ModelId}");

    private static readonly Action<ILogger, Exception?> LogRequestFailed =
        LoggerMessage.Define(
            LogLevel.Error,
            new EventId(2, nameof(LogRequestFailed)),
            "Shadow run initiation failed");

    public override void Configure()
    {
        Post("/api/shadow-runs");
        Roles("Admin", "Researcher");  // RBAC: Only Admin or Researcher can initiate
        Validator<InitiateShadowRunValidator>();
    }

    public override async Task HandleAsync(InitiateShadowRunRequest req, CancellationToken ct)
    {
        _handler = Resolve<InitiateShadowRunHandler>();
        _logger = Resolve<ILogger<InitiateShadowRunEndpoint>>();

        var correlationId = HttpContext.Items["CorrelationId"] as Guid? ?? Guid.NewGuid();

        try
        {
            LogRequestReceived(_logger, req.ModelId, null);

            var response = await _handler.HandleAsync(req, correlationId, ct);

            // 202 Accepted: Job queued, results available later via polling
            HttpContext.Response.StatusCode = 202;
            await HttpContext.Response.WriteAsJsonAsync(response, ct);
        }
        catch (InvalidOperationException ex)
        {
            ThrowError(ex.Message, 400);
        }
        catch (Exception ex)
        {
            LogRequestFailed(_logger, ex);
            ThrowError("Shadow run initiation failed. Please retry.", 500);
        }
    }
}