using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Mvc;

namespace JobTrackerApi.Services;

public sealed class PdfRenderExceptionHandler : IExceptionHandler
{
    public async ValueTask<bool> TryHandleAsync(HttpContext context, Exception exception, CancellationToken cancellationToken)
    {
        if (exception is not (PdfCapacityException or PdfRenderTimeoutException)) return false;
        var busy = exception is PdfCapacityException;
        var status = busy ? StatusCodes.Status503ServiceUnavailable : StatusCodes.Status504GatewayTimeout;
        context.Response.StatusCode = status;
        context.Response.Headers.CacheControl = "no-store";
        if (busy) context.Response.Headers.RetryAfter = "3";
        await context.Response.WriteAsJsonAsync(new ProblemDetails
        {
            Status = status,
            Title = busy ? "PDF generation is busy" : "PDF generation timed out",
            Detail = exception.Message,
            Extensions = { ["code"] = busy ? "pdf_capacity_exceeded" : "pdf_render_timeout", ["traceId"] = context.TraceIdentifier }
        }, cancellationToken);
        return true;
    }
}