using System.Net.ServerSentEvents;
using System.Text.Json.Serialization;
using System.Threading.Channels;

namespace s8n_runtime;

public class WorkflowEditApiChannel : WorkflowRuntimeNodeBase, IWorkflowNodeRunnable
{
    private WebApplication? _app;
    public static Channel<LogServerEvent>? LogServerChannel;
    public ushort Port { get; set; } = 3080;

    public async Task OnStart(WorkflowRuntime runtime, CancellationToken cancellation)
    {
        var builder = WebApplication.CreateBuilder();
        builder.WebHost.UseUrls($"http://localhost:{Port}");
        builder.Services.AddOpenApi().ConfigureHttpJsonOptions(options =>
        {
            var opts = options.SerializerOptions;
            opts.IncludeFields = true;
            opts.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
            opts.Converters.Add(new JsonStringEnumConverter());
        }).AddCors();
        builder.Services.AddSingleton(LogServerChannel = Channel.CreateBounded<LogServerEvent>(new BoundedChannelOptions(10000)
        {
            FullMode = BoundedChannelFullMode.DropOldest
        }));
        _app = builder.Build();

        _app.MapOpenApi();
        _app.UseCors(policy => policy.AllowAnyOrigin());
        _app.MapGet("/api/runtime", () => runtime);
        _app.MapGet("/api/log", (Channel<LogServerEvent> channel) =>
        {
            return TypedResults.ServerSentEvents(GetEvents());
            async IAsyncEnumerable<SseItem<LogServerEvent>> GetEvents()
            {
                if (channel == null) yield break;

                var reader = channel.Reader;
                while (await reader.WaitToReadAsync())
                {
                    if (reader.TryRead(out var message))
                    {
                        yield return new SseItem<LogServerEvent>(message);
                    }
                }
            }
        });
        await _app.StartAsync(cancellation);
    }

    public async Task OnStop()
    {
        if (_app != null) await _app.DisposeAsync();
    }
}