using System.Text.Json;
using Microsoft.Extensions.Logging.Abstractions;
using VolcanicCore.Api.Engine;
using VolcanicCore.Core;
using VolcanicCore.Nodes;

// ImplicitUsings pulls System.Threading → collision with our ExecutionContext.
using ExecutionContext = VolcanicCore.Api.Engine.ExecutionContext;

namespace VolcanicCore.Tests;

public class NatsPublishNodeTests
{
    private sealed class FakePublisher : NatsPublishNode.INatsPublisher
    {
        public List<(string subject, byte[] payload)> Sent { get; } = new();
        public Task PublishAsync(string subject, byte[] payload, CancellationToken ct)
        { Sent.Add((subject, payload)); return Task.CompletedTask; }
    }
    private sealed class FakeReg : IConnectionInstanceRegistry
    {
        private readonly object _h;
        public FakeReg(object h) => _h = h;
        public Task<object> GetAsync(string id, CancellationToken ct) => Task.FromResult(_h);
    }

    [Fact]
    public async Task Publishes_each_item_as_its_json_bytes()
    {
        var pub = new FakePublisher();
        var reg = new FakeReg(pub);
        var node = new NatsPublishNode();
        var ctx = new ExecutionContext("e", "wf", "n",
            JsonDocument.Parse("""{"subject":"out"}""").RootElement,
            null, NullLogger.Instance, "c1", reg);

        var input = new IReadOnlyList<Item>[]
        {
            new [] {
                new Item(JsonDocument.Parse("""{"a":1}""").RootElement.Clone()),
                new Item(JsonDocument.Parse("""{"a":2}""").RootElement.Clone()),
            }
        };
        var outputs = await node.ExecuteAsync(ctx, input, CancellationToken.None);
        Assert.Empty(outputs);
        Assert.Equal(2, pub.Sent.Count);
        Assert.All(pub.Sent, s => Assert.Equal("out", s.subject));
        Assert.Equal("""{"a":1}""", System.Text.Encoding.UTF8.GetString(pub.Sent[0].payload));
    }
}