using System.Text.Json;

namespace Zcbot.WindowsNode.Tests;

public sealed class NodeProtocolCodecTests
{
    [Fact]
    public void EncodeKeepsThePublishedEnvelopeShape()
    {
        var encoded = NodeProtocolCodec.Encode("heartbeat", new { available_slots = 1 });

        using var document = JsonDocument.Parse(encoded);
        var root = document.RootElement;
        Assert.Equal(1, root.GetProperty("protocol_version").GetInt32());
        Assert.True(Guid.TryParse(root.GetProperty("message_id").GetString(), out _));
        Assert.Equal("heartbeat", root.GetProperty("type").GetString());
        Assert.True(DateTimeOffset.TryParse(root.GetProperty("sent_at").GetString(), out _));
        Assert.Equal(1, root.GetProperty("payload").GetProperty("available_slots").GetInt32());
    }

    [Fact]
    public void DecodePreservesUnknownMessagesForTheBusinessDispatcher()
    {
        var message = NodeProtocolCodec.Decode(
            """{"type":"future_message","payload":{"value":42}}"""u8.ToArray());

        Assert.NotNull(message);
        Assert.Equal("future_message", message.Type);
        Assert.Equal(42, message.Payload.GetProperty("value").GetInt32());
    }

    [Fact]
    public void DecodeIgnoresAnEnvelopeWithoutAStringType()
    {
        Assert.Null(NodeProtocolCodec.Decode("""{"payload":{}}"""u8.ToArray()));
        Assert.Null(NodeProtocolCodec.Decode("""{"type":2,"payload":{}}"""u8.ToArray()));
    }

    [Fact]
    public void DecodeRejectsInvalidJson()
    {
        Assert.ThrowsAny<JsonException>(() => NodeProtocolCodec.Decode("{"u8.ToArray()));
    }
}