using System.Text.Json;
using GameCli;
using Xunit;

namespace GameCli.Tests;

public class ProtocolTests
{
    [Fact]
    public void StepInput_ParsesActionAndTarget()
    {
        var json = """{"action":2,"target":[0.35,0.60]}""";
        var input = JsonSerializer.Deserialize(json, ProtocolJsonContext.Default.StepInput);
        Assert.NotNull(input);
        Assert.Equal(2, input!.Action);
        Assert.NotNull(input.Target);
        Assert.Equal(0.35f, input.Target![0]);
        Assert.Equal(0.60f, input.Target![1]);
        Assert.Null(input.Cmd);
    }

    [Fact]
    public void StepInput_ParsesResetCommand()
    {
        var json = """{"cmd":"reset","seed":12345}""";
        var input = JsonSerializer.Deserialize(json, ProtocolJsonContext.Default.StepInput);
        Assert.NotNull(input);
        Assert.Equal("reset", input!.Cmd);
        Assert.Equal(12345, input.Seed);
    }

    [Fact]
    public void StepInput_ParsesResetCommandWithoutSeed()
    {
        var json = """{"cmd":"reset"}""";
        var input = JsonSerializer.Deserialize(json, ProtocolJsonContext.Default.StepInput);
        Assert.NotNull(input);
        Assert.Equal("reset", input!.Cmd);
        Assert.Null(input.Seed);
    }

    [Fact]
    public void StepOutput_SerializesAllFields()
    {
        var output = new StepOutput
        {
            Obs = new[] { 0.1f, 0.2f, 0.3f, 0.4f, 0.5f, 0.6f, 0.7f },
            State = new ShipStateDto { X = 0.5f, Y = 0.6f, Angle = 0.1f, Engine = 2 },
            Reward = -0.42f,
            Done = false,
            Step = 137,
        };
        var json = JsonSerializer.Serialize(output, ProtocolJsonContext.Default.StepOutput);
        Assert.Contains("\"obs\":", json);
        Assert.Contains("\"state\":", json);
        Assert.Contains("\"reward\":", json);
        Assert.Contains("\"done\":false", json);
        Assert.Contains("\"step\":137", json);
        Assert.Contains("\"engine\":2", json);
    }

    [Fact]
    public void InitMessage_SerializesExpectedShape()
    {
        var init = new InitMessage
        {
            Init = new InitPayload
            {
                World = new[] { 1.0f, 1.0f },
                Dt = 0.02f,
                ObsDim = 7,
                NActions = 4,
            },
        };
        var json = JsonSerializer.Serialize(init, ProtocolJsonContext.Default.InitMessage);
        Assert.Contains("\"world\":[1,1]", json);
        Assert.Contains("\"dt\":0.02", json);
        Assert.Contains("\"obs_dim\":7", json);
        Assert.Contains("\"n_actions\":4", json);
    }
}