using System.Text.Json;
using backend.Tools;
using FluentAssertions;
using Xunit;

namespace backend.tests;

public class SetVolumeToolTests
{
    [Fact]
    public async Task Forwards_call_to_pi_and_returns_its_result()
    {
        var fake = new RecordingChannel(
            JsonDocument.Parse("""{"ok":true}""").RootElement);
        var tool = new SetVolumeTool();
        var ctx = new DeviceContext(Guid.NewGuid(), Guid.NewGuid(), fake);

        var args = JsonDocument.Parse("""{"level":42}""").RootElement;
        var res = await tool.ExecuteAsync(new ToolInvocation("c1", args), ctx, default);

        fake.LastName.Should().Be("set_volume");
        fake.LastArgs.GetProperty("level").GetInt32().Should().Be(42);
        res.Output.GetProperty("ok").GetBoolean().Should().BeTrue();
    }

    [Fact]
    public async Task Rejects_out_of_range_level_without_calling_pi()
    {
        var fake = new RecordingChannel(JsonDocument.Parse("""{"ok":true}""").RootElement);
        var tool = new SetVolumeTool();
        var ctx = new DeviceContext(Guid.NewGuid(), Guid.NewGuid(), fake);

        var args = JsonDocument.Parse("""{"level":150}""").RootElement;
        var res = await tool.ExecuteAsync(new ToolInvocation("c1", args), ctx, default);

        fake.LastName.Should().BeNull();
        res.Output.GetProperty("ok").GetBoolean().Should().BeFalse();
        res.Output.GetProperty("error").GetString().Should().Contain("0..100");
    }

    private class RecordingChannel(JsonElement reply) : IDeviceChannel
    {
        public string? LastName { get; private set; }
        public JsonElement LastArgs { get; private set; }
        public Task<JsonElement> CallPiToolAsync(string name, JsonElement args, CancellationToken ct)
        {
            LastName = name;
            LastArgs = args;
            return Task.FromResult(reply);
        }
    }
}