using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
using System.Threading.Tasks;
using FluentAssertions;
using foodmarket.Pos.Core.Hardware;
using Xunit;
using PortKind = foodmarket.Pos.Core.Hardware.HardwareProbe.PortKind;
using PortDesc = foodmarket.Pos.Core.Hardware.HardwareProbe.PortDesc;

public class ScaleAutodiscoveryTests
{
    private static byte[] Frame(string payload, byte control = 0x71)
    {
        var body = new List<byte> { MassaK.SOH, MassaK.STX };
        body.AddRange(Encoding.ASCII.GetBytes(payload));
        body.Add(control); body.Add(MassaK.ETX); body.Add(MassaK.EOT);
        return body.ToArray();
    }

    // Требование 5: «зависающий» порт не должен задерживать поиск дольше таймаута;
    // живой порт вторым — должен быть найден.
    [Fact]
    public async Task Hanging_port_does_not_block_discovery_of_live_port()
    {
        var ports = new List<PortDesc>
        {
            new("COMHANG", PortKind.Unknown, "зависает на Open"),
            new("COMLIVE", PortKind.Unknown, "живой"),
        };
        var live = Frame("S  1.235kg");
        foodmarket.Pos.Core.Hardware.ISerialTransport Make(string p, int b) =>
            p == "COMHANG" ? new foodmarket.UnitTests.FakeScaleTransport { OpenDelayMs = 30000 }
                           : new foodmarket.UnitTests.FakeScaleTransport { AnswerAck = true, Frame = live };

        var sw = Stopwatch.StartNew();
        var res = await ScaleAutodiscovery.DiscoverAsync(
            log: null, transportFactory: Make, portsOverride: ports,
            perPortMs: 1500, maxParallel: 4, budgetMs: 15000);
        sw.Stop();

        res.Device.Should().NotBeNull();
        res.Device!.Port.Should().Be("COMLIVE");
        res.Device.SampleKg.Should().Be(1.235m);
        sw.ElapsedMilliseconds.Should().BeLessThan(5000); // не ждём 30 с зависшего порта
    }

    // Требование 2/3: USB-serial проверяется раньше Bluetooth — находим весы на CH340,
    // не трогая Bluetooth-порт первым.
    [Fact]
    public async Task UsbSerial_tier_is_probed_before_bluetooth()
    {
        var ports = new List<PortDesc>
        {
            new("COM7", PortKind.Bluetooth, "Bluetooth"),
            new("COM22", PortKind.UsbSerial, "USB-SERIAL CH340"),
        };
        var btTouched = false;
        var live = Frame("S  0.000kg");
        foodmarket.Pos.Core.Hardware.ISerialTransport Make(string p, int b)
        {
            if (p == "COM7") { btTouched = true; return new foodmarket.UnitTests.FakeScaleTransport { OpenDelayMs = 30000 }; }
            return new foodmarket.UnitTests.FakeScaleTransport { AnswerAck = true, Frame = live };
        }
        var res = await ScaleAutodiscovery.DiscoverAsync(transportFactory: Make, portsOverride: ports);
        res.Device!.Port.Should().Be("COM22");
        btTouched.Should().BeFalse("USB-serial найден в первом тире — до Bluetooth дело не дошло");
    }

    [Fact]
    public async Task No_device_reports_cleanly()
    {
        var ports = new List<PortDesc> { new("COMX", PortKind.Unknown, "пусто") };
        foodmarket.Pos.Core.Hardware.ISerialTransport Make(string p, int b)
            => new foodmarket.UnitTests.FakeScaleTransport { AnswerAck = false };
        var res = await ScaleAutodiscovery.DiscoverAsync(transportFactory: Make, portsOverride: ports, perPortMs: 400);
        res.Device.Should().BeNull();
    }
}