using System.Diagnostics;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Scripting;
using ZB.MOM.WW.OtOpcUa.Core.Scripting.OutOfProcess;

namespace ZB.MOM.WW.OtOpcUa.ScriptWorker.Tests;

/// <summary>
///     lmxopcua#780: the Windows installs have no .NET runtime, so a self-contained Host publish ships a self-contained
///     worker that the launcher must start through its apphost, while a framework-dependent worker (docker-dev, the
///     tests) keeps going through the dotnet muxer.
/// </summary>
[Collection(ScriptWorkerCollection.Name)]
[Trait("Category", "ScriptWorker")]
public sealed class WorkerEntryTests
{
    private static CancellationToken Ct => TestContext.Current.CancellationToken;

    private const string SelfContainedConfig = """
        { "runtimeOptions": { "tfm": "net10.0", "includedFrameworks": [ { "name": "Microsoft.NETCore.App", "version": "10.0.0" } ] } }
        """;

    private const string FrameworkDependentConfig = """
        { "runtimeOptions": { "tfm": "net10.0", "framework": { "name": "Microsoft.NETCore.App", "version": "10.0.0" } } }
        """;

    private static string ConfigPath(string folder) => Path.Combine(folder, "ZB.MOM.WW.OtOpcUa.ScriptWorker.runtimeconfig.json");

    private static void Touch(string path) => File.WriteAllText(path, "");

    [Fact]
    public void A_self_contained_worker_is_started_through_its_apphost()
    {
        using var dir = new Scripts.TempDir();
        Touch(Path.Combine(dir.Path, OutOfProcessScriptRunner.WorkerAppHostFileName));
        Touch(Path.Combine(dir.Path, OutOfProcessScriptRunner.WorkerAssemblyFileName));
        File.WriteAllText(ConfigPath(dir.Path), SelfContainedConfig);

        OutOfProcessScriptRunner.IsSelfContainedWorker(dir.Path).ShouldBeTrue();
        OutOfProcessScriptRunner.ResolveWorkerEntry(dir.Path)
            .ShouldBe(Path.Combine(Path.GetFullPath(dir.Path), OutOfProcessScriptRunner.WorkerAppHostFileName));
    }

    [Fact]
    public void A_framework_dependent_worker_keeps_the_muxer_even_with_an_apphost()
    {
        using var dir = new Scripts.TempDir();
        Touch(Path.Combine(dir.Path, OutOfProcessScriptRunner.WorkerAppHostFileName));
        Touch(Path.Combine(dir.Path, OutOfProcessScriptRunner.WorkerAssemblyFileName));
        File.WriteAllText(ConfigPath(dir.Path), FrameworkDependentConfig);

        OutOfProcessScriptRunner.IsSelfContainedWorker(dir.Path).ShouldBeFalse();
        OutOfProcessScriptRunner.ResolveWorkerEntry(dir.Path).ShouldEndWith(OutOfProcessScriptRunner.WorkerAssemblyFileName);
    }

    [Theory]
    [InlineData(true, null)]          // self-contained config but no apphost on disk
    [InlineData(false, "{ broken")]  // apphost present, unreadable config
    [InlineData(false, null)]         // apphost present, no config at all
    public void Anything_short_of_a_self_contained_apphost_falls_back_to_the_entry_assembly(bool omitAppHost, string? config)
    {
        using var dir = new Scripts.TempDir();
        if (!omitAppHost) Touch(Path.Combine(dir.Path, OutOfProcessScriptRunner.WorkerAppHostFileName));
        if (omitAppHost) File.WriteAllText(ConfigPath(dir.Path), SelfContainedConfig);
        else if (config is not null) File.WriteAllText(ConfigPath(dir.Path), config);

        OutOfProcessScriptRunner.ResolveWorkerEntry(dir.Path).ShouldEndWith(OutOfProcessScriptRunner.WorkerAssemblyFileName);
    }

    [Fact]
    public void An_explicit_executable_path_wins()
    {
        var path = Path.Combine(Path.GetTempPath(), "custom", "worker.exe");
        OutOfProcessScriptRunner.ResolveWorkerPath(new ScriptWorkerOptions { ExecutablePath = path }).ShouldBe(Path.GetFullPath(path));
    }

    /// <summary>The worker built beside the tests is framework-dependent, so the default stays the muxer path.</summary>
    [Fact]
    public void The_built_worker_resolves_to_the_entry_assembly()
    {
        OutOfProcessScriptRunner.ResolveWorkerPath(new ScriptWorkerOptions())
            .ShouldEndWith(Path.Combine(OutOfProcessScriptRunner.WorkerFolderName, OutOfProcessScriptRunner.WorkerAssemblyFileName));
    }

    /// <summary>
    ///     Runs only when <see cref="Scripts.WorkerUnderTestVariable"/> names a self-contained worker's apphost (the
    ///     windev gate over a <c>-r win-x64 --self-contained</c> Host publish): the worker process IS the apphost — no
    ///     dotnet muxer anywhere — and it evaluates.
    /// </summary>
    [Fact]
    public async Task A_published_self_contained_worker_runs_as_its_own_process()
    {
        var path = Scripts.WorkerUnderTest;
        if (path is null || !path.EndsWith(OutOfProcessScriptRunner.WorkerAppHostFileName, StringComparison.OrdinalIgnoreCase))
            Assert.Skip($"set {Scripts.WorkerUnderTestVariable} to a self-contained worker apphost to run this gate");
        OutOfProcessScriptRunner.IsSelfContainedWorker(Path.GetDirectoryName(path)!).ShouldBeTrue("the published folder is self-contained");
        OutOfProcessScriptRunner.ResolveWorkerEntry(Path.GetDirectoryName(path)!).ShouldBe(Path.GetFullPath(path));

        await using var runner = Scripts.Runner(Scripts.Options(workerPath: path));
        (await runner.RunAsync(Scripts.Vt("vt", "return System.Math.Abs(-3);"), Ct)).Value.ShouldBe(3);
        using var worker = Process.GetProcessById(runner.Shards[0].Current!.Pid);
        Path.GetFullPath(worker.MainModule!.FileName).ShouldBe(Path.GetFullPath(path), StringCompareShould.IgnoreCase);
    }
}