using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Host.Configuration;
using ZB.MOM.WW.Secrets;
using ZB.MOM.WW.Secrets.DependencyInjection;
using ZB.MOM.WW.Secrets.Sqlite;

namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;

/// <summary>
///     Positive-control probes of the Secrets 0.6.x fail-closed store-path validation as composed by
///     THIS host — a clean boot is equally consistent with the validator never being wired, so the
///     load-bearing assertions here are the rejections (the approach that caught the library's own
///     0.6.0 pre-host hole during the family adoption). Covers both compositions the host has:
///     <list type="number">
///         <item>in-host via <c>AddOtOpcUaSecrets</c> (an <see cref="IHostEnvironment"/> supplies the
///         content root);</item>
///         <item>the pre-host <c>${secret:}</c> expander shape from <c>Program.cs</c> — a bare
///         <see cref="ServiceCollection"/> with NO <see cref="IHostEnvironment"/>, where the content
///         root must be passed explicitly or the under-content-root rule silently vanishes at exactly
///         the moment the migrator creates the store file (the 0.6.0 defect).</item>
///     </list>
/// </summary>
public sealed class SecretsStorePathValidationTests : IDisposable
{
    private readonly string _contentRoot =
        Directory.CreateTempSubdirectory("otopcua-secrets-croot-").FullName;

    public void Dispose()
    {
        try { Directory.Delete(_contentRoot, recursive: true); } catch { /* best effort */ }
    }

    private static IConfiguration ConfigWithPath(string sqlitePath) =>
        new ConfigurationBuilder().AddInMemoryCollection(new Dictionary<string, string?>
        {
            ["Secrets:SqlitePath"] = sqlitePath,
            ["Secrets:MasterKey:Source"] = "Environment",
            ["Secrets:MasterKey:EnvVarName"] = "ZB_SECRETS_MASTER_KEY",
            ["Secrets:RunMigrationsOnStartup"] = "false",
        }).Build();

    private ServiceProvider BuildHostShapedProvider(string sqlitePath)
    {
        var services = new ServiceCollection();
        services.AddLogging();
        services.AddSingleton<IHostEnvironment>(new FakeHostEnvironment(_contentRoot));
        services.AddOtOpcUaSecrets(ConfigWithPath(sqlitePath));
        return services.BuildServiceProvider();
    }

    [Fact]
    public void A_relative_store_path_is_rejected()
    {
        using var sp = BuildHostShapedProvider("otopcua-secrets.db");

        var ex = Should.Throw<OptionsValidationException>(
            () => sp.GetRequiredService<IOptions<SecretsOptions>>().Value);

        ex.Message.ShouldContain("absolute", Case.Insensitive,
            "the rejection must name the rule, or the operator who caused it cannot act on it");
    }

    [Fact]
    public void An_absolute_path_inside_the_content_root_is_rejected()
    {
        // Absolute does NOT imply safe — this is the MxGateway outage shape: the path that lost
        // the credential store WAS absolute; it sat in the directory the deploy renames.
        var inside = Path.Combine(_contentRoot, "data", "otopcua-secrets.db");
        using var sp = BuildHostShapedProvider(inside);

        var ex = Should.Throw<OptionsValidationException>(
            () => sp.GetRequiredService<IOptions<SecretsOptions>>().Value);

        ex.Message.ShouldContain("content root", Case.Insensitive);
        File.Exists(inside).ShouldBeFalse("a rejected path must never gain a store file");
    }

    [Fact]
    public void An_absolute_path_outside_the_content_root_passes()
    {
        // The control for the two rejections above: proves the failures fail because of the RULES,
        // not because the whole subsystem is unresolvable in this composition.
        var outside = Path.Combine(Path.GetTempPath(), $"otopcua-secrets-{Guid.NewGuid():N}.db");
        using var sp = BuildHostShapedProvider(outside);

        sp.GetRequiredService<IOptions<SecretsOptions>>().Value.SqlitePath.ShouldBe(outside);
    }

    [Fact]
    public async Task The_prehost_expander_rejects_an_in_content_root_path_before_creating_the_store()
    {
        // Mirrors Program.cs's ${secret:} expansion container byte-for-byte: bare ServiceCollection,
        // no IHostEnvironment, content root passed EXPLICITLY (the 0.6.1 four-argument overload),
        // then RUN the migration — resolving the migrator alone never touches the filesystem, so a
        // resolve-only probe leaves the file assertions vacuous. The rejection must land BEFORE
        // creation: an empty store with -wal/-shm at the rejected path is the artifact that made
        // the MxGateway outage read as "the database is there, it's just empty".
        var inside = Path.Combine(_contentRoot, "data", "otopcua-secrets.db");
        await using var sp = new ServiceCollection()
            .AddZbSecrets(ConfigWithPath(inside), "Secrets", _contentRoot)
            .BuildServiceProvider();

        // Record rather than Should.Throw, so the ARTIFACT is asserted first: a regression that
        // stops the throw but still writes the store must fail on the file — which is the defect —
        // not on a missing exception that never mentions the database at the rejected path.
        var ex = await Record.ExceptionAsync(() =>
            sp.GetRequiredService<SqliteSecretsStoreMigrator>()
                .MigrateAsync(TestContext.Current.CancellationToken));

        File.Exists(inside).ShouldBeFalse("a rejected path must not be left holding a store file");
        File.Exists(inside + "-wal").ShouldBeFalse();
        File.Exists(inside + "-shm").ShouldBeFalse();
        ex.ShouldBeOfType<OptionsValidationException>();
    }

    [Fact]
    public async Task Without_the_explicit_content_root_the_prehost_hole_reopens()
    {
        // Falsification control for the test above, and the reason Program.cs's four-argument call
        // is load-bearing: the same composition WITHOUT the explicit root has no IHostEnvironment
        // to consult, the under-content-root rule is skipped, and the migration WRITES the store at
        // the rejected path. Running the migration (not just resolving) is what makes this a true
        // control — it proves the file assertions above are capable of failing. If the library ever
        // closes this differently (making this test fail), the source-scan pin on Program.cs can be
        // retired with it.
        var inside = Path.Combine(_contentRoot, "data", "otopcua-secrets.db");
        await using var sp = new ServiceCollection()
            .AddZbSecrets(ConfigWithPath(inside), "Secrets")
            .BuildServiceProvider();

        await sp.GetRequiredService<SqliteSecretsStoreMigrator>()
            .MigrateAsync(TestContext.Current.CancellationToken);

        File.Exists(inside).ShouldBeTrue(
            "the 3-argument overload with no IHostEnvironment must create the store at the "
            + "in-content-root path — the exact hole the explicit content root closes");
    }

    private sealed class FakeHostEnvironment(string contentRoot) : IHostEnvironment
    {
        public string EnvironmentName { get; set; } = "Production";
        public string ApplicationName { get; set; } = "OtOpcUa.Tests";
        public string ContentRootPath { get; set; } = contentRoot;
        public IFileProvider ContentRootFileProvider { get; set; } = new NullFileProvider();
    }
}