using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Jellyfin.Data;
using Jellyfin.Data.Enums;
using Jellyfin.Database.Implementations.Entities;
using Jellyfin.Database.Implementations.Enums;
using Jellyfin.Plugin.WatchedTogether.Auth;
using Jellyfin.Plugin.WatchedTogether.Configuration;
using Jellyfin.Plugin.WatchedTogether.Services;
using MediaBrowser.Controller.Authentication;
using MediaBrowser.Controller.Library;
using Microsoft.Extensions.Logging.Abstractions;
using Moq;
using Xunit;

namespace Jellyfin.Plugin.WatchedTogether.Tests;

/// <summary>
/// Covers the rule that a shared account is at least as restricted as every member who can unlock
/// it: how members' restrictions combine, and who an account with a chosen rating cap lets in.
/// </summary>
[Collection(nameof(PluginTestContext))]
public class RestrictionTests
{
    private const string AliceHash = "$PBKDF2-SHA512$iterations=210000$A1A1A1A1$AAAAAAAABBBBBBBB";
    private const string KidHash = "$PBKDF2-SHA512$iterations=210000$B2B2B2B2$CCCCCCCCDDDDDDDD";
    private const string TeenHash = "$PBKDF2-SHA512$iterations=210000$C3C3C3C3$EEEEEEEEFFFFFFFF";

    private static User MakeUser(string name, string? password = null)
        => new(name, "Prov", "ResetProv") { Password = password! };

    /// <summary>
    /// A user manager that resolves the given users by id and name and round-trips policies.
    /// </summary>
    private static Mock<IUserManager> MakeUserManager(List<User> users)
    {
        var userManager = new Mock<IUserManager>();
        userManager.Setup(m => m.GetUserById(It.IsAny<Guid>()))
            .Returns((Guid id) => users.Find(u => u.Id == id)!);
        userManager.Setup(m => m.GetUserByName(It.IsAny<string>()))
            .Returns((string n) => users.Find(
                u => string.Equals(u.Username, n, StringComparison.OrdinalIgnoreCase))!);
        userManager.Setup(m => m.CreateUserAsync(It.IsAny<string>()))
            .ReturnsAsync((string name) =>
            {
                var created = MakeUser(name);
                users.Add(created);
                return created;
            });
        userManager.Setup(m => m.UpdateUserAsync(It.IsAny<User>())).Returns(Task.CompletedTask);
        userManager.SetupChangePassword(users, (user, password) =>
        {
            user.Password = password;
            return Task.CompletedTask;
        });
        userManager.SetupPolicyRoundTrip(users);
        return userManager;
    }

    private static RestrictionService MakeService(List<User> users)
        => new(MakeUserManager(users).Object, NullLogger<RestrictionService>.Instance);

    private sealed record Harness(
        SharedAccountAuthenticationProvider Provider,
        ProvisioningService Provisioning,
        List<User> Users);

    /// <summary>
    /// Wires the real provisioning, group, dynamic-group, restriction and authentication services
    /// over a stub user manager, the same way <see cref="SharedAccountEndToEndTests"/> does.
    /// </summary>
    private static Harness MakeHarness(List<User> users, params (string Hash, string Password)[] validPairs)
    {
        var crypto = new StubCryptoProvider(validPairs);
        var userManager = MakeUserManager(users);

        var groupService = new GroupService(userManager.Object, NullLogger<GroupService>.Instance);
        var restrictions = new RestrictionService(userManager.Object, NullLogger<RestrictionService>.Instance);
        var provisioning = new ProvisioningService(
            userManager.Object,
            Mock.Of<ILibraryAccessService>(),
            restrictions,
            NullLogger<ProvisioningService>.Instance);
        var dynamicGroups = new DynamicGroupService(
            userManager.Object,
            provisioning,
            restrictions,
            crypto,
            NullLogger<DynamicGroupService>.Instance);
        var provider = new SharedAccountAuthenticationProvider(
            crypto,
            new Lazy<IGroupService>(() => groupService),
            new Lazy<IDynamicGroupService>(() => dynamicGroups),
            new Lazy<IRestrictionService>(() => restrictions),
            NullLogger<SharedAccountAuthenticationProvider>.Instance);

        return new Harness(provider, provisioning, users);
    }

    // ---- combining members ----------------------------------------------------------------

    [Theory]
    [InlineData(null, 13, 13)]
    [InlineData(13, null, 13)]
    [InlineData(7, 17, 7)]
    [InlineData(null, null, null)]
    public void Rating_StrictestScoreWins(int? a, int? b, int? expected)
    {
        var alice = MakeUser("alice").Restrict(maxRating: a);
        var bob = MakeUser("bob").Restrict(maxRating: b);

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        Assert.Equal(expected, result.MaxParentalRatingScore);
    }

    [Theory]
    [InlineData(null, 2, 2)]
    [InlineData(3, 2, 2)]
    [InlineData(2, 3, 2)]
    [InlineData(null, null, null)]
    public void Rating_AtEqualScore_StrictestSubScoreWins(int? a, int? b, int? expected)
    {
        // At the same score a null sub-cap allows every sub-score, so any value beats it.
        var alice = MakeUser("alice").Restrict(maxRating: 13, maxSubRating: a);
        var bob = MakeUser("bob").Restrict(maxRating: 13, maxSubRating: b);

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        Assert.Equal(13, result.MaxParentalRatingScore);
        Assert.Equal(expected, result.MaxParentalRatingSubScore);
    }

    [Fact]
    public void Rating_LowerScore_WinsRegardlessOfSubScore()
    {
        var alice = MakeUser("alice").Restrict(maxRating: 13, maxSubRating: 0);
        var bob = MakeUser("bob").Restrict(maxRating: 7, maxSubRating: null);

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        Assert.Equal(7, result.MaxParentalRatingScore);
        Assert.Null(result.MaxParentalRatingSubScore);
    }

    [Fact]
    public void UnratedAndBlockedTags_AreUnioned()
    {
        var alice = MakeUser("alice").Restrict(blockUnrated: [UnratedItem.Movie], blockedTags: ["horror"]);
        var bob = MakeUser("bob").Restrict(blockUnrated: [UnratedItem.Series], blockedTags: ["Gore", "horror"]);

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        Assert.Equal(new HashSet<UnratedItem> { UnratedItem.Movie, UnratedItem.Series }, result.BlockUnratedItems);
        Assert.Equal(2, result.BlockedTags.Count);
        Assert.Contains("horror", result.BlockedTags);
        Assert.Contains("gore", result.BlockedTags);
    }

    [Fact]
    public void AllowedTags_NoWhitelists_StaysNoWhitelist()
    {
        var alice = MakeUser("alice");
        var bob = MakeUser("bob");

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        Assert.False(result.HasAllowedTags);
        Assert.Empty(result.AllowedTagsForPolicy());
    }

    [Fact]
    public void AllowedTags_MemberWithoutWhitelist_AcceptsTheOthers()
    {
        // An empty allowed-tag list in Jellyfin is "no whitelist", not "allows nothing": it must
        // not wipe out the other member's whitelist.
        var alice = MakeUser("alice");
        var kid = MakeUser("kid").Restrict(allowedTags: ["kids", "family"]);

        var result = MakeService([alice, kid]).ComputeStrictest([alice.Id, kid.Id]);

        Assert.True(result.HasAllowedTags);
        Assert.Equal(new[] { "family", "kids" }, result.AllowedTagsForPolicy().OrderBy(t => t, StringComparer.Ordinal));
    }

    [Fact]
    public void AllowedTags_TwoWhitelists_Intersect()
    {
        var alice = MakeUser("alice").Restrict(allowedTags: ["kids", "family"]);
        var bob = MakeUser("bob").Restrict(allowedTags: ["Family", "documentary"]);

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        Assert.Equal(new[] { "family" }, result.AllowedTagsForPolicy());
    }

    [Fact]
    public void AllowedTags_DisjointWhitelists_AllowNothing_AndSurviveARoundTrip()
    {
        var alice = MakeUser("alice").Restrict(allowedTags: ["kids"]);
        var bob = MakeUser("bob").Restrict(allowedTags: ["documentary"]);

        var result = MakeService([alice, bob]).ComputeStrictest([alice.Id, bob.Id]);

        // In force, but empty. Jellyfin would read an empty list as unrestricted, so what gets
        // written is a tag no item carries...
        Assert.True(result.HasAllowedTags);
        Assert.Empty(result.AllowedTags!);
        Assert.Equal(new[] { ContentRestrictions.NothingAllowedTag }, result.AllowedTagsForPolicy());

        // ...and reading a user carrying only that tag comes back as "allows nothing", not as a
        // one-tag whitelist, so the unlock rule treats it as stricter than anything.
        var shared = MakeUser("shared").Restrict(allowedTags: result.AllowedTagsForPolicy());
        var read = ContentRestrictions.FromUser(shared);
        Assert.True(read.HasAllowedTags);
        Assert.Empty(read.AllowedTags!);
        Assert.True(read.IsAtLeastAsStrictAs(ContentRestrictions.FromUser(alice)));
    }

    [Fact]
    public void UnresolvableMember_YieldsFullyRestricted()
    {
        var alice = MakeUser("alice");

        var result = MakeService([alice]).ComputeStrictest([alice.Id, Guid.NewGuid()]);

        Assert.Equal(ContentRestrictions.FullyRestricted, result);
        Assert.True(result.IsAtLeastAsStrictAs(ContentRestrictions.FromUser(alice)));
    }

    [Fact]
    public async Task ApplyAsync_WritesTheStrictestPolicy_AndNeverAdministrator()
    {
        var alice = MakeUser("alice").Restrict(blockedTags: ["horror"]);
        var kid = MakeUser("kid").Restrict(maxRating: 7, blockUnrated: [UnratedItem.Movie]);
        var shared = MakeUser("shared");
        shared.SetPermission(PermissionKind.IsAdministrator, true);

        await MakeService([alice, kid, shared]).ApplyAsync(new SharedGroup
        {
            SharedUserId = shared.Id,
            MemberUserIds = [alice.Id, kid.Id]
        });

        Assert.Equal(7, shared.MaxParentalRatingScore);
        Assert.Equal([UnratedItem.Movie], shared.GetPreferenceValues<UnratedItem>(PreferenceKind.BlockUnratedItems));
        Assert.Equal(["horror"], shared.GetPreference(PreferenceKind.BlockedTags));
        Assert.False(shared.HasPermission(PermissionKind.IsAdministrator));
    }

    // ---- the unlock rule ------------------------------------------------------------------

    [Theory]
    [InlineData(null, null, true)]
    [InlineData(7, null, true)]
    [InlineData(7, 7, true)]
    [InlineData(7, 13, true)]
    [InlineData(13, 7, false)]
    [InlineData(null, 13, false)]
    public void IsAtLeastAsStrict_ComparesRatingCaps(int? shared, int? member, bool expected)
    {
        var sharedUser = MakeUser("shared").Restrict(maxRating: shared);
        var memberUser = MakeUser("member").Restrict(maxRating: member);

        Assert.Equal(expected, MakeService([]).IsAtLeastAsStrict(sharedUser, memberUser));
    }

    [Fact]
    public void IsAtLeastAsStrict_RequiresEverySetToBeCovered()
    {
        var service = MakeService([]);
        var member = MakeUser("member").Restrict(
            blockUnrated: [UnratedItem.Movie],
            blockedTags: ["horror"],
            allowedTags: ["kids", "family"]);

        Assert.True(service.IsAtLeastAsStrict(
            MakeUser("s").Restrict(blockUnrated: [UnratedItem.Movie, UnratedItem.Series], blockedTags: ["horror", "gore"], allowedTags: ["kids"]),
            member));
        Assert.False(service.IsAtLeastAsStrict(
            MakeUser("s").Restrict(blockedTags: ["horror"], allowedTags: ["kids"]),
            member));
        Assert.False(service.IsAtLeastAsStrict(
            MakeUser("s").Restrict(blockUnrated: [UnratedItem.Movie], allowedTags: ["kids"]),
            member));
        Assert.False(service.IsAtLeastAsStrict(
            MakeUser("s").Restrict(blockUnrated: [UnratedItem.Movie], blockedTags: ["horror"], allowedTags: ["kids", "family", "sport"]),
            member));

        // No whitelist on the shared side is looser than any whitelist on the member's.
        Assert.False(service.IsAtLeastAsStrict(
            MakeUser("s").Restrict(blockUnrated: [UnratedItem.Movie], blockedTags: ["horror"]),
            member));
    }

    // ---- the rating range ---------------------------------------------------------------

    [Fact]
    public void RatingRange_SpansStrictestToLoosest()
    {
        var alice = MakeUser("alice");
        var teen = MakeUser("teen").Restrict(maxRating: 13);
        var kid = MakeUser("kid").Restrict(maxRating: 7);
        var service = MakeService([alice, teen, kid]);

        Assert.Equal(new RatingRange(7, 13), service.GetRatingRange([teen.Id, kid.Id]));
        Assert.Equal(new RatingRange(7, null), service.GetRatingRange([alice.Id, teen.Id, kid.Id]));
        Assert.Equal(new RatingRange(null, null), service.GetRatingRange([alice.Id]));
        Assert.False(service.GetRatingRange([alice.Id]).HasChoice);
        Assert.Equal(new RatingRange(0, 13), service.GetRatingRange([teen.Id, Guid.NewGuid()]));
    }

    // ---- choosing a cap -----------------------------------------------------------------

    [Fact]
    public async Task ChosenCap_ShutsOutStricterMembers_AndLetsTheRestIn()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var teen = MakeUser("teen", TeenHash).Restrict(maxRating: 13);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7);
        var h = MakeHarness([alice, teen, kid], (AliceHash, "alice-pw"), (TeenHash, "teen-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, teen.Id, kid.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;

        // Inherited: the account carries the child's cap and everyone gets in.
        Assert.Equal(7, shared.MaxParentalRatingScore);
        await h.Provider.Authenticate(shared.Username, "kid-pw", shared);

        // Raised to the teen's level: the parent and the teen still unlock it, the child does not.
        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, teen.Id, kid.Id], true, false, false, false, 13);
        Assert.Equal(13, shared.MaxParentalRatingScore);
        await h.Provider.Authenticate(shared.Username, "alice-pw", shared);
        await h.Provider.Authenticate(shared.Username, "teen-pw", shared);
        await Assert.ThrowsAsync<AuthenticationException>(
            () => h.Provider.Authenticate(shared.Username, "kid-pw", shared));

        // No cap at all: only the parent.
        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, teen.Id, kid.Id], true, false, false, false, null);
        Assert.Null(shared.MaxParentalRatingScore);
        await h.Provider.Authenticate(shared.Username, "alice-pw", shared);
        await Assert.ThrowsAsync<AuthenticationException>(
            () => h.Provider.Authenticate(shared.Username, "teen-pw", shared));
    }

    [Fact]
    public async Task ChosenCap_LeavesEverythingElseStrictest()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash).Restrict(blockedTags: ["horror"]);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7, maxSubRating: 1, blockUnrated: [UnratedItem.Movie]);
        var h = MakeHarness([alice, kid], (AliceHash, "alice-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, kid.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;

        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, kid.Id], true, false, false, false, null);

        Assert.Null(shared.MaxParentalRatingScore);
        Assert.Null(shared.MaxParentalRatingSubScore);
        Assert.Equal([UnratedItem.Movie], shared.GetPreferenceValues<UnratedItem>(PreferenceKind.BlockUnratedItems));
        Assert.Equal(["horror"], shared.GetPreference(PreferenceKind.BlockedTags));
    }

    [Fact]
    public async Task ChosenCap_AboveTheLoosestMember_IsPulledBack()
    {
        using var ctx = PluginTestContext.Create();

        var teen = MakeUser("teen", TeenHash).Restrict(maxRating: 13);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7);
        var h = MakeHarness([teen, kid], (TeenHash, "teen-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([teen.Id, kid.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;

        // "No cap" past a group where everyone is capped would leave nobody able to unlock it.
        var updated = await h.Provisioning.UpdateGroupAsync(shared.Id, [teen.Id, kid.Id], true, false, false, false, null);

        Assert.False(updated.InheritParentalRating);
        Assert.Equal(13, updated.ParentalRatingCap);
        Assert.Equal(13, Assert.Single(ctx.Configuration.Groups).ParentalRatingCap);
        Assert.Equal(13, shared.MaxParentalRatingScore);
        await h.Provider.Authenticate(shared.Username, "teen-pw", shared);
    }

    [Theory]
    [InlineData(7)]
    [InlineData(3)]
    public async Task ChosenCap_AtOrBelowTheStrictestMember_IsJustInheriting(int cap)
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7, maxSubRating: 2);
        var h = MakeHarness([alice, kid], (AliceHash, "alice-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, kid.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;

        var updated = await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, kid.Id], true, false, false, false, cap);

        Assert.True(updated.InheritParentalRating);
        Assert.Null(updated.ParentalRatingCap);
        // Inheriting keeps the strictest member's sub-score too.
        Assert.Equal(7, shared.MaxParentalRatingScore);
        Assert.Equal(2, shared.MaxParentalRatingSubScore);
    }

    [Fact]
    public async Task ChosenCap_WhenNoMemberIsCapped_IsJustInheriting()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var bob = MakeUser("bob", KidHash);
        var h = MakeHarness([alice, bob]);

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, bob.Id], null);
        var updated = await h.Provisioning.UpdateGroupAsync(group.SharedUserId, [alice.Id, bob.Id], true, false, false, false, null);

        Assert.True(updated.InheritParentalRating);
    }

    [Fact]
    public async Task ChosenCap_IsReclampedWhenMembershipChanges()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var teen = MakeUser("teen", TeenHash).Restrict(maxRating: 13);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7);
        var h = MakeHarness([alice, teen, kid], (AliceHash, "alice-pw"), (TeenHash, "teen-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, teen.Id, kid.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;

        // "No cap" is valid while the uncapped parent is a member...
        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, teen.Id, kid.Id], true, false, false, false, null);
        Assert.Null(shared.MaxParentalRatingScore);

        // ...and is pulled back to the teen's level once the parent leaves, so the teen can still
        // unlock the account.
        var updated = await h.Provisioning.UpdateGroupAsync(shared.Id, [teen.Id, kid.Id], true, false, false, false, null);
        Assert.Equal(13, updated.ParentalRatingCap);
        Assert.Equal(13, shared.MaxParentalRatingScore);
        await h.Provider.Authenticate(shared.Username, "teen-pw", shared);
    }

    [Fact]
    public async Task InheritedGroup_MemberCapLoweredAfterLastReapply_IsRefusedUntilRecomputed()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 13);
        var h = MakeHarness([alice, kid], (AliceHash, "alice-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, kid.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;
        Assert.Equal(13, shared.MaxParentalRatingScore);

        // The drift case: the child's cap is lowered in the user editor, nothing recomputes the
        // shared account, and the unlock rule still holds because it reads both users live.
        kid.Restrict(maxRating: 7);
        await Assert.ThrowsAsync<AuthenticationException>(
            () => h.Provider.Authenticate(shared.Username, "kid-pw", shared));

        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, kid.Id], true, false, false, true, null);
        Assert.Equal(7, shared.MaxParentalRatingScore);
        await h.Provider.Authenticate(shared.Username, "kid-pw", shared);
    }

    [Fact]
    public async Task DynamicCreation_IsInherited_AndRestrictedBeforeTheFirstLoginCompletes()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7, blockUnrated: [UnratedItem.Movie]);
        var h = MakeHarness([alice, kid], (AliceHash, "alice-pw"), (KidHash, "kid-pw"));

        // The child types both names with their own password on a fresh server. The session this
        // creates must already be capped.
        var created = await h.Provider.Authenticate("alice+kid", "kid-pw", null);

        var shared = h.Users.Find(u => u.Username == created.Username)!;
        Assert.Equal(7, shared.MaxParentalRatingScore);
        Assert.Equal([UnratedItem.Movie], shared.GetPreferenceValues<UnratedItem>(PreferenceKind.BlockUnratedItems));
        Assert.True(Assert.Single(ctx.Configuration.Groups).InheritParentalRating);
    }

    [Fact]
    public async Task DynamicLogin_ToAnExistingGroupWithAChosenCap_AppliesTheUnlockRule()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var kid = MakeUser("kid", KidHash).Restrict(maxRating: 7);
        var h = MakeHarness([alice, kid], (AliceHash, "alice-pw"), (KidHash, "kid-pw"));

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, kid.Id], "family");
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;
        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, kid.Id], true, false, false, false, null);

        // "kid+alice" matches no account by name, so it reaches the dynamic path and resolves to
        // the existing group; the same rule must apply there.
        var asAlice = await h.Provider.Authenticate("kid+alice", "alice-pw", null);
        Assert.Equal("family", asAlice.Username);

        await Assert.ThrowsAsync<AuthenticationException>(
            () => h.Provider.Authenticate("kid+alice", "kid-pw", null));
    }

    [Fact]
    public async Task Provisioning_SharedAccountIsNeverAnAdministrator()
    {
        using var ctx = PluginTestContext.Create();

        var alice = MakeUser("alice", AliceHash);
        var bob = MakeUser("bob", KidHash);
        alice.SetPermission(PermissionKind.IsAdministrator, true);
        bob.SetPermission(PermissionKind.IsAdministrator, true);
        var h = MakeHarness([alice, bob]);

        var group = await h.Provisioning.CreateGroupAsync([alice.Id, bob.Id], null);
        var shared = h.Users.Find(u => u.Id == group.SharedUserId)!;
        Assert.False(shared.HasPermission(PermissionKind.IsAdministrator));

        // Not even if granted afterwards.
        shared.SetPermission(PermissionKind.IsAdministrator, true);
        await h.Provisioning.UpdateGroupAsync(shared.Id, [alice.Id, bob.Id], true, false, false, true, null);
        Assert.False(shared.HasPermission(PermissionKind.IsAdministrator));
    }
}