using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.Configuration.Services;

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

[Trait("Category", "Unit")]
public sealed class LdapGroupRoleMappingServiceTests
{
    private readonly RecordingContextFactory _db = new();

    private LdapGroupRoleMapping Make(string group, AdminRole role, string? clusterId = null, bool? isSystemWide = null) =>
        new()
        {
            LdapGroup = group,
            Role = role,
            ClusterId = clusterId,
            IsSystemWide = isSystemWide ?? (clusterId is null),
        };

    /// <summary>Verifies that Create sets Id and CreatedAtUtc.</summary>
    [Fact]
    public async Task Create_SetsId_AndCreatedAtUtc()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        var row = Make("cn=fleet,dc=x", AdminRole.Administrator);

        var saved = await svc.CreateAsync(row, CancellationToken.None);

        saved.Id.ShouldNotBe(Guid.Empty);
        saved.CreatedAtUtc.ShouldBeGreaterThan(DateTime.UtcNow.AddMinutes(-1));
    }

    /// <summary>Verifies that Create rejects empty LDAP group.</summary>
    [Fact]
    public async Task Create_Rejects_EmptyLdapGroup()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        var row = Make("", AdminRole.Administrator);

        await Should.ThrowAsync<InvalidLdapGroupRoleMappingException>(
            () => svc.CreateAsync(row, CancellationToken.None));
    }

    /// <summary>Verifies that Create rejects system-wide mapping with ClusterId.</summary>
    [Fact]
    public async Task Create_Rejects_SystemWide_With_ClusterId()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        var row = Make("cn=g", AdminRole.Viewer, clusterId: "c1", isSystemWide: true);

        await Should.ThrowAsync<InvalidLdapGroupRoleMappingException>(
            () => svc.CreateAsync(row, CancellationToken.None));
    }

    /// <summary>Verifies that Create rejects non-system-wide mapping without ClusterId.</summary>
    [Fact]
    public async Task Create_Rejects_NonSystemWide_WithoutClusterId()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        var row = Make("cn=g", AdminRole.Viewer, clusterId: null, isSystemWide: false);

        await Should.ThrowAsync<InvalidLdapGroupRoleMappingException>(
            () => svc.CreateAsync(row, CancellationToken.None));
    }

    /// <summary>Verifies that GetByGroups returns only matching grants.</summary>
    [Fact]
    public async Task GetByGroups_Returns_MatchingGrants_Only()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        await svc.CreateAsync(Make("cn=fleet,dc=x", AdminRole.Administrator), CancellationToken.None);
        await svc.CreateAsync(Make("cn=editor,dc=x", AdminRole.Designer), CancellationToken.None);
        await svc.CreateAsync(Make("cn=viewer,dc=x", AdminRole.Viewer), CancellationToken.None);

        var results = await svc.GetByGroupsAsync(
            ["cn=fleet,dc=x", "cn=viewer,dc=x"], CancellationToken.None);

        results.Count.ShouldBe(2);
        results.Select(r => r.Role).ShouldBe([AdminRole.Administrator, AdminRole.Viewer], ignoreOrder: true);
    }

    /// <summary>Verifies that GetByGroups returns empty when input is empty.</summary>
    [Fact]
    public async Task GetByGroups_Empty_Input_ReturnsEmpty()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        await svc.CreateAsync(Make("cn=fleet,dc=x", AdminRole.Administrator), CancellationToken.None);

        var results = await svc.GetByGroupsAsync([], CancellationToken.None);

        results.ShouldBeEmpty();
    }

    /// <summary>Verifies that ListAll orders results by group then cluster.</summary>
    [Fact]
    public async Task ListAll_Orders_ByGroupThenCluster()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        await svc.CreateAsync(Make("cn=b,dc=x", AdminRole.Administrator), CancellationToken.None);
        await svc.CreateAsync(Make("cn=a,dc=x", AdminRole.Designer, clusterId: "c2", isSystemWide: false), CancellationToken.None);
        await svc.CreateAsync(Make("cn=a,dc=x", AdminRole.Designer, clusterId: "c1", isSystemWide: false), CancellationToken.None);

        var results = await svc.ListAllAsync(CancellationToken.None);

        results[0].LdapGroup.ShouldBe("cn=a,dc=x");
        results[0].ClusterId.ShouldBe("c1");
        results[1].ClusterId.ShouldBe("c2");
        results[2].LdapGroup.ShouldBe("cn=b,dc=x");
    }

    /// <summary>Verifies that Delete removes the matching row.</summary>
    [Fact]
    public async Task Delete_Removes_Matching_Row()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        var saved = await svc.CreateAsync(Make("cn=fleet,dc=x", AdminRole.Administrator), CancellationToken.None);

        await svc.DeleteAsync(saved.Id, CancellationToken.None);

        var after = await svc.ListAllAsync(CancellationToken.None);
        after.ShouldBeEmpty();
    }

    /// <summary>Verifies that Delete with unknown Id is a no-op.</summary>
    [Fact]
    public async Task Delete_Unknown_Id_IsNoOp()
    {
        var svc = new LdapGroupRoleMappingService(_db);

        await svc.DeleteAsync(Guid.NewGuid(), CancellationToken.None);
        // no exception
    }

    /// <summary>Verifies that a system-wide row (IsSystemWide=true, ClusterId=null) appears in both ListAllAsync and GetByGroupsAsync.</summary>
    [Fact]
    public async Task SystemWide_Row_AppearsIn_ListAll_And_GetByGroups()
    {
        var svc = new LdapGroupRoleMappingService(_db);
        var saved = await svc.CreateAsync(
            Make("cn=sysadmins,dc=x", AdminRole.Administrator, clusterId: null, isSystemWide: true),
            CancellationToken.None);

        saved.IsSystemWide.ShouldBeTrue();
        saved.ClusterId.ShouldBeNull();

        var all = await svc.ListAllAsync(CancellationToken.None);
        all.ShouldContain(r => r.Id == saved.Id);

        var byGroup = await svc.GetByGroupsAsync(["cn=sysadmins,dc=x"], CancellationToken.None);
        byGroup.ShouldContain(r => r.Id == saved.Id);
    }

    /// <summary>
    ///     The service must take its context from the factory PER CALL and dispose it before returning —
    ///     it must never pin one context (and therefore one pooled connection) for its own lifetime. That
    ///     is what makes it safe on the RoleGrants Blazor page, where the DI scope is the circuit and two
    ///     renders can overlap: a pinned context would throw
    ///     "A second operation was started on this context instance" the first time they did.
    /// </summary>
    [Fact]
    public async Task Every_call_creates_and_disposes_its_own_context()
    {
        var svc = new LdapGroupRoleMappingService(_db);

        await svc.CreateAsync(Make("cn=fleet,dc=x", AdminRole.Administrator), CancellationToken.None);
        await svc.ListAllAsync(CancellationToken.None);
        await svc.GetByGroupsAsync(["cn=fleet,dc=x"], CancellationToken.None);

        // One context per call, and no leftovers: a service holding its own context would show 0.
        _db.Created.Count.ShouldBe(3);
        foreach (var ctx in _db.Created)
            Should.Throw<ObjectDisposedException>(() => ctx.LdapGroupRoleMappings.ToList());
    }

    /// <summary>
    ///     Hands out a fresh <see cref="OtOpcUaConfigDbContext"/> per call over one shared in-memory store
    ///     (an explicit <see cref="InMemoryDatabaseRoot"/>, so every context genuinely sees the same rows),
    ///     and records what it created so a test can assert the per-call create/dispose discipline.
    /// </summary>
    private sealed class RecordingContextFactory : IDbContextFactory<OtOpcUaConfigDbContext>
    {
        private readonly DbContextOptions<OtOpcUaConfigDbContext> _options =
            new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
                .UseInMemoryDatabase($"ldap-grm-{Guid.NewGuid():N}", new InMemoryDatabaseRoot())
                .Options;

        public List<OtOpcUaConfigDbContext> Created { get; } = [];

        public OtOpcUaConfigDbContext CreateDbContext()
        {
            var ctx = new OtOpcUaConfigDbContext(_options);
            Created.Add(ctx);
            return ctx;
        }
    }
}