using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.MxGateway.Contracts.Proto;
using ZB.MOM.WW.MxGateway.Server.Alarms;
using ZB.MOM.WW.MxGateway.Server.Configuration;
using ZB.MOM.WW.MxGateway.Server.Galaxy;

namespace ZB.MOM.WW.MxGateway.Tests.Alarms;

/// <summary>
///     Unit tests for <see cref="AlarmWatchListResolver"/>: discovery/config merge,
///     subtag-address composition, canonical reference shaping, and the
///     unavailable-discovery code path.
/// </summary>
public sealed class AlarmWatchListResolverTests
{
    private static AlarmWatchListResolver CreateResolver(IGalaxyRepository repository) =>
        new(repository, NullLogger<AlarmWatchListResolver>.Instance);

    private static AlarmsOptions Options(
        bool useGalaxyRepository = true,
        string area = "",
        string defaultArea = "",
        string[]? include = null,
        string[]? exclude = null,
        AlarmSubtagNameOptions? subtags = null) =>
        new()
        {
            DefaultArea = defaultArea,
            Fallback = new AlarmFallbackOptions
            {
                Discovery = new AlarmDiscoveryOptions
                {
                    UseGalaxyRepository = useGalaxyRepository,
                    Area = area,
                    IncludeAttributes = include ?? [],
                    ExcludeAttributes = exclude ?? [],
                },
                Subtags = subtags ?? new AlarmSubtagNameOptions(),
            },
        };

    [Fact]
    public async Task ResolveAsync_UnionsGalaxyRowsAndIncludes_RemovesExcludes_AndDeduplicates()
    {
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank01.Level.HiHi", SourceObjectReference = "Tank01", Area = "TestArea" },
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank02.Level.HiHi", SourceObjectReference = "Tank02", Area = "TestArea" },
            // Duplicate of an include below (case-insensitive) — should appear once.
            new GalaxyAlarmAttributeRow { FullTagReference = "Pump01.Fault", SourceObjectReference = "Pump01", Area = "TestArea" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            include: ["pump01.fault", "Valve03.Position.Lo"],
            exclude: ["Tank02.Level.HiHi"]));

        Assert.Equal(
            new[] { "Tank01.Level.HiHi", "Pump01.Fault", "Valve03.Position.Lo" },
            result.Select(t => t.ActiveSubtag.Replace(".InAlarm", string.Empty, StringComparison.Ordinal)));
        // De-dup preserved first (GR) occurrence; exclude removed Tank02.
        Assert.Equal(3, result.Count);
    }

    [Fact]
    public async Task ResolveAsync_ComposesSubtagAddressesFromConfigNames()
    {
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank01.Level.HiHi", SourceObjectReference = "Tank01", Area = "TestArea" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            subtags: new AlarmSubtagNameOptions
            {
                Active = "InAlarm",
                Acked = "Ack",
                Priority = "Pri",
                AckComment = "AckCmt",
            }));

        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Tank01.Level.HiHi.InAlarm", target.ActiveSubtag);
        Assert.Equal("Tank01.Level.HiHi.Ack", target.AckedSubtag);
        Assert.Equal("Tank01.Level.HiHi.Pri", target.PrioritySubtag);
        Assert.Equal("Tank01.Level.HiHi.AckCmt", target.AckCommentSubtag);
    }

    [Fact]
    public async Task ResolveAsync_EmptyPriorityAndAckComment_LeaveThoseFieldsEmpty()
    {
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank01.Level.HiHi", SourceObjectReference = "Tank01", Area = "TestArea" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        // Default Priority is "Priority"; force it empty alongside empty AckComment.
        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            subtags: new AlarmSubtagNameOptions { Priority = string.Empty, AckComment = string.Empty }));

        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Tank01.Level.HiHi.InAlarm", target.ActiveSubtag);
        Assert.Equal("Tank01.Level.HiHi.Acked", target.AckedSubtag);
        Assert.Equal(string.Empty, target.PrioritySubtag);
        Assert.Equal(string.Empty, target.AckCommentSubtag);
    }

    [Fact]
    public async Task ResolveAsync_ComposesCanonicalFullReference_FromRealGalaxyArea_NotConfigArea()
    {
        // The GR row carries the object's real Galaxy area (the alarmmgr group). The
        // composed reference must use that area, NOT the configured Discovery.Area.
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow
            {
                FullTagReference = "TestMachine_001.TestAlarm001",
                SourceObjectReference = "TestMachine_001",
                Area = "TestArea",
            },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        // Config area "DEV" must be ignored for a GR row that has a discovered area.
        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(
            Options(area: "DEV", defaultArea: "DEV"));

        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!TestArea.TestMachine_001.TestAlarm001", target.AlarmFullReference);
    }

    [Fact]
    public async Task ResolveAsync_ComposesCanonicalFullReference_WithoutArea()
    {
        // GR row with no discovered area and no config area -> bare Galaxy!{reference}.
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank01.Level.HiHi", SourceObjectReference = "Tank01", Area = "" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        // No discovery area and no default area.
        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options());

        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!Tank01.Level.HiHi", target.AlarmFullReference);
    }

    [Fact]
    public async Task ResolveAsync_ConfigInclude_UsesDiscoveryAreaFallback()
    {
        // A config IncludeAttributes entry has no discovered area, so it uses the
        // config fallback: Discovery.Area when set.
        StubGalaxyRepository repo = new([]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            area: "Site_A",
            include: ["Tank01.Level.HiHi"]));

        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!Site_A.Tank01.Level.HiHi", target.AlarmFullReference);
    }

    [Fact]
    public async Task ResolveAsync_ConfigInclude_FallsBackToDefaultArea_WhenDiscoveryAreaEmpty()
    {
        // A config IncludeAttributes entry with no Discovery.Area uses DefaultArea.
        StubGalaxyRepository repo = new([]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            area: "",
            defaultArea: "Plant",
            include: ["Tank01.Level.HiHi"]));

        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!Plant.Tank01.Level.HiHi", target.AlarmFullReference);
    }

    [Fact]
    public async Task ResolveAsync_UseGalaxyRepositoryFalse_DoesNotCallRepository_UsesIncludesOnly()
    {
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "ShouldNotAppear.X", SourceObjectReference = "ShouldNotAppear" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            useGalaxyRepository: false,
            include: ["Tank01.Level.HiHi"]));

        Assert.Equal(0, repo.GetAlarmAttributesCount);
        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!Tank01.Level.HiHi", target.AlarmFullReference);
    }

    [Fact]
    public async Task ResolveAsync_RepositoryThrows_LogsAndReturnsConfigOnlySet()
    {
        ThrowingGalaxyRepository repo = new(new InvalidOperationException("SQL unavailable"));

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            include: ["Tank01.Level.HiHi"]));

        // Did not throw; discovery set empty, include retained.
        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!Tank01.Level.HiHi", target.AlarmFullReference);
    }

    [Fact]
    public async Task ResolveAsync_DerivesSourceObjectForConfigEntry()
    {
        StubGalaxyRepository repo = new([]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            include: ["Tank01.Level.HiHi", "StandaloneTag"]));

        Assert.Equal("Tank01", result[0].SourceObjectReference);
        // No dot — whole string is the source object.
        Assert.Equal("StandaloneTag", result[1].SourceObjectReference);
    }

    /// <summary>
    ///     Fix 1: ExcludeAttributes must be ignored when UseGalaxyRepository is false.
    ///     A config-only include must survive even when the same path appears in ExcludeAttributes.
    /// </summary>
    [Fact]
    public async Task ResolveAsync_ExcludeIgnored_WhenGalaxyRepositoryDisabled()
    {
        // Repo is never consulted; only IncludeAttributes matters.
        StubGalaxyRepository repo = new([]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            useGalaxyRepository: false,
            include: ["Tank01.Level.HiHi"],
            exclude: ["Tank01.Level.HiHi"]));

        // ExcludeAttributes is ignored when GR is off — the include must be present.
        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Equal("Galaxy!Tank01.Level.HiHi", target.AlarmFullReference);
    }

    /// <summary>
    ///     Fix 1 (GR-on path): ExcludeAttributes still prunes GR rows when
    ///     UseGalaxyRepository is true.
    /// </summary>
    [Fact]
    public async Task ResolveAsync_ExcludeApplied_WhenGalaxyRepositoryEnabled()
    {
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank01.Level.HiHi", SourceObjectReference = "Tank01", Area = "TestArea" },
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank02.Level.HiHi", SourceObjectReference = "Tank02", Area = "TestArea" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            useGalaxyRepository: true,
            exclude: ["Tank02.Level.HiHi"]));

        // Tank02 was excluded; only Tank01 remains.
        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Contains("Tank01", target.ActiveSubtag, StringComparison.Ordinal);
    }

    /// <summary>
    ///     Fix 1: A whitespace-only ExcludeAttributes entry must be skipped and must
    ///     not accidentally exclude any real reference.
    /// </summary>
    [Fact]
    public async Task ResolveAsync_WhitespaceOnlyExcludeEntry_IsSkipped()
    {
        StubGalaxyRepository repo = new(
        [
            new GalaxyAlarmAttributeRow { FullTagReference = "Tank01.Level.HiHi", SourceObjectReference = "Tank01", Area = "TestArea" },
        ]);

        AlarmWatchListResolver resolver = CreateResolver(repo);

        // The exclude array contains a whitespace-only string — should be a no-op.
        IReadOnlyList<AlarmSubtagTarget> result = await resolver.ResolveAsync(Options(
            useGalaxyRepository: true,
            exclude: ["   "]));

        // Tank01 must not have been wrongly excluded.
        AlarmSubtagTarget target = Assert.Single(result);
        Assert.Contains("Tank01", target.ActiveSubtag, StringComparison.Ordinal);
    }

    /// <summary>In-memory <see cref="IGalaxyRepository"/> returning a fixed alarm rowset.</summary>
    private sealed class StubGalaxyRepository(List<GalaxyAlarmAttributeRow> rows) : IGalaxyRepository
    {
        /// <summary>Gets the number of times <see cref="GetAlarmAttributesAsync"/> was called.</summary>
        public int GetAlarmAttributesCount { get; private set; }

        /// <inheritdoc />
        public Task<bool> TestConnectionAsync(CancellationToken ct = default) => Task.FromResult(true);

        /// <inheritdoc />
        public Task<DateTime?> GetLastDeployTimeAsync(CancellationToken ct = default) =>
            Task.FromResult<DateTime?>(null);

        /// <inheritdoc />
        public Task<List<GalaxyHierarchyRow>> GetHierarchyAsync(CancellationToken ct = default) =>
            Task.FromResult(new List<GalaxyHierarchyRow>());

        /// <inheritdoc />
        public Task<List<GalaxyAttributeRow>> GetAttributesAsync(CancellationToken ct = default) =>
            Task.FromResult(new List<GalaxyAttributeRow>());

        /// <inheritdoc />
        public Task<List<GalaxyAlarmAttributeRow>> GetAlarmAttributesAsync(CancellationToken ct = default)
        {
            GetAlarmAttributesCount++;
            return Task.FromResult(rows);
        }
    }

    /// <summary><see cref="IGalaxyRepository"/> whose alarm-attribute query throws.</summary>
    private sealed class ThrowingGalaxyRepository(Exception toThrow) : IGalaxyRepository
    {
        /// <inheritdoc />
        public Task<bool> TestConnectionAsync(CancellationToken ct = default) => Task.FromResult(true);

        /// <inheritdoc />
        public Task<DateTime?> GetLastDeployTimeAsync(CancellationToken ct = default) =>
            Task.FromResult<DateTime?>(null);

        /// <inheritdoc />
        public Task<List<GalaxyHierarchyRow>> GetHierarchyAsync(CancellationToken ct = default) =>
            Task.FromResult(new List<GalaxyHierarchyRow>());

        /// <inheritdoc />
        public Task<List<GalaxyAttributeRow>> GetAttributesAsync(CancellationToken ct = default) =>
            Task.FromResult(new List<GalaxyAttributeRow>());

        /// <inheritdoc />
        public Task<List<GalaxyAlarmAttributeRow>> GetAlarmAttributesAsync(CancellationToken ct = default) =>
            Task.FromException<List<GalaxyAlarmAttributeRow>>(toThrow);
    }
}