using Akka.Actor;
using Akka.TestKit.Xunit2;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;
using ScadaLink.Commons.Entities.Audit;
using ScadaLink.Commons.Interfaces.Repositories;
using ScadaLink.Commons.Messages.Audit;
using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Audit;
using ScadaLink.ConfigurationDatabase;
using ScadaLink.ConfigurationDatabase.Repositories;
using ScadaLink.ConfigurationDatabase.Tests.Migrations;

namespace ScadaLink.SiteCallAudit.Tests;

/// <summary>
/// Bundle C1 (#22, #23 M3) tests for <see cref="SiteCallAuditActor"/>. Uses the
/// same <see cref="MsSqlMigrationFixture"/> as the Bundle B3 repository tests
/// so the actor exercises the real monotonic-upsert SQL end to end against the
/// <c>SiteCalls</c> schema. Each test scopes its data by minting a fresh
/// <see cref="TrackedOperationId"/> (and a per-test <c>SourceSite</c> suffix)
/// so tests neither collide nor require teardown.
/// </summary>
public class SiteCallAuditActorTests : TestKit, IClassFixture<MsSqlMigrationFixture>
{
    private readonly MsSqlMigrationFixture _fixture;

    public SiteCallAuditActorTests(MsSqlMigrationFixture fixture)
    {
        _fixture = fixture;
    }

    private ScadaLinkDbContext CreateContext()
    {
        var options = new DbContextOptionsBuilder<ScadaLinkDbContext>()
            .UseSqlServer(_fixture.ConnectionString)
            .Options;
        return new ScadaLinkDbContext(options);
    }

    private static string NewSiteId() =>
        "test-bundle-c1-" + Guid.NewGuid().ToString("N").Substring(0, 8);

    private static SiteCall NewRow(
        TrackedOperationId id,
        string sourceSite,
        string status = "Submitted",
        int retryCount = 0,
        string? lastError = null,
        DateTime? createdAtUtc = null,
        DateTime? updatedAtUtc = null,
        bool terminal = false)
    {
        var created = createdAtUtc ?? DateTime.UtcNow;
        var updated = updatedAtUtc ?? created;
        return new SiteCall
        {
            TrackedOperationId = id,
            Channel = "ApiOutbound",
            Target = "ERP.GetOrder",
            SourceSite = sourceSite,
            Status = status,
            RetryCount = retryCount,
            LastError = lastError,
            HttpStatus = null,
            CreatedAtUtc = created,
            UpdatedAtUtc = updated,
            TerminalAtUtc = terminal ? updated : null,
            IngestedAtUtc = DateTime.UtcNow,
        };
    }

    private IActorRef CreateActor(ISiteCallAuditRepository repository) =>
        Sys.ActorOf(Props.Create(() => new SiteCallAuditActor(
            repository,
            NullLogger<SiteCallAuditActor>.Instance)));

    [SkippableFact]
    public async Task Receive_UpsertSiteCallCommand_Persists_Replies_Accepted()
    {
        Skip.IfNot(_fixture.Available, _fixture.SkipReason);

        var siteId = NewSiteId();
        var id = TrackedOperationId.New();
        var row = NewRow(id, siteId, status: "Submitted", retryCount: 0);

        await using var context = CreateContext();
        var repo = new SiteCallAuditRepository(context);
        var actor = CreateActor(repo);

        actor.Tell(new UpsertSiteCallCommand(row), TestActor);

        var reply = ExpectMsg<UpsertSiteCallReply>(TimeSpan.FromSeconds(10));
        Assert.True(reply.Accepted, "Actor should reply Accepted=true on a successful upsert.");
        Assert.Equal(id, reply.TrackedOperationId);

        // Verify the row landed in MSSQL via a fresh context (separate from the
        // actor's repository context).
        await using var readContext = CreateContext();
        var rows = await readContext.Set<SiteCall>()
            .Where(s => s.SourceSite == siteId)
            .ToListAsync();
        Assert.Single(rows);
        Assert.Equal("Submitted", rows[0].Status);
    }

    [SkippableFact]
    public async Task Receive_DuplicateUpsert_OlderStatus_NoOp_StillRepliesAccepted()
    {
        Skip.IfNot(_fixture.Available, _fixture.SkipReason);

        // Idempotency contract: a stale/duplicate packet (lower rank than the
        // stored status) is a silent no-op at the repository — the actor must
        // still reply Accepted=true so the site is free to consider its
        // packet acked. Storage state is consistent either way.
        var siteId = NewSiteId();
        var id = TrackedOperationId.New();

        await using var context = CreateContext();
        var repo = new SiteCallAuditRepository(context);
        var actor = CreateActor(repo);

        // Land Attempted (rank 2) first.
        actor.Tell(new UpsertSiteCallCommand(NewRow(id, siteId, status: "Attempted", retryCount: 1, lastError: "first")), TestActor);
        var firstReply = ExpectMsg<UpsertSiteCallReply>(TimeSpan.FromSeconds(10));
        Assert.True(firstReply.Accepted);

        // Late-arriving Submitted (rank 0) — must be no-op in storage and
        // still acked by the actor.
        actor.Tell(new UpsertSiteCallCommand(NewRow(id, siteId, status: "Submitted", retryCount: 0)), TestActor);
        var secondReply = ExpectMsg<UpsertSiteCallReply>(TimeSpan.FromSeconds(10));
        Assert.True(secondReply.Accepted, "Stale upsert must still be acked (idempotent contract).");

        // Storage must still show the rank-2 row, not rolled back.
        await using var readContext = CreateContext();
        var stored = await readContext.Set<SiteCall>()
            .Where(s => s.TrackedOperationId == id)
            .ToListAsync();
        Assert.Single(stored);
        Assert.Equal("Attempted", stored[0].Status);
        Assert.Equal(1, stored[0].RetryCount);
        Assert.Equal("first", stored[0].LastError);
    }

    [SkippableFact]
    public async Task Receive_RepoThrowsTransient_RepliesAccepted_False_ActorStaysAlive()
    {
        Skip.IfNot(_fixture.Available, _fixture.SkipReason);

        // Per CLAUDE.md: audit-write failure NEVER aborts the user-facing
        // action. The actor must catch the throw, reply Accepted=false, and
        // stay alive — a follow-up message on the same actor must still be
        // processed (the singleton cannot die on a transient repo error).
        var siteId = NewSiteId();
        var poisonId = TrackedOperationId.New();
        var healthyId = TrackedOperationId.New();

        await using var context = CreateContext();
        var realRepo = new SiteCallAuditRepository(context);
        var wrappedRepo = new ThrowingRepository(realRepo, poisonId);
        var actor = CreateActor(wrappedRepo);

        // Poison row — the wrapper throws when this id arrives.
        actor.Tell(new UpsertSiteCallCommand(NewRow(poisonId, siteId, status: "Submitted")), TestActor);
        var poisonReply = ExpectMsg<UpsertSiteCallReply>(TimeSpan.FromSeconds(10));
        Assert.False(poisonReply.Accepted, "Actor should reply Accepted=false when the repo throws.");
        Assert.Equal(poisonId, poisonReply.TrackedOperationId);

        // Healthy follow-up on the SAME actor — must still be processed
        // (singleton staying alive proves the actor did not crash).
        actor.Tell(new UpsertSiteCallCommand(NewRow(healthyId, siteId, status: "Submitted")), TestActor);
        var healthyReply = ExpectMsg<UpsertSiteCallReply>(TimeSpan.FromSeconds(10));
        Assert.True(healthyReply.Accepted, "Actor must stay alive after a transient repo failure.");
        Assert.Equal(healthyId, healthyReply.TrackedOperationId);

        // Verify storage: healthy row landed, poison row did not.
        await using var readContext = CreateContext();
        var rows = await readContext.Set<SiteCall>()
            .Where(s => s.SourceSite == siteId)
            .ToListAsync();
        Assert.Single(rows);
        Assert.Equal(healthyId, rows[0].TrackedOperationId);
    }

    /// <summary>
    /// Tiny test double that delegates to a real repository but throws on a
    /// specified <see cref="TrackedOperationId"/>. Used to verify the actor's
    /// fault-isolation behaviour: a transient repository failure must produce
    /// <c>Accepted=false</c> without crashing the singleton.
    /// </summary>
    private sealed class ThrowingRepository : ISiteCallAuditRepository
    {
        private readonly ISiteCallAuditRepository _inner;
        private readonly TrackedOperationId _poisonId;

        public ThrowingRepository(ISiteCallAuditRepository inner, TrackedOperationId poisonId)
        {
            _inner = inner;
            _poisonId = poisonId;
        }

        public Task UpsertAsync(SiteCall siteCall, CancellationToken ct = default)
        {
            if (siteCall.TrackedOperationId == _poisonId)
            {
                throw new InvalidOperationException("simulated transient repo failure for poison row");
            }
            return _inner.UpsertAsync(siteCall, ct);
        }

        public Task<SiteCall?> GetAsync(TrackedOperationId id, CancellationToken ct = default) =>
            _inner.GetAsync(id, ct);

        public Task<IReadOnlyList<SiteCall>> QueryAsync(
            SiteCallQueryFilter filter, SiteCallPaging paging, CancellationToken ct = default) =>
            _inner.QueryAsync(filter, paging, ct);

        public Task<int> PurgeTerminalAsync(DateTime olderThanUtc, CancellationToken ct = default) =>
            _inner.PurgeTerminalAsync(olderThanUtc, ct);
    }
}