using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging.Abstractions;
using StellaOps.Signals.Models;
using StellaOps.Signals.Persistence;
using StellaOps.Signals.Services;
using Xunit;

public class RuntimeFactsIngestionServiceTests
{
    [Fact]
    public async Task IngestAsync_AggregatesHits_AndRecomputesReachability()
    {
        var factRepository = new InMemoryReachabilityFactRepository();
        var scoringService = new RecordingScoringService();
        var service = new RuntimeFactsIngestionService(
            factRepository,
            TimeProvider.System,
            scoringService,
            NullLogger<RuntimeFactsIngestionService>.Instance);

        var request = new RuntimeFactsIngestRequest
        {
            Subject = new ReachabilitySubject { Component = "web", Version = "2.1.0" },
            CallgraphId = "cg-123",
            Metadata = new Dictionary<string, string?> { { "source", "runtime" } },
            Events = new List<RuntimeFactEvent>
            {
                new() { SymbolId = "svc.foo", HitCount = 2, Metadata = new Dictionary<string, string?> { { "pid", "12" } } },
                new() { SymbolId = "svc.bar", HitCount = 1 },
                new() { SymbolId = "svc.foo", HitCount = 3 }
            }
        };

        var response = await service.IngestAsync(request, CancellationToken.None);

        Assert.Equal("web|2.1.0", response.SubjectKey);
        Assert.Equal("cg-123", response.CallgraphId);

        var persisted = factRepository.Last ?? throw new Xunit.Sdk.XunitException("Fact not persisted");
        Assert.Equal(2, persisted.RuntimeFacts?.Count);

        var foo = persisted.RuntimeFacts?.Single(f => f.SymbolId == "svc.foo");
        Assert.Equal(5, foo?.HitCount);

        var bar = persisted.RuntimeFacts?.Single(f => f.SymbolId == "svc.bar");
        Assert.Equal(1, bar?.HitCount);

        var recorded = scoringService.LastRequest ?? throw new Xunit.Sdk.XunitException("Recompute not triggered");
        Assert.Equal("cg-123", recorded.CallgraphId);
        Assert.Contains("svc.foo", recorded.Targets);
        Assert.Contains("svc.bar", recorded.RuntimeHits!);
        Assert.Equal("runtime", recorded.Metadata?["source"]);

        Assert.Equal("runtime", persisted.Metadata?["provenance.source"]);
        Assert.Equal("cg-123", persisted.Metadata?["provenance.callgraphId"]);
        Assert.NotNull(persisted.Metadata?["provenance.ingestedAt"]);
    }

    private sealed class InMemoryReachabilityFactRepository : IReachabilityFactRepository
    {
        public ReachabilityFactDocument? Last { get; private set; }

        public Task<ReachabilityFactDocument?> GetBySubjectAsync(string subjectKey, CancellationToken cancellationToken)
        {
            return Task.FromResult(Last);
        }

        public Task<ReachabilityFactDocument> UpsertAsync(ReachabilityFactDocument document, CancellationToken cancellationToken)
        {
            Last = document;
            return Task.FromResult(document);
        }
    }

    private sealed class RecordingScoringService : IReachabilityScoringService
    {
        public ReachabilityRecomputeRequest? LastRequest { get; private set; }

        public Task<ReachabilityFactDocument> RecomputeAsync(ReachabilityRecomputeRequest request, CancellationToken cancellationToken)
        {
            LastRequest = request;
            return Task.FromResult(new ReachabilityFactDocument
            {
                CallgraphId = request.CallgraphId,
                Subject = request.Subject,
                SubjectKey = request.Subject?.ToSubjectKey() ?? string.Empty,
                EntryPoints = request.EntryPoints,
                States = new List<ReachabilityStateDocument>(),
                RuntimeFacts = new List<RuntimeFactDocument>()
            });
        }
    }
}