using Marathon.Application.UseCases;
using Marathon.Domain.AnomalyDetection;
using DomainEventId = Marathon.Domain.ValueObjects.EventId;

namespace Marathon.UI.Services;

/// <summary>
/// Page-facing implementation of <see cref="IAnomalyInsightsService"/>. Runs
/// the application use case and reshapes its output for the page — event title
/// strings and severity buckets are computed once from the report's payload, so
/// the service performs no repository I/O of its own.
/// </summary>
public sealed class AnomalyInsightsService : IAnomalyInsightsService
{
    private readonly EvaluateAnomalyOutcomesUseCase _useCase;

    public AnomalyInsightsService(EvaluateAnomalyOutcomesUseCase useCase)
    {
        _useCase = useCase ?? throw new ArgumentNullException(nameof(useCase));
    }

    public async Task<AnomalyInsightsVm> GetReportAsync(CancellationToken ct)
    {
        var report = await _useCase.ExecuteAsync(ct).ConfigureAwait(false);

        var resolvedRows = report.Resolved
            .Select(r => ToRow(r, report.EventTitles))
            .ToList();
        var unresolvedRows = report.Unresolved
            .Select(r => ToRow(r, report.EventTitles))
            .ToList();

        return new AnomalyInsightsVm(
            TotalAnomalies: report.TotalAnomalies,
            ResolvedCount: report.ResolvedCount,
            UnresolvedCount: report.UnresolvedCount,
            HitCount: report.HitCount,
            MissCount: report.MissCount,
            HitRate: report.HitRate,
            BySeverity: report.BySeverity,
            BySport: report.BySport,
            ByScoreBin: report.ByScoreBin,
            ByKind: report.ByKind,
            Resolved: resolvedRows,
            Unresolved: unresolvedRows);
    }

    private static ResolvedAnomalyRow ToRow(
        ResolvedAnomaly src,
        IReadOnlyDictionary<DomainEventId, string> titles) =>
        new(
            AnomalyId: src.AnomalyId,
            EventId: src.EventId,
            EventTitle: titles.TryGetValue(src.EventId, out var t) ? t : src.EventId.Value,
            DetectedAt: src.DetectedAt,
            Score: src.Score,
            Severity: AnomalySeverityRules.FromScore(src.Score),
            Sport: src.Sport,
            PreFlipFavourite: src.PreFlipFavourite,
            PostFlipFavourite: src.PostFlipFavourite,
            ActualWinner: src.ActualWinner,
            Outcome: src.Outcome);
}