using PlotLine.Data;
using PlotLine.Models;
using PlotLine.ViewModels;

namespace PlotLine.Services;

// Read projections shared with Continuity Explorer, without its per-entity database adapters.
public sealed partial class StoryStateService
{
    public static StoryStateViewModel BuildAtScene(StoryPointInputs input, int sceneId)
    {
        var ordered = OrderScenes(input.Timeline).ToList();
        var indexes = BuildSceneIndexes(ordered);
        if (!indexes.TryGetValue(sceneId, out var maximum)) return new();
        var allowed = ordered.Take(maximum + 1).Select(x => x.SceneID).ToHashSet();
        var state = new StoryStateViewModel
        {
            Characters = BuildCharacterState(input.Characters, input.Appearances, sceneId, allowed, indexes),
            Assets = BuildAssetState(input.Assets, input.AssetEvents, input.History.AssetLocations, input.History.Custody,
                sceneId, allowed, indexes, ordered.ToDictionary(x => x.SceneID))
        };
        state.Locations = BuildLocationState(input.Locations, state);
        return state;
    }

    public static IReadOnlyList<CharacterKnowledgeItem> KnowledgeAtScene(
        IEnumerable<CharacterKnowledgeItem> items, IReadOnlyDictionary<int, int> indexes, int sceneId)
    {
        if (!indexes.TryGetValue(sceneId, out var maximum)) return [];
        return items.Where(x => indexes.TryGetValue(x.SceneID, out var index) && index <= maximum)
            .GroupBy(x => (x.CharacterID, Identity: KnowledgeIdentity(x)))
            .Select(x => x.OrderBy(y => indexes[y.SceneID]).ThenBy(y => y.CreatedDate).ThenBy(y => y.CharacterKnowledgeID).Last())
            .ToList();
    }

    public static IReadOnlyList<ContinuityWarningViewModel> WarningsAtScene(
        StoryPointInputs input, int sceneId, IReadOnlySet<int> characterIds, IReadOnlySet<int> assetIds)
    {
        var ordered = OrderScenes(input.Timeline).ToList();
        var maximum = ordered.FindIndex(x => x.SceneID == sceneId);
        if (maximum < 0) return [];
        // Bound inputs before invoking any warning algorithm: later evidence must not suppress earlier warnings.
        ordered = ordered.Take(maximum + 1).ToList();
        var allowed = ordered.Select(x => x.SceneID).ToHashSet();
        var context = new RangeContext(ordered, ordered, allowed, BuildSceneIndexes(ordered),
            ordered.ToDictionary(x => x.SceneID, x => SceneLabel(x.SceneNumber, x.SceneTitle)), BuildSceneContexts(input.Timeline));
        var appearances = input.Appearances.Where(x => allowed.Contains(x.SceneID)).ToList();
        var locations = input.History.AssetLocations.Where(x => allowed.Contains(x.SceneID)).ToList();
        var custodians = input.History.Custodians.Where(x => allowed.Contains(x.SceneID)).ToList();
        var warnings = new List<ContinuityWarningViewModel>();
        warnings.AddRange(BuildMultipleCharacterLocationWarnings(appearances, characterIds, context));
        warnings.AddRange(BuildImpossibleMovementWarnings(appearances, characterIds, context));
        warnings.AddRange(BuildUnknownCharacterLocationWarnings(input.Characters, appearances, characterIds, context));
        warnings.AddRange(BuildKnowledgeRegressionWarnings(input.Characters, characterIds, context,
            input.History.Knowledge.Where(x => allowed.Contains(x.SceneID)).ToList()));
        warnings.AddRange(BuildAssetLocationConflictWarnings(input.Assets, locations, custodians, assetIds, context));
        warnings.AddRange(BuildUnknownAssetLocationWarnings(input.Assets, input.AssetEvents.Where(x => allowed.Contains(x.SceneID)).ToList(),
            locations, custodians, assetIds, context));
        ApplyAcknowledgements(warnings, input.Acknowledgements);
        return warnings.Where(x => !x.IsAcknowledged && x.SceneID.HasValue && allowed.Contains(x.SceneID.Value)
            && (x.SceneID == sceneId || (x.CharacterID.HasValue && characterIds.Contains(x.CharacterID.Value))
                || (x.AssetID.HasValue && assetIds.Contains(x.AssetID.Value))))
            .OrderBy(x => WarningSeveritySort(x.Severity)).ThenBy(x => x.Message).ToList();
    }
}