using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using GameCult.Mesh;

#nullable enable

namespace GameCult.Aetheria.State.Verse
{
    public static class AetheriaRuntimeStateRefResolver
    {
        public static bool TryResolveDaemonStateRef(
            AetheriaRuntimeDaemonFrameDocument? frame,
            AetheriaRuntimeDaemonHealthDocument? health,
            AetheriaRuntimeDaemonCommandBoundaryDocument? commandBoundary,
            string stateRef,
            out string value)
        {
            value = "";
            frame ??= new AetheriaRuntimeDaemonFrameDocument();
            health ??= new AetheriaRuntimeDaemonHealthDocument();
            commandBoundary ??= new AetheriaRuntimeDaemonCommandBoundaryDocument();

            var run = frame.Run ?? new AetheriaRuntimeRunCheckpointCommit();
            var zone = FindCurrentZone(run);
            var entity = FindCurrentEntity(run, zone);
            var target = FindTargetEntity(zone, entity);

            switch (stateRef)
            {
                case AetheriaRuntimeDaemonStateRefs.FrameDaemonId:
                    value = frame.DaemonId ?? "";
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameVerseId:
                    value = health.VerseId ?? "";
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameId:
                    value = frame.FrameId.ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameTime:
                    value = frame.SimulationTimeSeconds.ToString("0.###", CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameStatus:
                    value = health.Status ?? "";
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameObservedCommands:
                    value = health.ObservedCommandCount.ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameAppliedCommands:
                    value = health.AppliedCommandCount.ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.FrameRejectedCommands:
                    value = health.RejectedCommandCount.ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentRunId:
                    value = run.RunId ?? "";
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentZoneIndex:
                    value = run.CurrentZoneIndex.ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentEntityKey:
                    value = run.CurrentEntityKey ?? "";
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentEntityName:
                    value = string.IsNullOrWhiteSpace(entity?.Name) ? "(no current entity)" : entity!.Name;
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentEntityPosition:
                    value = FormatPosition(entity);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentTargetName:
                    value = string.IsNullOrWhiteSpace(target?.Name) ? "(none)" : target!.Name;
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentEquipmentCount:
                    value = Count(entity?.Equipment).ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentCargoBayCount:
                    value = Count(entity?.CargoContents).ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CurrentWeaponGroupCount:
                    value = Count(entity?.WeaponGroups).ToString(CultureInfo.InvariantCulture);
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CommandBoundaryId:
                    value = commandBoundary.BoundaryId ?? "";
                    return true;
                case AetheriaRuntimeDaemonStateRefs.CommandCount:
                    value = Count(commandBoundary.Commands).ToString(CultureInfo.InvariantCulture);
                    return true;
                default:
                    return false;
            }
        }

        public static bool TryResolveDaemonItemStatRef(
            AetheriaRuntimeDaemonFrameDocument? frame,
            AetheriaRuntimeCatalogSnapshot? catalog,
            string stateRef,
            out string value)
        {
            value = "";
            if (!AetheriaRuntimeDaemonItemStatQueries.TryReadItemStatRef(
                    stateRef,
                    out var itemKey,
                    out var behaviorKind,
                    out var behaviorGroup,
                    out var fieldKey))
            {
                return false;
            }

            var item = FindDaemonItem(frame?.Run, itemKey);
            var typedItem = catalog?.FindItem(itemKey);
            var field = typedItem?.BehaviorPayloads?
                .FirstOrDefault(candidate =>
                    string.Equals(candidate.Kind, behaviorKind, StringComparison.Ordinal) &&
                    candidate.Group == behaviorGroup)
                ?.Fields?
                .FirstOrDefault(candidate => candidate.Key == fieldKey);
            if (item == null || field == null)
                return false;

            value = AetheriaRuntimeDaemonItemStatQueries.EvaluatePerformanceStat(
                    field.Value,
                    item,
                    item.Temperature)
                .ToString("0.###", CultureInfo.InvariantCulture);
            return true;
        }

        public static CultMeshStateRefResolver CreateEveSurfaceCultMeshStateRefResolver(
            Func<AetheriaRuntimeDaemonFrameDocument?> frameProvider,
            Func<AetheriaRuntimeDaemonHealthDocument?> healthProvider,
            Func<AetheriaRuntimeDaemonCommandBoundaryDocument?> commandBoundaryProvider,
            Func<AetheriaRuntimeCatalogSnapshot?>? catalogProvider = null,
            CultMeshRouteHint? routeHint = null)
        {
            var daemonRefs = CultMesh.StateRefResolver(
                "aetheria.daemon.refs",
                (stateRef, _context) => TryResolveDaemonStateRef(
                    frameProvider?.Invoke(),
                    healthProvider?.Invoke(),
                    commandBoundaryProvider?.Invoke(),
                    stateRef,
                    out var value)
                    ? value
                    : "",
                new[]
                {
                    CultMesh.ProjectionSource(AetheriaRuntimeVerseRecordKeys.DaemonFrameLatest.ToString()),
                    CultMesh.ProjectionSource(AetheriaRuntimeVerseRecordKeys.DaemonHealth.ToString()),
                    CultMesh.ProjectionSource(AetheriaRuntimeVerseRecordKeys.DaemonCommandBoundary.ToString())
                },
                routeHint);

            var itemStatRefs = CultMesh.StateRefResolver(
                "aetheria.daemon.item_stats.refs",
                (stateRef, _context) =>
                {
                    if (!stateRef.StartsWith(AetheriaRuntimeDaemonItemStatQueries.StateRefPrefix + "/", StringComparison.Ordinal))
                        return "";

                    return TryResolveDaemonItemStatRef(
                            frameProvider?.Invoke(),
                            catalogProvider?.Invoke(),
                            stateRef,
                            out var value)
                        ? value
                        : "";
                },
                new[]
                {
                    CultMesh.ProjectionSource(AetheriaRuntimeVerseRecordKeys.DaemonFrameLatest.ToString()),
                    CultMesh.ProjectionSource("catalog:aetheria.runtime")
                },
                routeHint);

            return daemonRefs.Or(itemStatRefs);
        }

        private static AetheriaRuntimeLoadoutItemCommit? FindDaemonItem(
            AetheriaRuntimeRunCheckpointCommit? run,
            string itemKey)
        {
            if (run == null || string.IsNullOrWhiteSpace(itemKey))
                return null;

            foreach (var zone in run.Zones ?? Array.Empty<AetheriaRuntimeZoneSnapshotCommit>())
            foreach (var entity in zone.Entities ?? Array.Empty<AetheriaRuntimeEntitySnapshotCommit>())
            {
                var item = FindDaemonItem(entity.Equipment, itemKey)
                    ?? FindDaemonItem(entity.CargoBays, itemKey)
                    ?? FindDaemonItem(entity.DockingBays, itemKey)
                    ?? FindDaemonItem(entity.CargoContents, itemKey)
                    ?? FindDaemonItem(entity.DockingBayContents, itemKey);
                if (item != null)
                    return item;
            }

            return null;
        }

        private static AetheriaRuntimeLoadoutItemCommit? FindDaemonItem(
            IReadOnlyList<AetheriaRuntimeLoadoutItemSlotCommit>? slots,
            string itemKey)
        {
            foreach (var slot in slots ?? Array.Empty<AetheriaRuntimeLoadoutItemSlotCommit>())
            {
                if (IsItemMatch(slot?.Item, itemKey))
                    return slot?.Item;
            }

            return null;
        }

        private static AetheriaRuntimeLoadoutItemCommit? FindDaemonItem(
            IReadOnlyList<AetheriaRuntimeCargoBayLoadoutCommit>? cargoBays,
            string itemKey)
        {
            foreach (var cargoBay in cargoBays ?? Array.Empty<AetheriaRuntimeCargoBayLoadoutCommit>())
            {
                var item = FindDaemonItem(cargoBay?.Items, itemKey);
                if (item != null)
                    return item;
            }

            return null;
        }

        private static bool IsItemMatch(AetheriaRuntimeLoadoutItemCommit? item, string itemKey)
        {
            return item != null &&
                   string.Equals(item.ItemKey ?? "", itemKey ?? "", StringComparison.Ordinal);
        }

        private static AetheriaRuntimeZoneSnapshotCommit FindCurrentZone(AetheriaRuntimeRunCheckpointCommit run)
        {
            return run.Zones.FirstOrDefault(zone => zone.ZoneIndex == run.CurrentZoneIndex)
                ?? run.Zones.FirstOrDefault()
                ?? new AetheriaRuntimeZoneSnapshotCommit();
        }

        private static AetheriaRuntimeEntitySnapshotCommit? FindCurrentEntity(
            AetheriaRuntimeRunCheckpointCommit run,
            AetheriaRuntimeZoneSnapshotCommit zone)
        {
            var entityIndex = TryParseEntityIndex(run.CurrentEntityKey);
            if (entityIndex >= 0)
                return zone.Entities.FirstOrDefault(entity => entity.EntityIndex == entityIndex);

            return zone.Entities.FirstOrDefault();
        }

        private static AetheriaRuntimeEntitySnapshotCommit? FindTargetEntity(
            AetheriaRuntimeZoneSnapshotCommit zone,
            AetheriaRuntimeEntitySnapshotCommit? entity)
        {
            if (entity == null || entity.TargetEntityIndex < 0)
                return null;

            return zone.Entities.FirstOrDefault(candidate => candidate.EntityIndex == entity.TargetEntityIndex);
        }

        private static int TryParseEntityIndex(string key)
        {
            if (string.IsNullOrWhiteSpace(key))
                return -1;

            var marker = ".entity.";
            var markerIndex = key.LastIndexOf(marker, StringComparison.Ordinal);
            if (markerIndex < 0)
                return -1;

            var start = markerIndex + marker.Length;
            var end = start;
            while (end < key.Length && char.IsDigit(key[end]))
                end++;

            return int.TryParse(key.Substring(start, end - start), NumberStyles.Integer, CultureInfo.InvariantCulture, out var value)
                ? value
                : -1;
        }

        private static string FormatPosition(AetheriaRuntimeEntitySnapshotCommit? entity)
        {
            if (entity == null)
                return "(none)";

            return string.Join(", ", new[]
            {
                entity.PositionX.ToString("0.###", CultureInfo.InvariantCulture),
                entity.PositionY.ToString("0.###", CultureInfo.InvariantCulture),
                entity.PositionZ.ToString("0.###", CultureInfo.InvariantCulture)
            });
        }

        private static int Count<T>(IReadOnlyCollection<T>? values)
        {
            return values?.Count ?? 0;
        }
    }
}