using Content.Shared.Audio;
using Content.Shared.Construction.Components;
using Content.Shared.Explosion;
using Content.Shared.Eye;
using Content.Shared.Interaction.Components;
using Content.Shared.Interaction.Events;
using Content.Shared.Maps;
using Content.Shared.Popups;
using JetBrains.Annotations;
using Robust.Shared.Map;
using Robust.Shared.Map.Components;
using Robust.Shared.Serialization;

namespace Content.Shared.SubFloor
{
    /// <summary>
    ///     Entity system backing <see cref="SubFloorHideComponent"/>.
    /// </summary>
    [UsedImplicitly]
    public abstract class SharedSubFloorHideSystem : EntitySystem
    {
        [Dependency] private readonly ITileDefinitionManager _tileDefinitionManager = default!;
        [Dependency] private readonly SharedAmbientSoundSystem _ambientSoundSystem = default!;
        [Dependency] protected readonly SharedMapSystem Map = default!;
        [Dependency] protected readonly SharedAppearanceSystem Appearance = default!;
        [Dependency] private readonly SharedVisibilitySystem _visibility = default!;
        [Dependency] protected readonly SharedPopupSystem _popup = default!;

        private EntityQuery<SubFloorHideComponent> _hideQuery;

        public override void Initialize()
        {
            base.Initialize();

            _hideQuery = GetEntityQuery<SubFloorHideComponent>();

            SubscribeLocalEvent<TileChangedEvent>(OnTileChanged);
            SubscribeLocalEvent<SubFloorHideComponent, ComponentStartup>(OnSubFloorStarted);
            SubscribeLocalEvent<SubFloorHideComponent, ComponentShutdown>(OnSubFloorTerminating);
            // Like 80% sure this doesn't need to handle re-anchoring.
            SubscribeLocalEvent<SubFloorHideComponent, AnchorStateChangedEvent>(HandleAnchorChanged);
            SubscribeLocalEvent<SubFloorHideComponent, GettingInteractedWithAttemptEvent>(OnInteractionAttempt);
            SubscribeLocalEvent<SubFloorHideComponent, GettingAttackedAttemptEvent>(OnAttackAttempt);
            SubscribeLocalEvent<SubFloorHideComponent, GetExplosionResistanceEvent>(OnGetExplosionResistance);
            SubscribeLocalEvent<SubFloorHideComponent, AnchorAttemptEvent>(OnAnchorAttempt);
            SubscribeLocalEvent<SubFloorHideComponent, UnanchorAttemptEvent>(OnUnanchorAttempt);
        }

        private void OnAnchorAttempt(EntityUid uid, SubFloorHideComponent component, AnchorAttemptEvent args)
        {
            // No teleporting entities through floor tiles when anchoring them.
            var xform = Transform(uid);

            if (TryComp<MapGridComponent>(xform.GridUid, out var grid)
                && HasFloorCover(xform.GridUid.Value, grid, Map.TileIndicesFor(xform.GridUid.Value, grid, xform.Coordinates)))
            {
                _popup.PopupClient(Loc.GetString("subfloor-anchor-failure", ("entity", uid)), args.User);
                args.Cancel();
            }
        }

        private void OnUnanchorAttempt(EntityUid uid, SubFloorHideComponent component, UnanchorAttemptEvent args)
        {
            // No un-anchoring things under the floor. Only required for something like vents, which are still interactable
            // despite being partially under the floor.
            if (component.IsUnderCover)
            {
                _popup.PopupClient(Loc.GetString("subfloor-unanchor-failure", ("entity", uid)), args.User);
                args.Cancel();
            }
        }

        private void OnGetExplosionResistance(EntityUid uid, SubFloorHideComponent component, ref GetExplosionResistanceEvent args)
        {
            if (component.BlockInteractions && component.IsUnderCover)
                args.DamageCoefficient = 0;
        }

        private void OnAttackAttempt(EntityUid uid, SubFloorHideComponent component, ref GettingAttackedAttemptEvent args)
        {
            if (component.BlockInteractions && component.IsUnderCover)
                args.Cancelled = true;
        }

        private void OnInteractionAttempt(EntityUid uid, SubFloorHideComponent component, ref GettingInteractedWithAttemptEvent args)
        {
            // Allow admins (e.g., mappers/aghosts) to twiddle with stuff under subfloors
            if (HasComp<BypassInteractionChecksComponent>(args.Uid))
                return;

            // No interactions with entities hidden under floor tiles.
            if (component.BlockInteractions && component.IsUnderCover)
                args.Cancelled = true;
        }

        private void OnSubFloorStarted(EntityUid uid, SubFloorHideComponent component, ComponentStartup _)
        {
            UpdateFloorCover(uid, component);
            UpdateAppearance(uid, component);
            EnsureComp<CollideOnAnchorComponent>(uid);
        }

        private void OnSubFloorTerminating(EntityUid uid, SubFloorHideComponent component, ComponentShutdown _)
        {
            // If component is being deleted don't need to worry about updating any component stuff because it won't matter very shortly.
            if (Comp<MetaDataComponent>(uid).EntityLifeStage >= EntityLifeStage.Terminating)
                return;

            // Regardless of whether we're on a subfloor or not, unhide.
            SetUnderCover((uid, component), false);
            UpdateAppearance(uid, component);
        }

        private void HandleAnchorChanged(EntityUid uid, SubFloorHideComponent component, ref AnchorStateChangedEvent args)
        {
            if (args.Anchored)
            {
                var xform = Transform(uid);
                UpdateFloorCover(uid, component, xform);
            }
            else if (component.IsUnderCover)
            {
                SetUnderCover((uid, component), false);
                UpdateAppearance(uid, component);
            }
        }

        private void OnTileChanged(ref TileChangedEvent args)
        {
            foreach (var change in args.Changes)
            {
                if (change.OldTile.IsEmpty)
                    continue; // Nothing is anchored here anyways.

                if (change.NewTile.IsEmpty)
                    continue; // Anything that was here will be unanchored anyways.

                UpdateTile(args.Entity, args.Entity.Comp, change.GridIndices);
            }
        }

        /// <summary>
        ///     Update whether a given entity is currently covered by a floor tile.
        /// </summary>
        private void UpdateFloorCover(EntityUid uid, SubFloorHideComponent? component = null, TransformComponent? xform = null)
        {
            if (!Resolve(uid, ref component, ref xform))
                return;

            if (xform.Anchored && TryComp<MapGridComponent>(xform.GridUid, out var grid))
                SetUnderCover((uid, component), HasFloorCover(xform.GridUid.Value, grid, Map.TileIndicesFor(xform.GridUid.Value, grid, xform.Coordinates)));
            else
                SetUnderCover((uid, component), false);

            UpdateAppearance(uid, component);
        }

        private void SetUnderCover(Entity<SubFloorHideComponent> entity, bool value)
        {
            // If it's not undercover or it always has visible layers then normal visibility.
            _visibility.SetLayer(entity.Owner, value && entity.Comp.VisibleLayers.Count == 0 ? (ushort) VisibilityFlags.Subfloor : (ushort) VisibilityFlags.Normal);

            if (entity.Comp.IsUnderCover == value)
                return;

            entity.Comp.IsUnderCover = value;
        }

        public bool HasFloorCover(EntityUid gridUid, MapGridComponent grid, Vector2i position)
        {
            // TODO Redo this function. Currently wires on an asteroid are always "below the floor"
            var tileDef = (ContentTileDefinition) _tileDefinitionManager[Map.GetTileRef(gridUid, grid, position).Tile.TypeId];
            return !tileDef.IsSubFloor;
        }

        private void UpdateTile(EntityUid gridUid, MapGridComponent grid, Vector2i position)
        {
            var covered = HasFloorCover(gridUid, grid, position);

            foreach (var uid in Map.GetAnchoredEntities(gridUid, grid, position))
            {
                if (!_hideQuery.TryComp(uid, out var hideComp))
                    continue;

                if (hideComp.IsUnderCover == covered)
                    continue;

                SetUnderCover((uid, hideComp), covered);
                UpdateAppearance(uid, hideComp);
            }
        }

        public void UpdateAppearance(
            EntityUid uid,
            SubFloorHideComponent? hideComp = null,
            AppearanceComponent? appearance = null)
        {
            if (!Resolve(uid, ref hideComp, false))
                return;

            if (hideComp.BlockAmbience && hideComp.IsUnderCover)
                _ambientSoundSystem.SetAmbience(uid, false);
            else if (hideComp.BlockAmbience && !hideComp.IsUnderCover)
                _ambientSoundSystem.SetAmbience(uid, true);

            if (Resolve(uid, ref appearance, false))
            {
                Appearance.SetData(uid, SubFloorVisuals.Covered, hideComp.IsUnderCover, appearance);
            }
        }

        [Serializable, NetSerializable]
        protected sealed class ShowSubfloorRequestEvent : EntityEventArgs
        {
            public bool Value;
        }
    }

    [Serializable, NetSerializable]
    public enum SubFloorVisuals : byte
    {
        /// <summary>
        /// Is there a floor tile over this entity
        /// </summary>
        Covered,

        /// <summary>
        /// Is this entity revealed by a scanner or some other entity?
        /// </summary>
        ScannerRevealed,
    }

    [Serializable, NetSerializable]
    public enum SubfloorLayers : byte
    {
        FirstLayer
    }
}