using System.Diagnostics.CodeAnalysis;
using Content.Server.Hands.Components;
using Content.Server.Pulling;
using Content.Shared.ActionBlocker;
using Content.Shared.Vehicle.Components;
using Content.Shared.Alert;
using Content.Shared.Buckle.Components;
using Content.Shared.Interaction;
using Content.Shared.MobState.Components;
using Content.Shared.MobState.EntitySystems;
using Content.Shared.Popups;
using Content.Shared.Pulling.Components;
using Content.Shared.Standing;
using Content.Shared.Stunnable;
using Robust.Server.GameObjects;
using Robust.Shared.Audio;
using Robust.Shared.Containers;
using Robust.Shared.Player;
using Robust.Shared.Timing;
using Content.Shared.IdentityManagement;

namespace Content.Server.Buckle.Components
{
    /// <summary>
    ///     Component that handles sitting entities into <see cref="StrapComponent"/>s.
    /// </summary>
    [RegisterComponent]
    [ComponentReference(typeof(SharedBuckleComponent))]
    public sealed class BuckleComponent : SharedBuckleComponent
    {
        [Dependency] private readonly IEntityManager _entMan = default!;
        [Dependency] private readonly IEntitySystemManager _sysMan = default!;
        [Dependency] private readonly IGameTiming _gameTiming = default!;

        [DataField("size")]
        private int _size = 100;

        /// <summary>
        ///     The amount of time that must pass for this entity to
        ///     be able to unbuckle after recently buckling.
        /// </summary>
        [DataField("delay")]
        [ViewVariables]
        private TimeSpan _unbuckleDelay = TimeSpan.FromSeconds(0.25f);

        /// <summary>
        ///     The time that this entity buckled at.
        /// </summary>
        [ViewVariables]
        private TimeSpan _buckleTime;

        /// <summary>
        ///     The position offset that is being applied to this entity if buckled.
        /// </summary>
        public Vector2 BuckleOffset { get; private set; }

        private StrapComponent? _buckledTo;

        /// <summary>
        ///     The strap that this component is buckled to.
        /// </summary>
        [ViewVariables]
        public StrapComponent? BuckledTo
        {
            get => _buckledTo;
            private set
            {
                _buckledTo = value;
                _buckleTime = _gameTiming.CurTime;
                _sysMan.GetEntitySystem<ActionBlockerSystem>().UpdateCanMove(Owner);
                Dirty(_entMan);
            }
        }

        [ViewVariables]
        public override bool Buckled => BuckledTo != null;

        /// <summary>
        ///     The amount of space that this entity occupies in a
        ///     <see cref="StrapComponent"/>.
        /// </summary>
        [ViewVariables]
        public int Size => _size;

        /// <summary>
        ///     Shows or hides the buckled status effect depending on if the
        ///     entity is buckled or not.
        /// </summary>
        private void UpdateBuckleStatus()
        {
            if (Buckled)
            {
                AlertType alertType = BuckledTo?.BuckledAlertType ?? AlertType.Buckled;
                EntitySystem.Get<AlertsSystem>().ShowAlert(Owner, alertType);
            }
            else
            {
                EntitySystem.Get<AlertsSystem>().ClearAlertCategory(Owner, AlertCategory.Buckled);
            }
        }

        /// <summary>
        ///     Reattaches this entity to the strap, modifying its position and rotation.
        /// </summary>
        /// <param name="strap">The strap to reattach to.</param>
        public void ReAttach(StrapComponent strap)
        {
            var ownTransform = _entMan.GetComponent<TransformComponent>(Owner);
            var strapTransform = _entMan.GetComponent<TransformComponent>(strap.Owner);

            ownTransform.AttachParent(strapTransform);
            ownTransform.LocalRotation = Angle.Zero;

            switch (strap.Position)
            {
                case StrapPosition.None:
                    break;
                case StrapPosition.Stand:
                    EntitySystem.Get<StandingStateSystem>().Stand(Owner);
                    break;
                case StrapPosition.Down:
                    EntitySystem.Get<StandingStateSystem>().Down(Owner, false, false);
                    break;
            }

            ownTransform.LocalPosition = strap.BuckleOffset;
        }

        public bool CanBuckle(EntityUid user, EntityUid to, [NotNullWhen(true)] out StrapComponent? strap)
        {
            var popupSystem = EntitySystem.Get<SharedPopupSystem>();
            strap = null;

            if (user == to)
            {
                return false;
            }

            if (!_entMan.TryGetComponent(to, out strap))
            {
                return false;
            }

            var strapUid = strap.Owner;
            bool Ignored(EntityUid entity) => entity == Owner || entity == user || entity == strapUid;

            if (!EntitySystem.Get<SharedInteractionSystem>().InRangeUnobstructed(Owner, strapUid, Range, predicate: Ignored, popup: true))
            {
                return false;
            }

            // If in a container
            if (Owner.TryGetContainer(out var ownerContainer))
            {
                // And not in the same container as the strap
                if (!strap.Owner.TryGetContainer(out var strapContainer) ||
                    ownerContainer != strapContainer)
                {
                    return false;
                }
            }

            if (!_entMan.HasComponent<HandsComponent>(user))
            {
                popupSystem.PopupEntity(Loc.GetString("buckle-component-no-hands-message"), user, Filter.Entities(user));
                return false;
            }

            if (Buckled)
            {
                var message = Loc.GetString(Owner == user
                    ? "buckle-component-already-buckled-message"
                    : "buckle-component-other-already-buckled-message", ("owner", Identity.Entity(Owner, _entMan)));
                popupSystem.PopupEntity(message, user, Filter.Entities(user));

                return false;
            }

            var parent = _entMan.GetComponent<TransformComponent>(to).Parent;
            while (parent != null)
            {
                if (parent == _entMan.GetComponent<TransformComponent>(user))
                {
                    var message = Loc.GetString(Owner == user
                        ? "buckle-component-cannot-buckle-message"
                        : "buckle-component-other-cannot-buckle-message", ("owner", Identity.Entity(Owner, _entMan)));
                    popupSystem.PopupEntity(message, user, Filter.Entities(user));

                    return false;
                }

                parent = parent.Parent;
            }

            if (!strap.HasSpace(this))
            {
                var message = Loc.GetString(Owner == user
                    ? "buckle-component-cannot-fit-message"
                    : "buckle-component-other-cannot-fit-message", ("owner", Identity.Entity(Owner, _entMan)));
                popupSystem.PopupEntity(message, user, Filter.Entities(user));

                return false;
            }

            return true;
        }

        public override bool TryBuckle(EntityUid user, EntityUid to)
        {
            var popupSystem = EntitySystem.Get<SharedPopupSystem>();
            if (!CanBuckle(user, to, out var strap))
            {
                return false;
            }

            SoundSystem.Play(strap.BuckleSound.GetSound(), Filter.Pvs(Owner), Owner);

            if (!strap.TryAdd(this))
            {
                var message = Loc.GetString(Owner == user
                    ? "buckle-component-cannot-buckle-message"
                    : "buckle-component-other-cannot-buckle-message", ("owner", Identity.Entity(Owner, _entMan)));
                popupSystem.PopupEntity(message, user, Filter.Entities(user));
                return false;
            }

            if(_entMan.TryGetComponent<AppearanceComponent>(Owner, out var appearance))
                appearance.SetData(BuckleVisuals.Buckled, true);

            ReAttach(strap);

            BuckledTo = strap;
            LastEntityBuckledTo = BuckledTo.Owner;
            DontCollide = true;

            UpdateBuckleStatus();

            var ev = new BuckleChangeEvent() { Buckling = true, Strap = BuckledTo.Owner, BuckledEntity = Owner };
            _entMan.EventBus.RaiseLocalEvent(ev.BuckledEntity, ev, false);
            _entMan.EventBus.RaiseLocalEvent(ev.Strap, ev, false);

            if (_entMan.TryGetComponent(Owner, out SharedPullableComponent? ownerPullable))
            {
                if (ownerPullable.Puller != null)
                {
                    EntitySystem.Get<PullingSystem>().TryStopPull(ownerPullable);
                }
            }

            if (_entMan.TryGetComponent(to, out SharedPullableComponent? toPullable))
            {
                if (toPullable.Puller == Owner)
                {
                    // can't pull it and buckle to it at the same time
                    EntitySystem.Get<PullingSystem>().TryStopPull(toPullable);
                }
            }

            return true;
        }

        /// <summary>
        ///     Tries to unbuckle the Owner of this component from its current strap.
        /// </summary>
        /// <param name="user">The entity doing the unbuckling.</param>
        /// <param name="force">
        ///     Whether to force the unbuckling or not. Does not guarantee true to
        ///     be returned, but guarantees the owner to be unbuckled afterwards.
        /// </param>
        /// <returns>
        ///     true if the owner was unbuckled, otherwise false even if the owner
        ///     was previously already unbuckled.
        /// </returns>
        public bool TryUnbuckle(EntityUid user, bool force = false)
        {
            if (BuckledTo == null)
            {
                return false;
            }

            var oldBuckledTo = BuckledTo;

            if (!force)
            {
                if (_gameTiming.CurTime < _buckleTime + _unbuckleDelay)
                {
                    return false;
                }

                if (!EntitySystem.Get<SharedInteractionSystem>().InRangeUnobstructed(user, oldBuckledTo.Owner, Range, popup: true))
                {
                    return false;
                }
                // If the strap is a vehicle and the rider is not the person unbuckling, return.
                if (_entMan.TryGetComponent<VehicleComponent>(oldBuckledTo.Owner, out var vehicle) &&
                        vehicle.Rider != user)
                    return false;
            }

            BuckledTo = null;

            var entManager = IoCManager.Resolve<IEntityManager>();
            var xform = entManager.GetComponent<TransformComponent>(Owner);
            var oldBuckledXform = entManager.GetComponent<TransformComponent>(oldBuckledTo.Owner);

            if (xform.ParentUid == oldBuckledXform.Owner)
            {
                xform.AttachParentToContainerOrGrid();
                xform.WorldRotation = oldBuckledXform.WorldRotation;

                if (oldBuckledTo.UnbuckleOffset != Vector2.Zero)
                    xform.Coordinates = oldBuckledXform.Coordinates.Offset(oldBuckledTo.UnbuckleOffset);
            }

            if(_entMan.TryGetComponent<AppearanceComponent>(Owner, out var appearance))
                appearance.SetData(BuckleVisuals.Buckled, false);

            if (_entMan.HasComponent<KnockedDownComponent>(Owner)
                | (_entMan.TryGetComponent<MobStateComponent>(Owner, out var mobState) && mobState.IsIncapacitated()))
            {
                EntitySystem.Get<StandingStateSystem>().Down(Owner);
            }
            else
            {
                EntitySystem.Get<StandingStateSystem>().Stand(Owner);
            }

            IoCManager.Resolve<IEntitySystemManager>().GetEntitySystem<SharedMobStateSystem>()
                .EnterState(mobState, mobState?.CurrentState);

            UpdateBuckleStatus();

            oldBuckledTo.Remove(this);
            SoundSystem.Play(oldBuckledTo.UnbuckleSound.GetSound(), Filter.Pvs(Owner), Owner);

            var ev = new BuckleChangeEvent() { Buckling = false, Strap = oldBuckledTo.Owner, BuckledEntity = Owner };
            _entMan.EventBus.RaiseLocalEvent(Owner, ev, false);
            _entMan.EventBus.RaiseLocalEvent(oldBuckledTo.Owner, ev, false);

            return true;
        }

        /// <summary>
        ///     Makes an entity toggle the buckling status of the owner to a
        ///     specific entity.
        /// </summary>
        /// <param name="user">The entity doing the buckling/unbuckling.</param>
        /// <param name="to">
        ///     The entity to toggle the buckle status of the owner to.
        /// </param>
        /// <param name="force">
        ///     Whether to force the unbuckling or not, if it happens. Does not
        ///     guarantee true to be returned, but guarantees the owner to be
        ///     unbuckled afterwards.
        /// </param>
        /// <returns>true if the buckling status was changed, false otherwise.</returns>
        public bool ToggleBuckle(EntityUid user, EntityUid to, bool force = false)
        {
            if (BuckledTo?.Owner == to)
            {
                return TryUnbuckle(user, force);
            }

            return TryBuckle(user, to);
        }

        protected override void Startup()
        {
            base.Startup();
            UpdateBuckleStatus();
        }

        protected override void Shutdown()
        {
            BuckledTo?.Remove(this);
            TryUnbuckle(Owner, true);

            _buckleTime = default;
            UpdateBuckleStatus();

            base.Shutdown();
        }

        public override ComponentState GetComponentState()
        {
            int? drawDepth = null;

            if (BuckledTo != null &&
                _entMan.GetComponent<TransformComponent>(BuckledTo.Owner).LocalRotation.GetCardinalDir() == Direction.North &&
                _entMan.TryGetComponent<SpriteComponent>(BuckledTo.Owner, out var spriteComponent))
            {
                drawDepth = spriteComponent.DrawDepth - 1;
            }

            return new BuckleComponentState(Buckled, drawDepth, LastEntityBuckledTo, DontCollide);
        }
    }
}