using Barotrauma.Networking;
using FarseerPhysics;
using FarseerPhysics.Dynamics;
using Microsoft.Xna.Framework;
using System;
using System.Linq;
using System.Xml.Linq;

namespace Barotrauma.Items.Components
{
    partial class Rope : ItemComponent, IServerSerializable
    {
        private ISpatialEntity source;
        private Item target;

        private float snapTimer;
        private const float SnapAnimDuration = 1.0f;

        private float raycastTimer;
        private const float RayCastInterval = 0.2f;

        [Serialize(0.0f, false, description: "How much force is applied to pull the projectile the rope is attached to.")]
        public float ProjectilePullForce
        {
            get;
            set;
        }

        [Serialize(0.0f, false, description: "How much force is applied to pull the target the rope is attached to.")]
        public float TargetPullForce
        {
            get;
            set;
        }

        [Serialize(0.0f, false, description: "How much force is applied to pull the source the rope is attached to.")]
        public float SourcePullForce
        {
            get;
            set;
        }

        [Serialize(1000.0f, false, description: "How far the source item can be from the projectile until the rope breaks.")]
        public float MaxLength
        {
            get;
            set;
        }

        [Serialize(true, false, description: "Should the rope snap when it collides with a structure/submarine (if not, it will just go through it).")]
        public bool SnapOnCollision
        {
            get;
            set;
        }

        private bool snapped;
        public bool Snapped
        {
            get { return snapped; }
            set
            {
                if (snapped == value) { return; }
                if (GameMain.NetworkMember != null)
                {
                    if (GameMain.NetworkMember.IsClient)
                    {
                        return;
                    }
                    else
                    {
#if SERVER
                        item.CreateServerEvent(this);
#endif
                    }
                }
                snapped = value;
            }
        }

        public Rope(Item item, XElement element) : base(item, element)
        {
            InitProjSpecific(element);
        }

        partial void InitProjSpecific(XElement element);

        
        public void Attach(ISpatialEntity source, Item target)
        {
            System.Diagnostics.Debug.Assert(source != null);
            System.Diagnostics.Debug.Assert(target != null);
            this.source = source;
            this.target = target;
            ApplyStatusEffects(ActionType.OnUse, 1.0f, worldPosition: item.WorldPosition);
            IsActive = true;
        }

        public override void Update(float deltaTime, Camera cam)
        {
            if (source == null || target == null || target.Removed ||
                (source is Entity sourceEntity && sourceEntity.Removed))
            {
                IsActive = false;
                return;
            }

            if (Snapped)
            {
                snapTimer += deltaTime;
                if (snapTimer >= SnapAnimDuration)
                {
                    IsActive = false;
                }
                return;
            }

            Vector2 diff = target.WorldPosition - source.WorldPosition;
            if (diff.LengthSquared() > MaxLength * MaxLength)
            {
                Snapped = true;
                return;
            }

#if CLIENT
            item.ResetCachedVisibleSize();
#endif

            if (SnapOnCollision)
            {
                raycastTimer += deltaTime;
                if (raycastTimer > RayCastInterval)
                {
                    if (Submarine.PickBody(ConvertUnits.ToSimUnits(source.WorldPosition), ConvertUnits.ToSimUnits(target.WorldPosition),
                        collisionCategory: Physics.CollisionLevel | Physics.CollisionWall,
                        customPredicate: (Fixture f) =>
                        {
                            var projectile = target?.GetComponent<Projectile>();
                            if (projectile != null)
                            {
                                foreach (Body body in projectile.Hits)
                                {
                                    Submarine alreadyHitSub = null;
                                    if (body.UserData is Structure hitStructure)
                                    {
                                        alreadyHitSub = hitStructure.Submarine;
                                    }
                                    else if (body.UserData is Submarine hitSub)
                                    {
                                        alreadyHitSub = hitSub;
                                    }
                                    if (alreadyHitSub != null)
                                    {
                                        if (f.Body?.UserData is MapEntity me && me.Submarine == alreadyHitSub) { return false; }
                                        if (f.Body?.UserData as Submarine == alreadyHitSub) { return false; }
                                    }
                                }
                            }
                            Submarine targetSub = target?.GetComponent<Projectile>()?.StickTarget?.UserData as Submarine ?? target.Submarine;

                            if (f.Body?.UserData is MapEntity mapEntity && mapEntity.Submarine != null)
                            {
                                if (mapEntity.Submarine == targetSub || mapEntity.Submarine == source.Submarine)
                                {
                                    return false;
                                }
                            }
                            else if (f.Body?.UserData is Submarine sub)
                            {
                                if (sub == targetSub || sub == source.Submarine)
                                {
                                    return false;
                                }
                            }
                            return true;
                        }) != null)
                    {
                        Snapped = true;
                        return;
                    }
                    raycastTimer = 0.0f;
                }
            }

            Vector2 forceDir = diff;
            if (forceDir.LengthSquared() > 0.01f)
            {
                forceDir = Vector2.Normalize(forceDir);
            }

            if (Math.Abs(ProjectilePullForce) > 0.001f)
            {
                var projectile = target.GetComponent<Projectile>();
                projectile?.Item?.body?.ApplyForce(-forceDir * ProjectilePullForce);                
            }

            if (Math.Abs(SourcePullForce) > 0.001f)
            {
                var sourceBody = GetBodyToPull(source);
                sourceBody?.ApplyForce(forceDir * SourcePullForce);
            }

            if (Math.Abs(TargetPullForce) > 0.001f)
            {
                var targetBody = GetBodyToPull(target);
                targetBody?.ApplyForce(-forceDir * TargetPullForce);
            }
        }

        public override void UpdateBroken(float deltaTime, Camera cam)
        {
            base.UpdateBroken(deltaTime, cam); 
            if (Snapped)
            {
                snapTimer += deltaTime;
                if (snapTimer >= SnapAnimDuration)
                {
                    IsActive = false;
                }
            }
        }

        private PhysicsBody GetBodyToPull(ISpatialEntity target)
        {
            if (target is Item targetItem)
            {
                if (targetItem.ParentInventory is CharacterInventory characterInventory &&
                    characterInventory.Owner is Character ownerCharacter)
                {
                    if (ownerCharacter.Removed) { return null; }
                    return ownerCharacter.AnimController.Collider;
                }
                var projectile = targetItem.GetComponent<Projectile>();
                if (projectile != null)
                {
                    if (projectile.StickTarget?.UserData is Structure structure)
                    {
                        return structure.Submarine?.PhysicsBody;
                    }
                    else if (projectile.StickTarget?.UserData is Submarine sub)
                    {
                        return sub?.PhysicsBody;
                    }
                    else if (projectile.StickTarget?.UserData is Character character)
                    {
                        return character.AnimController.Collider;
                    }
                    return null;
                }
                if (targetItem.body != null) { return targetItem.body; }
            }
            else if (target is Limb targetLimb)
            {
                return targetLimb.body;
            }

            return null;
        }
    }
}