using System.Collections.Generic;
using System.Linq;
using Mirror;
using SanAndreasUnity.Importing.Items;
using SanAndreasUnity.Importing.Items.Definitions;
using SanAndreasUnity.Net;
using SanAndreasUnity.Utilities;
using UnityEngine;
using Object = UnityEngine.Object;
using Random = UnityEngine.Random;

namespace SanAndreasUnity.Behaviours.Peds
{
    public class DeadBody : NetworkBehaviour
    {
        private static List<DeadBody> _deadBodies = new List<DeadBody>();
        public static IEnumerable<DeadBody> DeadBodies => _deadBodies;
        public static int NumDeadBodies => _deadBodies.Count;

        public PushableByDamage PushableByDamage { get; private set; }

        private struct BoneInfo
        {
            public BoneInfo(Transform transform)
            {
                this.Transform = transform;
                this.Rigidbody = transform.GetComponent<Rigidbody>();
            }

            public Transform Transform { get; set; }
            public Rigidbody Rigidbody { get; set; }
        }

        private Dictionary<int, BoneInfo> m_framesDict = new Dictionary<int, BoneInfo>();

        private Dictionary<int, Rigidbody> m_rigidBodiesDict = new Dictionary<int, Rigidbody>();

        [SyncVar] private int m_net_modelId;

        private class SyncDictionaryIntVector3 : SyncDictionary<int, Vector3>
        {
        }

        private SyncDictionaryIntVector3 m_syncDictionaryBonePositions = new SyncDictionaryIntVector3();
        private SyncDictionaryIntVector3 m_syncDictionaryBoneRotations = new SyncDictionaryIntVector3();
        private SyncDictionaryIntVector3 m_syncDictionaryBoneVelocities = new SyncDictionaryIntVector3();



        private void Awake()
        {
            this.PushableByDamage = this.GetComponentOrThrow<PushableByDamage>();
            this.PushableByDamage.forceMultiplier = PedManager.Instance.ragdollDamageForceWhenDetached;

            this.RefreshSyncRate();
        }

        private void OnEnable()
        {
            _deadBodies.Add(this);
        }

        private void OnDisable()
        {
            _deadBodies.Remove(this);
        }

        public override void OnStartClient()
        {
            if (NetStatus.IsServer)
                return;

            F.RunExceptionSafe(this.InitialClientOnlySetup);
        }

        private void InitialClientOnlySetup()
        {
            var def = Item.GetDefinition<PedestrianDef>(m_net_modelId);
            if (null == def)
            {
                Debug.LogError($"Failed to initialize dead body: ped definition not found by id {m_net_modelId}");
                return;
            }

            this.gameObject.name = $"dead body {m_net_modelId} {def.ModelName}";

            var model = this.gameObject.GetOrAddComponent<PedModel>();
            model.Load(m_net_modelId);

            // build character joints - we need them to constraint the bones
            model.RagdollBuilder.BuildBodies();
            foreach (var rb in this.transform.GetComponentsInChildren<Rigidbody>())
            {
                rb.useGravity = false;
                rb.detectCollisions = false;
                rb.interpolation = PedManager.Instance.ragdollInterpolationMode;
            }
            model.RagdollBuilder.BuildJoints();

            m_framesDict = model.Frames.ToDictionary(f => f.BoneId, f => new BoneInfo(f.transform));

            Object.Destroy(model.AnimComponent);
            Object.Destroy(model);

            // apply initial sync data
            foreach (var pair in m_framesDict)
            {
                int boneId = pair.Key;
                BoneInfo boneInfo = pair.Value;

                if (m_syncDictionaryBonePositions.TryGetValue(boneId, out Vector3 pos))
                    SetPosition(boneInfo, pos);
                if (m_syncDictionaryBoneRotations.TryGetValue(boneId, out Vector3 rotation))
                    SetRotation(boneInfo, rotation);
                if (m_syncDictionaryBoneVelocities.TryGetValue(boneId, out Vector3 receivedVelocity))
                    SetVelocity(boneInfo, receivedVelocity);
            }

            // register to dictionary callbacks
            // RegisterDictionaryCallback(
            //     m_syncDictionaryBonePositions,
            //     (tr, pos) => tr.localPosition = pos);
            // RegisterDictionaryCallback(
            //     m_syncDictionaryBoneRotations,
            //     (tr, rotation) => tr.localRotation = Quaternion.Euler(rotation));
            RegisterDictionaryCallback(
                m_syncDictionaryBoneVelocities,
                SetVelocity);
        }

        private void RegisterDictionaryCallback<T>(SyncDictionary<int, T> dict, System.Action<BoneInfo, T> action)
        {
            dict.Callback += (op, key, item) => F.RunExceptionSafe(() =>
            {
                if (m_framesDict.TryGetValue(key, out BoneInfo boneInfo))
                    action(boneInfo, item);
            });
        }

        public static DeadBody Create(Transform ragdollTransform, Ped ped)
        {
            NetStatus.ThrowIfNotOnServer();

            GameObject ragdollGameObject = Object.Instantiate(PedManager.Instance.ragdollPrefab);
            DeadBody deadBody = ragdollGameObject.GetComponentOrThrow<DeadBody>();

            Object.Destroy(ragdollGameObject, PedManager.Instance.ragdollLifetime * Random.Range(0.85f, 1.15f));

            ragdollGameObject.name = "dead body " + ped.name;

            ragdollTransform.SetParent(ragdollGameObject.transform);

            deadBody.m_framesDict = ragdollTransform.GetComponentsInChildren<Frame>()
                .ToDictionary(f => f.BoneId, f => new BoneInfo(f.transform));

            foreach (var pair in deadBody.m_framesDict)
            {
                var rb = pair.Value.Rigidbody;
                if (rb != null)
                    deadBody.m_rigidBodiesDict.Add(pair.Key, rb);
            }

            deadBody.InitSyncVarsOnServer(ped);

            NetManager.Spawn(ragdollGameObject);

            return deadBody;
        }

        private void InitSyncVarsOnServer(Ped ped)
        {
            m_net_modelId = ped.PedDef.Id;

            // assign initial bones transformations
            foreach (var pair in m_framesDict)
            {
                m_syncDictionaryBonePositions.Add(pair.Key, pair.Value.Transform.localPosition);
                m_syncDictionaryBoneRotations.Add(pair.Key, pair.Value.Transform.localRotation.eulerAngles);
            }

            // assign initial velocities
            foreach (var pair in m_rigidBodiesDict)
            {
                m_syncDictionaryBoneVelocities.Add(pair.Key, GetVelocityForSending(pair.Value));
            }
        }

        private void Update()
        {
            if (NetStatus.IsServer)
            {
                foreach (var pair in m_framesDict)
                {
                    Vector3 pos = pair.Value.Transform.localPosition;
                    Vector3 rotation = pair.Value.Transform.localRotation.eulerAngles;

                    if (m_syncDictionaryBonePositions[pair.Key] != pos)
                        m_syncDictionaryBonePositions[pair.Key] = pos;
                    if (m_syncDictionaryBoneRotations[pair.Key] != rotation)
                        m_syncDictionaryBoneRotations[pair.Key] = rotation;
                }

                foreach (var pair in m_rigidBodiesDict)
                {
                    Vector3 velocity = GetVelocityForSending(pair.Value);
                    if (m_syncDictionaryBoneVelocities[pair.Key] != velocity)
                        m_syncDictionaryBoneVelocities[pair.Key] = velocity;
                }
            }
            else
            {
                foreach (var pair in m_framesDict)
                {
                    int boneId = pair.Key;
                    BoneInfo boneInfo = pair.Value;
                    Transform tr = boneInfo.Transform;

                    // rotation
                    if (m_syncDictionaryBoneRotations.TryGetValue(boneId, out Vector3 rotation))
                        SetRotation(boneInfo, rotation);

                    // after rotation is applied, transform velocity to local space and predict position based on it
                    if (m_syncDictionaryBonePositions.TryGetValue(boneId, out Vector3 pos))
                    {
                        Vector3 targetPos = pos;

                        // predict position based on velocity and sync interval
                        // if (boneId == 0) // only for root bone
                        // {
                        //     if (m_syncDictionaryBoneVelocities.TryGetValue(boneId, out Vector3 receivedVelocity))
                        //     {
                        //         Vector3 localVelocity = GetReceivedVelocityAsLocal(tr, receivedVelocity);
                        //         targetPos += localVelocity * this.syncInterval;
                        //     }
                        // }

                        SetPosition(boneInfo, targetPos);
                    }

                }

                // apply velocity on clients - this is done by rigid bodies ?
                // foreach (var pair in m_syncDictionaryBoneVelocities)
                // {
                //     int boneId = pair.Key;
                //     Vector3 receivedVelocity = pair.Value;
                //     if (m_framesDict.TryGetValue(boneId, out BoneInfo boneInfo))
                //     {
                //         if (null == boneInfo.Rigidbody) // only for bones which don't have rigid body
                //         {
                //             Vector3 localVelocity = GetReceivedVelocityAsLocal(boneInfo.Transform, receivedVelocity);
                //             boneInfo.Transform.localPosition += localVelocity * Time.deltaTime;
                //         }
                //     }
                // }
            }
        }

        public void RefreshSyncRate()
        {
            this.syncInterval = 1.0f / PedManager.Instance.ragdollSyncRate;
        }

        private static Vector3 GetVelocityForSending(Rigidbody rb)
        {
            // it's better to send local velocity, because rotation of ragdoll can change very fast, and so
            // will the world velocity
            return rb.transform.InverseTransformVector(rb.velocity);
        }

        private static Vector3 GetReceivedVelocityAsLocal(Transform tr, Vector3 receivedVelocity)
        {
            return receivedVelocity;
        }

        private static Vector3 GetReceivedVelocityAsWorld(Transform tr, Vector3 receivedVelocity)
        {
            return tr.TransformVector(receivedVelocity);
        }

        private static void SetPosition(BoneInfo boneInfo, Vector3 receivedPosition)
        {
            boneInfo.Transform.localPosition = receivedPosition;
        }

        private static void SetRotation(BoneInfo boneInfo, Vector3 receivedRotation)
        {
            boneInfo.Transform.localRotation = Quaternion.Euler(receivedRotation);
        }

        private static void SetVelocity(BoneInfo boneInfo, Vector3 receivedVelocity)
        {
            boneInfo.Rigidbody.velocity = GetReceivedVelocityAsWorld(boneInfo.Transform, receivedVelocity);
        }
    }
}