using System;
using System.Collections.Generic;
using UnityEngine;

namespace NBF
{
    public class FishingLineNode : MonoBehaviour
    {
        public enum NodeType
        {
            Start,
            Float,
            Weight,
            Tail,
            Virtual,
        }
        
        private FishingLineSolver _solver;

        [Header("Node")] [SerializeField] private NodeType nodeType = NodeType.Tail;
        [SerializeField] private Rigidbody body;
        [SerializeField] private MonoBehaviour interaction;

        [Header("Segment To Next Logical Node")] [Min(0f)] [SerializeField]
        private float segmentLengthToNext = 0.5f;

        [Min(0)] [SerializeField] private int fixedVirtualNodesToNext = 2;

        [Header("Runtime")] [SerializeField] private bool runtimeVirtualNode;
        [SerializeField] private int runtimeChainIndex = -1;

        [Header("Debug")] [SerializeField] private bool drawDebugGizmo = true;
        [Min(0.001f)] [SerializeField] private float debugGizmoRadius = 0.03f;
        [SerializeField] private Color logicalNodeColor = new(0.2f, 0.9f, 0.2f, 1f);
        [SerializeField] private Color virtualNodeColor = new(1f, 0.6f, 0.1f, 1f);


        
        [SerializeField] private List<FishingLineNodeFeature> features = new();
        [SerializeField] private List<FishingLineNodeMotionFeature> motionFeatures = new();
        private bool featureCacheReady;
        [SerializeField] private FishingLineNodeMotionFeature activeMotionFeature;

        /// <summary>
        /// 当前正在接管节点运动的组件。
        /// </summary>
        public FishingLineNodeMotionFeature ActiveMotionFeature => activeMotionFeature;

        public NodeType Type
        {
            get => nodeType;
            set => nodeType = value;
        }

        public Rigidbody Body => body;

        public MonoBehaviour Interaction => interaction;

        public float SegmentLengthToNext
        {
            get => segmentLengthToNext;
            set => segmentLengthToNext = Mathf.Max(0f, value);
        }

        public int FixedVirtualNodesToNext
        {
            get => fixedVirtualNodesToNext;
            set => fixedVirtualNodesToNext = Mathf.Max(0, value);
        }

        public bool IsRuntimeVirtualNode => runtimeVirtualNode;

        public int RuntimeChainIndex => runtimeChainIndex;

        public Vector3 Position => transform.position;

        public string GetDebugName()
        {
            return runtimeVirtualNode
                ? $"V[{runtimeChainIndex}]"
                : $"{nodeType}[{runtimeChainIndex}]";
        }

        public string GetDebugSummary()
        {
            var bodySummary = body == null
                ? "NoBody"
                : $"v:{body.linearVelocity.magnitude:F2}";

            return $"{GetDebugName()} pos:{Position} next:{segmentLengthToNext:F2} {bodySummary}";
        }

        private void Reset()
        {
            TryGetComponent(out body);
        }

        private void Awake()
        {
            _solver = GetComponentInParent<FishingLineSolver>();
            EnsureFeatureCache();
        }

        private void Start()
        {
            BindFeatures(_solver);
        }

        private void FixedUpdate()
        {
            EnsureFeatureCache();
            UpdateMotionControl(Time.fixedDeltaTime);
        }

        private void OnValidate()
        {
            if (body == null)
            {
                TryGetComponent(out body);
            }

            segmentLengthToNext = Mathf.Max(0f, segmentLengthToNext);
            fixedVirtualNodesToNext = Mathf.Max(0, fixedVirtualNodesToNext);
        }

        public void SetRuntimeVirtual(bool isVirtual, int chainIndex)
        {
            runtimeVirtualNode = isVirtual;
            runtimeChainIndex = chainIndex;

            if (isVirtual)
            {
                nodeType = NodeType.Virtual;
            }
        }

        public void SetVisualPosition(Vector3 position)
        {
            transform.position = position;
        }

        #region Feature

        /// <summary>
        /// 获取节点上的第一个指定类型功能组件。
        /// </summary>
        public T GetFeature<T>() where T : FishingLineNodeFeature
        {
            EnsureFeatureCache();
            for (var i = 0; i < features.Count; i++)
            {
                if (features[i] is T result)
                {
                    return result;
                }
            }

            return null;
        }

        /// <summary>
        /// 尝试获取节点上的指定类型功能组件。
        /// </summary>
        public bool TryGetFeature<T>(out T feature) where T : FishingLineNodeFeature
        {
            feature = GetFeature<T>();
            return feature != null;
        }

        /// <summary>
        /// 刷新并重新绑定当前节点上的功能组件。
        /// </summary>
        public void BindFeatures(FishingLineSolver solver)
        {
            EnsureFeatureCache();
            foreach (var t in features)
            {
                t.Bind(this, solver);
            }

            ResolveMotionFeature(forceRefresh: true);
        }

        /// <summary>
        /// 通知当前节点上的所有功能组件，鱼线已重建完成。
        /// </summary>
        public void NotifyLineBuilt()
        {
            EnsureFeatureCache();
            foreach (var t in features)
            {
                t.OnLineBuilt();
            }

            ResolveMotionFeature(forceRefresh: true);
        }

        /// <summary>
        /// 通知当前节点上的所有功能组件，鱼线已经达到断线条件。
        /// </summary>
        public void NotifyLineBreakRequested()
        {
            EnsureFeatureCache();
            foreach (var t in features)
            {
                t.OnLineBreakRequested();
            }
        }
        
        

        private void EnsureFeatureCache()
        {
            if (!featureCacheReady)
            {
                RefreshFeatures();
            }
        }

        private void RefreshFeatures()
        {
            features.Clear();
            motionFeatures.Clear();
            GetComponents(features);
            for (var i = 0; i < features.Count; i++)
            {
                if (features[i] is FishingLineNodeMotionFeature motionFeature)
                {
                    motionFeatures.Add(motionFeature);
                }
            }

            activeMotionFeature = null;
            featureCacheReady = true;
        }

        private void UpdateMotionControl(float deltaTime)
        {
            var motionFeature = ResolveMotionFeature(forceRefresh: false);
            if (motionFeature == null)
            {
                return;
            }

            motionFeature.TickMotion(deltaTime);
        }

        private FishingLineNodeMotionFeature ResolveMotionFeature(bool forceRefresh)
        {
            EnsureFeatureCache();

            var bestMotionFeature = default(FishingLineNodeMotionFeature);
            var bestPriority = int.MinValue;

            foreach (var motionFeature in motionFeatures)
            {
                var r = !motionFeature.IsSupportedNode(this);
                var n = !motionFeature.CanControl();
                if (motionFeature == null || !motionFeature.IsSupportedNode(this) || !motionFeature.CanControl())
                {
                    continue;
                }

                if (bestMotionFeature != null && motionFeature.Priority <= bestPriority)
                {
                    continue;
                }

                bestMotionFeature = motionFeature;
                bestPriority = motionFeature.Priority;
            }

            if (!forceRefresh && ReferenceEquals(activeMotionFeature, bestMotionFeature))
            {
                return activeMotionFeature;
            }

            if (activeMotionFeature != null && !ReferenceEquals(activeMotionFeature, bestMotionFeature))
            {
                activeMotionFeature.OnMotionDeactivated();
            }

            activeMotionFeature = bestMotionFeature;
            if (activeMotionFeature != null)
            {
                activeMotionFeature.OnMotionActivated();
            }

            return activeMotionFeature;
        }

        #endregion

        private void OnDrawGizmos()
        {
            if (!drawDebugGizmo)
            {
                return;
            }

            Gizmos.color = runtimeVirtualNode ? virtualNodeColor : logicalNodeColor;
            Gizmos.DrawSphere(transform.position, debugGizmoRadius);
        }
    }
}