using Games.Scene;
using UnityEngine;

// 注：Unity不支持在运行时获得材质Property列表，因此具体每个链接特效都需要按材质属性订做
// 规格统一为，所有Mesh类型Y方向不翻转，所有Particle类型Y方向翻转90度
// 该虚构类型仅作为接口使用
public abstract class LinkFxController : MonoBehaviour
{
    protected abstract bool isBillboard { get; }
    private float _baseLength;
    private Vector3 _baseScale;
    private float _currentRotation;
    protected LinkFxMaterialRecord[] materialRecords;

    protected ParticleRecord[] particleRecords;
    public bool revertLink;
    public float rotationSpeed;

    protected float endTime;

    [HideInInspector] public Vector3 sourcePoint;

    [HideInInspector] public Vector3 targetPoint;

    private void Awake()
    {
        RegisterParticleSystems();
        var normalMeshRenderer = RegisterMeshMaterials();
        _baseScale = transform.localScale;
        _baseLength = normalMeshRenderer.bounds.size.x;
    }

    private void OnDestroy()
    {
        for (var i = 0; i < materialRecords.Length; i++)
            materialRecords[i].DestroyMaterial();
    }

    protected void RegisterParticleSystems()
    {
        // 不节约那几毛钱的运算量了
        var particleSystems = transform.GetComponentsInChildren<ParticleSystem>(false);
        particleRecords = new ParticleRecord[particleSystems.Length];
        for (var i = 0; i < particleSystems.Length; i++)
            particleRecords[i] = new ParticleRecord(particleSystems[i]);
    }

    protected abstract MeshRenderer RegisterMeshMaterials();

    public virtual bool TryUpdateLink()
    {
        // 源角色或者目标不存在时，隐藏锁链效果
        if (sourcePoint == targetPoint)
        {
            transform.localScale = Vector3.zero;
            return false;
        }
        else
        {
            _currentRotation += Time.deltaTime * rotationSpeed;
            // 计算面板位置
            var delta = sourcePoint - targetPoint;
            if (revertLink)
                delta = -delta;
            var valid = false;
            if (delta != Vector3.zero)
            {
                var scale = delta.magnitude / _baseLength;
                transform.position = (sourcePoint + targetPoint) * 0.5f;
                transform.localScale = new Vector3(_baseScale.x * scale, _baseScale.y, _baseScale.z);
                // 计算面板UV
                for (var i = 0; i < particleRecords.Length; i++)
                    particleRecords[i].SetScale(scale);
                for (var i = 0; i < materialRecords.Length; i++)
                    materialRecords[i].SetScale(scale);
                // 计算面板方向 - 面板修改为定时旋转
                var x = delta.normalized;
                if (isBillboard && SceneLogic.CameraController != null && SceneLogic.CameraController.MainCamera != null)
                {
                    var z = -SceneLogic.CameraController.MainCamera.transform.forward;
                    var y = Vector3.Cross(z, x);
                    if (y != Vector3.zero)
                    {
                        valid = true;
                        z = Vector3.Cross(x, y);
                        transform.rotation = Quaternion.LookRotation(z, y);
                    }
                }
                else
                {
                    var y = Vector3.up;
                    var z = Vector3.Cross(x, y);
                    if (z != Vector3.zero)
                    {
                        valid = true;
                        // 将z方向按照旋转角度校正
                        z = Quaternion.AngleAxis(_currentRotation, x) * z;
                        y = Vector3.Cross(z, x);
                        //y = Quaternion.AngleAxis(currentRotation, x) * y;
                        transform.rotation = Quaternion.LookRotation(z, y);
                    }
                }
            }

            // 连线长度为0或者同摄像机视线完全平行
            if (!valid)
                transform.localScale = Vector3.zero;
            return valid;
        }
    }
    /// <summary>
    /// 部分需要在结束时做出特殊表现的锁链需要结束时间
    /// </summary>
    public void ResetEndTime(float pEndTime)
    {
        endTime = pEndTime;
    }
    
    protected class ParticleRecord
    {
        public readonly Vector3 boxSize;
        public readonly float emission;
        public readonly ParticleSystem particleSystem;

        public ParticleRecord(ParticleSystem particle)
        {
            particleSystem = particle;
            boxSize = particle.shape.scale;
            emission = particle.emission.rate.constant;
        }

        public void SetScale(float scale)
        {
            var newBoxSize = boxSize;
            newBoxSize.z *= scale;
            var newShape = particleSystem.shape;
            newShape.scale = newBoxSize;
            var emissionModule = particleSystem.emission;
            var rate = emissionModule.rate;
            rate.constant = emission * scale;
            emissionModule.rate = rate;
        }
    }

    protected class LinkFxTextureRecord
    {
        public readonly Vector2 baseTiling;
        public readonly string propertyName;

        public LinkFxTextureRecord(string propertyName, Vector2 baseTiling)
        {
            this.propertyName = propertyName;
            this.baseTiling = baseTiling;
        }
    }

    protected class LinkFxMaterialRecord
    {
        public readonly Material material;
        public readonly LinkFxTextureRecord[] textures;

        public LinkFxMaterialRecord(Material material, string[] textureNames)
        {
            this.material = material;
            textures = new LinkFxTextureRecord[textureNames.Length];
            for (var i = 0; i < textures.Length; i++)
            {
                var tiling = material.GetTextureScale(textureNames[i]);
                textures[i] = new LinkFxTextureRecord(textureNames[i], tiling);
            }
        }

        public void SetScale(float scale)
        {
            for (var i = 0; i < textures.Length; i++)
            {
                var tiling = textures[i].baseTiling;
                tiling.x *= scale;
                material.SetTextureScale(textures[i].propertyName, tiling);
            }
        }

        public void DestroyMaterial()
        {
            Destroy(material);
        }
    }
}