using System;
using UnityEngine;

namespace Thousandto.Editor.Test
{

    [Serializable]
    public class RendererInfo
    {
        //网格索引
        public int MeshIndex = -1;
        public int OldLightmapIndex = -1;
        //原始场景中的uv缩放偏移信息
        public Vector4 OldLightmapScaleOffset;
        //新生成lightmap中uv信息
        public Vector4 NewLightmapScaleOffset;
        public Renderer SourceRenderer;

        public Vector4 UV2Bound;

        public void SetRendererDataWhileAwake()
        {
            if(SourceRenderer != null)
            {
                //lightmapIndex是动态变化的
                //SourceRenderer.lightmapIndex = LightmapIndex;
                SourceRenderer.lightmapScaleOffset = NewLightmapScaleOffset;
            }
        }
    }

    /// <summary>
    /// 场景烘焙完后，保存lightmap信息
    /// </summary>
    [ExecuteInEditMode]
    public class PrefabLightmapInfo : MonoBehaviour
    {
        [SerializeField]
        public RendererInfo[] RendererInfos;
        public bool CalcUV2Bound = false;

        [SerializeField]
        public int MeshIndex = -1;
        private int _lastLightmapIndex = -1;

        void Awake()
        {
            if(Application.isPlaying)
            {
                for (int i = 0; RendererInfos != null && i < RendererInfos.Length; ++i)
                {
                    RendererInfos[i].SetRendererDataWhileAwake();
                }
            }
        }

        public void OnBakeFinish()
        {
            var Renderers = GetComponentsInChildren<MeshRenderer>();
            RendererInfos = new RendererInfo[Renderers.Length];
            for (int i = 0; i < Renderers.Length; ++i)
            {
                RendererInfo rdInfo = new RendererInfo();
                rdInfo.OldLightmapScaleOffset = Renderers[i].lightmapScaleOffset;
                rdInfo.OldLightmapIndex = Renderers[i].lightmapIndex;
                rdInfo.SourceRenderer = Renderers[i];
                RendererInfos[i] = rdInfo;
            }
        }

        public void SetMeshIndex(int meshIndex)
        {
            if (RendererInfos == null)
                return;

            for (int i = 0; i < RendererInfos.Length; ++i)
            {
                RendererInfos[i].MeshIndex = meshIndex;
            }

            MeshIndex = meshIndex;
        }

        public void SetLightmapScaleOffset(Renderer rd, Vector4 lightmapScaleOffset)
        {
            if (RendererInfos == null)
                return;

            for(int i =0; i < RendererInfos.Length; ++i)
            {
                if(RendererInfos[i].SourceRenderer == rd)
                {
                    RendererInfos[i].NewLightmapScaleOffset = lightmapScaleOffset;
                }
            }
        }

        void Update()
        {
            if(CalcUV2Bound)
            {
                CalcUV2Bound = false;
                for (int i = 0; i < RendererInfos.Length; ++i)
                {
                    var mesh = RendererInfos[i].SourceRenderer.gameObject.GetComponent<MeshFilter>();
                    if(mesh != null)
                    {
                        var uv2 = GetMeshUV2(mesh.sharedMesh);
                        RendererInfos[i].UV2Bound = GetBounds(uv2, RendererInfos[i].SourceRenderer);
                    }
                }
            }

            int lightmapIndex = Core.Asset.TerrainPrefabManager.Instance.GetLightmapIndexByMeshIndex(MeshIndex);
            if(lightmapIndex != _lastLightmapIndex)
            {
                _lastLightmapIndex = lightmapIndex;
                for (int i = 0; RendererInfos != null && i < RendererInfos.Length; ++i)
                {
                    RendererInfos[i].SourceRenderer.lightmapIndex = lightmapIndex;
                }
            }
        }

        //如果不存在uv2，则使用uv代替
        public static Vector2[] GetMeshUV2(Mesh m)
        {
            var uv2 = m.uv2;
            if (uv2 == null || uv2.Length == 0)
                uv2 = m.uv;

            return uv2;
        }

        /// <summary>
        /// 计算该renderer在lightmap贴图中的包围范围
        /// </summary>
        /// <param name="uv">uv2光照uv</param>
        /// <param name="r"></param>
        /// <returns>(minx, miny, maxX, maxY)</returns>
        public static Vector4 GetBounds(Vector2[] uv, Renderer r)
        {
            if (uv != null)
            {
                var __uv = new Vector2[uv.Length];
                Array.Copy(uv, __uv, uv.Length);
                uv = __uv;
                var minx = float.MaxValue;
                var miny = float.MaxValue;
                var maxx = float.MinValue;
                var maxy = float.MinValue;
                for (var _j = 0; _j < uv.Length; ++_j)
                {
                    var _uv = uv[_j];
                    if (_uv.x < minx)
                    {
                        minx = _uv.x;
                    }
                    if (_uv.y < miny)
                    {
                        miny = _uv.y;
                    }
                    if (_uv.x > maxx)
                    {
                        maxx = _uv.x;
                    }
                    if (_uv.y > maxy)
                    {
                        maxy = _uv.y;
                    }
                }
                var bounds = new Vector4(minx, miny, maxx, maxy);
                return bounds;
            }

            return Vector4.zero;
        }
    }
}