using System;
using UnityEngine;
using System.Linq;
using MeshUtility;
using VrmLib;

namespace UniVRM10
{
    public static class EditorUnityBuilder
    {
        static public ModelAsset ToUnityAsset(VrmLib.Model model, string assetPath, IExternalUnityObject scriptedImporter)
        {
            var modelAsset = new ModelAsset();
            CreateTextureAsset(model, modelAsset, scriptedImporter);
            CreateMaterialAsset(model, modelAsset, scriptedImporter);
            CreateMeshAsset(model, modelAsset);

            // node
            RuntimeUnityBuilder.CreateNodes(model.Root, null, modelAsset.Map.Nodes);
            modelAsset.Root = modelAsset.Map.Nodes[model.Root];

            // renderer
            var map = modelAsset.Map;
            foreach (var (node, go) in map.Nodes)
            {
                if (node.MeshGroup is null)
                {
                    continue;
                }

                if (node.MeshGroup.Meshes.Count > 1)
                {
                    throw new NotImplementedException("invalid isolated vertexbuffer");
                }

                var renderer = RuntimeUnityBuilder.CreateRenderer(node, go, map);
                map.Renderers.Add(node, renderer);
                modelAsset.Renderers.Add(renderer);
            }

            if (model.Vrm != null)
            {
                // humanoid
                var humanoid = modelAsset.Root.AddComponent<MeshUtility.Humanoid>();
                humanoid.AssignBones(modelAsset.Map.Nodes.Select(x => (x.Key.HumanoidBone.GetValueOrDefault().ToUnity(), x.Value.transform)));
                modelAsset.HumanoidAvatar = humanoid.CreateAvatar();
                modelAsset.HumanoidAvatar.name = "VRM";

                var animator = modelAsset.Root.AddComponent<Animator>();
                animator.avatar = modelAsset.HumanoidAvatar;
            }

            return modelAsset;
        }

        static private void CreateTextureAsset(VrmLib.Model model, ModelAsset modelAsset, IExternalUnityObject scriptedImporter)
        {
            var externalObjects = scriptedImporter.GetExternalUnityObjects<Texture2D>();

            // textures
            for (int i = 0; i < model.Textures.Count; ++i)
            {
                if (model.Textures[i] is VrmLib.ImageTexture imageTexture)
                {
                    if (string.IsNullOrEmpty(model.Textures[i].Name))
                    {
                        model.Textures[i].Name = string.Format("{0}_img{1}", model.Root.Name, i);
                    }
                    if (externalObjects.ContainsKey(model.Textures[i].Name))
                    {
                        modelAsset.Map.Textures.Add(imageTexture, externalObjects[model.Textures[i].Name]);
                        modelAsset.Textures.Add(externalObjects[model.Textures[i].Name]);
                    }
                    else
                    {
                        var name = !string.IsNullOrEmpty(imageTexture.Name)
                            ? imageTexture.Name
                            : string.Format("{0}_img{1}", model.Root.Name, i);

                        var texture = RuntimeUnityBuilder.CreateTexture(imageTexture);
                        texture.name = name;

                        modelAsset.Map.Textures.Add(imageTexture, texture);
                        modelAsset.Textures.Add(texture);
                    }
                }
                else
                {
                    Debug.LogWarning($"{i} not ImageTexture");
                }
            }
        }


        static private void CreateMaterialAsset(VrmLib.Model model, ModelAsset modelAsset, IExternalUnityObject scriptedImporter)
        {
            var externalObjects = scriptedImporter.GetExternalUnityObjects<UnityEngine.Material>();

            foreach (var src in model.Materials)
            {
                if (externalObjects.ContainsKey(src.Name))
                {
                    modelAsset.Map.Materials.Add(src, externalObjects[src.Name]);
                    modelAsset.Materials.Add(externalObjects[src.Name]);
                }
                else
                {
                    // TODO: material has VertexColor
                    var material = RuntimeUnityMaterialBuilder.CreateMaterialAsset(src, hasVertexColor: false, modelAsset.Map.Textures);
                    material.name = src.Name;
                    modelAsset.Map.Materials.Add(src, material);
                    modelAsset.Materials.Add(material);
                }
            }
        }

        static private void CreateMeshAsset(VrmLib.Model model, ModelAsset modelAsset)
        {
            for (int i = 0; i < model.MeshGroups.Count; ++i)
            {
                var src = model.MeshGroups[i];
                if (src.Meshes.Count == 1)
                {
                    // submesh 方式
                    var mesh = new UnityEngine.Mesh();
                    mesh.name = src.Name;
                    mesh.LoadMesh(src.Meshes[0], src.Skin);
                    modelAsset.Map.Meshes.Add(src, mesh);
                    modelAsset.Meshes.Add(mesh);
                }
                else
                {
                    // 頂点バッファの連結が必用
                    throw new NotImplementedException();
                }
            }
        }
    }
}