using UnityEngine;
using System.Collections.Generic;

using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms;
using Unity.Rendering;

public static class SpriteManager
{
    public static Entity[] spritePrefabs;
}

[RequiresEntityConversion]
public class SpriteAuthor : MonoBehaviour
{
    public Sprite sprite;
    public List<Sprite> sprites;

    private void Awake()
    {
        Convert();
    }

    public void Convert()
    {
        EntityManager em = World.DefaultGameObjectInjectionWorld.EntityManager;

        EntityArchetype spriteArchetype = em.CreateArchetype(typeof(Prefab), typeof(RenderMesh), typeof(LocalToWorld), typeof(Translation), typeof(Rotation), typeof(Scale));

        SpriteManager.spritePrefabs = new Entity[sprites.Count];

        for (int i = 0; i < sprites.Count; i++)
        {
            Sprite s = sprites[i];

            Vector3[] verts = new Vector3[s.vertices.Length];
            int[] tris = new int[s.triangles.Length];

            for (int v = 0; v < verts.Length; v++)
            {
                verts[v] = new Vector3(s.vertices[v].x, 0f, s.vertices[v].y);
            }

            for (int t = 0; t < tris.Length; t++)
            {
                tris[t] = s.triangles[t];
            }

            Mesh mesh = new Mesh
            {
                vertices = verts,
                triangles = tris,
                uv = s.uv
            };

            Material material = new Material(Shader.Find("Sprites/Default"));
            material.mainTexture = s.texture;

            var renderMesh = new RenderMesh
            {
                castShadows = UnityEngine.Rendering.ShadowCastingMode.On,
                layer = 0,
                mesh = mesh,
                material = material,
                receiveShadows = true,
                subMesh = -1
            };

            Entity spritePrefabEntity = em.CreateEntity();

            em.AddComponent<RenderMesh>(spritePrefabEntity);
            em.AddComponent<LocalToWorld>(spritePrefabEntity);
            em.AddComponent<Translation>(spritePrefabEntity);
            em.AddComponent<Prefab>(spritePrefabEntity);

            em.SetSharedComponentData(spritePrefabEntity, renderMesh);

            SpriteManager.spritePrefabs[i] = spritePrefabEntity;
        }
    }
}

public class TestSystem : ComponentSystem
{
    bool init;
    EntityManager em;

    protected override void OnCreate()
    {
        init = false;
        em = this.World.EntityManager;
    }

    protected override void OnUpdate()
    {
        if (!init)
        {
            float3 pos = float3.zero;
            float3 scale = new float3(1f, 1f, 1f);
            foreach (Entity e in SpriteManager.spritePrefabs)
            {
                Entity sprite = em.Instantiate(e);

                em.SetComponentData<Translation>(sprite, new Translation { Value = pos });
                em.RemoveComponent<Prefab>(sprite);

                pos += new float3 { x = 2, y = 0, z = 0 };
            }

            init = true;
        }
    }
}