using UnityEngine;

namespace TAO.VertexAnimation
{
    public static class VA_Texture2DArrayUtils
    {
        public static Texture2DArray CreateTextureArray(Texture2D[] a_textures, bool a_useMipChain, bool a_isLinear,
            TextureWrapMode a_wrapMode = TextureWrapMode.Repeat, FilterMode a_filterMode = FilterMode.Bilinear, int a_anisoLevel = 1, string a_name = "")
        {
            if(!IsValidForTextureArray(a_textures) || !IsValidCopyTexturePlatform())
            {
                return null;
            }

            Texture2DArray textureArray = new Texture2DArray(a_textures[0].width, a_textures[0].height, a_textures.Length, a_textures[0].format, a_useMipChain, a_isLinear);

            if (IsValidCopyTexturePlatform())
            {
                for (int i = 0; i < a_textures.Length; i++)
                {
                    Graphics.CopyTexture(a_textures[i], 0, 0, textureArray, i, 0);
                }
            }

            textureArray.wrapMode = a_wrapMode;
            textureArray.filterMode = a_filterMode;
            textureArray.anisoLevel = a_anisoLevel;
            textureArray.name = a_name;

            textureArray.Apply(false, false);

            return textureArray;
        }

        public static bool IsValidForTextureArray(Texture2D[] a_textures)
        {
            if (a_textures == null || a_textures.Length <= 0)
            {
                Debug.LogError("No textures assigned!");
                return false;
            }

            for (int i = 0; i < a_textures.Length; i++)
            {
                if (a_textures[i] == null)
                {
                    Debug.LogError("Texture " + i.ToString() + " not assigned!");
                    return false;
                }

                if (a_textures[0].width != a_textures[i].width || a_textures[0].height != a_textures[i].height)
                {
                    Debug.LogError("Texture " + a_textures[i].name + " has a different size!");
                    return false;
                }

                if (a_textures[0].format != a_textures[i].format || a_textures[0].graphicsFormat != a_textures[i].graphicsFormat)
                {
                    Debug.LogError("Texture " + a_textures[i].name + " has a different format/graphics format!");
                    return false;
                }

                if (!a_textures[0].isReadable)
                {
#if UNITY_EDITOR
                    Debug.LogWarning("Texture " + a_textures[i].name + " is not readable!");
                    return true;
#else
                    Debug.LogError("Texture " + a_textures[i].name + " is not readable!");
                    return false;
#endif
                }
            }

            return true;
        }

        public static bool IsValidCopyTexturePlatform()
        {
            switch (SystemInfo.copyTextureSupport)
            {
                case UnityEngine.Rendering.CopyTextureSupport.None:
                    Debug.LogError("No CopyTextureSupport on this platform!");
                    return false;
                case UnityEngine.Rendering.CopyTextureSupport.Basic:
                    return true;
                case UnityEngine.Rendering.CopyTextureSupport.Copy3D:
                    return true;
                case UnityEngine.Rendering.CopyTextureSupport.DifferentTypes:
                    return true;
                case UnityEngine.Rendering.CopyTextureSupport.TextureToRT:
                    return true;
                case UnityEngine.Rendering.CopyTextureSupport.RTToTexture:
                    return true;
                default:
#if UNITY_EDITOR
                    return true;
#else
                    Debug.LogError("No CopyTextureSupport on this platform!");
                    return false;
#endif
            }
        }
    }
}