using UnityEditor;
using System.IO;
using UnityEngine;

public static class CreateAssetBundles
{
    private const string AssetBundleDirectory2D = "Assets/AssetBundles/2D";
    private const string AssetBundleDirectoryAR = "Assets/AssetBundles/AR";
    private const string AssetBundleDirectoryVR = "Assets/AssetBundles/VR";

    [MenuItem("Assets/Build AssetBundles (All)")]
    static void BuildAssetBundlesAll()
    {
        // use the 2D Assets for generating the preview images
        CreatePreviews(BuildAssetBundles2D(), AssetBundleDirectory2D);
        BuildAssetBundlesVR();
        BuildAssetBundlesAR();
    }

    [MenuItem("Assets/Build AssetBundles (2D)")]
    static void BuildAssetBundles2DWithPreview()
    {
        CreatePreviews(BuildAssetBundles2D(), AssetBundleDirectory2D);
    }

    [MenuItem("Assets/Build AssetBundles (AR)")]
    static void BuildAssetBundlesARWithPreview()
    {
        CreatePreviews(BuildAssetBundlesAR(), AssetBundleDirectoryAR);
    }

    [MenuItem("Assets/Build AssetBundles (VR)")]
    static void BuildAssetBundlesVRWithPreview()
    {
        CreatePreviews(BuildAssetBundlesVR(), AssetBundleDirectoryVR);
    }

    /// <summary>
    /// Create preview images of all assets found in the manifest and store them at the same level as
    /// <c>assetBundleDirectory</c>
    /// </summary>
    /// <param name="manifest">Manifest containing all assets that have to be processed</param>
    /// <param name="assetBundleDirectory">The folder where the assets can be found</param>
    private static void CreatePreviews(AssetBundleManifest manifest, string assetBundleDirectory)
    {
        foreach (var assetBundleName in manifest.GetAllAssetBundles())
        {
            var path = assetBundleDirectory + "/" + assetBundleName;
            var assetBundle = AssetBundle.LoadFromFile(path);
            var data = AssetPreview.GetAssetPreview(assetBundle.LoadAllAssets()[0]).EncodeToPNG();
            
            var previewPath = $"{assetBundleDirectory}/../Preview";
            Directory.CreateDirectory(previewPath);
            File.WriteAllBytes($"{previewPath}/{assetBundleName}.png", data);
        }
    }

    private static AssetBundleManifest BuildAssetBundles2D()
    {
        Directory.CreateDirectory(AssetBundleDirectory2D);

        return BuildPipeline.BuildAssetBundles(AssetBundleDirectory2D,
            BuildAssetBundleOptions.None,
            BuildTarget.StandaloneWindows64);
    }

    private static AssetBundleManifest BuildAssetBundlesAR()
    {
        Directory.CreateDirectory(AssetBundleDirectoryAR);

        return BuildPipeline.BuildAssetBundles(AssetBundleDirectoryAR,
            BuildAssetBundleOptions.None,
            BuildTarget.WSAPlayer);
    }

    private static AssetBundleManifest BuildAssetBundlesVR()
    {
        Directory.CreateDirectory(AssetBundleDirectoryVR);

        return BuildPipeline.BuildAssetBundles(AssetBundleDirectoryVR,
            BuildAssetBundleOptions.None,
            BuildTarget.Android);
    }
}