using System;
using Models.Interferences;
using UnityEngine;
using UnityEngine.Networking;
using System.Collections;
using System.IO;
using Helpers;
using Models;

public class ResourceProvider : MonoBehaviour
{
    // Load an extra layout resource
    public IEnumerator LoadResource(Resource resource, Action<GameObject> callback)
    {
        yield return LoadResource(resource, resource.assetBundle, resource.prefabName, callback);
    }

    public IEnumerator LoadResource(AnimatedInterference interference, Action<GameObject> callback)
    {
        yield return LoadResource(interference, interference.assetBundle, interference.prefabName, callback);
    }

    /// <summary>
    /// Asynchronously load asset bundles and store them in the scene. 
    /// </summary>
    /// <param name="resource">A resource object on which the loading state will be set</param>
    /// <param name="assetBundle">Path to the asset bundle</param>
    /// <param name="prefabName">Name of the prefab to load</param>
    /// <param name="callback">Callback to execute once the resource is fully loaded and instantiated</param>
    /// <returns></returns>
    private IEnumerator LoadResource(ILoadableResource resource, string assetBundle, string prefabName, Action<GameObject> callback)
    {
        // Create a web request to the asset bundle. This bundle can be online or locally stored
        var path = ResourceHelper.GetPath(assetBundle, ResourceHelper.Type.AssetBundles);
        using var www = UnityWebRequestAssetBundle.GetAssetBundle(path);
        yield return www.SendWebRequest();

        // Only accept success
        if (www.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError(www.error);
            resource.SetLoadingState(ResourceLoadingState.Error);
            yield break;
        }
    
        // Download the GameObject and create a new instance inside the scene
        var bundle = DownloadHandlerAssetBundle.GetContent(www);
        var prefab = bundle.LoadAsset<GameObject>(prefabName);
        if (prefab is null)
        {
            // unload the AssetBundle in case the prefab does not exist
            bundle.Unload(false);
            Debug.LogError($"The prefab {prefabName} cannot be found in bundle {assetBundle}");
            resource.SetLoadingState(ResourceLoadingState.Error);
            yield break;
        }
        
        var go = Instantiate(prefab, transform.parent);
        
        // unload the AssetBundle data instantly
        bundle.Unload(false);

        // Make sure the object has been initialized
        if (go is null)
        {
            Debug.LogError($"GameObject from {assetBundle} is null");
            resource.SetLoadingState(ResourceLoadingState.Error);
            yield break;
        }
        // make sure the animator of the object is disabled, if any
        var animator = go.GetComponent<Animator>();
        if (animator != null)
        {
            animator.enabled = false;
        }

        try
        {
            callback(go);
            resource.SetLoadingState(ResourceLoadingState.Loaded);
        }
        catch (InvalidDataException e)
        {
            resource.SetLoadingState(ResourceLoadingState.Error);
        }
    }
}