using System.Collections.Generic;

using UnityEngine;

using UnityEditor;

using UnityEditor.Animations;

using System.IO;

public class AnimationImporter : AssetPostprocessor

{

   // Purpose: Turn on looping for animation clips

   // Note: This function can also be used to automize other import settings

   //       in the future if desired

   void OnPreprocessAnimation()

   {

       ModelImporter importer = assetImporter as ModelImporter;

       var animations = importer.defaultClipAnimations; // Source animations

       if (animations.Length == 0)

       {

           return;

       }

       // Turn looping on for animation clips

       // -Comment this out if you don't want looping on

       foreach (var clip in animations)

       {

           clip.loopTime = true;

       }

       // Assign clip animations back source animations, finalize changes

       importer.clipAnimations = animations;

   }

   // Purpose: Automatically create animator controller, state, and transition

   //          for imported animation clip

   void OnPostprocessAnimation(GameObject root, AnimationClip clip)

   {

       if (clip == null || root == null) return;

       // Clean up naming convention from Blender (remove illegals)

       string clipName = clip.name;

       string safeName = SanitizeFileName(clipName);

       string clipPath = assetPath;

       // The folder/filepath that controllers will be saved to

       string controllerPath = $"Assets/Mecanim/{safeName}_Controller.controller";

       // Delay controller creation until after import is fully finished

       EditorApplication.delayCall += () =>

       {

           // Uncomment the line below if you are having trouble finding the controllers

           // Debug.Log($"Creating controller at: {controllerPath}");

           // Ensure Mecanim folder exists

           if (!AssetDatabase.IsValidFolder("Assets/Mecanim"))

               AssetDatabase.CreateFolder("Assets", "Mecanim");

           // Avoid overwriting if controller already exists

           if (AssetDatabase.LoadAssetAtPath<AnimatorController>(controllerPath) != null)

           {

               Debug.LogWarning($"Animator controller already exists: {controllerPath} — skipping creation.");

               return;

           }

           // Create controller

           var controller = AnimatorController.CreateAnimatorControllerAtPath(controllerPath);

           var stateMachine = controller.layers[0].stateMachine;

           // Re-access animation clip

           AnimationClip importedClip = null;

           Object[] importedAssets = AssetDatabase.LoadAllAssetsAtPath(clipPath);

           foreach (var a in importedAssets)

           {

               if (a is AnimationClip && a.name == clipName)

               {

                   importedClip = a as AnimationClip;

                   break;

               }

           }

           // Assign motion as anim clip

           if (importedClip != null)

           {

               // Add state for the clip

               var state = stateMachine.AddState(safeName);

               state.motion = importedClip;

               // Add entry transition

               // - Change this if you want a different transition from/to your animation clip

               stateMachine.AddEntryTransition(state);

           }

           else

           {

               Debug.LogWarning($"Could not find imported clip {clipName} at {clipPath}");

           }

       };

   }

   // Purpose: This function removes illegal characters from filenames

   private static string SanitizeFileName(string name)

   {

       char[] invalidChars = Path.GetInvalidFileNameChars();

       string sanitized = "";

       foreach (char c in name)

       {

           if (System.Array.Exists(invalidChars, invalidChar => invalidChar == c) || c == '|')

           {

               Debug.Log($"Illegal character found: '{c}' (ASCII {(int)c}), replacing illegal with _");

               sanitized += '_'; // Replace illegals with underscore

           }

           else

           {

               sanitized += c;

           }

       }

       Debug.Log($"Final sanitized name: {sanitized}");

       return sanitized;

   }

}