using System.Collections.Generic;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;

namespace AR
{
    public class TrackedImageChanged : MonoBehaviour
    {
        [SerializeField] ARTrackedImageManager m_TrackedImageManager;

        [SerializeField] private List<ARTrackedImage> _arTrackedImagePrefabs = new ();
        
        private List<ARTrackedImage> _spawned = new ();

#if UNITY_EDITOR
        [Header("Debug")]
        [SerializeField] private InputAction m_DebugListImages;
#endif

        void OnEnable()
        {
            m_TrackedImageManager.trackedImagesChanged += OnChange;
            
#if UNITY_EDITOR
            m_DebugListImages.Enable();
            m_DebugListImages.performed += Debug_ListImages;
#endif
        }

        void OnDisable()
        {
            m_TrackedImageManager.trackedImagesChanged -= OnChange;
            
#if UNITY_EDITOR
            m_DebugListImages.performed -= Debug_ListImages;
            m_DebugListImages.Disable();
#endif
        }

        private void OnChange(ARTrackedImagesChangedEventArgs eventArgs)
        {
            foreach (var newImage in eventArgs.added)
            {
                // Handle added event
                Debug.Log($"Added image: {newImage.referenceImage.name}");

                foreach (var prefab in _arTrackedImagePrefabs)
                {
                    if (prefab.referenceImage.name.Equals(newImage.referenceImage.name))
                    {
                        if (_spawned == null)
                        {
                            _spawned = new List<ARTrackedImage>();
                        }

                        // Spawn new object
                        Debug.Log("Spawning object...");
                        _spawned.Add(Instantiate(prefab, newImage.transform));
                    }
                }
            }

            foreach (var updatedImage in eventArgs.updated)
            {
                // Handle updated event
                Debug.Log($"Updated image: {updatedImage.trackableId} - {updatedImage.trackingState}");

                foreach (var spawnedObject in _spawned)
                {
                    if (spawnedObject.trackableId == updatedImage.trackableId)
                    {
                        // Update position
                        Debug.Log("Updating position...");
                        spawnedObject.transform.position = updatedImage.transform.position;
                    }
                }
            }

            foreach (var removedImage in eventArgs.removed)
            {
                // Handle removed event
                Debug.Log($"Removed image: {removedImage.referenceImage.name}");

                for (int i = _spawned.Count - 1; i >= 0; i--)
                {
                    var spawnedObject = _spawned[i];
                    
                    if (spawnedObject.trackableId == removedImage.trackableId)
                    {
                        // Handle object removal
                        Debug.Log("Removing object...");
                        if (_spawned.Remove(spawnedObject))
                        {
                            // Destroy object
                            Debug.Log("Destroying object...");
                            Destroy(spawnedObject.gameObject);
                        }
                    }
                }
            }
        }
        
        private void ListAllImages()
        {
            Debug.Log(
                $"There are {m_TrackedImageManager.trackables.count} images being tracked.");

            foreach (var trackedImage in m_TrackedImageManager.trackables)
            {
                Debug.Log($"Image: {trackedImage.referenceImage.name} is at " +
                          $"{trackedImage.transform.position}");
            }
        }
        
        private ARTrackedImage GetImageAt(TrackableId trackableId)
        {
            return m_TrackedImageManager.trackables[trackableId];
        }

        private void Debug_ListImages(InputAction.CallbackContext _) => ListAllImages();
    }
}