using TMPro;
using UnityEngine;

namespace InteractiveVideo
{
    /// <summary>
    /// Optional UI: shows the selected object's name, current action and track id (confidence in debug mode).
    /// Purely a listener on the tracking manager; the core system works without it.
    /// </summary>
    [AddComponentMenu("Interactive Video/Video Object Info Panel")]
    public sealed class VideoObjectInfoPanel : MonoBehaviour
    {
        [SerializeField] private VideoTrackingManager trackingManager;
        [Tooltip("Root that is shown/hidden. Defaults to this GameObject.")]
        [SerializeField] private GameObject panelRoot;

        [Header("Texts (any may be left empty)")]
        [SerializeField] private TMP_Text nameText;
        [SerializeField] private TMP_Text actionText;
        [SerializeField] private TMP_Text trackIdText;
        [SerializeField] private TMP_Text confidenceText;

        [Header("Behaviour")]
        [SerializeField] private bool hideWhenNothingSelected = true;
        [SerializeField] private bool showConfidence;
        [SerializeField] private string notVisibleActionText = "(not visible right now)";
        [SerializeField] private string noActionText = "-";

        private string _lastName, _lastAction, _lastTrackId, _lastConfidence;
        private bool _lastShown = true;   // children start active in the scene; first Refresh() may hide them

        private void Awake()
        {
            if (panelRoot == null) panelRoot = gameObject;
        }

        private void OnEnable()
        {
            if (trackingManager == null) trackingManager = FindAnyObjectByType<VideoTrackingManager>();
            if (trackingManager != null)
            {
                trackingManager.SelectionChanged += Refresh;
                trackingManager.FrameChanged += OnFrameChanged;
                trackingManager.TrackingLoaded += OnTrackingLoaded;
            }
            _lastName = _lastAction = _lastTrackId = _lastConfidence = null;
            Refresh();
        }

        private void OnDisable()
        {
            if (trackingManager != null)
            {
                trackingManager.SelectionChanged -= Refresh;
                trackingManager.FrameChanged -= OnFrameChanged;
                trackingManager.TrackingLoaded -= OnTrackingLoaded;
            }
        }

        private void OnFrameChanged(long frame) => Refresh();
        private void OnTrackingLoaded(TrackingData data) => Refresh();

        /// <summary>Re-reads the selection and updates the texts (only touching texts whose content changed).</summary>
        public void Refresh()
        {
            if (trackingManager == null || !trackingManager.HasSelection)
            {
                Show(!hideWhenNothingSelected);
                if (!hideWhenNothingSelected) SetTexts("", "", "", "");
                return;
            }

            string trackId = trackingManager.SelectedTrackId;
            TrackedObject def = trackingManager.GetDefinition(trackId);
            string displayName = def != null && !string.IsNullOrEmpty(def.Name) ? def.Name : trackId;

            string action, confidence;
            if (trackingManager.TryGetSelectedObject(out var state) && state.Visible)
            {
                action = string.IsNullOrEmpty(state.Action) ? noActionText : Capitalise(state.Action);
                confidence = showConfidence ? $"{state.Confidence:P0}" : "";
            }
            else
            {
                action = notVisibleActionText;
                confidence = "";
            }

            Show(true);
            SetTexts(displayName, action, trackId, confidence);
        }

        private void Show(bool shown)
        {
            if (panelRoot != null && panelRoot != gameObject && panelRoot.activeSelf != shown) panelRoot.SetActive(shown);
            else if (panelRoot == gameObject && _lastShown != shown)
            {
                // Cannot deactivate ourselves (we would stop receiving events); toggle the children instead.
                for (int i = 0; i < transform.childCount; i++) transform.GetChild(i).gameObject.SetActive(shown);
                var graphic = GetComponent<UnityEngine.UI.Graphic>();
                if (graphic != null) graphic.enabled = shown;
            }
            _lastShown = shown;
        }

        private void SetTexts(string displayName, string action, string trackId, string confidence)
        {
            if (nameText != null && _lastName != displayName) nameText.text = displayName;
            if (actionText != null && _lastAction != action) actionText.text = action;
            if (trackIdText != null && _lastTrackId != trackId) trackIdText.text = trackId;
            if (confidenceText != null && _lastConfidence != confidence)
            {
                confidenceText.text = confidence;
                confidenceText.gameObject.SetActive(!string.IsNullOrEmpty(confidence));
            }
            _lastName = displayName; _lastAction = action; _lastTrackId = trackId; _lastConfidence = confidence;
        }

        private static string Capitalise(string s) =>
            string.IsNullOrEmpty(s) ? s : char.ToUpperInvariant(s[0]) + s.Substring(1);
    }
}