using System;
using TMPro;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace BriarQueen.UI.Menus.Components
{
    public class SaveSlotUI : MonoBehaviour,
        IPointerEnterHandler,
        IPointerExitHandler
    {
        [Header("Clickable Root")]
        [SerializeField]
        private Button _slotButton;

        [Header("Labels")]
        [SerializeField]
        private TextMeshProUGUI _saveNameText;

        [SerializeField]
        private TextMeshProUGUI _saveDateText;

        [Header("Delete")]
        [SerializeField]
        private Button _deleteButton;

        [Header("Empty Text")]
        [SerializeField]
        private TextMeshProUGUI _emptyImage;

        [Header("Highlight")]
        [SerializeField]
        private SaveSlotHighlight _highlight;

        private Action<SaveFileInfo> _onDeleteClick;
        private Action               _onEmptyClick;
        private Action<SaveFileInfo> _onFilledClick;

        public SaveFileInfo SaveInfo   { get; private set; }
        public bool         IsEmpty    { get; private set; }
        public bool         IsSelected { get; private set; }

        private void Awake()
        {
            if (_slotButton != null)
            {
                _slotButton.onClick.RemoveAllListeners();
                _slotButton.onClick.AddListener(HandleSlotClicked);
            }

            if (_deleteButton != null)
            {
                _deleteButton.onClick.RemoveAllListeners();
                _deleteButton.onClick.AddListener(HandleDeleteClicked);
            }
        }

        private void OnDestroy()
        {
            if (_slotButton != null)   _slotButton.onClick.RemoveAllListeners();
            if (_deleteButton != null) _deleteButton.onClick.RemoveAllListeners();
        }

        // ── Pointer events ────────────────────────────────────────────

        public void OnPointerEnter(PointerEventData eventData)
        {
            _highlight?.SetHovered(true);
        }

        public void OnPointerExit(PointerEventData eventData)
        {
            _highlight?.SetHovered(false);
        }

        // ── Public API ────────────────────────────────────────────────

        public GameObject GetSelectableGameObject()
        {
            return _slotButton != null ? _slotButton.gameObject : gameObject;
        }

        public void SetSelected(bool selected, bool immediate = false)
        {
            IsSelected = selected;

            if (immediate)
                _highlight?.SetSelectedImmediate(selected);
            else
                _highlight?.SetSelected(selected);
        }

        public void SetFilled(
            SaveFileInfo saveInfo,
            Action<SaveFileInfo> onClickFilled,
            Action<SaveFileInfo> onDelete)
        {
            SaveInfo = saveInfo;
            IsEmpty  = false;

            _onFilledClick = onClickFilled;
            _onEmptyClick  = null;
            _onDeleteClick = onDelete;

            if (_emptyImage != null)   _emptyImage.gameObject.SetActive(false);

            if (_saveNameText != null)
            {
                _saveNameText.gameObject.SetActive(true);
                _saveNameText.text = saveInfo.FileName;
            }

            if (_saveDateText != null)
            {
                _saveDateText.gameObject.SetActive(true);
                _saveDateText.text = saveInfo.LastModified.ToString("g");
            }

            if (_deleteButton != null)
            {
                _deleteButton.gameObject.SetActive(true);
                _deleteButton.interactable = true;
            }

            if (_slotButton != null)
                _slotButton.interactable = true;
        }

        public void SetEmpty(Action onClickEmpty)
        {
            SaveInfo = default;
            IsEmpty  = true;

            _onFilledClick = null;
            _onEmptyClick  = onClickEmpty;
            _onDeleteClick = null;

            if (_saveNameText != null) _saveNameText.text = string.Empty;
            if (_saveDateText != null) _saveDateText.text = string.Empty;

            if (_emptyImage != null)   _emptyImage.gameObject.SetActive(true);

            if (_deleteButton != null)
            {
                _deleteButton.gameObject.SetActive(false);
                _deleteButton.interactable = false;
            }

            if (_slotButton != null)
                _slotButton.interactable = true;
        }

        public void SetInteractable(bool interactable)
        {
            if (_slotButton != null)
                _slotButton.interactable = interactable;

            if (_deleteButton != null)
                _deleteButton.interactable = interactable && !IsEmpty;
        }

        // ── Internal ──────────────────────────────────────────────────

        private void HandleSlotClicked()
        {
            if (IsEmpty)
                _onEmptyClick?.Invoke();
            else if (!string.IsNullOrWhiteSpace(SaveInfo.FileName))
                _onFilledClick?.Invoke(SaveInfo);
        }

        private void HandleDeleteClicked()
        {
            if (IsEmpty) return;

            if (!string.IsNullOrWhiteSpace(SaveInfo.FileName))
                _onDeleteClick?.Invoke(SaveInfo);
        }
    }

    public struct SaveFileInfo
    {
        public readonly string   FileName;
        public readonly DateTime LastModified;

        public SaveFileInfo(string fileName, DateTime lastModified)
        {
            FileName     = fileName;
            LastModified = lastModified;
        }
    }
}