using System.Collections.Generic;
using System.Linq;
using BrewMonster.Scripts.Chat;
using BrewMonster.Scripts.Chat.EmotionData;
using UnityEngine;
using UnityEngine.UI;

namespace BrewMonster.Scripts.ChatUI
{
    /// <summary>
    /// MonoBehaviour gắn trên EmojiPanel — quản lý lưới emoji để người chơi chọn.
    /// MonoBehaviour placed on EmojiPanel — manages the emoji grid for player selection.
    ///
    /// Cách dùng trên Inspector:
    ///   1) Kéo component này lên EmojiPanel GameObject trong prefab.
    ///   2) Gán EmotionLibrarySpriteMap SO (đã build từ Emotion Atlas Converter).
    ///   3) Gán GridContent = child "Context" của EmojiPanel.
    ///   4) Tạo prefab EmojiButtonCell → gán vào CellPrefab.
    ///   5) Gán ChatInputHandler và ChatSystemlUI.
    /// </summary>
    public class EmojiPickerUI : MonoBehaviour
    {
        [Header("Emotion Data")]
        [Tooltip("SO chứa Library + TMP Sprite Asset. Tạo qua Perfect World → Chat → Emotion Atlas Converter.")]
        [SerializeField] EmotionLibrarySpriteMap _emotionSpriteMap;

        [Header("Grid")]
        [Tooltip("RectTransform chứa các ô emoji (child 'Context' của EmojiPanel). GridLayoutGroup được thêm tự động nếu chưa có.")]
        [SerializeField] RectTransform _gridContent;

        [Tooltip("Prefab một ô emoji (Button + Image + EmojiButtonCell). Cell prefab.")]
        [SerializeField] EmojiButtonCell _cellPrefab;

        [Tooltip("Kích thước mỗi ô (pixel). Cell size in pixels.")]
        [SerializeField] Vector2 _cellSize = new Vector2(64f, 64f);

        [Tooltip("Khoảng cách giữa các ô. Spacing between cells.")]
        [SerializeField] Vector2 _cellSpacing = new Vector2(4f, 4f);

        [Tooltip("Số cột cố định. Fixed column count.")]
        [SerializeField] int _columnCount = 8;

        [Header("Wiring")]
        [Tooltip("ChatInputHandler để nhét emoji code vào ô nhập liệu.")]
        [SerializeField] ChatInputHandler _chatInput;

        [Tooltip("ChatSystemlUI để đóng EmojiPanel sau khi chọn.")]
        [SerializeField] ChatSystemlUI _chatSystemUI;

        private readonly List<EmojiButtonCell> _cells = new();
        private bool _built;

        private void Awake()
        {
            TryAutoWireIfNeeded();
        }

        private void Start()
        {
            BuildGrid();
        }

        private void OnEnable()
        {
            if (!_built)
                BuildGrid();
        }

        /// <summary>
        /// Xây dựng lưới emoji từ EmotionLibrarySpriteMap.
        /// Build emoji grid from EmotionLibrarySpriteMap.
        /// </summary>
        public void BuildGrid()
        {
            ClearGrid();
            TryAutoWireIfNeeded();

            if (_gridContent == null || _cellPrefab == null)
            {
                Debug.LogWarning("[Cuong] GridContent hoặc CellPrefab chưa được gán.", this);
                return;
            }

            if (_emotionSpriteMap == null || _emotionSpriteMap.Library == null)
            {
                Debug.LogWarning("[Cuong] EmotionLibrarySpriteMap chưa được gán hoặc chưa có Library.", this);
                return;
            }

            EnsureGridLayout();

            _gridContent.gameObject.SetActive(true);

            // Keep UI stable: always render in set index order.
            foreach (var set in _emotionSpriteMap.Library.Sets.OrderBy(x => x?.EmotionSetIndex ?? int.MaxValue))
            {
                if (set == null) continue;
                if (set.Entries == null || set.Entries.Count == 0) continue;

                for (int i = 0; i < set.Entries.Count; i++)
                {
                    var entry = set.Entries[i];
                    if (entry == null) continue;

                    Sprite icon = (entry.FrameSprites != null && entry.FrameSprites.Length > 0)
                        ? entry.FrameSprites[0]
                        : null;

                    var cell = Instantiate(_cellPrefab, _gridContent, false);
                    cell.Bind(set.EmotionSetIndex, i, icon, entry.Hint);
                    cell.OnClicked += HandleEmojiClicked;
                    _cells.Add(cell);
                }
            }

            _built = true;
        }

        private void ClearGrid()
        {
            foreach (var c in _cells)
            {
                if (c == null) continue;
                c.OnClicked -= HandleEmojiClicked;
                Destroy(c.gameObject);
            }
            _cells.Clear();
            _built = false;
        }

        private void TryAutoWireIfNeeded()
        {
            _chatInput ??= GetComponentInParent<ChatInputHandler>();
            _chatSystemUI ??= GetComponentInParent<ChatSystemlUI>();
        }

        private void EnsureGridLayout()
        {
            var layout = _gridContent.GetComponent<GridLayoutGroup>();
            if (layout == null)
                layout = _gridContent.gameObject.AddComponent<GridLayoutGroup>();

            layout.cellSize = _cellSize;
            layout.spacing = _cellSpacing;
            layout.constraint = GridLayoutGroup.Constraint.FixedColumnCount;
            layout.constraintCount = _columnCount;
            layout.startCorner = GridLayoutGroup.Corner.UpperLeft;
            layout.startAxis = GridLayoutGroup.Axis.Horizontal;
            layout.childAlignment = TextAnchor.UpperLeft;

            var fitter = _gridContent.GetComponent<ContentSizeFitter>();
            if (fitter == null)
                fitter = _gridContent.gameObject.AddComponent<ContentSizeFitter>();
            fitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;
        }

        /// <summary>
        /// Gọi khi người chơi click một ô emoji — Called when player clicks an emoji cell.
        /// Chèn mã emoji vào input field và đóng panel.
        /// Inserts the emotion code into the chat input and closes the panel.
        /// </summary>
        private void HandleEmojiClicked(int emotionSet, int emotionIndex)
        {
            TryAutoWireIfNeeded();
            if (_chatInput != null)
            {
                // Keep wire body as source of truth to avoid TMP tag race/corruption
                // when player taps emoji repeatedly.
                _chatInput.InsertEmoji(emotionSet, emotionIndex);
                Debug.Log("[Cuong] HandleEmojiClicked.");
            }
            else
            {
                Debug.LogWarning("[Cuong] Không tìm thấy ChatInputHandler để insert emoji.", this);
            }

            /*if (_chatSystemUI != null)
            {
                _chatSystemUI.CloseEmojiPanel();
            }*/
        }

        private void OnDestroy()
        {
            ClearGrid();
        }
    }
}