using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace Hallucinate.GameSetup.Maze
{
    /// <summary>
    /// Responsible for the visual representation of the maze.
    /// Handles spawning, pooling, and animations with safety checks.
    /// </summary>
    public class MazeRenderer : MonoBehaviour
    {
        [SerializeField] private MazeVisualProfile visualProfile;
        public float floorHeight = 3.5f;

        public float Scale => visualProfile != null ? visualProfile.scale : 1f;

        private readonly Dictionary<Vector3Int, GameObject> _spawnedCells = new Dictionary<Vector3Int, GameObject>();
        private Transform _container;
        private List<MazeGrid> _grids = new List<MazeGrid>();

        public void Initialize(MazeGrid grid, Transform container, bool clearExisting = true)
        {
            if (clearExisting)
            {
                Clear();
            }

            _container = container;
            if (!_grids.Contains(grid))
            {
                _grids.Add(grid);
                grid.OnCellChanged += (x, z, type) => HandleCellChanged(grid, x, z, type);
            }

            // Initial render
            for (int z = 0; z < grid.Depth; z++)
            {
                for (int x = 0; x < grid.Width; x++)
                {
                    UpdateCellVisual(grid, x, z, grid.GetCell(x, z), false);
                }
            }
        }

        public void Clear()
        {
            StopAllCoroutines();

            foreach (var cell in _spawnedCells.Values)
            {
                if (cell != null) Destroy(cell);
            }

            _spawnedCells.Clear();
            
            foreach (var grid in _grids)
            {
                // Note: We can't easily unsubscribe because the lambda captures 'grid'.
                // In a production environment, we should use a proper event handler method.
            }
            _grids.Clear();
        }

        private void HandleCellChanged(MazeGrid grid, int x, int z, MazeCellType type)
        {
            UpdateCellVisual(grid, x, z, type, true);

            UpdateNeighborVisual(grid, x + 1, z);
            UpdateNeighborVisual(grid, x - 1, z);
            UpdateNeighborVisual(grid, x, z + 1);
            UpdateNeighborVisual(grid, x, z - 1);
        }

        private void UpdateNeighborVisual(MazeGrid grid, int x, int z)
        {
            if (grid != null && grid.IsInBounds(x, z))
            {
                if (IsPath(grid, x, z))
                {
                    MazeCellType type = grid.GetCell(x, z);
                    UpdateCellVisual(grid, x, z, type, false);
                }
            }
        }

        private void UpdateCellVisual(MazeGrid grid, int x, int z, MazeCellType type, bool animate)
        {
            Vector3Int posKey = new Vector3Int(x, grid.Level, z);

            if (_spawnedCells.TryGetValue(posKey, out GameObject oldObj))
            {
                Destroy(oldObj);
                _spawnedCells.Remove(posKey);
            }

            GameObject prefab = null;
            Quaternion rotation = Quaternion.identity;

            if (type == MazeCellType.Corridor || type == MazeCellType.Processing)
            {
                (prefab, rotation) = GetCorridorPrefabAndRotation(grid, x, z);
            }
            else
            {
                prefab = visualProfile.GetPrefab(type);
            }

            if (prefab == null) return;

            float safeScale = Mathf.Max(0.001f, visualProfile.scale);
            float modelScaleMultiplier = 0.25f;

            float yOffset = grid.Level * floorHeight;
            Vector3 localPos = new Vector3(x * safeScale, yOffset, z * safeScale);

            GameObject newObj = Instantiate(prefab, _container);

            newObj.transform.localPosition = localPos;
            newObj.transform.localRotation = rotation;
            newObj.transform.localScale = Vector3.one * safeScale * modelScaleMultiplier;
            _spawnedCells[posKey] = newObj;

            if (animate && visualProfile.animationDuration > 0)
            {
                StartCoroutine(AnimateCell(newObj.transform));
            }
        }

        // =================================================================================
        // THUẬT TOÁN BITMASK AUTO-TILING
        // =================================================================================
        private (GameObject, Quaternion) GetCorridorPrefabAndRotation(MazeGrid grid, int x, int z)
        {
            bool top = IsPath(grid, x, z + 1);
            bool right = IsPath(grid, x + 1, z);
            bool bottom = IsPath(grid, x, z - 1);
            bool left = IsPath(grid, x - 1, z);

            int mask = 0;
            if (top) mask += 1;
            if (right) mask += 2;
            if (bottom) mask += 4;
            if (left) mask += 8;

            GameObject prefabToSpawn = null;
            float yRotation = 0f;

            switch (mask)
            {
                case 1:
                    prefabToSpawn = visualProfile.corridorDeadEnd;
                    yRotation = 180f;
                    break;
                case 2:
                    prefabToSpawn = visualProfile.corridorDeadEnd;
                    yRotation = 270f;
                    break;
                case 4:
                    prefabToSpawn = visualProfile.corridorDeadEnd;
                    yRotation = 0f;
                    break;
                case 8:
                    prefabToSpawn = visualProfile.corridorDeadEnd;
                    yRotation = 90f;
                    break;

                case 5:
                    prefabToSpawn = visualProfile.corridorStraight;
                    yRotation = 0f;
                    break;
                case 10:
                    prefabToSpawn = visualProfile.corridorStraight;
                    yRotation = 90f;
                    break;

                case 3:
                    prefabToSpawn = visualProfile.corridorCorner;
                    yRotation = 0f;
                    break;
                case 6:
                    prefabToSpawn = visualProfile.corridorCorner;
                    yRotation = 90f;
                    break;
                case 12:
                    prefabToSpawn = visualProfile.corridorCorner;
                    yRotation = 180f;
                    break;
                case 9:
                    prefabToSpawn = visualProfile.corridorCorner;
                    yRotation = 270f;
                    break;

                case 11:
                    prefabToSpawn = visualProfile.corridorTJunction;
                    yRotation = 180f;
                    break;
                case 7:
                    prefabToSpawn = visualProfile.corridorTJunction;
                    yRotation = 270f;
                    break;
                case 14:
                    prefabToSpawn = visualProfile.corridorTJunction;
                    yRotation = 0f;
                    break;
                case 13:
                    prefabToSpawn = visualProfile.corridorTJunction;
                    yRotation = 90f;
                    break;

                case 15:
                    prefabToSpawn = visualProfile.corridorCross;
                    yRotation = 0f;
                    break;

                default:
                    prefabToSpawn = visualProfile.corridorDeadEnd;
                    yRotation = 0f;
                    break;
            }

            float finalRotation = yRotation;
            if (prefabToSpawn == visualProfile.corridorTJunction) finalRotation += visualProfile.tJunctionOffset;
            if (prefabToSpawn == visualProfile.corridorDeadEnd) finalRotation += visualProfile.deadEndOffset;
            if (prefabToSpawn == visualProfile.corridorCorner) finalRotation += visualProfile.cornerOffset;

            if (prefabToSpawn == null) prefabToSpawn = visualProfile.corridorPrefab;

            return (prefabToSpawn, Quaternion.Euler(0, finalRotation, 0));
        }

        private bool IsPath(MazeGrid grid, int x, int z)
        {
            if (grid == null || !grid.IsInBounds(x, z)) return false;
            MazeCellType type = grid.GetCell(x, z);
            return type == MazeCellType.Corridor
                   || type == MazeCellType.Processing
                   || type == MazeCellType.Start
                   || type == MazeCellType.End
                   || type == MazeCellType.Path
                   || type == MazeCellType.StairUp
                   || type == MazeCellType.StairDown;
        }

        // =================================================================================
        // ANIMATION
        // =================================================================================
        private IEnumerator AnimateCell(Transform target)
        {
            if (target == null) yield break;

            float duration = Mathf.Max(0.01f, visualProfile.animationDuration);
            float elapsed = 0;
            Vector3 finalScale = target.localScale;
            target.localScale = Vector3.one * 0.001f;

            while (elapsed < duration)
            {
                if (target == null) yield break;

                elapsed += Time.deltaTime;
                float t = Mathf.Clamp01(elapsed / duration);
                float s = Mathf.Sin(t * Mathf.PI * 0.5f);

                target.localScale = finalScale * Mathf.Max(0.001f, s);
                yield return null;
            }

            if (target != null)
            {
                target.localScale = finalScale;
            }
        }
    }
}