using System;

#if UNITY_EDITOR
using UnityEditor;
#endif

namespace UnityEngine.Tilemaps
{
    /// <summary>
    /// Terrain Tiles, similar to Pipeline Tiles, are tiles which take into consideration its orthogonal and diagonal neighboring tiles and displays a sprite depending on whether the neighboring tile is the same tile.
    /// </summary>
    [Serializable]
    public class TerrainTile : TileBase
    {
        /// <summary>
        /// The Sprites used for defining the Terrain.
        /// </summary>
        [SerializeField]
        public Sprite[] m_Sprites;

        /// <summary>
        /// This method is called when the tile is refreshed.
        /// </summary>
        /// <param name="position">Position of the Tile on the Tilemap.</param>
        /// <param name="tilemap">The Tilemap the tile is present on.</param>
        public override void RefreshTile(Vector3Int position, ITilemap tilemap)
        {
            for (int yd = -1; yd <= 1; yd++)
                for (int xd = -1; xd <= 1; xd++)
                {
                    Vector3Int pos = new Vector3Int(position.x + xd, position.y + yd, position.z);
                    if (TileValue(tilemap, pos))
                        tilemap.RefreshTile(pos);
                }
        }

        /// <summary>
        /// Retrieves any tile rendering data from the scripted tile.
        /// </summary>
        /// <param name="position">Position of the Tile on the Tilemap.</param>
        /// <param name="tilemap">The Tilemap the tile is present on.</param>
        /// <param name="tileData">Data to render the tile.</param>
        public override void GetTileData(Vector3Int position, ITilemap tilemap, ref TileData tileData)
        {
            UpdateTile(position, tilemap, ref tileData);
        }

        private void UpdateTile(Vector3Int location, ITilemap tileMap, ref TileData tileData)
        {
            tileData.transform = Matrix4x4.identity;
            tileData.color = Color.white;

            int mask = TileValue(tileMap, location + new Vector3Int(0, 1, 0)) ? 1 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(1, 1, 0)) ? 2 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(1, 0, 0)) ? 4 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(1, -1, 0)) ? 8 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(0, -1, 0)) ? 16 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(-1, -1, 0)) ? 32 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(-1, 0, 0)) ? 64 : 0;
            mask += TileValue(tileMap, location + new Vector3Int(-1, 1, 0)) ? 128 : 0;

            byte original = (byte)mask;
            if ((original | 254) < 255) { mask = mask & 125; }
            if ((original | 251) < 255) { mask = mask & 245; }
            if ((original | 239) < 255) { mask = mask & 215; }
            if ((original | 191) < 255) { mask = mask & 95; }

            int index = GetIndex((byte)mask);
            if (index >= 0 && index < m_Sprites.Length && TileValue(tileMap, location))
            {
                tileData.sprite = m_Sprites[index];
                tileData.transform = GetTransform((byte)mask);
                tileData.color = Color.white;
                tileData.flags = TileFlags.LockTransform | TileFlags.LockColor;
                tileData.colliderType = Tile.ColliderType.Sprite;
            }
        }

        private bool TileValue(ITilemap tileMap, Vector3Int position)
        {
            TileBase tile = tileMap.GetTile(position);
            return (tile != null && tile == this);
        }

        private int GetIndex(byte mask)
        {
            switch (mask)
            {
                case 0: return 0;
                case 1:
                case 4:
                case 16:
                case 64: return 1;
                case 5:
                case 20:
                case 80:
                case 65: return 2;
                case 7:
                case 28:
                case 112:
                case 193: return 3;
                case 17:
                case 68: return 4;
                case 21:
                case 84:
                case 81:
                case 69: return 5;
                case 23:
                case 92:
                case 113:
                case 197: return 6;
                case 29:
                case 116:
                case 209:
                case 71: return 7;
                case 31:
                case 124:
                case 241:
                case 199: return 8;
                case 85: return 9;
                case 87:
                case 93:
                case 117:
                case 213: return 10;
                case 95:
                case 125:
                case 245:
                case 215: return 11;
                case 119:
                case 221: return 12;
                case 127:
                case 253:
                case 247:
                case 223: return 13;
                case 255: return 14;
            }
            return -1;
        }

        private Matrix4x4 GetTransform(byte mask)
        {
            switch (mask)
            {
                case 4:
                case 20:
                case 28:
                case 68:
                case 84:
                case 92:
                case 116:
                case 124:
                case 93:
                case 125:
                case 221:
                case 253:
                    return Matrix4x4.TRS(Vector3.zero, Quaternion.Euler(0f, 0f, -90f), Vector3.one);
                case 16:
                case 80:
                case 112:
                case 81:
                case 113:
                case 209:
                case 241:
                case 117:
                case 245:
                case 247:
                    return Matrix4x4.TRS(Vector3.zero, Quaternion.Euler(0f, 0f, -180f), Vector3.one);
                case 64:
                case 65:
                case 193:
                case 69:
                case 197:
                case 71:
                case 199:
                case 213:
                case 215:
                case 223:
                    return Matrix4x4.TRS(Vector3.zero, Quaternion.Euler(0f, 0f, -270f), Vector3.one);
            }
            return Matrix4x4.identity;
        }
    }

#if UNITY_EDITOR
    [CustomEditor(typeof(TerrainTile))]
    public class TerrainTileEditor : Editor
    {
        private TerrainTile tile { get { return (target as TerrainTile); } }

        /// <summary>
        /// OnEnable for TerrainTile.
        /// </summary>
        public void OnEnable()
        {
            if (tile.m_Sprites == null || tile.m_Sprites.Length != 15)
            {
                tile.m_Sprites = new Sprite[15];
                EditorUtility.SetDirty(tile);
            }
        }

        /// <summary>
        /// Draws an Inspector for the Terrain Tile.
        /// </summary>
        public override void OnInspectorGUI()
        {
            EditorGUILayout.LabelField("Place sprites shown based on the contents of the sprite.");
            EditorGUILayout.Space();

            float oldLabelWidth = EditorGUIUtility.labelWidth;
            EditorGUIUtility.labelWidth = 210;

            EditorGUI.BeginChangeCheck();
            tile.m_Sprites[0] = (Sprite) EditorGUILayout.ObjectField("Filled", tile.m_Sprites[0], typeof(Sprite), false, null);
            tile.m_Sprites[1] = (Sprite) EditorGUILayout.ObjectField("Three Sides", tile.m_Sprites[1], typeof(Sprite), false, null);
            tile.m_Sprites[2] = (Sprite) EditorGUILayout.ObjectField("Two Sides and One Corner", tile.m_Sprites[2], typeof(Sprite), false, null);
            tile.m_Sprites[3] = (Sprite) EditorGUILayout.ObjectField("Two Adjacent Sides", tile.m_Sprites[3], typeof(Sprite), false, null);
            tile.m_Sprites[4] = (Sprite) EditorGUILayout.ObjectField("Two Opposite Sides", tile.m_Sprites[4], typeof(Sprite), false, null);
            tile.m_Sprites[5] = (Sprite) EditorGUILayout.ObjectField("One Side and Two Corners", tile.m_Sprites[5], typeof(Sprite), false, null);
            tile.m_Sprites[6] = (Sprite) EditorGUILayout.ObjectField("One Side and One Lower Corner", tile.m_Sprites[6], typeof(Sprite), false, null);
            tile.m_Sprites[7] = (Sprite) EditorGUILayout.ObjectField("One Side and One Upper Corner", tile.m_Sprites[7], typeof(Sprite), false, null);
            tile.m_Sprites[8] = (Sprite) EditorGUILayout.ObjectField("One Side", tile.m_Sprites[8], typeof(Sprite), false, null);
            tile.m_Sprites[9] = (Sprite) EditorGUILayout.ObjectField("Four Corners", tile.m_Sprites[9], typeof(Sprite), false, null);
            tile.m_Sprites[10] = (Sprite) EditorGUILayout.ObjectField("Three Corners", tile.m_Sprites[10], typeof(Sprite), false, null);
            tile.m_Sprites[11] = (Sprite) EditorGUILayout.ObjectField("Two Adjacent Corners", tile.m_Sprites[11], typeof(Sprite), false, null);
            tile.m_Sprites[12] = (Sprite) EditorGUILayout.ObjectField("Two Opposite Corners", tile.m_Sprites[12], typeof(Sprite), false, null);
            tile.m_Sprites[13] = (Sprite) EditorGUILayout.ObjectField("One Corner", tile.m_Sprites[13], typeof(Sprite), false, null);
            tile.m_Sprites[14] = (Sprite) EditorGUILayout.ObjectField("Empty", tile.m_Sprites[14], typeof(Sprite), false, null);
            if (EditorGUI.EndChangeCheck())
                EditorUtility.SetDirty(tile);

            EditorGUIUtility.labelWidth = oldLabelWidth;
        }
    }
#endif
}
