using System;

namespace MonoGame.Extended.Tilemaps
{
    /// <summary>
    /// Represents a tile instance in a tile layer.
    /// </summary>
    /// <remarks>
    /// A tile references a tileset and local tile ID through its global ID,
    /// and may include flip flags for horizontal, vertical, or diagonal transformations.
    /// </remarks>
    public readonly struct TilemapTile
    {
        /// <summary>
        /// Gets the global tile ID.
        /// </summary>
        /// <remarks>
        /// The global ID uniquely identifies a tile across all tilesets in the tilemap.
        /// It combines the tileset's first global ID with the local tile ID.
        /// </remarks>
        public int GlobalId { get; }

        /// <summary>
        /// Gets the flip transformation flags applied to this tile.
        /// </summary>
        public TilemapTileFlipFlags FlipFlags { get; }

        /// <summary>
        /// Initializes a new instance of the <see cref="TilemapTile"/> struct.
        /// </summary>
        /// <param name="globalId">The global tile ID.</param>
        /// <param name="flipFlags">The flip transformation flags.</param>
        public TilemapTile(int globalId, TilemapTileFlipFlags flipFlags = TilemapTileFlipFlags.None)
        {
            GlobalId = globalId;
            FlipFlags = flipFlags;
        }

        /// <summary>
        /// Gets the tileset that contains this tile.
        /// </summary>
        /// <param name="tilesets">The collection of tilesets.</param>
        /// <returns>The tileset containing this tile, or <see langword="null"/> if not found.</returns>
        public TilemapTileset GetTileset(TilemapTilesetCollection tilesets)
        {
            return tilesets.GetTilesetForGid(GlobalId);
        }

        /// <summary>
        /// Gets the local tile ID within the tileset.
        /// </summary>
        /// <param name="tilesets">The collection of tilesets.</param>
        /// <returns>The local tile ID.</returns>
        public int GetLocalId(TilemapTilesetCollection tilesets)
        {
            return tilesets.GetLocalId(GlobalId, out _);
        }

        /// <summary>
        /// Gets the local tile ID within the specified tileset.
        /// </summary>
        /// <param name="tilesets">The collection of tilesets.</param>
        /// <param name="tileset">When this method returns, contains the tileset that owns this tile.</param>
        /// <returns>The local tile ID within the tileset.</returns>
        public int GetLocalId(TilemapTilesetCollection tilesets, out TilemapTileset tileset)
        {
            return tilesets.GetLocalId(GlobalId, out tileset);
        }

        public TilemapTileData? GetTileData(TilemapTilesetCollection tilesets)
        {
            var tileset = GetTileset(tilesets);
            if (tileset == null)
            {
                return null;
            }

            var localId = GlobalId - tileset.FirstGlobalId;
            return tileset.GetTileData(localId);

        }
    }
}