using System;
using Substrate.Core;
using Substrate.Nbt;

namespace Substrate
{
    /// <summary>
    /// Represents a Tile Entity record, which provides additional data to a block.
    /// </summary>
    /// <remarks>Generally, this class should be subtyped into new concrete Tile Entity types, as this generic type is unable to
    /// capture any of the custom data fields that make Tile Entities useful in the first place.  It is however still possible to
    /// create instances of <see cref="TileEntity"/> objects, which may allow for graceful handling of unknown Tile Entities.</remarks>
    public class TileEntity : INBTObject<TileEntity>, ICopyable<TileEntity>
    {
        private static readonly SchemaNodeCompound _schema = new SchemaNodeCompound("")
        {
            new SchemaNodeScaler("id", TagType.TAG_STRING),
            new SchemaNodeScaler("x", TagType.TAG_INT),
            new SchemaNodeScaler("y", TagType.TAG_INT),
            new SchemaNodeScaler("z", TagType.TAG_INT),
        };

        private string _id;
        private int _x;
        private int _y;
        private int _z;

        /// <summary>
        /// Gets the id (name) of the Tile Entity.
        /// </summary>
        public string ID
        {
            get { return _id; }
        }

        /// <summary>
        /// Gets or sets the global X-coordinate of the block that this Tile Entity is associated with.
        /// </summary>
        public int X
        {
            get { return _x; }
            set { _x = value; }
        }

        /// <summary>
        /// Gets or sets the global Y-coordinate of the block that this Tile Entity is associated with.
        /// </summary>
        public int Y
        {
            get { return _y; }
            set { _y = value; }
        }

        /// <summary>
        /// Gets or sets the global Z-coordinate of the block that this Tile Entity is associated with.
        /// </summary>
        public int Z
        {
            get { return _z; }
            set { _z = value; }
        }

        /// <summary>
        /// Constructs a nonspecific <see cref="TileEntity"/> with a given ID.
        /// </summary>
        /// <param name="id">The id (name) of the Tile Entity.</param>
        public TileEntity (string id)
        {
            _id = id;
        }

        /// <summary>
        /// Constructs a <see cref="TileEntity"/> by copying an existing one.
        /// </summary>
        /// <param name="te">The <see cref="TileEntity"/> to copy.</param>
        public TileEntity (TileEntity te)
        {
            _id = te._id;
            _x = te._x;
            _y = te._y;
            _z = te._z;
        }

        /// <summary>
        /// Checks whether the Tile Entity is located (associated with a block) at the specific global coordinates.
        /// </summary>
        /// <param name="x">The global X-coordinate to test.</param>
        /// <param name="y">The global Y-coordinate to test.</param>
        /// <param name="z">The global Z-coordinate to test.</param>
        /// <returns>Status indicating whether the Tile Entity is located at the specified global coordinates.</returns>
        public bool LocatedAt (int x, int y, int z)
        {
            return _x == x && _y == y && _z == z;
        }


        #region ICopyable<TileEntity> Members

        /// <summary>
        /// Creates a deep-copy of the <see cref="TileEntity"/> including any data defined in a subtype.
        /// </summary>
        /// <returns>A deep-copy of the <see cref="TileEntity"/>.</returns>
        public virtual TileEntity Copy ()
        {
            return new TileEntity(this);
        }

        #endregion


        #region INBTObject<TileEntity> Members

        /// <summary>
        /// Gets a <see cref="SchemaNode"/> representing the basic schema of a Tile Entity.
        /// </summary>
        public static SchemaNodeCompound Schema
        {
            get { return _schema; }
        }

        /// <summary>
        /// Attempt to load a Tile Entity subtree into the <see cref="TileEntity"/> without validation.
        /// </summary>
        /// <param name="tree">The root node of a Tile Entity subtree.</param>
        /// <returns>The <see cref="TileEntity"/> returns itself on success, or null if the tree was unparsable.</returns>
        public virtual TileEntity LoadTree (TagNode tree)
        {
            TagNodeCompound ctree = tree as TagNodeCompound;
            if (ctree == null) {
                return null;
            }

            _id = ctree["id"].ToTagString();
            _x = ctree["x"].ToTagInt();
            _y = ctree["y"].ToTagInt();
            _z = ctree["z"].ToTagInt();

            return this;
        }

        /// <summary>
        /// Attempt to load a Tile Entity subtree into the <see cref="TileEntity"/> with validation.
        /// </summary>
        /// <param name="tree">The root node of a Tile Entity subtree.</param>
        /// <returns>The <see cref="TileEntity"/> returns itself on success, or null if the tree failed validation.</returns>
        public virtual TileEntity LoadTreeSafe (TagNode tree)
        {
            if (!ValidateTree(tree)) {
                return null;
            }

            return LoadTree(tree);
        }

        /// <summary>
        /// Builds a Tile Entity subtree from the current data.
        /// </summary>
        /// <returns>The root node of a Tile Entity subtree representing the current data.</returns>
        public virtual TagNode BuildTree ()
        {
            TagNodeCompound tree = new TagNodeCompound();
            tree["id"] = new TagNodeString(_id);
            tree["x"] = new TagNodeInt(_x);
            tree["y"] = new TagNodeInt(_y);
            tree["z"] = new TagNodeInt(_z);

            return tree;
        }

        /// <summary>
        /// Validate a Tile Entity subtree against a basic schema.
        /// </summary>
        /// <param name="tree">The root node of a Tile Entity subtree.</param>
        /// <returns>Status indicating whether the tree was valid against the internal schema.</returns>
        public virtual bool ValidateTree (TagNode tree)
        {
            return new NBTVerifier(tree, _schema).Verify();
        }

        #endregion
    }

}