using System;

using Substrate.Core;

//TODO: Benchmark struct vs. class. If no difference, prefer class.

namespace Substrate

{

/// <summary>

/// A reference to a single Alpha-compatible block in an <see cref="AlphaBlockCollection"/>.

/// </summary>

/// <remarks><para>The <see cref="AlphaBlockRef"/> type provides a reasonably lightweight reference to an individual block in a

/// <see cref="AlphaBlockCollection"/>. The <see cref="AlphaBlockRef"/> does not store any of the data itself. If the referenced

/// block in the <see cref="AlphaBlockCollection"/> is updated externally, those changes will be automatically reflected in the

/// <see cref="AlphaBlockRef"/>, and any changes made via the <see cref="AlphaBlockRef"/> will be applied directly to the corresponding

/// block within the <see cref="AlphaBlockCollection"/>. Such changes will also set the dirty status of the <see cref="AlphaBlockCollection"/>,

/// which can make this type particularly useful.</para>

/// <para>Despite being lightweight, using an <see cref="AlphaBlockRef"/> to get and set block data is still more expensive then directly

/// getting and setting data in the <see cref="AlphaBlockCollection"/> object, and can be significantly slow in a tight loop

/// (<see cref="AlphaBlockCollection"/> does not provide an interface for enumerating <see cref="AlphaBlockRef"/> objects specifically

/// to discourage this kind of use).</para>

/// <para><see cref="AlphaBlockRef"/> objects are most appropriate in cases where looking up an object requires expensive checks, such as

/// accessing blocks through a derived <see cref="BlockManager"/> type with enhanced block filtering. By getting an <see cref="AlphaBlockRef"/>,

/// any number of block attributes can be read or written to while only paying the lookup cost once to get the reference. Using the

/// <see cref="BlockManager"/> (or similar) directly would incur the expensive lookup on each operation. See NBToolkit for an example of this

/// use case.</para>

/// <para>Unlike the <see cref="AlphaBlock"/> object, this type exposed access to context-dependent data such as lighting.</para></remarks>

public struct AlphaBlockRef : IVersion10BlockRef

{

private readonly AlphaBlockCollection _collection;

private readonly int _index;

internal AlphaBlockRef (AlphaBlockCollection collection, int index)

{

_collection = collection;

_index = index;

}

/// <summary>

/// Checks if this object is currently a valid ref into another <see cref="AlphaBlockCollection"/>.

/// </summary>

public bool IsValid

{

get { return _collection != null; }

}

#region IBlock Members

/// <summary>

/// Gets information on the type of the block.

/// </summary>

public BlockInfo Info

{

get { return _collection.GetInfo(_index); }

}

/// <summary>

/// Gets or sets the id (type) of the block.

/// </summary>

public int ID

{

get

{

return _collection.GetID(_index);

}

set

{

_collection.SetID(_index, value);

}

}

#endregion

#region IDataBlock Members

/// <summary>

/// Gets or sets the supplementary data value of the block.

/// </summary>

public int Data

{

get

{

return _collection.GetData(_index);

}

set

{

_collection.SetData(_index, value);

}

}

#endregion

#region ILitBlock Members

/// <summary>

/// Gets or sets the block-source light component of the block.

/// </summary>

public int BlockLight

{

get

{

return _collection.GetBlockLight(_index);

}

set

{

_collection.SetBlockLight(_index, value);

}

}

/// <summary>

/// Gets or sets the sky-source light component of the block.

/// </summary>

public int SkyLight

{

get

{

return _collection.GetSkyLight(_index);

}

set

{

_collection.SetSkyLight(_index, value);

}

}

#endregion

#region IPropertyBlock Members

/// <summary>

/// Gets the Tile Entity record of the block if it has one.

/// </summary>

/// <returns>The <see cref="TileEntity"/> attached to this block, or null if the block type does not require a Tile Entity.</returns>

public TileEntity GetTileEntity ()

{

return _collection.GetTileEntity(_index);

}

/// <summary>

/// Sets a new Tile Entity record for the block.

/// </summary>

/// <param name="te">A Tile Entity record compatible with the block's type.</param>

public void SetTileEntity (TileEntity te)

{

_collection.SetTileEntity(_index, te);

}

/// <summary>

/// Creates a default Tile Entity record appropriate for the block.

/// </summary>

public void CreateTileEntity ()

{

_collection.CreateTileEntity(_index);

}

/// <summary>

/// Removes any Tile Entity currently attached to the block.

/// </summary>

public void ClearTileEntity ()

{

_collection.ClearTileEntity(_index);

}

#endregion

#region IActiveBlock Members

public int TileTickValue

{

get { return _collection.GetTileTickValue(_index); }

set { _collection.SetTileTickValue(_index, value); }

}

/// <summary>

/// Gets the <see cref="TileTick"/> record of the block if it has one.

/// </summary>

/// <returns>The <see cref="TileTick"/> attached to this block, or null if the block type does not require a Tile Entity.</returns>

public TileTick GetTileTick ()

{

return _collection.GetTileTick(_index);

}

/// <summary>

/// Sets a new <see cref="TileTick"/> record for the block.

/// </summary>

/// <param name="te">A <see cref="TileTick"/> record compatible with the block's type.</param>

public void SetTileTick (TileTick te)

{

_collection.SetTileTick(_index, te);

}

/// <summary>

/// Creates a default <see cref="TileTick"/> record appropriate for the block.

/// </summary>

public void CreateTileTick ()

{

_collection.CreateTileTick(_index);

}

/// <summary>

/// Removes any <see cref="TileTick"/> currently attached to the block.

/// </summary>

public void ClearTileTick ()

{

_collection.ClearTileTick(_index);

}

#endregion

}

}