using System;
using System.Reflection;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace Server.Commands.Generic
{
public sealed class SortExtension : BaseExtension
{
public static ExtensionInfo ExtInfo = new ExtensionInfo( 40, "Order", -1, delegate() { return new SortExtension(); } );

public static void Initialize()
{
ExtensionInfo.Register( ExtInfo );
}

public override ExtensionInfo Info
{
get { return ExtInfo; }
}

private List<OrderInfo> m_Orders;

private IComparer m_Comparer;

public SortExtension()
{
m_Orders = new List<OrderInfo>();
}

public override void Optimize( Mobile from, Type baseType, ref AssemblyEmitter assembly )
{
if ( baseType == null )
throw new Exception( "The ordering extension may only be used in combination with an object conditional." );

foreach ( OrderInfo order in m_Orders )
{
order.Property.BindTo( baseType, PropertyAccess.Read );
order.Property.CheckAccess( from );
}

if ( assembly == null )
assembly = new AssemblyEmitter( "__dynamic", false );

m_Comparer = SortCompiler.Compile( assembly, baseType, m_Orders.ToArray() );
}

public override void Parse( Mobile from, string[] arguments, int offset, int size )
{
if ( size < 1 )
throw new Exception( "Invalid ordering syntax." );

if ( Insensitive.Equals( arguments[offset], "by" ) )
{
++offset;
--size;

if ( size < 1 )
throw new Exception( "Invalid ordering syntax." );
}

int end = offset + size;

while ( offset < end )
{
string binding = arguments[offset++];

bool isAscending = true;

if ( offset < end )
{
string next = arguments[offset];

switch ( next.ToLower() )
{
case "+":
case "up":
case "asc":
case "ascending":
isAscending = true;
++offset;
break;

case "-":
case "down":
case "desc":
case "descending":
isAscending = false;
++offset;
break;
}
}

Property property = new Property( binding );

m_Orders.Add( new OrderInfo( property, isAscending ) );
}
}

public override void Filter( ArrayList list )
{
if ( m_Comparer == null )
throw new InvalidOperationException( "The extension must first be optimized." );

list.Sort( m_Comparer );
}
}
}