/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

* 

* Description:

*

*/

using System;

using System.Collections.Generic;

namespace SymbianUtils.Settings

{

	public class XmlSettingsBoundedList

	{

		#region Constructors

		public XmlSettingsBoundedList( string aCategory, XmlSettings aSettings )

		{

			// Since the max capacity was not supplied, we can attempt to read

			// it from the settings or then if not found, we default to 10.

			iSettings = aSettings;

			iCategory = aCategory;

			iMaxCapacity = SettingsMaxCapacity;

			//

			Restore();

		}

		public XmlSettingsBoundedList( string aCategory, XmlSettings aSettings, int aMaxCapacity )

		{

			iSettings = aSettings;

			iCategory = aCategory;

			iMaxCapacity = aMaxCapacity;

			//

			Restore();

		}

		#endregion

		#region API

		public void Restore()

		{

			// Newest additions are stored at the front of the list.

			// Oldest items are therefore at the end

			iList.Clear();

			//

			int settingsCount = SettingsCount;

            for ( int i = 0; i < settingsCount && i < MaxCapacity; i++ )

			{

				string item = SettingItem(i);

				iList.Add( item );

			}

		}

		public void Store()

		{

			// Remove all entries that already exist

			// within the settings object

			RemoveAllExistingSettings();

			// Now add the replacement items

			int settingsCount = iList.Count;

			SettingsCount = settingsCount;

			for(int i=0; i<settingsCount; i++)

			{

				string itemKey = MakeSettingsKey( i );

				string itemValue = iList[ i ];

				//

				iSettings[ Category, itemKey ] = itemValue;

			}

		}

		public void Add( string aValue )

		{

			// First, add the item

			iList.Insert( 0, aValue );

			// If the capacity has reached the limit, we remove the last (oldest) item

			if	( iList.Count > MaxCapacity )

			{

				iList.RemoveAt( MaxCapacity );

			}

		}

		#endregion

		#region Properties

		public int MaxCapacity

		{

			get { return iMaxCapacity; }

		}

		public string Category

		{

			get { return iCategory; }

		}

		public int Count

		{

			get { return iList.Count; }

		}

		#endregion

		#region Internal properties

		private int SettingsCount

		{

			get

			{

				int count = 0;

				string countAsString = iSettings[Category, "_NumberOfItems"];

				if	(countAsString != null)

				{

					count = System.Convert.ToInt32(countAsString);

				}

				return count;

			}

			set

			{

				iSettings[Category, "_NumberOfItems"] = value.ToString();

			}

		}

		private int SettingsMaxCapacity

		{

			get

			{

				int capacity = 0;

				string capacityAsString = iSettings[Category, "_MaxCapacity"];

				if	(capacityAsString != null)

				{

					capacity = System.Convert.ToInt32(capacityAsString);

				}

				return capacity;

			}

			set

			{

				iSettings[Category, "_MaxCapacity"] = value.ToString();

			}

		}

		#endregion

		#region Internal methods

		private string MakeSettingsKey( int aIndex )

		{

			return "_Entry_Id_" + aIndex.ToString( "0000" );

		}

		private string SettingItem( int aIndex )

		{

			string key = MakeSettingsKey( aIndex );

			string itemValue = iSettings[ Category, key ];

			//

			return itemValue;

		}

		private void RemoveAllExistingSettings()

		{

			iSettings.Remove( Category );

		}

		#endregion

		#region Data members

		int iMaxCapacity = 100;

		readonly string iCategory;

		readonly XmlSettings iSettings;

		List<string> iList = new List<string>(10);

		#endregion

	}

}