//******************************************************************************************************
//  IMetadataProvider.cs - Gbtc
//
//  Copyright © 2012, Grid Protection Alliance.  All Rights Reserved.
//
//  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See
//  the NOTICE file distributed with this work for additional information regarding copyright ownership.
//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may
//  not use this file except in compliance with the License. You may obtain a copy of the License at:
//
//      http://www.opensource.org/licenses/MIT
//
//  Unless agreed to in writing, the subject software distributed under the License is distributed on an
//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the
//  License for the specific language governing permissions and limitations.
//
//  Code Modification History:
//  ----------------------------------------------------------------------------------------------------
//  07/06/2009 - Pinal C. Patel
//       Generated original version of source code.
//  09/15/2009 - Stephen C. Wills
//       Added new header and license agreement.
//  10/11/2010 - Mihir Brahmbhatt
//       Updated header and license agreement.
//  12/14/2012 - Starlynn Danyelle Gilliam
//       Modified Header.
//
//******************************************************************************************************

using System;
using GSF.Adapters;
using GSF.Historian.Files;

namespace GSF.Historian.MetadataProviders
{
    /// <summary>
    /// Defines a provider of updates to the data in a <see cref="MetadataFile"/>.
    /// </summary>
    /// <seealso cref="MetadataFile"/>
    public interface IMetadataProvider : IAdapter
    {
        #region [ Members ]

        // Events

        /// <summary>
        /// Occurs when <see cref="Refresh()"/> of <see cref="Metadata"/> is started.
        /// </summary>
        event EventHandler MetadataRefreshStart;

        /// <summary>
        /// Occurs when <see cref="Refresh()"/> of <see cref="Metadata"/> is completed.
        /// </summary>
        event EventHandler MetadataRefreshComplete;

        /// <summary>
        /// Occurs when <see cref="Refresh()"/> of <see cref="Metadata"/> times out.
        /// </summary>
        event EventHandler MetadataRefreshTimeout;

        /// <summary>
        /// Occurs when an <see cref="Exception"/> is encountered during <see cref="Refresh()"/> of <see cref="Metadata"/>.
        /// </summary>
        event EventHandler<EventArgs<Exception>> MetadataRefreshException;

        #endregion

        #region [ Properties ]

        /// <summary>
        /// Gets or sets the number of seconds to wait for the <see cref="Refresh()"/> to complete.
        /// </summary>
        int RefreshTimeout { get; set; }

        /// <summary>
        /// Gets or sets the number of minutes at which the <see cref="Metadata"/> if to be refreshed automatically.
        /// </summary>
        int RefreshInterval { get; set; }

        /// <summary>
        /// Gets or sets the <see cref="MetadataFile"/> to be refreshed by the metadata provider.
        /// </summary>
        MetadataFile Metadata { get; set; }

        #endregion

        #region [ Methods ]

        /// <summary>
        /// Refreshes the <see cref="Metadata"/> from an external source.
        /// </summary>
        /// <returns>true if the <see cref="Metadata"/> is refreshed; otherwise false.</returns>
        bool Refresh();

        #endregion
    }
}