/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2020 Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using System;

namespace Greenshot.Interop {
	/// <summary>
	/// An attribute to specifiy the ProgID of the COM class to create. (As suggested by Kristen Wegner)
	/// </summary>
	[AttributeUsage(AttributeTargets.Interface)]
	public sealed class ComProgIdAttribute : Attribute {
		/// <summary>
		/// Extracts the attribute from the specified type.
		/// </summary>
		/// <param name="interfaceType">
		/// The interface type.
		/// </param>
		/// <returns>
		/// The <see cref="ComProgIdAttribute"/>.
		/// </returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="interfaceType"/> is <see langword="null"/>.
		/// </exception>
		public static ComProgIdAttribute GetAttribute(Type interfaceType) {
			if (null == interfaceType) {
				throw new ArgumentNullException(nameof(interfaceType));
			}

			Type attributeType = typeof(ComProgIdAttribute);
			object[] attributes = interfaceType.GetCustomAttributes(attributeType, false);

			if (0 == attributes.Length) {
				Type[] interfaces = interfaceType.GetInterfaces();
				for (int i = 0; i < interfaces.Length; i++) {
					interfaceType = interfaces[i];
					attributes = interfaceType.GetCustomAttributes(attributeType, false);
					if (0 != attributes.Length) {
						break;
					}
				}
			}

			if (0 == attributes.Length) {
				return null;
			}
			return (ComProgIdAttribute)attributes[0];
		}

		/// <summary>Constructor</summary>
		/// <param name="value">The COM ProgID.</param>
		public ComProgIdAttribute(string value) {
			Value = value;
		}

		/// <summary>
		/// Returns the COM ProgID
		/// </summary>
		public string Value { get; }
	}
}