#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2008 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab 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 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab 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 HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

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

namespace HeuristicLab.PluginInfrastructure {
  /// <summary>
  /// Default implementation of the IPlugin interface.
  /// </summary>
  public abstract class PluginBase : IPlugin {
    /// <summary>
    /// Initializes a new instance of <see cref="PluginBase"/>.
    /// </summary>
    public PluginBase() { }

    private PluginDescriptionAttribute PluginDescriptionAttribute {
      get {
        object[] pluginAttributes = this.GetType().GetCustomAttributes(typeof(PluginDescriptionAttribute), false);
        // exactly one attribute of the type PluginDescriptionAttribute must be given
        if (pluginAttributes.Length != 1) {
          throw new InvalidPluginException("Found multiple PluginDescriptionAttributes on type " + this.GetType());
        }
        return (PluginDescriptionAttribute)pluginAttributes[0];
      }
    }

    #region IPlugin Members
    /// <inheritdoc />
    public string Name {
      get {
        return PluginDescriptionAttribute.Name;
      }
    }

    /// <inheritdoc />
    public Version Version {
      get {
        var pluginAttribute = PluginDescriptionAttribute;
        // if the version is not set in the attribute then the version of the assembly is used as default
        if (string.IsNullOrEmpty(pluginAttribute.Version)) {
          return this.GetType().Assembly.GetName().Version;
        } else {
          return new Version(pluginAttribute.Version);
        }
      }
    }

    /// <inheritdoc />
    public string Description {
      get {
        var pluginAttribute = PluginDescriptionAttribute;
        // if the description is not explicitly set in the attribute then the name of the plugin is used as default
        if (string.IsNullOrEmpty(pluginAttribute.Description)) {
          return pluginAttribute.Name;
        } else {
          return pluginAttribute.Description;
        }
      }
    }

    /// <inheritdoc/>
    public IEnumerable<string> FileNames {
      get {
        // get all attributes of type PluginFileAttribute, multiple usage is possible
        return from x in this.GetType().GetCustomAttributes(typeof(PluginFileAttribute), false)
               let pluginFileAttr = (PluginFileAttribute)x
               select pluginFileAttr.Filename;
      }
    }

    /// <inhertitdoc>
    public virtual void OnLoad() { }
    #endregion

  }
}