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 * *   Redistributions of source code must retain the above 
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 *     following disclaimer. 
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 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
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 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
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using System;
using XenAPI;

namespace XenAdmin.Actions.GUIActions
{
    /// <summary>
    /// Specifcation for a task
    /// </summary>
    public interface ITaskSpecification
    {
        bool IsSatisfiedBy(Task task);
    }

    /// <summary>
    /// Is the task unwanted by XenCenter?
    /// </summary>
    public class TaskIsUnwantedSpecification : ITaskSpecification
    {
        public bool IsSatisfiedBy(Task task)
        {
            return (task.XenCenterUUID == Program.XenCenterUUID ||
                    task.Connection.Resolve(task.subtask_of) != null ||
                    task.Hidden);
        }
    }

    /// <summary>
    /// Is the task suitable to create a meddling action from?
    /// </summary>
    public class TaskIsSuitableForMeddlingActionSpecification : ITaskSpecification
    {
        /// <summary>
        /// Heuristic to determine whether a new task was created by a client aware of our task.AppliesTo scheme, or by some other client.
        /// </summary>
        private readonly TimeSpan awareClientHeuristic = TimeSpan.FromSeconds(5);

        public bool IsSatisfiedBy(Task task)
        {
            return (task.AppliesTo != null ||
                    task.created + task.Connection.ServerTimeOffset < DateTime.UtcNow - awareClientHeuristic);
        }
    }

    /// <summary>
    /// Has the task successfully finished?
    /// </summary>
    public class TaskHasFinishedSuccessfullySpecification : ITaskSpecification
    {
        public bool IsSatisfiedBy(Task task)
        {
            return task.status == task_status_type.success;
        }
    }

}