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using System.Collections.Generic;
using System.Linq;
using XenAdmin.Core;
using XenAdmin.Diagnostics.Problems;
using XenAdmin.Diagnostics.Problems.PoolProblem;
using XenAPI;

namespace XenAdmin.Diagnostics.Checks
{
    class ServerSelectionCheck : HostPostLivenessCheck
    {
        private readonly Pool_update update;
        private readonly Pool pool;
        private readonly List<Host> selectedServers;

        public ServerSelectionCheck(Pool pool, Pool_update update, List<Host> selectedServers)
            : base(Helpers.GetMaster(pool.Connection))
        {
            this.pool = pool;
            this.update = update;
            this.selectedServers = selectedServers;
        }

        protected override Problem RunHostCheck()
        {
            if (update == null || !update.EnforceHomogeneity()) 
                return null;

            //If mixed pool, skip the precheck and issue warning, because the update may not be compatible to all servers.
            if (!pool.IsPoolFullyUpgraded())
                return new MixedPoolServerSelectionWarning(this, pool);
            
            if (pool.Connection.Cache.Hosts.Any(h => !update.AppliedOn(h) && !selectedServers.Contains(h)))
                return new ServerSelectionProblem(this, pool);

            return null;
        }

        public override string Description
        {
            get { return Messages.SERVER_SELECTION_CHECK_DESCRIPTION; }
        }
    }
}
