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using System;
using System.Collections.Generic;
using System.Text;

using XenAdmin.Core;
using XenAdmin.Network;
using XenAPI;


namespace XenAdmin.Actions
{
    /// <summary>
    /// Sets HA restart priorities and ntol. Never sets ha_always_run, but will unset it for VMs given priority DoNotRestart.
    /// </summary>
    public class SetHaPrioritiesAction : PureAsyncAction
    {
        private readonly Dictionary<VM, VMStartupOptions> settings = new Dictionary<VM, VMStartupOptions>();
        private readonly long ntol;
        private readonly Pool pool;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="connection">May not be null.</param>
        /// <param name="settings">May not be null.</param>
        /// <param name="suppressHistory"></param>
        public SetHaPrioritiesAction(IXenConnection connection, Dictionary<VM, VMStartupOptions> settings, long ntol, bool suppressHistory)
            : base(connection, Messages.HA_SETTING_PRIORITIES, suppressHistory)
        {
            System.Diagnostics.Trace.Assert(connection != null);
            System.Diagnostics.Trace.Assert(settings != null);
            System.Diagnostics.Trace.Assert(ntol >= 0);

            this.settings = settings;
            this.ntol = ntol;
            this.pool = Helpers.GetPoolOfOne(this.Connection);
            if (this.pool == null)
            {
                throw new Exception("Could not resolve pool in constructor");
            }
            this.Pool = pool;
        }

        protected override void Run()
        {
            // First move any VMs from protected -> unprotected
            int i = 0;
            foreach (VM vm in settings.Keys)
            {
                if (VM.HaPriorityIsRestart(vm.Connection, (VM.HA_Restart_Priority)settings[vm].HaRestartPriority))
                    continue;

                this.Description = string.Format(Messages.HA_SETTING_PRIORITY_ON_X, Helpers.GetName(vm));

                // Set new VM restart priority and ha_always_run
                XenAPI.VM.SetHaRestartPriority(this.Session, vm, (VM.HA_Restart_Priority)settings[vm].HaRestartPriority);
                // If the above succeeded, then at least some changes have been committed

                // Set new VM order and delay
                VM.set_order(this.Session, vm.opaque_ref, settings[vm].Order);
                VM.set_start_delay(this.Session, vm.opaque_ref, settings[vm].StartDelay);

                this.PercentComplete = (int)(++i * (60.0 / settings.Count));
                if (Cancelling)
                    throw new CancelledException();
            }

            // Set new ntol
            XenAPI.Pool.set_ha_host_failures_to_tolerate(this.Session, pool.opaque_ref, ntol);

            // Then move any VMs from unprotected -> protected
            foreach (VM vm in settings.Keys)
            {
                if (!VM.HaPriorityIsRestart(vm.Connection, (VM.HA_Restart_Priority)settings[vm].HaRestartPriority))
                    continue;

                this.Description = string.Format(Messages.HA_SETTING_PRIORITY_ON_X, Helpers.GetName(vm));

                // Set new VM restart priority and ha_always_run
                XenAPI.VM.SetHaRestartPriority(this.Session, vm, (VM.HA_Restart_Priority)settings[vm].HaRestartPriority);
                // If the above succeeded, then at least some changes have been committed

                // Set new VM order and delay
                VM.set_order(this.Session, vm.opaque_ref, settings[vm].Order);
                VM.set_start_delay(this.Session, vm.opaque_ref, settings[vm].StartDelay);

                this.PercentComplete = (int)(++i * (60.0 / settings.Count));
                if (Cancelling)
                    throw new CancelledException();
            }

            // Sync database to ensure new settings are saved to all hosts
            this.RelatedTask = XenAPI.Pool.async_sync_database(this.Session);
            this.PollToCompletion(60, 100);

            this.Description = Messages.COMPLETED;
        }
    }
}