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 * with or without modification, are permitted provided 
 * that the following conditions are met: 
 * 
 * *   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 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
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using System;
using System.Linq;
using System.Windows.Forms;
using XenAdmin.Core;
using XenAPI;

namespace XenAdmin.Controls
{
    public partial class PvsCacheStorageRow : UserControl
    {

        public Host Host { get; private set; }
        public PVS_site PvsSite { get; private set; }
        public PVS_cache_storage OrigPvsCacheStorage { get; private set; }

        public event EventHandler Changed;

        private const long MIN_CACHE_SIZE_GB = 1;
        private const long MAX_CACHE_SIZE_GB = 200;
        private const long DEFAULT_CACHE_SIZE_GB = 10;
        private decimal origCacheSizeGb;

        public PvsCacheStorageRow(Host host, PVS_site site)
        {
            InitializeComponent();
            Host = host;
            PvsSite = site;
            OrigPvsCacheStorage = site != null ? site.PvsCacheStorage(host) : null;
            Populate();
        }

        private void Populate()
        {
            labelHostName.Text = Host.Name;

            PopulateCacheSrCombobox();

            // initialize cacheSize
            numericUpDownCacheSize.Minimum = MIN_CACHE_SIZE_GB;
            numericUpDownCacheSize.Maximum = MAX_CACHE_SIZE_GB;

            var value = OrigPvsCacheStorage == null ? DEFAULT_CACHE_SIZE_GB : (decimal)Util.ToGB(OrigPvsCacheStorage.size, 1, RoundingBehaviour.Nearest);
            if (value < numericUpDownCacheSize.Minimum)
                value = numericUpDownCacheSize.Minimum;
            if (value > numericUpDownCacheSize.Maximum)
                value = numericUpDownCacheSize.Maximum;
            numericUpDownCacheSize.Value = origCacheSizeGb = value;
        }

        private void PopulateCacheSrCombobox()
        {
            comboBoxCacheSr.Items.Clear();

            // add Memeory SR first; if no memory SR  found, add a placeholder (we will create the memory SR in ConfigurePvsCacheAction)
            var memorySr = Host.Connection.Cache.SRs.FirstOrDefault(s => s.GetSRType(false) == SR.SRTypes.tmpfs && s.CanBeSeenFrom(Host));
            if (memorySr == null)
            {
                // create a placeholder for the memory SR
                memorySr = new SR
                {
                    type = SR.SRTypes.tmpfs.ToString(),
                    name_label = Messages.PVS_CACHE_MEMORY_SR_NAME,
                    shared = false,
                    opaque_ref = Helper.NullOpaqueRef
                };
            }
            var memorySrItem = new ToStringWrapper<SR>(memorySr, Messages.PVS_CACHE_MEMORY_ONLY);
            comboBoxCacheSr.Items.Add(memorySrItem);
            if (OrigPvsCacheStorage != null && memorySr.opaque_ref == OrigPvsCacheStorage.SR.opaque_ref)
                comboBoxCacheSr.SelectedItem = memorySrItem;

            // add all suitable SRs
            var availableSRs = Host.Connection.Cache.SRs.Where(s => s.CanBeSeenFrom(Host) && SrIsSuitableForPvsCache(s)).ToList();
            availableSRs.Sort();
            foreach (var sr in availableSRs)
            {
                var newItem = new ToStringWrapper<SR>(sr, sr.Name);
                comboBoxCacheSr.Items.Add(newItem);
                if (OrigPvsCacheStorage != null && sr.opaque_ref == OrigPvsCacheStorage.SR.opaque_ref)
                    comboBoxCacheSr.SelectedItem = newItem;
            }
        }

        private bool SrIsSuitableForPvsCache(SR sr)
        {
            return sr.Show(Properties.Settings.Default.ShowHiddenVMs) && sr.SupportsVdiCreate() && sr.FreeSpace >= MIN_CACHE_SIZE_GB * Util.BINARY_GIGA;
        }

        private bool _showHeader;
        public bool ShowHeader
        {
            get { return _showHeader; }
            set
            {
                _showHeader = value;
                labelCacheStorage.Visible = labelCacheSize.Visible = _showHeader;
                tableLayoutPanel1.Refresh();
            }

        }

        public SR CacheSr
        {
            get
            {
                var selectedItem = (ToStringWrapper<SR>)comboBoxCacheSr.SelectedItem;
                return selectedItem != null ? selectedItem.item : null;
            }

        }

        public long CacheSize
        {
            get { return (long)numericUpDownCacheSize.Value * Util.BINARY_GIGA;  }
        }


        public bool ValidToSave
        {
            get { return comboBoxCacheSr.SelectedItem != null && numericUpDownCacheSize.Validate(); }
        }

        public bool HasChanged
        {
            get
            {
                if (OrigPvsCacheStorage == null)
                    return true;
                return OrigPvsCacheStorage.SR.opaque_ref != CacheSr.opaque_ref || origCacheSizeGb != numericUpDownCacheSize.Value;
            }
        }

        private void SomethingChanged(object sender, EventArgs e)
        {
            if (Changed != null)
                Changed(this, e);
        }
    }
}