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//
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// which is part of MySQL Connector/NET, is also subject to the
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// See the GNU General Public License, version 2.0, for more details.
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using System.Collections.Generic;

namespace MySql.Data.Failover
{
    internal abstract class FailoverGroup
    {
        #region Properties

        /// <summary>
        /// Gets and sets the host list.
        /// </summary>
        protected internal List<FailoverServer> Hosts { get; set; }

        /// <summary>
        /// Gets the active host.
        /// </summary>
        protected internal FailoverServer ActiveHost
        {
            get
            {
                if (this.Hosts == null)
                {
                    return null;
                }

                if (this._activeHost != null)
                {
                    return this._activeHost;
                }

                foreach (var host in this.Hosts)
                {
                    if (host.IsActive)
                    {
                        return host;
                    }
                }

                return null;
            }
        }

        #endregion

        #region Fields

        /// <summary>
        /// Active host.
        /// </summary>
        protected internal FailoverServer _activeHost;

        #endregion

        internal FailoverGroup(List<FailoverServer> hosts)
        {
            this.Hosts = hosts;
            this.SetInitialActiveServer();
        }

        /// <summary>
        /// Sets the initial active host.
        /// </summary>
        protected internal abstract void SetInitialActiveServer();

        /// <summary>
        /// Determines the next host.
        /// </summary>
        /// <returns><see cref="FailoverServer"/> object that represents the next available host.</returns>
        protected internal abstract FailoverServer GetNextHost();
    }
}