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 * See CONTRIBUTORS.TXT for a full list of copyright holders.
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 * modification, are permitted provided that the following conditions are met:
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 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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.Collections.Generic;
using System.Text;

using OpenMetaverse.StructuredData;

namespace OpenSim.Framework.Monitoring
{
    public class PercentageStat : Stat
    {
        public long Antecedent { get; set; }
        public long Consequent { get; set; }

        public override double Value
        {
            get
            {
                // Asking for an update here means that the updater cannot access this value without infinite recursion.
                // XXX: A slightly messy but simple solution may be to flick a flag so we can tell if this is being
                // called by the pull action and just return the value.
                try
                {
                    if (StatType == StatType.Pull)
                        PullAction(this);

                    long c = Consequent;

                    // Avoid any chance of a multi-threaded divide-by-zero
                    if (c == 0)
                        return 0;

                    return (double)Antecedent / c * 100;
                }
                catch
                {
                    return 0;
                }
            }

            set
            {
                throw new InvalidOperationException("Cannot set value on a PercentageStat");
            }
        }

        public PercentageStat(
            string shortName,
            string name,
            string description,
            string category,
            string container,
            StatType type,
            Action<Stat> pullAction,
            StatVerbosity verbosity)
            : base(shortName, name, description, "%", category, container, type, pullAction, verbosity) {}

        public override string ToConsoleString()
        {
            StringBuilder sb = new StringBuilder();

            sb.AppendFormat(
                "{0}.{1}.{2} : {3:0.##}{4} ({5}/{6})",
                Category, Container, ShortName, Value, UnitName, Antecedent, Consequent);

            AppendMeasuresOfInterest(sb);

            return sb.ToString();
        }

        // PercentageStat is a basic stat plus percent calc
        public override OSDMap ToOSDMap()
        {
            // Get the foundational instance
            OSDMap map = base.ToOSDMap();

            map["StatType"] = "PercentageStat";

            map.Add("Antecedent", OSD.FromLong(Antecedent));
            map.Add("Consequent", OSD.FromLong(Consequent));

            return map;
        }
    }
}