/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       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 OpenSim 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
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using libsecondlife;
using Nini.Config;
using OpenSim.Framework;
using OpenSim.Region.Environment.Interfaces;
using OpenSim.Region.Environment.Scenes;

namespace OpenSim.Region.Environment.Modules
{
    public class SunModule : IRegionModule
    {
        //private static readonly log4net.ILog m_log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        private const double m_real_day = 24.0;
        private const int m_default_frame = 100;
        private int m_frame_mod;
        private double m_day_length;
        private int m_dilation;
        private int m_frame;
        private long m_start;

        private Scene m_scene;

        public void Initialise(Scene scene, IConfigSource config)
        {
            m_start = DateTime.Now.Ticks;
            m_frame = 0;

            // Just in case they don't have the stanzas
            try
            {
                m_day_length = config.Configs["Sun"].GetDouble("day_length", m_real_day);
                m_frame_mod = config.Configs["Sun"].GetInt("frame_rate", m_default_frame);
            }
            catch (Exception)
            {
                m_day_length = m_real_day;
                m_frame_mod = m_default_frame;
            }

            m_dilation = (int) (m_real_day/m_day_length);
            m_scene = scene;
            scene.EventManager.OnFrame += SunUpdate;
            scene.EventManager.OnNewClient += SunToClient;
        }

        public void PostInitialise()
        {
        }

        public void Close()
        {
        }

        public string Name
        {
            get { return "SunModule"; }
        }

        public bool IsSharedModule
        {
            get { return false; }
        }

        public void SunToClient(IClientAPI client)
        {
            client.SendSunPos(SunPos(HourOfTheDay()), new LLVector3(0, 0.0f, 10.0f));
        }

        public void SunUpdate()
        {
            if (m_frame < m_frame_mod)
            {
                m_frame++;
                return;
            }
            // m_log.InfoFormat("[SUN]: I've got an update {0} => {1}", m_scene.RegionsInfo.RegionName, HourOfTheDay());
            List<ScenePresence> avatars = m_scene.GetAvatars();
            foreach (ScenePresence avatar in avatars)
            {
                avatar.ControllingClient.SendSunPos(SunPos(HourOfTheDay()), new LLVector3(0, 0.0f, 10.0f));
            }
            m_frame = 0;
        }

        // Hour of the Day figures out the hour of the day as a float.
        // The intent here is that we seed hour of the day with real
        // time when the simulator starts, then run time forward
        // faster based on time dilation factor.  This means that
        // ticks don't get out of hand
        private double HourOfTheDay()
        {
            long m_addticks = (DateTime.Now.Ticks - m_start)*m_dilation;
            DateTime dt = new DateTime(m_start + m_addticks);
            return (double) dt.Hour + ((double) dt.Minute/60.0);
        }

        private LLVector3 SunPos(double hour)
        {
            // now we have our radian position
            double rad = (hour/m_real_day)*2*Math.PI - (Math.PI/2.0);
            double z = Math.Sin(rad);
            double x = Math.Cos(rad);
            return new LLVector3((float) x, 0f, (float) z);
        }

        // TODO: clear this out.  This is here so that I remember to
        // figure out if we need those other packet fields that I've
        // left out so far
        //
        //        public void SendViewerTime(int phase)
        //  {
        //             Console.WriteLine("SunPhase: {0}", phase);
        //             SimulatorViewerTimeMessagePacket viewertime = new SimulatorViewerTimeMessagePacket();
        //             //viewertime.TimeInfo.SecPerDay = 86400;
        //             // viewertime.TimeInfo.SecPerYear = 31536000;
        //             viewertime.TimeInfo.SecPerDay = 1000;
        //             viewertime.TimeInfo.SecPerYear = 365000;
        //             viewertime.TimeInfo.SunPhase = 1;
        //             int sunPhase = (phase + 2)/2;
        //             if ((sunPhase < 6) || (sunPhase > 36))
        //             {
        //                 viewertime.TimeInfo.SunDirection = new LLVector3(0f, 0.8f, -0.8f);
        //                 Console.WriteLine("sending night");
        //             }
        //             else
        //             {
        //                 if (sunPhase < 12)
        //                 {
        //                     sunPhase = 12;
        //                 }
        //                 sunPhase = sunPhase - 12;
        //
        //                 float yValue = 0.1f*(sunPhase);
        //                 Console.WriteLine("Computed SunPhase: {0}, yValue: {1}", sunPhase, yValue);
        //                 if (yValue > 1.2f)
        //                 {
        //                     yValue = yValue - 1.2f;
        //                 }
        //                 if (yValue > 1)
        //                 {
        //                     yValue = 1;
        //                 }
        //                 if (yValue < 0)
        //                 {
        //                     yValue = 0;
        //                 }
        //                 if (sunPhase < 14)
        //                 {
        //                     yValue = 1 - yValue;
        //                 }
        //                 if (sunPhase < 12)
        //                 {
        //                     yValue *= -1;
        //                 }
        //                 viewertime.TimeInfo.SunDirection = new LLVector3(0f, yValue, 0.3f);
        //                 Console.WriteLine("sending sun update " + yValue);
        //             }
        //             viewertime.TimeInfo.SunAngVelocity = new LLVector3(0, 0.0f, 10.0f);
        //             viewertime.TimeInfo.UsecSinceStart = (ulong) Util.UnixTimeSinceEpoch();
        //             // OutPacket(viewertime);
        // }
    }
}
