/*
 * 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.World.Sun
{
    public class SunModule : IRegionModule
    {
        //private static readonly log4net.ILog m_log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

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

        private Scene m_scene;
        private long m_start;

        #region IRegionModule Members

        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; }
        }

        #endregion

        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));
            }
            // set estate settings for region access to sun position 
            m_scene.RegionInfo.EstateSettings.sunPosition = SunPos(HourOfTheDay());

            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 dt.Hour + (dt.Minute / 60.0);
        }

        private static 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);
        }
    }
}