using System;
using System.Collections.Generic;
using System.Text;
using SalsaModel.Actions;
using SalsaModel.Scheduling;

namespace SalsaModel
{
    public class SequenceAttribute : Attribute
    {
        public string Name;
        public SequenceAttribute(string name)
        {
            Name = name;
        }
    }

    public class SequenceHandler : ISequence
    {
        Dictionary<string, ISequenceProvider> _providers =new Dictionary<string,ISequenceProvider>();

        Timing _timing = new Timing();
        public Timing Timing
        {
            get { return _timing; }
        }

        private SalsaMover _Boy;
        public SalsaMover Boy
        {
            get { return _Boy; }
            set { _Boy = value; }
        }
        private SalsaMover _Girl;
        public SalsaMover Girl
        {
            get { return _Girl; }
            set { _Girl = value; }
        }

        TimeLine _timeLine = new TimeLine();
        public TimeLine TimeLine
        {
            get
            {
                return _timeLine;
            }
        }

        public SequenceHandler()
        {
            Boy = new SalsaMover(BodyGeometry.Andy(), new Location(5, -BodyGeometry.Andy().LowerArm, 0));
            Girl = new SalsaMover(BodyGeometry.Girl(), new Location(-5, BodyGeometry.Girl().LowerArm, 0));
            Girl.Model.IsGirl = true;
            Girl.Flip();

            FindSequenceProviders();

            // just to get us started
            CompositeActions.OneBasicWithFollower(_timeLine, 1.0, Boy, Girl, 70);
        }

        private void FindSequenceProviders()
        {
            foreach (System.Type type in System.Reflection.Assembly.GetCallingAssembly().GetTypes())
            {
                object[] attrs = type.GetCustomAttributes(typeof(SequenceAttribute), true);
                if (attrs.Length > 0)
                {
                    // it's a sequence.  Construct one, and register it along
                    // with the name from the attribute.
                    if (attrs.Length > 1)
                    {
                        throw new ApplicationException("too many Sequence attributes");
                    }
                    SequenceAttribute attr = attrs[0] as SequenceAttribute;
                    object provObj = System.Activator.CreateInstance(type);
                    if (provObj == null)
                    {
                        throw new ApplicationException("cannot create object");
                    }
                    ISequenceProvider prov = provObj as ISequenceProvider;
                    if (prov == null)
                    {
                        throw new ApplicationException("Type " + type.ToString() + " does not implement ISequencePRovider");
                    }
                    RegisterSequenceProvider(attr.Name, prov);
                }
            }
        }

        private void RegisterSequenceProvider(string name, ISequenceProvider prov)
        {
            _providers.Add(name, prov);
        }

        public IEnumerable<string> AvailableSequences
        {
            get
            {
                return _providers.Keys;
            }
        }

        string _nextSequence = "Basic";

        private void SetupTimeLine(double from)
        {
            ISequenceProvider prov;
            if (_providers.TryGetValue(_nextSequence, out prov))
            {
                prov.AddMoves(_timeLine, from, Boy, Girl);
            }
            else 
            {
                throw new ApplicationException("Unknown sequence " + _nextSequence);
            }
        }

        double _prev = -1.0;
        public void Update()
        {
            double now = Timing.GlobalBeat() + Timing.Percent();
            _timeLine.RunActions(_prev, now);
            _prev = now;

            Boy.AlignKnees();
            Boy.CheckPosture();
            Girl.AlignKnees();
            Girl.CheckPosture();

            // assumes that the sequence is 2 bars long
            // XXX a multiple of 2 bars? -- Andy
            if (!_timeLine.HasEventsAfter(now))
            {
                if (Timing.Beat() == 8)
                {
                    SetupTimeLine(Timing.GlobalBeat() + 1.0);
                }
                //else if (Timing.Beat() == 1)
                //{
                    // is this wise?
                    // no
                    // SetupTimeLine(Timing.GlobalBeat());
                //}
            }
        }

        public string Status()
        {
            return _nextSequence;
        }

        internal void SetNextSequence(string p)
        {
            _nextSequence = p;
        }
    }
}